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avm1: Clean up SWF4 string ops 

Clean up SWF4 string ops:
 * Operate on UTF-16 code units (in SWF6+)
 * StringExtract indices are 1-based
This commit is contained in:
Mike Welsh 2020-09-16 00:49:56 -07:00
parent 4f6c017bc0
commit 7eeba10bef
1 changed files with 84 additions and 45 deletions
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129
core/src/avm1/activation.rs
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@ -20,6 +20,7 @@ use rand::Rng;
use smallvec::SmallVec;
use std::borrow::Cow;
use std::cell::{Ref, RefMut};
use std::convert::TryFrom;
use std::fmt;
use swf::avm1::read::Reader;
use swf::avm1::types::{Action, CatchVar, Function, TryBlock};
@ -623,20 +624,34 @@ impl<'a, 'gc, 'gc_context> Activation<'a, 'gc, 'gc_context> {
}
fn action_ascii_to_char(&mut self) -> Result<FrameControl<'gc>, Error<'gc>> {
// TODO(Herschel): Results on incorrect operands?
let val = (self.context.avm1.pop().coerce_to_f64(self)? as u8) as char;
// In SWF6+, this operates on UTF-16 code units.
// TODO: In SWF5 and below, this operates on bytes, regardless of the locale encoding.
let char_code = u32::from(self.context.avm1.pop().coerce_to_u16(self)?);
let result = if char_code != 0 {
// Unpaired surrogates turn into replacement char.
char::try_from(char_code)
.unwrap_or(std::char::REPLACEMENT_CHARACTER)
.to_string()
} else {
String::default()
};
self.context
.avm1
.push(AvmString::new(self.context.gc_context, val.to_string()));
.push(AvmString::new(self.context.gc_context, result));
Ok(FrameControl::Continue)
}
fn action_char_to_ascii(&mut self) -> Result<FrameControl<'gc>, Error<'gc>> {
// TODO(Herschel): Results on incorrect operands?
// SWF4 ord function
// In SWF6+, this operates on UTF-16 code units.
// TODO: In SWF5 and below, this operates on bytes, regardless of the locale.
let val = self.context.avm1.pop();
let string = val.coerce_to_string(self)?;
let result = string.bytes().next().unwrap_or(0);
self.context.avm1.push(result);
let s = val.coerce_to_string(self)?;
let char_code = s.encode_utf16().next().unwrap_or(0);
// Unpaired surrogate characters should return the code point for the replacement character.
// Try to convert the code unit back to a character, which will fail if this is invalid UTF-16 (unpaired surrogate).
let c = crate::string_utils::utf16_code_unit_to_char(char_code);
self.context.avm1.push(u32::from(c));
Ok(FrameControl::Continue)
}
@ -1483,39 +1498,56 @@ impl<'a, 'gc, 'gc_context> Activation<'a, 'gc, 'gc_context> {
}
fn action_mb_ascii_to_char(&mut self) -> Result<FrameControl<'gc>, Error<'gc>> {
// TODO(Herschel): Results on incorrect operands?
use std::convert::TryFrom;
let result = char::try_from(self.context.avm1.pop().coerce_to_f64(self)? as u32);
match result {
Ok(val) => self
.context
.avm1
.push(AvmString::new(self.context.gc_context, val.to_string())),
Err(e) => avm_warn!(
self,
"Couldn't parse char for action_mb_ascii_to_char: {}",
e
),
}
// In SWF6+, this operates on UTF-16 code units.
// TODO: In SWF5 and below, this operates on locale-dependent characters.
let char_code = u32::from(self.context.avm1.pop().coerce_to_u16(self)?);
let result = if char_code != 0 {
// Unpaired surrogates turn into replacement char.
char::try_from(char_code)
.unwrap_or(std::char::REPLACEMENT_CHARACTER)
.to_string()
} else {
String::default()
};
self.context
.avm1
.push(AvmString::new(self.context.gc_context, result));
Ok(FrameControl::Continue)
}
fn action_mb_char_to_ascii(&mut self) -> Result<FrameControl<'gc>, Error<'gc>> {
// TODO(Herschel): Results on incorrect operands?
// SWF4 mbord function
// In SWF6+, this operates on UTF-16 code units.
// TODO: In SWF5 and below, this operates on locale-dependent characters.
let val = self.context.avm1.pop();
let s = val.coerce_to_string(self)?;
let result = s.chars().next().unwrap_or('\0') as u32;
self.context.avm1.push(result);
let char_code = s.encode_utf16().next().unwrap_or(0);
// Unpaired surrogate characters should return the code point for the replacement character.
// Try to convert the code unit back to a character, which will fail if this is invalid UTF-16 (unpaired surrogate).
let c = crate::string_utils::utf16_code_unit_to_char(char_code);
self.context.avm1.push(u32::from(c));
Ok(FrameControl::Continue)
}
fn action_mb_string_extract(&mut self) -> Result<FrameControl<'gc>, Error<'gc>> {
// TODO(Herschel): Result with incorrect operands?
let len = self.context.avm1.pop().coerce_to_f64(self)? as usize;
let start = self.context.avm1.pop().coerce_to_f64(self)? as usize;
// SWF4 mbsubstring
// In SWF6+, this operates on UTF-16 code units.
// TODO: In SWF5 and below, this operates on locale-dependent characters.
let len = self.context.avm1.pop().coerce_to_i32(self)?;
let len = if len >= 0 { len as usize } else { usize::MAX };
// Index is 1-based for this opcode.
let start = self.context.avm1.pop().coerce_to_i32(self)?;
let start = if start >= 1 { start as usize - 1 } else { 0 };
let val = self.context.avm1.pop();
let s = val.coerce_to_string(self)?;
let result = s[len..len + start].to_string(); // TODO(Herschel): Flash uses UTF-16 internally.
let result = crate::string_utils::utf16_iter_to_string(
s.encode_utf16()
.skip(start) // - 1 safe because max(1) above
.take(len),
);
self.context
.avm1
.push(AvmString::new(self.context.gc_context, result));
@ -1523,9 +1555,10 @@ impl<'a, 'gc, 'gc_context> Activation<'a, 'gc, 'gc_context> {
}
fn action_mb_string_length(&mut self) -> Result<FrameControl<'gc>, Error<'gc>> {
// TODO(Herschel): Result with non-string operands?
// In SWF6+, this is the same as String.length (returns number of UTF-16 code units).
// TODO: In SWF5, this returns the number of characters using the locale encoding.
let val = self.context.avm1.pop();
let len = val.coerce_to_string(self)?.len();
let len = val.coerce_to_string(self)?.encode_utf16().count();
self.context.avm1.push(len as f64);
Ok(FrameControl::Continue)
}
@ -1945,20 +1978,26 @@ impl<'a, 'gc, 'gc_context> Activation<'a, 'gc, 'gc_context> {
}
fn action_string_extract(&mut self) -> Result<FrameControl<'gc>, Error<'gc>> {
// SWFv4 substring
// TODO(Herschel): Result with incorrect operands?
let len = self.context.avm1.pop().coerce_to_f64(self)? as usize;
let start = self.context.avm1.pop().coerce_to_f64(self)? as usize;
// SWF4 substring function
// In SWF6+, this operates on UTF-16 code units.
// TODO: In SWF5 and below, this operates on bytes, regardless of the locale encoding.
// len < 0 returns to the end of the string.
let len = self.context.avm1.pop().coerce_to_i32(self)?;
let len = if len >= 0 { len as usize } else { usize::MAX };
// Index is 1-based for this opcode.
let start = self.context.avm1.pop().coerce_to_i32(self)?;
let start = if start >= 1 { start as usize - 1 } else { 0 };
let val = self.context.avm1.pop();
let s = val.coerce_to_string(self)?;
// This is specifically a non-UTF8 aware substring.
// SWFv4 only used ANSI strings.
let result = s
.bytes()
.skip(start)
.take(len)
.map(|c| c as char)
.collect::<String>();
let result = crate::string_utils::utf16_iter_to_string(
s.encode_utf16()
.skip(start) // - 1 safe because max(1) above
.take(len),
);
self.context
.avm1
.push(AvmString::new(self.context.gc_context, result));
@ -1982,10 +2021,10 @@ impl<'a, 'gc, 'gc_context> Activation<'a, 'gc, 'gc_context> {
fn action_string_length(&mut self) -> Result<FrameControl<'gc>, Error<'gc>> {
// AS1 strlen
// Only returns byte length.
// TODO(Herschel): Result with non-string operands?
// In SWF6+, this is the same as String.length (returns number of UTF-16 code units).
// TODO: In SWF5, this returns the byte length, even though the encoding is locale dependent.
let val = self.context.avm1.pop();
let len = val.coerce_to_string(self)?.bytes().len() as f64;
let len = val.coerce_to_string(self)?.encode_utf16().count();
self.context.avm1.push(len);
Ok(FrameControl::Continue)
}