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PNG: Let PNG use the new compress I/O routines.

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This commit is contained in:
Jeroen van Rijn
2021-06-27 13:51:52 +02:00
parent 02f9668185
commit eaf88bcc4d
4 changed files with 35 additions and 345 deletions
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core/compress/zlib/zlib.odin
+5 -80
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@@ -423,7 +423,7 @@ parse_huffman_block :: proc(z: ^$C, z_repeat, z_offset: ^Huffman_Table) -> (err:
}
@(optimization_mode="speed")
__inflate_from_memory :: proc(using ctx: ^compress.Context_Memory_Input, raw := false, expected_output_size := -1, allocator := context.allocator) -> (err: Error) #no_bounds_check {
inflate_from_context :: proc(using ctx: ^compress.Context_Memory_Input, raw := false, expected_output_size := -1, allocator := context.allocator) -> (err: Error) #no_bounds_check {
/*
ctx.output must be a bytes.Buffer for now. We'll add a separate implementation that writes to a stream.
@@ -432,83 +432,8 @@ __inflate_from_memory :: proc(using ctx: ^compress.Context_Memory_Input, raw :=
*/
if !raw {
if len(ctx.input_data) < 6 {
return E_General.Stream_Too_Short;
}
cmf, _ := compress.read_u8(ctx);
method := Compression_Method(cmf & 0xf);
if method != .DEFLATE {
return E_General.Unknown_Compression_Method;
}
cinfo := (cmf >> 4) & 0xf;
if cinfo > 7 {
return E_ZLIB.Unsupported_Window_Size;
}
flg, _ := compress.read_u8(ctx);
fcheck := flg & 0x1f;
fcheck_computed := (cmf << 8 | flg) & 0x1f;
if fcheck != fcheck_computed {
return E_General.Checksum_Failed;
}
fdict := (flg >> 5) & 1;
/*
We don't handle built-in dictionaries for now.
They're application specific and PNG doesn't use them.
*/
if fdict != 0 {
return E_ZLIB.FDICT_Unsupported;
}
// flevel := Compression_Level((flg >> 6) & 3);
/*
Inflate can consume bits belonging to the Adler checksum.
We pass the entire stream to Inflate and will unget bytes if we need to
at the end to compare checksums.
*/
}
// Parse ZLIB stream without header.
err = inflate_raw(z=ctx, expected_output_size=expected_output_size);
if err != nil {
return err;
}
if !raw {
compress.discard_to_next_byte_lsb(ctx);
adler32 := compress.read_bits_lsb(ctx, 8) << 24 | compress.read_bits_lsb(ctx, 8) << 16 | compress.read_bits_lsb(ctx, 8) << 8 | compress.read_bits_lsb(ctx, 8);
output_hash := hash.adler32(ctx.output.buf[:]);
if output_hash != u32(adler32) {
return E_General.Checksum_Failed;
}
}
return nil;
}
@(optimization_mode="speed")
__inflate_from_stream :: proc(using ctx: ^$C, raw := false, expected_output_size := -1, allocator := context.allocator) -> (err: Error) #no_bounds_check {
/*
ctx.input must be an io.Stream backed by an implementation that supports:
- read
- size
ctx.output must be a bytes.Buffer for now. We'll add a separate implementation that writes to a stream.
raw determines whether the ZLIB header is processed, or we're inflating a raw
DEFLATE stream.
*/
if !raw {
data_size := io.size(ctx.input);
if data_size < 6 {
size, size_err := compress.input_size(ctx);
if size < 6 || size_err != nil {
return E_General.Stream_Too_Short;
}
@@ -773,7 +698,7 @@ inflate_from_byte_array :: proc(input: []u8, buf: ^bytes.Buffer, raw := false, e
ctx.input_data = input;
ctx.output = buf;
err = __inflate_from_memory(ctx=&ctx, raw=raw, expected_output_size=expected_output_size);
err = inflate_from_context(ctx=&ctx, raw=raw, expected_output_size=expected_output_size);
return err;
}
@@ -787,4 +712,4 @@ inflate_from_byte_array_raw :: proc(input: []u8, buf: ^bytes.Buffer, raw := fals
return inflate_raw(z=&ctx, expected_output_size=expected_output_size);
}
inflate :: proc{__inflate_from_stream, inflate_from_byte_array};
inflate :: proc{inflate_from_context, inflate_from_byte_array};