core: Switch from libflate to flate2

Cargo.lock

@@ -2682,6 +2682,7 @@ dependencies = [
  "chrono",
  "downcast-rs",
  "enumset",
+ "flate2",
  "fnv",
  "gc-arena",
  "gc-arena-derive",
@@ -2691,7 +2692,6 @@ dependencies = [
  "instant",
  "jpeg-decoder",
  "json",
- "libflate",
  "log",
  "minimp3",
  "num-traits 0.2.12",

core/Cargo.toml

@@ -7,13 +7,13 @@ license = "MIT OR Apache-2.0"
 
 [dependencies]
 bitstream-io = "0.9.0"
+flate2 = "1.0.18"
 fnv = "1.0.7"
 gc-arena = "0.2.0"
 gc-arena-derive = "0.2.0"
 generational-arena = "0.2.8"
 gif = "0.11.1"
 indexmap = "1.6.0"
-libflate = "1.0.2"
 log = "0.4"
 minimp3 = { version = "0.5.0", optional = true }
 png = { version = "0.16.7" }

core/src/backend/render.rs

@@ -265,12 +265,7 @@ pub fn decode_jpeg(
 
     // Decompress the alpha data (DEFLATE compression).
     if let Some(alpha_data) = alpha_data {
-        let alpha_data = {
-            let mut data = vec![];
-            let mut decoder = libflate::zlib::Decoder::new(alpha_data)?;
-            decoder.read_to_end(&mut data)?;
-            data
-        };
+        let alpha_data = decompress_zlib(alpha_data)?;
 
         if alpha_data.len() == decoded_data.len() / 3 {
             let mut rgba = Vec::with_capacity((decoded_data.len() / 3) * 4);
@@ -315,12 +310,7 @@ pub fn decode_define_bits_lossless(
     swf_tag: &swf::DefineBitsLossless,
 ) -> Result<Bitmap, Box<dyn std::error::Error>> {
     // Decompress the image data (DEFLATE compression).
-    let mut decoded_data = {
-        let mut data = vec![];
-        let mut decoder = libflate::zlib::Decoder::new(&swf_tag.data[..])?;
-        decoder.read_to_end(&mut data)?;
-        data
-    };
+    let mut decoded_data = decompress_zlib(&swf_tag.data[..])?;
 
     // Swizzle/de-palettize the bitmap.
     let out_data = match (swf_tag.version, swf_tag.format) {
@@ -513,3 +503,12 @@ pub fn srgb_to_linear(color: [f32; 4]) -> [f32; 4] {
         color[3],
     ]
 }
+
+/// Decodes zlib-compressed data.
+fn decompress_zlib(data: &[u8]) -> Result<Vec<u8>, std::io::Error> {
+    let mut out_data = Vec::new();
+    let mut decoder = flate2::bufread::ZlibDecoder::new(data);
+    decoder.read_to_end(&mut out_data)?;
+    out_data.shrink_to_fit();
+    Ok(out_data)
+}

swf/Cargo.toml

@@ -23,5 +23,5 @@ xz2 = {version = "0.1.6", optional = true}
 approx = "0.3.2"
 
 [features]
-default = ["libflate"]
+default = ["flate2"]
 lzma = ["xz2"]