ruffle/src/read.rs

#![cfg_attr(any(feature="clippy", feature="cargo-clippy"), allow(float_cmp))]

use byteorder::{LittleEndian, ReadBytesExt};
use flate2::read::ZlibDecoder;
use std::collections::HashSet;
use std::io::{Error, ErrorKind, Read, Result};
use types::*;

/// Reads SWF data from a stream.
pub fn read_swf<R: Read>(input: R) -> Result<Swf> {
    let (mut swf, mut reader) = read_swf_header(input)?;
    swf.tags = reader.read_tag_list()?;
    Ok(swf)
}

fn read_swf_header<'a, R: Read + 'a>(mut input: R) -> Result<(Swf, Reader<Box<Read + 'a>>)> {
    // Read SWF header.
    let compression = Reader::read_compression_type(&mut input)?;
    let version = input.read_u8()?;
    let _uncompressed_length = input.read_u32::<LittleEndian>()?;

    // Now the SWF switches to a compressed stream.
    let decompressed_input: Box<Read> = match compression {
        Compression::None => Box::new(input),
        Compression::Zlib => Box::new(ZlibDecoder::new(input)),
        Compression::Lzma => make_lzma_reader(input)?,
    };

    let mut reader = Reader::new(decompressed_input, version);
    let stage_size = reader.read_rectangle()?;
    let frame_rate = reader.read_fixed8()?;
    let num_frames = reader.read_u16()?;
    let swf = Swf {
        version: version,
        compression: compression,
        stage_size: stage_size,
        frame_rate: frame_rate,
        num_frames: num_frames,
        tags: vec![],
    };
    Ok((swf, reader))
}

#[cfg(feature = "lzma-support")]
fn make_lzma_reader<'a, R: Read + 'a>(mut input: R) -> Result<Box<Read + 'a>> {
    // Flash uses a mangled LZMA header, so we have to massage it into the normal
    // format.
    use std::io::{Cursor, Write};
    use xz2::stream::{Action, Stream};
    use byteorder::WriteBytesExt;
    input.read_u32::<LittleEndian>()?; // Compressed length
    let mut lzma_properties = [0u8; 5];
    input.read_exact(&mut lzma_properties)?;
    let mut lzma_header = Cursor::new(Vec::with_capacity(13));
    lzma_header.write_all(&lzma_properties)?;
    lzma_header.write_u64::<LittleEndian>(uncompressed_length as u64)?;
    let mut lzma_stream = Stream::new_lzma_decoder(u64::max_value())?;
    lzma_stream.process(&lzma_header.into_inner(), &mut [0u8; 1], Action::Run)?;
    Box::new(XzDecoder::new_stream(input, lzma_stream))
}

#[cfg(not(feature = "lzma-support"))]
fn make_lzma_reader<'a, R: Read + 'a>(_: R) -> Result<Box<Read + 'a>> {
    Err(Error::new(ErrorKind::InvalidData, "Support for LZMA compressed SWFs is not enabled."))
}

pub trait SwfRead<R: Read> {
    fn get_inner(&mut self) -> &mut R;

    fn read_u8(&mut self) -> Result<u8> {
        self.get_inner().read_u8()
    }

    fn read_u16(&mut self) -> Result<u16> {
        self.get_inner().read_u16::<LittleEndian>()
    }

    fn read_u32(&mut self) -> Result<u32> {
        self.get_inner().read_u32::<LittleEndian>()
    }

    fn read_i8(&mut self) -> Result<i8> {
        self.get_inner().read_i8()
    }

    fn read_i16(&mut self) -> Result<i16> {
        self.get_inner().read_i16::<LittleEndian>()
    }

    fn read_i32(&mut self) -> Result<i32> {
        self.get_inner().read_i32::<LittleEndian>()
    }

    fn read_fixed8(&mut self) -> Result<f32> {
        self.read_i16().map(|n| n as f32 / 256f32)
    }

    fn read_fixed16(&mut self) -> Result<f64> {
        self.read_i32().map(|n| n as f64 / 65536f64)
    }

    fn read_f32(&mut self) -> Result<f32> {
        self.get_inner().read_f32::<LittleEndian>()
    }

    fn read_f64(&mut self) -> Result<f64> {
        // Flash weirdly stores f64 as two LE 32-bit chunks.
        // First word is the hi-word, second word is the lo-word.
        let mut num = [0u8; 8];
        self.get_inner().read_exact(&mut num)?;
        num.swap(0, 4);
        num.swap(1, 5);
        num.swap(2, 6);
        num.swap(3, 7);
        (&num[..]).read_f64::<LittleEndian>()
    }

    fn read_c_string(&mut self) -> Result<String> {
        let mut bytes = Vec::new();
        loop {
            let byte = self.read_u8()?;
            if byte == 0 {
                break;
            }
            bytes.push(byte)
        }
        // TODO: There is probably a better way to do this.
        // TODO: Verify ANSI for SWF 5 and earlier.
        String::from_utf8(bytes).map_err(|_| {
            Error::new(ErrorKind::InvalidData, "Invalid string data")
        })
    }
}

pub struct Reader<R: Read> {
    input: R,
    version: u8,

    byte: u8,
    bit_index: u8,

    num_fill_bits: u8,
    num_line_bits: u8,
}

impl<R: Read> SwfRead<R> for Reader<R> {
    fn get_inner(&mut self) -> &mut R {
        &mut self.input
    }

    fn read_u8(&mut self) -> Result<u8> {
        self.byte_align();
        self.input.read_u8()
    }

    fn read_u16(&mut self) -> Result<u16> {
        self.byte_align();
        self.input.read_u16::<LittleEndian>()
    }

    fn read_u32(&mut self) -> Result<u32> {
        self.byte_align();
        self.input.read_u32::<LittleEndian>()
    }

    fn read_i8(&mut self) -> Result<i8> {
        self.byte_align();
        self.input.read_i8()
    }

    fn read_i16(&mut self) -> Result<i16> {
        self.byte_align();
        self.input.read_i16::<LittleEndian>()
    }

    fn read_i32(&mut self) -> Result<i32> {
        self.byte_align();
        self.input.read_i32::<LittleEndian>()
    }

    fn read_f32(&mut self) -> Result<f32> {
        self.byte_align();
        self.input.read_f32::<LittleEndian>()
    }

    fn read_f64(&mut self) -> Result<f64> {
        self.byte_align();
        self.input.read_f64::<LittleEndian>()
    }
}

impl<R: Read> Reader<R> {
    pub fn new(input: R, version: u8) -> Reader<R> {
        Reader {
            input: input,
            version: version,
            byte: 0,
            bit_index: 0,
            num_fill_bits: 0,
            num_line_bits: 0,
        }
    }

    fn read_compression_type(mut input: R) -> Result<Compression> {
        let mut signature = [0u8; 3];
        input.read_exact(&mut signature)?;
        let compression = match &signature {
            b"FWS" => Compression::None,
            b"CWS" => Compression::Zlib,
            b"ZWS" => Compression::Lzma,
            _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid SWF")),
        };
        Ok(compression)
    }

    fn read_rectangle(&mut self) -> Result<Rectangle> {
        self.byte_align();
        let num_bits = self.read_ubits(5)? as usize;
        Ok(Rectangle {
            x_min: self.read_sbits(num_bits)? as f32 / 20f32,
            x_max: self.read_sbits(num_bits)? as f32 / 20f32,
            y_min: self.read_sbits(num_bits)? as f32 / 20f32,
            y_max: self.read_sbits(num_bits)? as f32 / 20f32,
        })
    }

    fn read_bit(&mut self) -> Result<bool> {
        if self.bit_index == 0 {
            self.byte = self.input.read_u8()?;
            self.bit_index = 8;
        }
        self.bit_index -= 1;
        let val = self.byte & (1 << self.bit_index) != 0;
        Ok(val)
    }

    fn byte_align(&mut self) {
        self.bit_index = 0;
    }

    fn read_ubits(&mut self, num_bits: usize) -> Result<u32> {
        let mut val = 0u32;
        for _ in 0..num_bits {
            val <<= 1;
            val |= if self.read_bit()? { 1 } else { 0 };
        }
        Ok(val)
    }

    fn read_sbits(&mut self, num_bits: usize) -> Result<i32> {
        if num_bits > 0 {
            self.read_ubits(num_bits)
                .map(|n| (n as i32) << (32 - num_bits) >> (32 - num_bits))
        } else {
            Ok(0)
        }
    }

    fn read_fbits(&mut self, num_bits: usize) -> Result<f32> {
        self.read_sbits(num_bits).map(|n| (n as f32) / 65536f32)
    }

    fn read_encoded_u32(&mut self) -> Result<u32> {
        let mut val = 0u32;
        for i in 0..5 {
            let byte = self.read_u8()?;
            val |= ((byte & 0b01111111) as u32) << (i * 7);
            if byte & 0b10000000 == 0 {
                break;
            }
        }
        Ok(val)
    }

    fn read_character_id(&mut self) -> Result<CharacterId> {
        self.read_u16()
    }

    fn read_rgb(&mut self) -> Result<Color> {
        let r = self.read_u8()?;
        let g = self.read_u8()?;
        let b = self.read_u8()?;
        Ok(Color {
            r: r,
            g: g,
            b: b,
            a: 255,
        })
    }

    fn read_rgba(&mut self) -> Result<Color> {
        let r = self.read_u8()?;
        let g = self.read_u8()?;
        let b = self.read_u8()?;
        let a = self.read_u8()?;
        Ok(Color {
            r: r,
            g: g,
            b: b,
            a: a,
        })
    }

    fn read_color_transform_no_alpha(&mut self) -> Result<ColorTransform> {
        self.byte_align();
        let has_add = self.read_bit()?;
        let has_mult = self.read_bit()?;
        let num_bits = self.read_ubits(4)? as usize;
        let mut color_transform = ColorTransform {
            r_multiply: 1f32,
            g_multiply: 1f32,
            b_multiply: 1f32,
            a_multiply: 1f32,
            r_add: 0i16,
            g_add: 0i16,
            b_add: 0i16,
            a_add: 0i16,
        };
        if has_mult {
            color_transform.r_multiply = self.read_sbits(num_bits)? as f32 / 256f32;
            color_transform.g_multiply = self.read_sbits(num_bits)? as f32 / 256f32;
            color_transform.b_multiply = self.read_sbits(num_bits)? as f32 / 256f32;
        }
        if has_add {
            color_transform.r_add = self.read_sbits(num_bits)? as i16;
            color_transform.g_add = self.read_sbits(num_bits)? as i16;
            color_transform.b_add = self.read_sbits(num_bits)? as i16;
        }
        Ok(color_transform)
    }

    fn read_color_transform(&mut self) -> Result<ColorTransform> {
        self.byte_align();
        let has_add = self.read_bit()?;
        let has_mult = self.read_bit()?;
        let num_bits = self.read_ubits(4)? as usize;
        let mut color_transform = ColorTransform {
            r_multiply: 1f32,
            g_multiply: 1f32,
            b_multiply: 1f32,
            a_multiply: 1f32,
            r_add: 0i16,
            g_add: 0i16,
            b_add: 0i16,
            a_add: 0i16,
        };
        if has_mult {
            color_transform.r_multiply = self.read_sbits(num_bits)? as f32 / 256f32;
            color_transform.g_multiply = self.read_sbits(num_bits)? as f32 / 256f32;
            color_transform.b_multiply = self.read_sbits(num_bits)? as f32 / 256f32;
            color_transform.a_multiply = self.read_sbits(num_bits)? as f32 / 256f32;
        }
        if has_add {
            color_transform.r_add = self.read_sbits(num_bits)? as i16;
            color_transform.g_add = self.read_sbits(num_bits)? as i16;
            color_transform.b_add = self.read_sbits(num_bits)? as i16;
            color_transform.a_add = self.read_sbits(num_bits)? as i16;
        }
        Ok(color_transform)
    }

    fn read_matrix(&mut self) -> Result<Matrix> {
        self.byte_align();
        let mut m = Matrix::new();
        // Scale
        if self.read_bit()? {
            let num_bits = self.read_ubits(5)? as usize;
            m.scale_x = self.read_fbits(num_bits)?;
            m.scale_y = self.read_fbits(num_bits)?;
        }
        // Rotate/Skew
        if self.read_bit()? {
            let num_bits = self.read_ubits(5)? as usize;
            m.rotate_skew_0 = self.read_fbits(num_bits)?;
            m.rotate_skew_1 = self.read_fbits(num_bits)?;
        }
        // Translate (always present)
        let num_bits = self.read_ubits(5)? as usize;
        m.translate_x = self.read_sbits(num_bits)? as f32 / 20f32;
        m.translate_y = self.read_sbits(num_bits)? as f32 / 20f32;
        Ok(m)
    }

    fn read_language(&mut self) -> Result<Language> {
        Ok(match self.read_u8()? {
            0 => Language::Unknown,
            1 => Language::Latin,
            2 => Language::Japanese,
            3 => Language::Korean,
            4 => Language::SimplifiedChinese,
            5 => Language::TraditionalChinese,
            _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid language code.")),
        })
    }

    fn read_tag_list(&mut self) -> Result<Vec<Tag>> {
        let mut tags = Vec::new();
        loop {
            match self.read_tag() {
                Ok(Some(tag)) => tags.push(tag),
                Ok(None) => break,
                Err(err) => {
                    // We screwed up reading this tag in some way.
                    // TODO: We could recover more gracefully in some way.
                    // Simply throw away this tag, but keep going.
                    if cfg!(debug_assertions) {
                        panic!("Error reading tag");
                    }
                    use std::convert::From;
                    return Err(From::from(err));
                }
            };
        }
        Ok(tags)
    }

    fn read_tag(&mut self) -> Result<Option<Tag>> {
        use num_traits::FromPrimitive;

        let (tag_code, length) = self.read_tag_code_and_length()?;

        let mut tag_reader = Reader::new(self.input.by_ref().take(length as u64), self.version);
        use tag_codes::TagCode;
        let tag = match TagCode::from_u16(tag_code) {
            Some(TagCode::End) => return Ok(None),
            Some(TagCode::ShowFrame) => Tag::ShowFrame,
            Some(TagCode::CsmTextSettings) => tag_reader.read_csm_text_settings()?,
            Some(TagCode::DefineBinaryData) => {
                let id = tag_reader.read_u16()?;
                tag_reader.read_u32()?; // Reserved
                let mut data = Vec::with_capacity(length - 6);
                tag_reader.input.read_to_end(&mut data)?;
                Tag::DefineBinaryData { id: id, data: data }
            }
            Some(TagCode::DefineBits) => {
                let id = tag_reader.read_u16()?;
                let mut jpeg_data = Vec::with_capacity(length - 2);
                tag_reader.input.read_to_end(&mut jpeg_data)?;
                Tag::DefineBits {
                    id: id,
                    jpeg_data: jpeg_data,
                }
            }
            Some(TagCode::DefineBitsJpeg2) => {
                let id = tag_reader.read_u16()?;
                let mut jpeg_data = Vec::with_capacity(length - 2);
                tag_reader.input.read_to_end(&mut jpeg_data)?;
                Tag::DefineBitsJpeg2 {
                    id: id,
                    jpeg_data: jpeg_data,
                }
            }
            Some(TagCode::DefineBitsJpeg3) => tag_reader.read_define_bits_jpeg_3(3)?,
            Some(TagCode::DefineBitsJpeg4) => tag_reader.read_define_bits_jpeg_3(4)?,
            Some(TagCode::DefineButton) => tag_reader.read_define_button()?,
            Some(TagCode::DefineButton2) => tag_reader.read_define_button_2()?,
            Some(TagCode::DefineButtonCxform) => {
                let id = tag_reader.read_u16()?;
                // SWF19 is incorrect here. It seems you can have many color transforms in this
                // tag, one for each character inside the button? In order of state/depth?
                let mut color_transforms = Vec::new();
                while let Ok(color_transform) = tag_reader.read_color_transform_no_alpha() {
                    color_transforms.push(color_transform);
                }
                Tag::DefineButtonColorTransform {
                    id: id,
                    color_transforms: color_transforms,
                }
            }
            Some(TagCode::DefineButtonSound) => {
                let button_id = tag_reader.read_u16()?;

                let sound_id = tag_reader.read_u16()?;
                let over_to_up_sound = if sound_id != 0 {
                    Some((sound_id, tag_reader.read_sound_info()?))
                } else {
                    None
                };

                let sound_id = tag_reader.read_u16()?;
                let up_to_over_sound = if sound_id != 0 {
                    Some((sound_id, tag_reader.read_sound_info()?))
                } else {
                    None
                };

                let sound_id = tag_reader.read_u16()?;
                let over_to_down_sound = if sound_id != 0 {
                    Some((sound_id, tag_reader.read_sound_info()?))
                } else {
                    None
                };

                let sound_id = tag_reader.read_u16()?;
                let down_to_over_sound = if sound_id != 0 {
                    Some((sound_id, tag_reader.read_sound_info()?))
                } else {
                    None
                };

                Tag::DefineButtonSound(Box::new(ButtonSounds {
                    id: button_id,
                    over_to_up_sound: over_to_up_sound,
                    up_to_over_sound: up_to_over_sound,
                    over_to_down_sound: over_to_down_sound,
                    down_to_over_sound: down_to_over_sound,
                }))
            }
            Some(TagCode::DefineEditText) => tag_reader.read_define_edit_text()?,
            Some(TagCode::DefineFont) => tag_reader.read_define_font()?,
            Some(TagCode::DefineFont2) => tag_reader.read_define_font_2(2)?,
            Some(TagCode::DefineFont3) => tag_reader.read_define_font_2(3)?,
            Some(TagCode::DefineFont4) => tag_reader.read_define_font_4()?,
            Some(TagCode::DefineFontAlignZones) => tag_reader.read_define_font_align_zones()?,
            Some(TagCode::DefineFontInfo) => tag_reader.read_define_font_info(1)?,
            Some(TagCode::DefineFontInfo2) => tag_reader.read_define_font_info(2)?,
            Some(TagCode::DefineFontName) => tag_reader.read_define_font_name()?,
            Some(TagCode::DefineMorphShape) => tag_reader.read_define_morph_shape(1)?,
            Some(TagCode::DefineMorphShape2) => tag_reader.read_define_morph_shape(2)?,
            Some(TagCode::DefineShape) => tag_reader.read_define_shape(1)?,
            Some(TagCode::DefineShape2) => tag_reader.read_define_shape(2)?,
            Some(TagCode::DefineShape3) => tag_reader.read_define_shape(3)?,
            Some(TagCode::DefineShape4) => tag_reader.read_define_shape(4)?,
            Some(TagCode::DefineSound) => tag_reader.read_define_sound()?,
            Some(TagCode::DefineText) => tag_reader.read_define_text()?,
            Some(TagCode::DefineVideoStream) => tag_reader.read_define_video_stream()?,
            Some(TagCode::EnableTelemetry) => {
                tag_reader.read_u16()?; // Reserved
                let password_hash = if length > 2 {
                    let mut data = Vec::with_capacity(32);
                    data.resize(32, 0);
                    tag_reader.input.read_exact(&mut data)?;
                    data
                } else {
                    vec![]
                };
                Tag::EnableTelemetry {
                    password_hash: password_hash,
                }
            }
            Some(TagCode::ImportAssets) => {
                let url = tag_reader.read_c_string()?;
                let num_imports = tag_reader.read_u16()?;
                let mut imports = Vec::with_capacity(num_imports as usize);
                for _ in 0..num_imports {
                    imports.push(ExportedAsset {
                        id: tag_reader.read_u16()?,
                        name: tag_reader.read_c_string()?,
                    });
                }
                Tag::ImportAssets {
                    url: url,
                    imports: imports,
                }
            }
            Some(TagCode::ImportAssets2) => {
                let url = tag_reader.read_c_string()?;
                tag_reader.read_u8()?; // Reserved; must be 1
                tag_reader.read_u8()?; // Reserved; must be 0
                let num_imports = tag_reader.read_u16()?;
                let mut imports = Vec::with_capacity(num_imports as usize);
                for _ in 0..num_imports {
                    imports.push(ExportedAsset {
                        id: tag_reader.read_u16()?,
                        name: tag_reader.read_c_string()?,
                    });
                }
                Tag::ImportAssets {
                    url: url,
                    imports: imports,
                }
            }

            Some(TagCode::JpegTables) => {
                let mut data = Vec::with_capacity(length);
                tag_reader.input.read_to_end(&mut data)?;
                Tag::JpegTables(data)
            }

            Some(TagCode::Metadata) => Tag::Metadata(tag_reader.read_c_string()?),

            Some(TagCode::SetBackgroundColor) => Tag::SetBackgroundColor(tag_reader.read_rgb()?),

            Some(TagCode::SoundStreamBlock) => {
                let mut data = Vec::with_capacity(length);
                tag_reader.input.read_to_end(&mut data)?;
                Tag::SoundStreamBlock(data)
            }

            Some(TagCode::SoundStreamHead) => Tag::SoundStreamHead(
                // TODO: Disallow certain compressions.
                Box::new(tag_reader.read_sound_stream_info()?),
            ),

            Some(TagCode::SoundStreamHead2) => {
                Tag::SoundStreamHead2(Box::new(tag_reader.read_sound_stream_info()?))
            }

            Some(TagCode::StartSound) => Tag::StartSound {
                id: tag_reader.read_u16()?,
                sound_info: Box::new(tag_reader.read_sound_info()?),
            },

            Some(TagCode::StartSound2) => Tag::StartSound2 {
                class_name: tag_reader.read_c_string()?,
                sound_info: Box::new(tag_reader.read_sound_info()?),
            },

            Some(TagCode::DefineBitsLossless) => tag_reader.read_define_bits_lossless(1)?,
            Some(TagCode::DefineBitsLossless2) => tag_reader.read_define_bits_lossless(2)?,

            Some(TagCode::DefineScalingGrid) => Tag::DefineScalingGrid {
                id: tag_reader.read_u16()?,
                splitter_rect: tag_reader.read_rectangle()?,
            },

            Some(TagCode::DoAbc) => {
                let flags = tag_reader.read_u32()?;
                let name = tag_reader.read_c_string()?;
                let mut abc_data = Vec::with_capacity(length - 4 - name.len());
                tag_reader.input.read_to_end(&mut abc_data)?;
                Tag::DoAbc(DoAbc {
                    name: name,
                    is_lazy_initialize: flags & 1 != 0,
                    data: abc_data,
                })
            }

            Some(TagCode::DoAction) => {
                let mut action_data = Vec::with_capacity(length);
                tag_reader.input.read_to_end(&mut action_data)?;
                Tag::DoAction(action_data)
            }

            Some(TagCode::DoInitAction) => {
                let id = tag_reader.read_u16()?;
                let mut action_data = Vec::with_capacity(length);
                tag_reader.input.read_to_end(&mut action_data)?;
                Tag::DoInitAction {
                    id: id,
                    action_data: action_data,
                }
            }

            Some(TagCode::EnableDebugger) => Tag::EnableDebugger(tag_reader.read_c_string()?),
            Some(TagCode::EnableDebugger2) => {
                tag_reader.read_u16()?; // Reserved
                Tag::EnableDebugger(tag_reader.read_c_string()?)
            }

            Some(TagCode::ScriptLimits) => Tag::ScriptLimits {
                max_recursion_depth: tag_reader.read_u16()?,
                timeout_in_seconds: tag_reader.read_u16()?,
            },

            Some(TagCode::SetTabIndex) => Tag::SetTabIndex {
                depth: tag_reader.read_i16()?,
                tab_index: tag_reader.read_u16()?,
            },

            Some(TagCode::SymbolClass) => {
                let num_symbols = tag_reader.read_u16()?;
                let mut symbols = Vec::with_capacity(num_symbols as usize);
                for _ in 0..num_symbols {
                    symbols.push(SymbolClassLink {
                        id: tag_reader.read_u16()?,
                        class_name: tag_reader.read_c_string()?,
                    });
                }
                Tag::SymbolClass(symbols)
            }

            Some(TagCode::ExportAssets) => {
                let num_exports = tag_reader.read_u16()?;
                let mut exports = Vec::with_capacity(num_exports as usize);
                for _ in 0..num_exports {
                    exports.push(ExportedAsset {
                        id: tag_reader.read_u16()?,
                        name: tag_reader.read_c_string()?,
                    });
                }
                Tag::ExportAssets(exports)
            }

            Some(TagCode::FileAttributes) => {
                let flags = tag_reader.read_u32()?;
                Tag::FileAttributes(FileAttributes {
                    use_direct_blit: (flags & 0b01000000) != 0,
                    use_gpu: (flags & 0b00100000) != 0,
                    has_metadata: (flags & 0b00010000) != 0,
                    is_action_script_3: (flags & 0b00001000) != 0,
                    use_network_sandbox: (flags & 0b00000001) != 0,
                })
            }

            Some(TagCode::Protect) => {
                tag_reader.read_u16()?; // Two null bytes? Not specified in SWF19.
                Tag::Protect(if length > 0 {
                    Some(tag_reader.read_c_string()?)
                } else {
                    None
                })
            }

            Some(TagCode::DefineSceneAndFrameLabelData) => {
                tag_reader.read_define_scene_and_frame_label_data()?
            }

            Some(TagCode::FrameLabel) => {
                let label = tag_reader.read_c_string()?;
                Tag::FrameLabel {
                    is_anchor: tag_reader.version >= 6 && length > label.len() + 1 &&
                        tag_reader.read_u8()? != 0,
                    label: label,
                }
            }

            Some(TagCode::DefineSprite) => {
                // TODO: There's probably a better way to prevent the infinite type recursion.
                // Tags can only be nested one level deep, so perhaps I can implement
                // read_tag_list for Reader<Take<R>> to enforce this.
                let mut sprite_reader =
                    Reader::new(&mut tag_reader.input as &mut Read, self.version);
                sprite_reader.read_define_sprite()?
            }

            Some(TagCode::PlaceObject) => tag_reader.read_place_object()?,
            Some(TagCode::PlaceObject2) => tag_reader.read_place_object_2_or_3(2)?,
            Some(TagCode::PlaceObject3) => tag_reader.read_place_object_2_or_3(3)?,
            Some(TagCode::PlaceObject4) => tag_reader.read_place_object_2_or_3(4)?,

            Some(TagCode::RemoveObject) => Tag::RemoveObject {
                character_id: Some(tag_reader.read_u16()?),
                depth: tag_reader.read_i16()?,
            },

            Some(TagCode::RemoveObject2) => Tag::RemoveObject {
                depth: tag_reader.read_i16()?,
                character_id: None,
            },

            Some(TagCode::VideoFrame) => tag_reader.read_video_frame()?,

            _ => {
                let size = length as usize;
                let mut data = Vec::with_capacity(size);
                data.resize(size, 0);
                tag_reader.input.read_exact(&mut data[..])?;
                Tag::Unknown {
                    tag_code: tag_code,
                    data: data,
                }
            }
        };

        if cfg!(debug_assertions) && tag_reader.read_u8().is_ok() {
            // There should be no data remaining in the tag if we read it correctly.
            // If there is data remaining, we probably screwed up, so panic in debug builds.
            panic!("Error reading tag {:?}", tag_code);
        }

        Ok(Some(tag))
    }

    fn read_tag_code_and_length(&mut self) -> Result<(u16, usize)> {
        let tag_code_and_length = self.read_u16()?;
        let tag_code = tag_code_and_length >> 6;
        let mut length = (tag_code_and_length & 0b111111) as usize;
        if length == 0b111111 {
            // Extended tag.
            length = self.read_u32()? as usize;
        }
        Ok((tag_code, length))
    }

    fn read_define_button(&mut self) -> Result<Tag> {
        let id = self.read_u16()?;
        let mut records = Vec::new();
        while let Some(record) = self.read_button_record(1)? {
            records.push(record);
        }
        let mut action_data = Vec::new();
        self.input.read_to_end(&mut action_data)?;
        Ok(Tag::DefineButton(Box::new(Button {
            id: id,
            is_track_as_menu: false,
            records: records,
            actions: vec![
                ButtonAction {
                    conditions: vec![ButtonActionCondition::OverDownToOverUp]
                        .into_iter()
                        .collect(),
                    key_code: None,
                    action_data: action_data,
                },
            ],
        })))
    }

    fn read_define_button_2(&mut self) -> Result<Tag> {
        let id = self.read_u16()?;
        let flags = self.read_u8()?;
        let is_track_as_menu = (flags & 0b1) != 0;
        let action_offset = self.read_u16()?;

        let mut records = Vec::new();
        while let Some(record) = self.read_button_record(2)? {
            records.push(record);
        }

        let mut actions = Vec::new();
        if action_offset != 0 {
            loop {
                let (button_action, has_more_actions) = self.read_button_action()?;
                actions.push(button_action);
                if !has_more_actions {
                    break;
                }
            }
        }

        Ok(Tag::DefineButton2(Box::new(Button {
            id: id,
            is_track_as_menu: is_track_as_menu,
            records: records,
            actions: actions,
        })))
    }

    fn read_button_record(&mut self, version: u8) -> Result<Option<ButtonRecord>> {
        let flags = self.read_u8()?;
        if flags == 0 {
            return Ok(None);
        }
        let mut states = HashSet::with_capacity(4);
        if (flags & 0b1) != 0 {
            states.insert(ButtonState::Up);
        }
        if (flags & 0b10) != 0 {
            states.insert(ButtonState::Over);
        }
        if (flags & 0b100) != 0 {
            states.insert(ButtonState::Down);
        }
        if (flags & 0b1000) != 0 {
            states.insert(ButtonState::HitTest);
        }
        let id = self.read_u16()?;
        let depth = self.read_i16()?;
        let matrix = self.read_matrix()?;
        let color_transform = if version >= 2 {
            self.read_color_transform()?
        } else {
            ColorTransform::new()
        };
        let mut filters = vec![];
        if (flags & 0b1_0000) != 0 {
            let num_filters = self.read_u8()?;
            for _ in 0..num_filters {
                filters.push(self.read_filter()?);
            }
        }
        let blend_mode = if (flags & 0b10_0000) != 0 {
            self.read_blend_mode()?
        } else {
            BlendMode::Normal
        };
        Ok(Some(ButtonRecord {
            states: states,
            id: id,
            depth: depth,
            matrix: matrix,
            color_transform: color_transform,
            filters: filters,
            blend_mode: blend_mode,
        }))
    }

    fn read_button_action(&mut self) -> Result<(ButtonAction, bool)> {
        let length = self.read_u16()?;
        let flags = self.read_u16()?;
        let mut conditions = HashSet::with_capacity(8);
        if (flags & 0b1) != 0 {
            conditions.insert(ButtonActionCondition::IdleToOverUp);
        }
        if (flags & 0b10) != 0 {
            conditions.insert(ButtonActionCondition::OverUpToIdle);
        }
        if (flags & 0b100) != 0 {
            conditions.insert(ButtonActionCondition::OverUpToOverDown);
        }
        if (flags & 0b1000) != 0 {
            conditions.insert(ButtonActionCondition::OverDownToOverUp);
        }
        if (flags & 0b1_0000) != 0 {
            conditions.insert(ButtonActionCondition::OverDownToOutDown);
        }
        if (flags & 0b10_0000) != 0 {
            conditions.insert(ButtonActionCondition::OutDownToOverDown);
        }
        if (flags & 0b100_0000) != 0 {
            conditions.insert(ButtonActionCondition::OutDownToIdle);
        }
        if (flags & 0b1000_0000) != 0 {
            conditions.insert(ButtonActionCondition::IdleToOverDown);
        }

        if (flags & 0b1_0000_0000) != 0 {
            conditions.insert(ButtonActionCondition::OverDownToIdle);
        }
        let key_code = (flags >> 9) as u8;
        if key_code != 0 {
            conditions.insert(ButtonActionCondition::KeyPress);
        }
        let mut action_data = Vec::with_capacity(length as usize);
        if length > 0 {
            action_data.resize(length as usize - 4, 0);
            self.input.read_exact(&mut action_data)?;
        } else {
            self.input.read_to_end(&mut action_data)?;
        }
        Ok((
            ButtonAction {
                conditions: conditions,
                key_code: if key_code != 0 { Some(key_code) } else { None },
                action_data: action_data,
            },
            length != 0,
        ))
    }

    fn read_csm_text_settings(&mut self) -> Result<Tag> {
        let id = self.read_character_id()?;
        let flags = self.read_u8()?;
        let thickness = self.read_f32()?;
        let sharpness = self.read_f32()?;
        self.read_u8()?; // Reserved (0).
        Ok(Tag::CsmTextSettings(CsmTextSettings {
            id: id,
            use_advanced_rendering: flags & 0b01000000 != 0,
            grid_fit: match flags & 0b11_000 {
                0b00_000 => TextGridFit::None,
                0b01_000 => TextGridFit::Pixel,
                0b10_000 => TextGridFit::SubPixel,
                _ => {
                    return Err(Error::new(
                        ErrorKind::InvalidData,
                        "Invalid text grid fitting",
                    ))
                }
            },
            thickness: thickness,
            sharpness: sharpness,
        }))
    }

    fn read_define_scene_and_frame_label_data(&mut self) -> Result<Tag> {
        let num_scenes = self.read_encoded_u32()? as usize;
        let mut scenes = Vec::with_capacity(num_scenes);
        for _ in 0..num_scenes {
            scenes.push(FrameLabel {
                frame_num: self.read_encoded_u32()?,
                label: self.read_c_string()?,
            });
        }

        let num_frame_labels = self.read_encoded_u32()? as usize;
        let mut frame_labels = Vec::with_capacity(num_frame_labels);
        for _ in 0..num_frame_labels {
            frame_labels.push(FrameLabel {
                frame_num: self.read_encoded_u32()?,
                label: self.read_c_string()?,
            });
        }

        Ok(Tag::DefineSceneAndFrameLabelData {
            scenes: scenes,
            frame_labels: frame_labels,
        })
    }

    fn read_define_font(&mut self) -> Result<Tag> {
        let id = self.read_u16()?;
        let num_glyphs = self.read_u16()? / 2;

        let mut glyphs = vec![];
        if num_glyphs > 0 {
            for _ in 0..(num_glyphs - 1) {
                self.read_u16()?;
            }

            for _ in 0..num_glyphs {
                let mut glyph = vec![];
                self.num_fill_bits = self.read_ubits(4)? as u8;
                self.num_line_bits = self.read_ubits(4)? as u8;
                while let Some(record) = self.read_shape_record(1)? {
                    glyph.push(record);
                }
                glyphs.push(glyph);
                self.byte_align();
            }
        }

        Ok(Tag::DefineFont(Box::new(FontV1 {
            id: id,
            glyphs: glyphs,
        })))
    }

    fn read_define_font_2(&mut self, version: u8) -> Result<Tag> {
        let id = self.read_character_id()?;

        let flags = self.read_u8()?;
        let has_layout = flags & 0b10000000 != 0;
        let is_shift_jis = flags & 0b1000000 != 0;
        let is_small_text = flags & 0b100000 != 0;
        let is_ansi = flags & 0b10000 != 0;
        let has_wide_offsets = flags & 0b1000 != 0;
        let has_wide_codes = flags & 0b100 != 0;
        let is_italic = flags & 0b10 != 0;
        let is_bold = flags & 0b1 != 0;

        let language = self.read_language()?;
        let name_len = self.read_u8()?;
        let mut name = String::with_capacity(name_len as usize);
        self.input
            .by_ref()
            .take(name_len as u64)
            .read_to_string(&mut name)?;

        let num_glyphs = self.read_u16()? as usize;
        let mut glyphs = Vec::with_capacity(num_glyphs);
        glyphs.resize(
            num_glyphs,
            Glyph {
                shape_records: vec![],
                code: 0,
                advance: None,
                bounds: None,
            },
        );

        // OffsetTable
        // We are throwing these away.
        for _ in &mut glyphs {
            if has_wide_offsets {
                self.read_u32()?
            } else {
                self.read_u16()? as u32
            };
        }

        // CodeTableOffset
        if has_wide_offsets {
            self.read_u32()?;
        } else {
            self.read_u16()?;
        }

        // ShapeTable
        for glyph in &mut glyphs {
            self.num_fill_bits = self.read_ubits(4)? as u8;
            self.num_line_bits = self.read_ubits(4)? as u8;
            while let Some(record) = self.read_shape_record(1)? {
                glyph.shape_records.push(record);
            }
            self.byte_align();
        }

        // CodeTable
        for glyph in &mut glyphs {
            glyph.code = if has_wide_codes {
                self.read_u16()?
            } else {
                self.read_u8()? as u16
            };
        }

        let layout = if has_layout {
            let ascent = self.read_u16()?;
            let descent = self.read_u16()?;
            let leading = self.read_i16()?;

            for glyph in &mut glyphs {
                glyph.advance = Some(self.read_i16()?);
            }

            for glyph in &mut glyphs {
                glyph.bounds = Some(self.read_rectangle()?);
            }

            let num_kerning_records = self.read_u16()? as usize;
            let mut kerning_records = Vec::with_capacity(num_kerning_records);
            for _ in 0..num_kerning_records {
                kerning_records.push(self.read_kerning_record(has_wide_codes)?);
            }

            Some(FontLayout {
                ascent: ascent,
                descent: descent,
                leading: leading,
                kerning: kerning_records,
            })
        } else {
            None
        };

        Ok(Tag::DefineFont2(Box::new(Font {
            version: version,
            id: id,
            name: name,
            language: language,
            layout: layout,
            glyphs: glyphs,
            is_small_text: is_small_text,
            is_shift_jis: is_shift_jis,
            is_ansi: is_ansi,
            is_bold: is_bold,
            is_italic: is_italic,
        })))
    }

    fn read_define_font_4(&mut self) -> Result<Tag> {
        let id = self.read_character_id()?;
        let flags = self.read_u8()?;
        let name = self.read_c_string()?;
        let has_font_data = flags & 0b100 != 0;
        let data = if has_font_data {
            let mut data = vec![];
            self.input.read_to_end(&mut data)?;
            Some(data)
        } else {
            None
        };
        Ok(Tag::DefineFont4(Font4 {
            id: id,
            is_italic: flags & 0b10 != 0,
            is_bold: flags & 0b1 != 0,
            name: name,
            data: data,
        }))
    }

    fn read_kerning_record(&mut self, has_wide_codes: bool) -> Result<KerningRecord> {
        Ok(KerningRecord {
            left_code: if has_wide_codes {
                self.read_u16()?
            } else {
                self.read_u8()? as u16
            },
            right_code: if has_wide_codes {
                self.read_u16()?
            } else {
                self.read_u8()? as u16
            },
            adjustment: self.read_i16()?, // TODO(Herschel): Twips
        })
    }

    fn read_define_font_align_zones(&mut self) -> Result<Tag> {
        let id = self.read_character_id()?;
        let thickness = match self.read_u8()? {
            0b00_000000 => FontThickness::Thin,
            0b01_000000 => FontThickness::Medium,
            0b10_000000 => FontThickness::Thick,
            _ => {
                return Err(Error::new(
                    ErrorKind::InvalidData,
                    "Invalid font thickness type.",
                ))
            }
        };
        let mut zones = vec![];
        while let Ok(zone) = self.read_font_align_zone() {
            zones.push(zone);
        }
        Ok(Tag::DefineFontAlignZones {
            id: id,
            thickness: thickness,
            zones: zones,
        })
    }

    fn read_font_align_zone(&mut self) -> Result<FontAlignZone> {
        self.read_u8()?; // Always 2.
        let zone = FontAlignZone {
            left: self.read_i16()?,
            width: self.read_i16()?,
            bottom: self.read_i16()?,
            height: self.read_i16()?,
        };
        self.read_u8()?; // Always 0b000000_11 (2 dimensions).
        Ok(zone)
    }

    fn read_define_font_info(&mut self, version: u8) -> Result<Tag> {
        let id = self.read_u16()?;

        let font_name_len = self.read_u8()?;
        let mut font_name = String::with_capacity(font_name_len as usize);
        self.input
            .by_ref()
            .take(font_name_len as u64)
            .read_to_string(&mut font_name)?;

        let flags = self.read_u8()?;
        let use_wide_codes = flags & 0b1 != 0; // TODO(Herschel): Warn if false for version 2.

        let language = if version >= 2 {
            self.read_language()?
        } else {
            Language::Unknown
        };

        let mut code_table = vec![];
        if use_wide_codes {
            while let Ok(code) = self.read_u16() {
                code_table.push(code);
            }
        } else {
            while let Ok(code) = self.read_u8() {
                code_table.push(code as u16);
            }
        }

        // SWF19 has ANSI and Shift-JIS backwards?
        Ok(Tag::DefineFontInfo(Box::new(FontInfo {
            id: id,
            version: version,
            name: font_name,
            is_small_text: flags & 0b100000 != 0,
            is_ansi: flags & 0b10000 != 0,
            is_shift_jis: flags & 0b1000 != 0,
            is_italic: flags & 0b100 != 0,
            is_bold: flags & 0b10 != 0,
            language: language,
            code_table: code_table,
        })))
    }

    fn read_define_font_name(&mut self) -> Result<Tag> {
        Ok(Tag::DefineFontName {
            id: self.read_character_id()?,
            name: self.read_c_string()?,
            copyright_info: self.read_c_string()?,
        })
    }

    fn read_define_morph_shape(&mut self, shape_version: u8) -> Result<Tag> {
        let id = self.read_character_id()?;
        let start_shape_bounds = self.read_rectangle()?;
        let end_shape_bounds = self.read_rectangle()?;
        let (start_edge_bounds, end_edge_bounds, has_non_scaling_strokes, has_scaling_strokes) =
            if shape_version >= 2 {
                let start_edge_bounds = self.read_rectangle()?;
                let end_edge_bounds = self.read_rectangle()?;
                let flags = self.read_u8()?;
                (
                    start_edge_bounds,
                    end_edge_bounds,
                    flags & 0b10 != 0,
                    flags & 0b1 != 0,
                )
            } else {
                (
                    start_shape_bounds.clone(),
                    end_shape_bounds.clone(),
                    true,
                    false,
                )
            };

        self.read_u32()?; // Offset to EndEdges.

        let num_fill_styles = match self.read_u8()? {
            0xff => self.read_u16()? as usize,
            n => n as usize,
        };
        let mut start_fill_styles = Vec::with_capacity(num_fill_styles);
        let mut end_fill_styles = Vec::with_capacity(num_fill_styles);
        for _ in 0..num_fill_styles {
            let (start, end) = self.read_morph_fill_style(shape_version)?;
            start_fill_styles.push(start);
            end_fill_styles.push(end);
        }

        let num_line_styles = match self.read_u8()? {
            0xff => self.read_u16()? as usize,
            n => n as usize,
        };
        let mut start_line_styles = Vec::with_capacity(num_line_styles);
        let mut end_line_styles = Vec::with_capacity(num_line_styles);
        for _ in 0..num_line_styles {
            let (start, end) = self.read_morph_line_style(shape_version)?;
            start_line_styles.push(start);
            end_line_styles.push(end);
        }

        // TODO(Herschel): Add read_shape
        self.num_fill_bits = self.read_ubits(4)? as u8;
        self.num_line_bits = self.read_ubits(4)? as u8;
        let mut start_shape = Vec::new();
        while let Some(record) = self.read_shape_record(1)? {
            start_shape.push(record);
        }

        self.byte_align();
        let mut end_shape = Vec::new();
        self.read_u8()?; // NumFillBits and NumLineBits are written as 0 for the end shape.
        while let Some(record) = self.read_shape_record(1)? {
            end_shape.push(record);
        }
        Ok(Tag::DefineMorphShape(Box::new(DefineMorphShape {
            id: id,
            version: shape_version,
            has_non_scaling_strokes: has_non_scaling_strokes,
            has_scaling_strokes: has_scaling_strokes,
            start: MorphShape {
                shape_bounds: start_shape_bounds,
                edge_bounds: start_edge_bounds,
                shape: start_shape,
                fill_styles: start_fill_styles,
                line_styles: start_line_styles,
            },
            end: MorphShape {
                shape_bounds: end_shape_bounds,
                edge_bounds: end_edge_bounds,
                shape: end_shape,
                fill_styles: end_fill_styles,
                line_styles: end_line_styles,
            },
        })))
    }

    fn read_morph_line_style(&mut self, shape_version: u8) -> Result<(LineStyle, LineStyle)> {
        if shape_version < 2 {
            let start_width = self.read_u16()?;
            let end_width = self.read_u16()?;
            let start_color = self.read_rgba()?;
            let end_color = self.read_rgba()?;

            Ok((
                LineStyle::new_v1(start_width, start_color),
                LineStyle::new_v1(end_width, end_color),
            ))
        } else {
            // MorphLineStyle2 in DefineMorphShape2.
            let start_width = self.read_u16()?;
            let end_width = self.read_u16()?;
            let start_cap = match self.read_ubits(2)? {
                0 => LineCapStyle::Round,
                1 => LineCapStyle::None,
                2 => LineCapStyle::Square,
                _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid line cap type.")),
            };
            let join_style_id = self.read_ubits(2)?;
            let has_fill = self.read_bit()?;
            let allow_scale_x = !self.read_bit()?;
            let allow_scale_y = !self.read_bit()?;
            let is_pixel_hinted = self.read_bit()?;
            self.read_ubits(5)?;
            let allow_close = !self.read_bit()?;
            let end_cap = match self.read_ubits(2)? {
                0 => LineCapStyle::Round,
                1 => LineCapStyle::None,
                2 => LineCapStyle::Square,
                _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid line cap type.")),
            };
            let join_style = match join_style_id {
                0 => LineJoinStyle::Round,
                1 => LineJoinStyle::Bevel,
                2 => LineJoinStyle::Miter(self.read_fixed8()?),
                _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid line cap type.")),
            };
            let (start_color, end_color) = if !has_fill {
                (self.read_rgba()?, self.read_rgba()?)
            } else {
                (
                    Color {
                        r: 0,
                        g: 0,
                        b: 0,
                        a: 0,
                    },
                    Color {
                        r: 0,
                        g: 0,
                        b: 0,
                        a: 0,
                    },
                )
            };
            let (start_fill_style, end_fill_style) = if has_fill {
                let (start, end) = self.read_morph_fill_style(shape_version)?;
                (Some(start), Some(end))
            } else {
                (None, None)
            };
            Ok((
                LineStyle {
                    width: start_width,
                    color: start_color,
                    start_cap: start_cap,
                    end_cap: end_cap,
                    join_style: join_style,
                    allow_scale_x: allow_scale_x,
                    allow_scale_y: allow_scale_y,
                    is_pixel_hinted: is_pixel_hinted,
                    allow_close: allow_close,
                    fill_style: start_fill_style,
                },
                LineStyle {
                    width: end_width,
                    color: end_color,
                    start_cap: start_cap,
                    end_cap: end_cap,
                    join_style: join_style,
                    allow_scale_x: allow_scale_x,
                    allow_scale_y: allow_scale_y,
                    is_pixel_hinted: is_pixel_hinted,
                    allow_close: allow_close,
                    fill_style: end_fill_style,
                },
            ))
        }
    }

    fn read_morph_fill_style(&mut self, shape_version: u8) -> Result<(FillStyle, FillStyle)> {
        let fill_style_type = self.read_u8()?;
        let fill_style = match fill_style_type {
            0x00 => {
                let start_color = self.read_rgba()?;
                let end_color = self.read_rgba()?;
                (FillStyle::Color(start_color), FillStyle::Color(end_color))
            }

            0x10 => {
                let (start_gradient, end_gradient) = self.read_morph_gradient()?;
                (
                    FillStyle::LinearGradient(start_gradient),
                    FillStyle::LinearGradient(end_gradient),
                )
            }

            0x12 => {
                let (start_gradient, end_gradient) = self.read_morph_gradient()?;
                (
                    FillStyle::RadialGradient(start_gradient),
                    FillStyle::RadialGradient(end_gradient),
                )
            }

            0x13 => {
                if self.version < 8 || shape_version < 2 {
                    return Err(Error::new(
                        ErrorKind::InvalidData,
                        "Focal gradients are only supported in SWF version 8 \
                         or higher.",
                    ));
                }
                // TODO(Herschel): How is focal_point stored?
                let (start_gradient, end_gradient) = self.read_morph_gradient()?;
                let start_focal_point = self.read_fixed8()?;
                let end_focal_point = self.read_fixed8()?;
                (
                    FillStyle::FocalGradient {
                        gradient: start_gradient,
                        focal_point: start_focal_point,
                    },
                    FillStyle::FocalGradient {
                        gradient: end_gradient,
                        focal_point: end_focal_point,
                    },
                )
            }

            0x40...0x43 => {
                let id = self.read_character_id()?;
                (
                    FillStyle::Bitmap {
                        id: id,
                        matrix: self.read_matrix()?,
                        is_smoothed: (fill_style_type & 0b10) == 0,
                        is_repeating: (fill_style_type & 0b01) == 0,
                    },
                    FillStyle::Bitmap {
                        id: id,
                        matrix: self.read_matrix()?,
                        is_smoothed: (fill_style_type & 0b10) == 0,
                        is_repeating: (fill_style_type & 0b01) == 0,
                    },
                )
            }

            _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid fill style.")),
        };
        Ok(fill_style)
    }

    fn read_morph_gradient(&mut self) -> Result<(Gradient, Gradient)> {
        let start_matrix = self.read_matrix()?;
        let end_matrix = self.read_matrix()?;
        let num_records = self.read_u8()? as usize;
        let mut start_records = Vec::with_capacity(num_records);
        let mut end_records = Vec::with_capacity(num_records);
        for _ in 0..num_records {
            start_records.push(GradientRecord {
                ratio: self.read_u8()?,
                color: self.read_rgba()?,
            });
            end_records.push(GradientRecord {
                ratio: self.read_u8()?,
                color: self.read_rgba()?,
            });
        }
        Ok((
            Gradient {
                matrix: start_matrix,
                spread: GradientSpread::Pad, // TODO(Herschel): What are the defaults?
                interpolation: GradientInterpolation::RGB,
                records: start_records,
            },
            Gradient {
                matrix: end_matrix,
                spread: GradientSpread::Pad, // TODO(Herschel): What are the defaults?
                interpolation: GradientInterpolation::RGB,
                records: end_records,
            },
        ))
    }

    fn read_define_shape(&mut self, version: u8) -> Result<Tag> {
        let id = self.read_u16()?;
        let shape_bounds = self.read_rectangle()?;
        let (edge_bounds, has_fill_winding_rule, has_non_scaling_strokes, has_scaling_strokes) =
            if version >= 4 {
                let edge_bounds = self.read_rectangle()?;
                let flags = self.read_u8()?;
                (
                    edge_bounds,
                    (flags & 0b100) != 0,
                    (flags & 0b10) != 0,
                    (flags & 0b1) != 0,
                )
            } else {
                (shape_bounds.clone(), false, true, false)
            };
        let styles = self.read_shape_styles(version)?;
        let mut records = Vec::new();
        while let Some(record) = self.read_shape_record(version)? {
            records.push(record);
        }
        Ok(Tag::DefineShape(Shape {
            version: version,
            id: id,
            shape_bounds: shape_bounds,
            edge_bounds: edge_bounds,
            has_fill_winding_rule: has_fill_winding_rule,
            has_non_scaling_strokes: has_non_scaling_strokes,
            has_scaling_strokes: has_scaling_strokes,
            styles: styles,
            shape: records,
        }))
    }

    fn read_define_sound(&mut self) -> Result<Tag> {
        let id = self.read_u16()?;
        let format = self.read_sound_format()?;
        let num_samples = self.read_u32()?;
        let mut data = Vec::new();
        self.input.read_to_end(&mut data)?;
        Ok(Tag::DefineSound(Box::new(Sound {
            id: id,
            format: format,
            num_samples: num_samples,
            data: data,
        })))
    }

    fn read_sound_stream_info(&mut self) -> Result<SoundStreamInfo> {
        // TODO: Verify version requirements.
        let playback_format = self.read_sound_format()?;
        let stream_format = self.read_sound_format()?;
        let num_samples_per_block = self.read_u16()?;
        let latency_seek = if stream_format.compression == AudioCompression::Mp3 {
            // Specs say this is i16, not u16. How are negative values used?
            self.read_i16()?
        } else {
            0
        };
        Ok(SoundStreamInfo {
            stream_format: stream_format,
            playback_format: playback_format,
            num_samples_per_block: num_samples_per_block,
            latency_seek: latency_seek,
        })
    }

    fn read_shape_styles(&mut self, shape_version: u8) -> Result<ShapeStyles> {
        let num_fill_styles = match self.read_u8()? {
            0xff if shape_version >= 2 => self.read_u16()? as usize,
            n => n as usize,
        };
        let mut fill_styles = Vec::with_capacity(num_fill_styles);
        for _ in 0..num_fill_styles {
            fill_styles.push(self.read_fill_style(shape_version)?);
        }

        let num_line_styles = match self.read_u8()? {
            // TODO: is this true for linestyles too? SWF19 says not.
            0xff if shape_version >= 2 => self.read_u16()? as usize,
            n => n as usize,
        };
        let mut line_styles = Vec::with_capacity(num_line_styles);
        for _ in 0..num_line_styles {
            line_styles.push(self.read_line_style(shape_version)?);
        }

        self.num_fill_bits = self.read_ubits(4)? as u8;
        self.num_line_bits = self.read_ubits(4)? as u8;
        Ok(ShapeStyles {
            fill_styles: fill_styles,
            line_styles: line_styles,
        })
    }

    fn read_fill_style(&mut self, shape_version: u8) -> Result<FillStyle> {
        let fill_style_type = self.read_u8()?;
        let fill_style = match fill_style_type {
            0x00 => {
                let color = if shape_version >= 3 {
                    self.read_rgba()?
                } else {
                    self.read_rgb()?
                };
                FillStyle::Color(color)
            }

            0x10 => FillStyle::LinearGradient(self.read_gradient(shape_version)?),

            0x12 => FillStyle::RadialGradient(self.read_gradient(shape_version)?),

            0x13 => {
                if self.version < 8 || shape_version < 4 {
                    return Err(Error::new(
                        ErrorKind::InvalidData,
                        "Focal gradients are only supported in SWF version 8 \
                         or higher.",
                    ));
                }
                FillStyle::FocalGradient {
                    gradient: self.read_gradient(shape_version)?,
                    focal_point: self.read_fixed8()?,
                }
            }

            0x40...0x43 => FillStyle::Bitmap {
                id: self.read_u16()?,
                matrix: self.read_matrix()?,
                is_smoothed: (fill_style_type & 0b10) == 0,
                is_repeating: (fill_style_type & 0b01) == 0,
            },

            _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid fill style.")),
        };
        Ok(fill_style)
    }

    fn read_line_style(&mut self, shape_version: u8) -> Result<LineStyle> {
        if shape_version < 4 {
            // LineStyle1
            Ok(LineStyle::new_v1(
                self.read_u16()?, // TODO: Twips
                if shape_version >= 3 {
                    self.read_rgba()?
                } else {
                    self.read_rgb()?
                },
            ))
        } else {
            // LineStyle2 in DefineShape4
            let width = self.read_u16()?;
            let start_cap = match self.read_ubits(2)? {
                0 => LineCapStyle::Round,
                1 => LineCapStyle::None,
                2 => LineCapStyle::Square,
                _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid line cap type.")),
            };
            let join_style_id = self.read_ubits(2)?;
            let has_fill = self.read_bit()?;
            let allow_scale_x = !self.read_bit()?;
            let allow_scale_y = !self.read_bit()?;
            let is_pixel_hinted = self.read_bit()?;
            self.read_ubits(5)?;
            let allow_close = !self.read_bit()?;
            let end_cap = match self.read_ubits(2)? {
                0 => LineCapStyle::Round,
                1 => LineCapStyle::None,
                2 => LineCapStyle::Square,
                _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid line cap type.")),
            };
            let join_style = match join_style_id {
                0 => LineJoinStyle::Round,
                1 => LineJoinStyle::Bevel,
                2 => LineJoinStyle::Miter(self.read_fixed8()?),
                _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid line cap type.")),
            };
            let color = if !has_fill {
                self.read_rgba()?
            } else {
                Color {
                    r: 0,
                    g: 0,
                    b: 0,
                    a: 0,
                }
            };
            let fill_style = if has_fill {
                Some(self.read_fill_style(shape_version)?)
            } else {
                None
            };
            Ok(LineStyle {
                width: width,
                color: color,
                start_cap: start_cap,
                end_cap: end_cap,
                join_style: join_style,
                allow_scale_x: allow_scale_x,
                allow_scale_y: allow_scale_y,
                is_pixel_hinted: is_pixel_hinted,
                allow_close: allow_close,
                fill_style: fill_style,
            })
        }
    }

    fn read_gradient(&mut self, shape_version: u8) -> Result<Gradient> {
        let matrix = self.read_matrix()?;
        self.byte_align();
        let spread = match self.read_ubits(2)? {
            0 => GradientSpread::Pad,
            1 => GradientSpread::Reflect,
            2 => GradientSpread::Repeat,
            _ => {
                return Err(Error::new(
                    ErrorKind::InvalidData,
                    "Invalid gradient spread mode.",
                ))
            }
        };
        let interpolation = match self.read_ubits(2)? {
            0 => GradientInterpolation::RGB,
            1 => GradientInterpolation::LinearRGB,
            _ => {
                return Err(Error::new(
                    ErrorKind::InvalidData,
                    "Invalid gradient interpolation mode.",
                ))
            }
        };
        let num_records = self.read_ubits(4)? as usize;
        let mut records = Vec::with_capacity(num_records);
        for _ in 0..num_records {
            records.push(GradientRecord {
                ratio: self.read_u8()?,
                color: if shape_version >= 3 {
                    self.read_rgba()?
                } else {
                    self.read_rgb()?
                },
            });
        }
        Ok(Gradient {
            matrix: matrix,
            spread: spread,
            interpolation: interpolation,
            records: records,
        })
    }

    fn read_shape_record(&mut self, shape_version: u8) -> Result<Option<ShapeRecord>> {
        // TODO: Twips
        let is_edge_record = self.read_bit()?;
        let shape_record = if is_edge_record {
            let is_straight_edge = self.read_bit()?;
            if is_straight_edge {
                // StraightEdge
                let num_bits = self.read_ubits(4)? as usize + 2;
                let is_axis_aligned = !self.read_bit()?;
                let is_vertical = is_axis_aligned && self.read_bit()?;
                let delta_x = if !is_axis_aligned || !is_vertical {
                    self.read_sbits(num_bits)?
                } else {
                    0
                };
                let delta_y = if !is_axis_aligned || is_vertical {
                    self.read_sbits(num_bits)?
                } else {
                    0
                };
                Some(ShapeRecord::StraightEdge {
                    delta_x: (delta_x as f32) / 20f32,
                    delta_y: (delta_y as f32) / 20f32,
                })
            } else {
                // CurvedEdge
                let num_bits = self.read_ubits(4)? as usize + 2;
                Some(ShapeRecord::CurvedEdge {
                    control_delta_x: (self.read_sbits(num_bits)? as f32) / 20f32,
                    control_delta_y: (self.read_sbits(num_bits)? as f32) / 20f32,
                    anchor_delta_x: (self.read_sbits(num_bits)? as f32) / 20f32,
                    anchor_delta_y: (self.read_sbits(num_bits)? as f32) / 20f32,
                })
            }
        } else {
            let flags = self.read_ubits(5)?;
            if flags != 0 {
                // StyleChange
                let num_fill_bits = self.num_fill_bits as usize;
                let num_line_bits = self.num_line_bits as usize;
                let mut new_style = StyleChangeData {
                    move_to: None,
                    fill_style_0: None,
                    fill_style_1: None,
                    line_style: None,
                    new_styles: None,
                };
                if (flags & 0b1) != 0 {
                    // move
                    let num_bits = self.read_ubits(5)? as usize;
                    new_style.move_to = Some((
                        (self.read_sbits(num_bits)? as f32) / 20f32,
                        (self.read_sbits(num_bits)? as f32) / 20f32,
                    ));
                }
                if (flags & 0b10) != 0 {
                    new_style.fill_style_0 = Some(self.read_ubits(num_fill_bits)?);
                }
                if (flags & 0b100) != 0 {
                    new_style.fill_style_1 = Some(self.read_ubits(num_fill_bits)?);
                }
                if (flags & 0b1000) != 0 {
                    new_style.line_style = Some(self.read_ubits(num_line_bits)?);
                }
                if shape_version >= 2 && (flags & 0b10000) != 0 {
                    let new_styles = self.read_shape_styles(shape_version)?;
                    new_style.new_styles = Some(new_styles);
                }
                Some(ShapeRecord::StyleChange(new_style))
            } else {
                None
            }
        };
        Ok(shape_record)
    }

    fn read_define_sprite(&mut self) -> Result<Tag> {
        Ok(Tag::DefineSprite(Sprite {
            id: self.read_u16()?,
            num_frames: self.read_u16()?,
            tags: self.read_tag_list()?,
        }))
    }

    fn read_place_object(&mut self) -> Result<Tag> {
        // TODO: What's a best way to know if the tag has a color transform?
        Ok(Tag::PlaceObject(Box::new(PlaceObject {
            version: 1,
            action: PlaceObjectAction::Place(self.read_u16()?),
            depth: self.read_i16()?,
            matrix: Some(self.read_matrix()?),
            color_transform: self.read_color_transform_no_alpha().ok(),
            ratio: None,
            name: None,
            clip_depth: None,
            class_name: None,
            filters: vec![],
            background_color: None,
            blend_mode: BlendMode::Normal,
            clip_actions: vec![],
            is_image: false,
            is_bitmap_cached: false,
            is_visible: true,
            amf_data: None,
        })))
    }

    fn read_place_object_2_or_3(&mut self, place_object_version: u8) -> Result<Tag> {
        let flags = if place_object_version >= 3 {
            self.read_u16()?
        } else {
            self.read_u8()? as u16
        };

        let depth = self.read_i16()?;

        // PlaceObject3
        let is_image = (flags & 0b10000_00000000) != 0;
        let has_class_name = (flags & 0b1000_00000000) != 0 || (is_image && (flags & 0b10) != 0);
        let class_name = if has_class_name {
            Some(self.read_c_string()?)
        } else {
            None
        };

        let action = match flags & 0b11 {
            0b01 => PlaceObjectAction::Modify,
            0b10 => PlaceObjectAction::Place(self.read_u16()?),
            0b11 => PlaceObjectAction::Replace(self.read_u16()?),
            _ => {
                return Err(Error::new(
                    ErrorKind::InvalidData,
                    "Invalid PlaceObject type",
                ))
            }
        };
        let matrix = if (flags & 0b100) != 0 {
            Some(self.read_matrix()?)
        } else {
            None
        };
        let color_transform = if (flags & 0b1000) != 0 {
            Some(self.read_color_transform()?)
        } else {
            None
        };
        let ratio = if (flags & 0b1_0000) != 0 {
            Some(self.read_u16()?)
        } else {
            None
        };
        let name = if (flags & 0b10_0000) != 0 {
            Some(self.read_c_string()?)
        } else {
            None
        };
        let clip_depth = if (flags & 0b100_0000) != 0 {
            Some(self.read_i16()?)
        } else {
            None
        };

        // PlaceObject3
        let mut filters = vec![];
        if (flags & 0b1_00000000) != 0 {
            let num_filters = self.read_u8()?;
            for _ in 0..num_filters {
                filters.push(self.read_filter()?);
            }
        }
        let blend_mode = if (flags & 0b10_00000000) != 0 {
            self.read_blend_mode()?
        } else {
            BlendMode::Normal
        };
        let is_bitmap_cached = (flags & 0b100_00000000) != 0 && self.read_u8()? != 0;
        let is_visible = (flags & 0b100000_00000000) == 0 || self.read_u8()? != 0;
        let background_color = if (flags & 0b1000000_00000000) != 0 {
            Some(self.read_rgba()?)
        } else {
            None
        };

        let clip_actions = if (flags & 0b1000_0000) != 0 {
            self.read_clip_actions()?
        } else {
            vec![]
        };
        let amf_data = if place_object_version >= 4 {
            let mut amf = vec![];
            self.input.read_to_end(&mut amf)?;
            Some(amf)
        } else {
            None
        };
        Ok(Tag::PlaceObject(Box::new(PlaceObject {
            version: place_object_version,
            action: action,
            depth: depth,
            matrix: matrix,
            color_transform: color_transform,
            ratio: ratio,
            name: name,
            clip_depth: clip_depth,
            clip_actions: clip_actions,
            is_image: is_image,
            is_bitmap_cached: is_bitmap_cached,
            is_visible: is_visible,
            class_name: class_name,
            filters: filters,
            background_color: background_color,
            blend_mode: blend_mode,
            amf_data: amf_data,
        })))
    }

    fn read_blend_mode(&mut self) -> Result<BlendMode> {
        Ok(match self.read_u8()? {
            0 | 1 => BlendMode::Normal,
            2 => BlendMode::Layer,
            3 => BlendMode::Multiply,
            4 => BlendMode::Screen,
            5 => BlendMode::Lighten,
            6 => BlendMode::Darken,
            7 => BlendMode::Difference,
            8 => BlendMode::Add,
            9 => BlendMode::Subtract,
            10 => BlendMode::Invert,
            11 => BlendMode::Alpha,
            12 => BlendMode::Erase,
            13 => BlendMode::Overlay,
            14 => BlendMode::HardLight,
            _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid blend mode")),
        })
    }

    fn read_clip_actions(&mut self) -> Result<Vec<ClipAction>> {
        self.read_u16()?; // Must be 0
        self.read_clip_event_flags()?; // All event flags
        let mut clip_actions = vec![];
        while let Some(clip_action) = self.read_clip_action()? {
            clip_actions.push(clip_action);
        }
        Ok(clip_actions)
    }

    fn read_clip_action(&mut self) -> Result<Option<ClipAction>> {
        let events = self.read_clip_event_flags()?;
        if events.is_empty() {
            Ok(None)
        } else {
            let mut length = self.read_u32()?;
            let key_code = if events.contains(&ClipEvent::KeyPress) {
                // ActionData length includes the 1 byte key code.
                length -= 1;
                Some(self.read_u8()?)
            } else {
                None
            };

            let mut action_data = Vec::with_capacity(length as usize);
            action_data.resize(length as usize, 0);
            self.input.read_exact(&mut action_data)?;

            Ok(Some(ClipAction {
                events: events,
                key_code: key_code,
                action_data: action_data,
            }))
        }
    }

    fn read_clip_event_flags(&mut self) -> Result<HashSet<ClipEvent>> {
        // TODO: Switch to a bitset.
        let mut event_list = HashSet::with_capacity(32);
        if self.read_bit()? {
            event_list.insert(ClipEvent::KeyUp);
        }
        if self.read_bit()? {
            event_list.insert(ClipEvent::KeyDown);
        }
        if self.read_bit()? {
            event_list.insert(ClipEvent::MouseUp);
        }
        if self.read_bit()? {
            event_list.insert(ClipEvent::MouseDown);
        }
        if self.read_bit()? {
            event_list.insert(ClipEvent::MouseMove);
        }
        if self.read_bit()? {
            event_list.insert(ClipEvent::Unload);
        }
        if self.read_bit()? {
            event_list.insert(ClipEvent::EnterFrame);
        }
        if self.read_bit()? {
            event_list.insert(ClipEvent::Load);
        }
        if self.version < 6 {
            self.read_u16()?;
            self.read_u8()?;
        } else {
            if self.read_bit()? {
                event_list.insert(ClipEvent::DragOver);
            }
            if self.read_bit()? {
                event_list.insert(ClipEvent::RollOut);
            }
            if self.read_bit()? {
                event_list.insert(ClipEvent::RollOver);
            }
            if self.read_bit()? {
                event_list.insert(ClipEvent::ReleaseOutside);
            }
            if self.read_bit()? {
                event_list.insert(ClipEvent::Release);
            }
            if self.read_bit()? {
                event_list.insert(ClipEvent::Press);
            }
            if self.read_bit()? {
                event_list.insert(ClipEvent::Initialize);
            }
            if self.read_bit()? {
                event_list.insert(ClipEvent::Data);
            }
            if self.version < 6 {
                self.read_u16()?;
            } else {
                self.read_ubits(5)?;
                if self.read_bit()? && self.version >= 7 {
                    event_list.insert(ClipEvent::Construct);
                }
                if self.read_bit()? {
                    event_list.insert(ClipEvent::KeyPress);
                }
                if self.read_bit()? {
                    event_list.insert(ClipEvent::DragOut);
                }
                self.read_u8()?;
            }
        }
        Ok(event_list)
    }

    fn read_filter(&mut self) -> Result<Filter> {
        self.byte_align();
        let filter = match self.read_u8()? {
            0 => Filter::DropShadowFilter(Box::new(DropShadowFilter {
                color: self.read_rgba()?,
                blur_x: self.read_fixed16()?,
                blur_y: self.read_fixed16()?,
                angle: self.read_fixed16()?,
                distance: self.read_fixed16()?,
                strength: self.read_fixed8()?,
                is_inner: self.read_bit()?,
                is_knockout: self.read_bit()?,
                num_passes: self.read_ubits(6)? as u8 & 0b011111,
            })),
            1 => Filter::BlurFilter(Box::new(BlurFilter {
                blur_x: self.read_fixed16()?,
                blur_y: self.read_fixed16()?,
                num_passes: self.read_ubits(5)? as u8,
            })),
            2 => Filter::GlowFilter(Box::new(GlowFilter {
                color: self.read_rgba()?,
                blur_x: self.read_fixed16()?,
                blur_y: self.read_fixed16()?,
                strength: self.read_fixed8()?,
                is_inner: self.read_bit()?,
                is_knockout: self.read_bit()?,
                num_passes: self.read_ubits(6)? as u8 & 0b011111,
            })),
            3 => Filter::BevelFilter(Box::new(BevelFilter {
                shadow_color: self.read_rgba()?,
                highlight_color: self.read_rgba()?,
                blur_x: self.read_fixed16()?,
                blur_y: self.read_fixed16()?,
                angle: self.read_fixed16()?,
                distance: self.read_fixed16()?,
                strength: self.read_fixed8()?,
                is_inner: self.read_bit()?,
                is_knockout: self.read_bit()?,
                is_on_top: (self.read_ubits(2)? & 0b1) != 0,
                num_passes: self.read_ubits(4)? as u8 & 0b011111,
            })),
            4 => {
                let num_colors = self.read_u8()?;
                let mut colors = Vec::with_capacity(num_colors as usize);
                for _ in 0..num_colors {
                    colors.push(self.read_rgba()?);
                }
                let mut gradient_records = Vec::with_capacity(num_colors as usize);
                for color in colors {
                    gradient_records.push(GradientRecord {
                        color: color,
                        ratio: self.read_u8()?,
                    });
                }
                Filter::GradientGlowFilter(Box::new(GradientGlowFilter {
                    colors: gradient_records,
                    blur_x: self.read_fixed16()?,
                    blur_y: self.read_fixed16()?,
                    angle: self.read_fixed16()?,
                    distance: self.read_fixed16()?,
                    strength: self.read_fixed8()?,
                    is_inner: self.read_bit()?,
                    is_knockout: self.read_bit()?,
                    is_on_top: (self.read_ubits(2)? & 0b1) != 0,
                    num_passes: self.read_ubits(4)? as u8,
                }))
            }
            5 => {
                let num_matrix_cols = self.read_u8()?;
                let num_matrix_rows = self.read_u8()?;
                let divisor = self.read_fixed16()?;
                let bias = self.read_fixed16()?;
                let num_entries = num_matrix_cols * num_matrix_rows;
                let mut matrix = Vec::with_capacity(num_entries as usize);
                for _ in 0..num_entries {
                    matrix.push(self.read_fixed16()?);
                }
                let default_color = self.read_rgba()?;
                let flags = self.read_u8()?;
                Filter::ConvolutionFilter(Box::new(ConvolutionFilter {
                    num_matrix_cols: num_matrix_cols,
                    num_matrix_rows: num_matrix_rows,
                    divisor: divisor,
                    bias: bias,
                    matrix: matrix,
                    default_color: default_color,
                    is_clamped: (flags & 0b10) != 0,
                    is_preserve_alpha: (flags & 0b1) != 0,
                }))
            }
            6 => {
                let mut matrix = [0f64; 20];
                for m in &mut matrix {
                    *m = self.read_fixed16()?;
                }
                Filter::ColorMatrixFilter(Box::new(ColorMatrixFilter { matrix: matrix }))
            }
            7 => {
                let num_colors = self.read_u8()?;
                let mut colors = Vec::with_capacity(num_colors as usize);
                for _ in 0..num_colors {
                    colors.push(self.read_rgba()?);
                }
                let mut gradient_records = Vec::with_capacity(num_colors as usize);
                for color in colors {
                    gradient_records.push(GradientRecord {
                        color: color,
                        ratio: self.read_u8()?,
                    });
                }
                Filter::GradientBevelFilter(Box::new(GradientBevelFilter {
                    colors: gradient_records,
                    blur_x: self.read_fixed16()?,
                    blur_y: self.read_fixed16()?,
                    angle: self.read_fixed16()?,
                    distance: self.read_fixed16()?,
                    strength: self.read_fixed8()?,
                    is_inner: self.read_bit()?,
                    is_knockout: self.read_bit()?,
                    is_on_top: (self.read_ubits(2)? & 0b1) != 0,
                    num_passes: self.read_ubits(4)? as u8 & 0b011111,
                }))
            }
            _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid filter type")),
        };
        self.byte_align();
        Ok(filter)
    }

    fn read_sound_format(&mut self) -> Result<SoundFormat> {
        let flags = self.read_u8()?;
        let compression = match flags >> 4 {
            0 => AudioCompression::UncompressedUnknownEndian,
            1 => AudioCompression::Adpcm,
            2 => AudioCompression::Mp3,
            3 => AudioCompression::Uncompressed,
            4 => AudioCompression::Nellymoser16Khz,
            5 => AudioCompression::Nellymoser8Khz,
            6 => AudioCompression::Nellymoser,
            11 => AudioCompression::Speex,
            _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid audio format.")),
        };
        let sample_rate = match (flags & 0b11_00) >> 2 {
            0 => 5512,
            1 => 11025,
            2 => 22050,
            3 => 44100,
            _ => unreachable!(),
        };
        let is_16_bit = (flags & 0b10) != 0;
        let is_stereo = (flags & 0b1) != 0;
        Ok(SoundFormat {
            compression: compression,
            sample_rate: sample_rate,
            is_16_bit: is_16_bit,
            is_stereo: is_stereo,
        })
    }

    fn read_sound_info(&mut self) -> Result<SoundInfo> {
        let flags = self.read_u8()?;
        let event = match (flags >> 4) & 0b11 {
            0b10 | 0b11 => SoundEvent::Stop,
            0b00 => SoundEvent::Event,
            0b01 => SoundEvent::Start,
            _ => unreachable!(),
        };
        let in_sample = if (flags & 0b1) != 0 {
            Some(self.read_u32()?)
        } else {
            None
        };
        let out_sample = if (flags & 0b10) != 0 {
            Some(self.read_u32()?)
        } else {
            None
        };
        let num_loops = if (flags & 0b100) != 0 {
            self.read_u16()?
        } else {
            1
        };
        let envelope = if (flags & 0b1000) != 0 {
            let num_points = self.read_u8()?;
            let mut envelope = SoundEnvelope::new();
            for _ in 0..num_points {
                envelope.push(SoundEnvelopePoint {
                    sample: self.read_u32()?,
                    left_volume: self.read_u16()? as f32 / 32768f32,
                    right_volume: self.read_u16()? as f32 / 32768f32,
                })
            }
            Some(envelope)
        } else {
            None
        };
        Ok(SoundInfo {
            event: event,
            in_sample: in_sample,
            out_sample: out_sample,
            num_loops: num_loops,
            envelope: envelope,
        })
    }

    fn read_define_text(&mut self) -> Result<Tag> {
        let id = self.read_character_id()?;
        let bounds = self.read_rectangle()?;
        let matrix = self.read_matrix()?;
        let num_glyph_bits = self.read_u8()?;
        let num_advance_bits = self.read_u8()?;

        let mut records = vec![];
        while let Some(record) = self.read_text_record(num_glyph_bits, num_advance_bits)? {
            records.push(record);
        }

        Ok(Tag::DefineText(Box::new(Text {
            id: id,
            bounds: bounds,
            matrix: matrix,
            records: records,
        })))
    }

    fn read_text_record(
        &mut self,
        num_glyph_bits: u8,
        num_advance_bits: u8,
    ) -> Result<Option<TextRecord>> {
        let flags = self.read_u8()?;

        if flags == 0 {
            // End of text records.
            return Ok(None);
        }

        let font_id = if flags & 0b1000 != 0 {
            Some(self.read_character_id()?)
        } else {
            None
        };
        let color = if flags & 0b100 != 0 {
            Some(self.read_rgb()?)
        } else {
            None
        };
        let x_offset = if flags & 0b1 != 0 {
            Some(self.read_i16()? as f32 / 20.0)
        } else {
            None
        };
        let y_offset = if flags & 0b10 != 0 {
            Some(self.read_i16()? as f32 / 20.0)
        } else {
            None
        };
        let height = if flags & 0b1000 != 0 {
            Some(self.read_u16()?)
        } else {
            None
        };
        // TODO(Herschel): font_id and height are tied together. Merge them into a struct?
        let num_glyphs = self.read_u8()?;
        let mut glyphs = Vec::with_capacity(num_glyphs as usize);
        for _ in 0..num_glyphs {
            glyphs.push(GlyphEntry {
                index: self.read_ubits(num_glyph_bits as usize)?,
                advance: self.read_sbits(num_advance_bits as usize)?,
            });
        }

        Ok(Some(TextRecord {
            font_id: font_id,
            color: color,
            x_offset: x_offset,
            y_offset: y_offset,
            height: height,
            glyphs: glyphs,
        }))
    }

    fn read_define_edit_text(&mut self) -> Result<Tag> {
        let id = self.read_character_id()?;
        let bounds = self.read_rectangle()?;
        let flags = self.read_u8()?;
        let flags2 = self.read_u8()?;
        let font_id = if flags & 0b1 != 0 {
            Some(self.read_character_id()?)
        } else {
            None
        };
        let font_class_name = if flags2 & 0b10000000 != 0 {
            Some(self.read_c_string()?)
        } else {
            None
        };
        let height = if flags & 0b1 != 0 {
            Some(self.read_u16()?)
        } else {
            None
        };
        let color = if flags & 0b100 != 0 {
            Some(self.read_rgba()?)
        } else {
            None
        };
        let max_length = if flags & 0b10 != 0 {
            Some(self.read_u16()?)
        } else {
            None
        };
        let layout = if flags2 & 0b100000 != 0 {
            Some(TextLayout {
                align: match self.read_u8()? {
                    0 => TextAlign::Left,
                    1 => TextAlign::Right,
                    2 => TextAlign::Center,
                    3 => TextAlign::Justify,
                    _ => {
                        return Err(Error::new(
                            ErrorKind::InvalidData,
                            "Invalid edit text alignment",
                        ))
                    }
                },
                left_margin: self.read_u16()? as f32 / 20.0,
                right_margin: self.read_u16()? as f32 / 20.0,
                indent: self.read_u16()? as f32 / 20.0,
                leading: self.read_i16()? as f32 / 20.0,
            })
        } else {
            None
        };
        let variable_name = self.read_c_string()?;
        let initial_text = if flags & 0b10000000 != 0 {
            Some(self.read_c_string()?)
        } else {
            None
        };
        Ok(Tag::DefineEditText(Box::new(EditText {
            id: id,
            bounds: bounds,
            font_id: font_id,
            font_class_name: font_class_name,
            height: height,
            color: color,
            max_length: max_length,
            layout: layout,
            variable_name: variable_name,
            initial_text: initial_text,
            is_word_wrap: flags & 0b1000000 != 0,
            is_multiline: flags & 0b100000 != 0,
            is_password: flags & 0b10000 != 0,
            is_read_only: flags & 0b1000 != 0,
            is_auto_size: flags2 & 0b1000000 != 0,
            is_selectable: flags2 & 0b10000 == 0,
            has_border: flags2 & 0b1000 != 0,
            was_static: flags2 & 0b100 != 0,
            is_html: flags2 & 0b10 != 0,
            is_device_font: flags2 & 0b1 == 0,
        })))
    }

    fn read_define_video_stream(&mut self) -> Result<Tag> {
        let id = self.read_character_id()?;
        let num_frames = self.read_u16()?;
        let width = self.read_u16()?;
        let height = self.read_u16()?;
        let flags = self.read_u8()?;
        // TODO(Herschel): Check SWF version.
        let codec = match self.read_u8()? {
            2 => VideoCodec::H263,
            3 => VideoCodec::ScreenVideo,
            4 => VideoCodec::VP6,
            5 => VideoCodec::VP6WithAlpha,
            _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid video codec.")),
        };
        Ok(Tag::DefineVideoStream(DefineVideoStream {
            id: id,
            num_frames: num_frames,
            width: width,
            height: height,
            is_smoothed: flags & 0b1 != 0,
            codec: codec,
            deblocking: match flags & 0b100_0 {
                0b000_0 => VideoDeblocking::UseVideoPacketValue,
                0b001_0 => VideoDeblocking::None,
                0b010_0 => VideoDeblocking::Level1,
                0b011_0 => VideoDeblocking::Level2,
                0b100_0 => VideoDeblocking::Level3,
                0b101_0 => VideoDeblocking::Level4,
                _ => {
                    return Err(Error::new(
                        ErrorKind::InvalidData,
                        "Invalid video deblocking value.",
                    ))
                }
            },
        }))
    }

    fn read_video_frame(&mut self) -> Result<Tag> {
        let stream_id = self.read_character_id()?;
        let frame_num = self.read_u16()?;
        let mut data = vec![];
        self.input.read_to_end(&mut data)?;
        Ok(Tag::VideoFrame(VideoFrame {
            stream_id: stream_id,
            frame_num: frame_num,
            data: data,
        }))
    }

    fn read_define_bits_jpeg_3(&mut self, version: u8) -> Result<Tag> {
        let id = self.read_character_id()?;
        let data_size = self.read_u32()? as usize;
        let deblocking = if version >= 4 {
            self.read_fixed8()?
        } else {
            0.0
        };
        let mut data = vec![];
        data.resize(data_size, 0);
        self.input.read_exact(&mut data)?;
        let mut alpha_data = vec![];
        self.input.read_to_end(&mut alpha_data)?;
        Ok(Tag::DefineBitsJpeg3(DefineBitsJpeg3 {
            version: version,
            id: id,
            deblocking: deblocking,
            data: data,
            alpha_data: alpha_data,
        }))
    }

    fn read_define_bits_lossless(&mut self, version: u8) -> Result<Tag> {
        let id = self.read_character_id()?;
        let format = match self.read_u8()? {
            3 => BitmapFormat::ColorMap8,
            4 if version == 1 => BitmapFormat::Rgb15,
            5 => BitmapFormat::Rgb32,
            _ => return Err(Error::new(ErrorKind::InvalidData, "Invalid bitmap format.")),
        };
        let width = self.read_u16()?;
        let height = self.read_u16()?;
        let num_colors = if format == BitmapFormat::ColorMap8 {
            self.read_u8()?
        } else {
            0
        };
        let mut data = Vec::new();
        self.input.read_to_end(&mut data)?;
        Ok(Tag::DefineBitsLossless(DefineBitsLossless {
            version: version,
            id: id,
            format: format,
            width: width,
            height: height,
            num_colors: num_colors,
            data: data,
        }))
    }
}

#[cfg(test)]
pub mod tests {
    use std::fs::File;
    use std::io::{Cursor, Read};
    use std::vec::Vec;
    use super::*;
    use test_data;
    use tag_codes::TagCode;

    fn reader(data: &[u8]) -> Reader<&[u8]> {
        let default_version = 13;
        Reader::new(data, default_version)
    }

    fn read_from_file(path: &str) -> Swf {
        let mut file = File::open(path).unwrap();
        let mut data = Vec::new();
        file.read_to_end(&mut data).unwrap();
        read_swf(&data[..]).unwrap()
    }

    pub fn read_tag_bytes_from_file_with_index(
        path: &str,
        tag_code: TagCode,
        mut index: usize,
    ) -> Vec<u8> {
        let mut file = File::open(path).unwrap();
        let mut data = Vec::new();
        file.read_to_end(&mut data).unwrap();

        // Halfway parse the SWF file until we find the tag we're searching for.
        let (swf, mut reader) = super::read_swf_header(&data[..]).unwrap();

        let mut data = Vec::new();
        reader.input.read_to_end(&mut data).unwrap();
        let mut cursor = Cursor::new(data);
        loop {
            let pos = cursor.position();
            let (swf_tag_code, length) = {
                let mut tag_reader = Reader::new(&mut cursor, swf.version);
                tag_reader.read_tag_code_and_length().unwrap()
            };
            let tag_header_length = cursor.position() - pos;
            let mut data = Vec::new();
            data.resize(length + tag_header_length as usize, 0);
            cursor.set_position(pos);
            cursor.read_exact(&mut data[..]).unwrap();
            if swf_tag_code == 0 {
                panic!("Tag not found");
            } else if swf_tag_code == tag_code as u16 {
                if index == 0 {
                    // Flash tends to export tags with the extended header even if the size
                    // would fit with the standard header.
                    // This screws up our tests, because swf-rs writes tags with the
                    // minimum header necessary.
                    // We want to easily write new tests by exporting SWFs from the Flash
                    // software, so rewrite with a standard header to match swf-rs output.
                    if length < 0b111111 && (data[0] & 0b111111) == 0b111111 {
                        let mut tag_data = Vec::with_capacity(length + 2);
                        tag_data.extend_from_slice(&data[0..2]);
                        tag_data.extend_from_slice(&data[6..]);
                        tag_data[0] = (data[0] & !0b111111) | (length as u8);
                        data = tag_data;
                    }
                    return data;
                } else {
                    index -= 1;
                }
            }
        }
    }

    pub fn read_tag_bytes_from_file(path: &str, tag_code: TagCode) -> Vec<u8> {
        read_tag_bytes_from_file_with_index(path, tag_code, 0)
    }

    #[test]
    fn read_swfs() {
        assert_eq!(
            read_from_file("tests/swfs/uncompressed.swf").compression,
            Compression::None
        );
        assert_eq!(
            read_from_file("tests/swfs/zlib.swf").compression,
            Compression::Zlib
        );
        if cfg!(feature = "lzma-support") {
            assert_eq!(
                read_from_file("tests/swfs/lzma.swf").compression,
                Compression::Lzma
            );
        }
    }

    #[test]
    fn read_invalid_swf() {
        let junk = [0u8; 128];
        let result = read_swf(&junk[..]);
        // TODO: Verify correct error.
        assert!(result.is_err());
    }

    #[test]
    fn read_compression_type() {
        assert_eq!(
            Reader::read_compression_type(&b"FWS"[..]).unwrap(),
            Compression::None
        );
        assert_eq!(
            Reader::read_compression_type(&b"CWS"[..]).unwrap(),
            Compression::Zlib
        );
        assert_eq!(
            Reader::read_compression_type(&b"ZWS"[..]).unwrap(),
            Compression::Lzma
        );
        assert!(Reader::read_compression_type(&b"ABC"[..]).is_err());
    }

    #[test]
    fn read_bit() {
        let mut buf: &[u8] = &[0b01010101, 0b00100101];
        let mut reader = Reader::new(&mut buf, 1);
        assert_eq!(
            (0..16)
                .map(|_| reader.read_bit().unwrap())
                .collect::<Vec<_>>(),
            [
                false,
                true,
                false,
                true,
                false,
                true,
                false,
                true,
                false,
                false,
                true,
                false,
                false,
                true,
                false,
                true
            ]
        );
    }

    #[test]
    fn read_ubits() {
        let mut buf: &[u8] = &[0b01010101, 0b00100101];
        let mut reader = Reader::new(&mut buf, 1);
        assert_eq!(
            (0..8)
                .map(|_| reader.read_ubits(2).unwrap())
                .collect::<Vec<_>>(),
            [1, 1, 1, 1, 0, 2, 1, 1]
        );
    }

    #[test]
    fn read_sbits() {
        let mut buf: &[u8] = &[0b01010101, 0b00100101];
        let mut reader = Reader::new(&mut buf, 1);
        assert_eq!(
            (0..8)
                .map(|_| reader.read_sbits(2).unwrap())
                .collect::<Vec<_>>(),
            [1, 1, 1, 1, 0, -2, 1, 1]
        );
    }

    #[test]
    fn read_fbits() {
        assert_eq!(Reader::new(&[0][..], 1).read_fbits(5).unwrap(), 0f32);
        assert_eq!(
            Reader::new(&[0b01000000, 0b00000000, 0b0_0000000][..], 1)
                .read_fbits(17)
                .unwrap(),
            0.5f32
        );
        assert_eq!(
            Reader::new(&[0b10000000, 0b00000000][..], 1)
                .read_fbits(16)
                .unwrap(),
            -0.5f32
        );
    }

    #[test]
    fn read_fixed8() {
        let buf = [
            0b00000000,
            0b00000000,
            0b00000000,
            0b00000001,
            0b10000000,
            0b00000110,
            0b01000000,
            0b11101011,
        ];
        let mut reader = Reader::new(&buf[..], 1);
        assert_eq!(reader.read_fixed8().unwrap(), 0f32);
        assert_eq!(reader.read_fixed8().unwrap(), 1f32);
        assert_eq!(reader.read_fixed8().unwrap(), 6.5f32);
        assert_eq!(reader.read_fixed8().unwrap(), -20.75f32);
    }

    #[test]
    fn read_encoded_u32() {
        let read = |data: &[u8]| reader(data).read_encoded_u32().unwrap();
        assert_eq!(read(&[0]), 0);
        assert_eq!(read(&[2]), 2);
        assert_eq!(read(&[0b1_0000001, 0b0_0000001]), 129);
        assert_eq!(
            read(&[0b1_0000001, 0b1_0000001, 0b0_1100111]),
            0b1100111_0000001_0000001
        );
        assert_eq!(
            read(&[
                0b1_0000000,
                0b1_0000000,
                0b1_0000000,
                0b1_0000000,
                0b0000_1111
            ]),
            0b1111_0000000_0000000_0000000_0000000
        );
        assert_eq!(
            read(&[
                0b1_0000000,
                0b1_0000000,
                0b1_0000000,
                0b1_0000000,
                0b1111_1111
            ]),
            0b1111_0000000_0000000_0000000_0000000
        );
    }

    #[test]
    fn read_rectangle_zero() {
        let buf = [0b00000_000];
        let mut reader = Reader::new(&buf[..], 1);
        let rectangle = reader.read_rectangle().unwrap();
        assert_eq!(
            rectangle,
            Rectangle {
                x_min: 0f32,
                x_max: 0f32,
                y_min: 0f32,
                y_max: 0f32,
            }
        );
    }

    #[test]
    fn read_rectangle_signed() {
        let buf = [0b00110_101, 0b100_01010, 0b0_101100_0, 0b10100_000];
        let mut reader = Reader::new(&buf[..], 1);
        let rectangle = reader.read_rectangle().unwrap();
        assert_eq!(
            rectangle,
            Rectangle {
                x_min: -1f32,
                x_max: 1f32,
                y_min: -1f32,
                y_max: 1f32,
            }
        );
    }

    #[test]
    fn read_matrix() {
        {
            let buf = [0b0_0_00001_0, 0b0_0000000];
            let mut reader = Reader::new(&buf[..], 1);
            let matrix = reader.read_matrix().unwrap();
            assert_eq!(
                matrix,
                Matrix {
                    translate_x: 0f32,
                    translate_y: 0f32,
                    scale_x: 1f32,
                    scale_y: 1f32,
                    rotate_skew_0: 0f32,
                    rotate_skew_1: 0f32,
                }
            );
        }
    }

    #[test]
    fn read_color() {
        {
            let buf = [1, 128, 255];
            let mut reader = Reader::new(&buf[..], 1);
            assert_eq!(
                reader.read_rgb().unwrap(),
                Color {
                    r: 1,
                    g: 128,
                    b: 255,
                    a: 255,
                }
            );
        }
        {
            let buf = [1, 128, 235, 44];
            let mut reader = Reader::new(&buf[..], 1);
            assert_eq!(
                reader.read_rgba().unwrap(),
                Color {
                    r: 1,
                    g: 128,
                    b: 235,
                    a: 44,
                }
            );
        }
    }

    #[test]
    fn read_c_string() {
        {
            let buf = b"Testing\0";
            let mut reader = Reader::new(&buf[..], 1);
            assert_eq!(reader.read_c_string().unwrap(), "Testing");
        }
        {
            let buf = "12🤖12\0".as_bytes();
            let mut reader = Reader::new(&buf[..], 1);
            assert_eq!(reader.read_c_string().unwrap(), "12🤖12");
        }
    }

    #[test]
    fn read_end_tag() {
        let buf = [0, 0];
        let mut reader = Reader::new(&buf[..], 1);
        assert_eq!(reader.read_tag().unwrap(), None);
    }

    #[test]
    fn read_shape_styles() {}

    #[test]
    fn read_fill_style() {
        let read = |buf: &[u8], shape_version| reader(buf).read_fill_style(shape_version).unwrap();

        let fill_style = FillStyle::Color(Color {
            r: 255,
            g: 0,
            b: 0,
            a: 255,
        });
        assert_eq!(read(&[0, 255, 0, 0], 1), fill_style);

        // DefineShape3 and 4 read RGBA colors.
        let fill_style = FillStyle::Color(Color {
            r: 255,
            g: 0,
            b: 0,
            a: 50,
        });
        assert_eq!(read(&[0, 255, 0, 0, 50], 3), fill_style);

        let fill_style = FillStyle::Bitmap {
            id: 20,
            matrix: Matrix::new(),
            is_smoothed: false,
            is_repeating: true,
        };
        assert_eq!(
            read(&[0x42, 20, 0, 0b00_00001_0, 0b0_0000000], 3),
            fill_style
        );

        let mut matrix = Matrix::new();
        matrix.translate_x = 1f32;
        let fill_style = FillStyle::Bitmap {
            id: 33,
            matrix: matrix,
            is_smoothed: false,
            is_repeating: false,
        };
        assert_eq!(
            read(&[0x43, 33, 0, 0b00_00110_0, 0b10100_000, 0b000_00000], 3),
            fill_style
        );
    }

    #[test]
    fn read_line_style() {
        // DefineShape1 and 2 read RGB colors.
        let line_style = LineStyle::new_v1(
            0,
            Color {
                r: 255,
                g: 0,
                b: 0,
                a: 255,
            },
        );
        assert_eq!(
            reader(&[0, 0, 255, 0, 0]).read_line_style(2).unwrap(),
            line_style
        );

        // DefineShape3 and 4 read RGBA colors.
        // let line_style = LineStyle { width: 3, color: Color { r: 1, g: 2, b: 3, a: 10 } };
        //assert_eq!(reader(&[3, 0, 1, 2, 3, 10]).read_line_style(3).unwrap(), line_style);

        // TODO: Read LineStyle2 from DefineShape4.
    }

    #[test]
    fn read_gradient() {
        // TODO
    }

    #[test]
    fn read_shape_record() {
        let read = |buf: &[u8]| reader(buf).read_shape_record(2).unwrap().unwrap();

        let shape_record = ShapeRecord::StraightEdge {
            delta_x: 1f32,
            delta_y: 1f32,
        };
        assert_eq!(
            read(&[0b11_0100_1_0, 0b1010_0010, 0b100_00000]),
            shape_record
        );

        let shape_record = ShapeRecord::StraightEdge {
            delta_x: 0f32,
            delta_y: -1f32,
        };
        assert_eq!(read(&[0b11_0100_0_1, 0b101100_00]), shape_record);

        let shape_record = ShapeRecord::StraightEdge {
            delta_x: -1.5f32,
            delta_y: 0f32,
        };
        assert_eq!(read(&[0b11_0100_0_0, 0b100010_00]), shape_record);
    }

    #[test]
    fn read_tags() {
        for (swf_version, expected_tag, tag_bytes) in test_data::tag_tests() {
            let mut reader = Reader::new(&tag_bytes[..], swf_version);
            let parsed_tag = reader.read_tag().unwrap().unwrap();
            if parsed_tag != expected_tag {
                // Failed, result doesn't match.
                panic!(
                    "Incorrectly parsed tag.\nRead:\n{:?}\n\nExpected:\n{:?}",
                    parsed_tag,
                    expected_tag
                );
            }
        }
    }

    #[test]
    fn read_tag_list() {
        {
            let buf = [0, 0];
            let mut reader = Reader::new(&buf[..], 1);
            assert_eq!(reader.read_tag_list().unwrap(), []);
        }

        {
            let buf = [0b01_000000, 0b00000000, 0, 0];
            let mut reader = Reader::new(&buf[..], 1);
            assert_eq!(reader.read_tag_list().unwrap(), [Tag::ShowFrame]);
        }
    }
}