lz4stream/block: compute block checksum on the block not its source.

pierrec · pierrec · commit fdaa7e2eae24 · 2024-12-12T17:53:43.000+01:00
Fixes #223.
diff --git a/internal/lz4stream/block.go b/internal/lz4stream/block.go
@@ -246,7 +246,7 @@ func (b *FrameDataBlock) Compress(f *Frame, src []byte, level lz4block.Compressi
 	b.src = src // keep track of the source for content checksum
 
 	if f.Descriptor.Flags.BlockChecksum() {
-		b.Checksum = xxh32.ChecksumZero(src)
+		b.Checksum = xxh32.ChecksumZero(b.Data)
 	}
 	return b
 }
@@ -328,7 +328,7 @@ func (b *FrameDataBlock) Uncompress(f *Frame, dst, dict []byte, sum bool) ([]byt
 		dst = dst[:n]
 	}
 	if f.Descriptor.Flags.BlockChecksum() {
-		if c := xxh32.ChecksumZero(dst); c != b.Checksum {
+		if c := xxh32.ChecksumZero(b.data); c != b.Checksum {
 			err := fmt.Errorf("%w: got %x; expected %x", lz4errors.ErrInvalidBlockChecksum, c, b.Checksum)
 			return nil, err
 		}

Original file line number	Diff line number	Diff line change
`@@ -246,7 +246,7 @@ func (b FrameDataBlock) Compress(f Frame, src []byte, level lz4block.Compressi`
`246`	`246`	`b.src = src // keep track of the source for content checksum`
`247`	`247`
`248`	`248`	`if f.Descriptor.Flags.BlockChecksum() {`
`249`		`- b.Checksum = xxh32.ChecksumZero(src)`
	`249`	`+ b.Checksum = xxh32.ChecksumZero(b.Data)`
`250`	`250`	`}`
`251`	`251`	`return b`
`252`	`252`	`}`
`@@ -328,7 +328,7 @@ func (b FrameDataBlock) Uncompress(f Frame, dst, dict []byte, sum bool) ([]byt`
`328`	`328`	`dst = dst[:n]`
`329`	`329`	`}`
`330`	`330`	`if f.Descriptor.Flags.BlockChecksum() {`
`331`		`- if c := xxh32.ChecksumZero(dst); c != b.Checksum {`
	`331`	`+ if c := xxh32.ChecksumZero(b.data); c != b.Checksum {`
`332`	`332`	`err := fmt.Errorf("%w: got %x; expected %x", lz4errors.ErrInvalidBlockChecksum, c, b.Checksum)`
`333`	`333`	`return nil, err`
`334`	`334`	`}`