vendor github.com/containers/image/v5@v5.5.1

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 21 insertions, 6 deletions

diff --git a/vendor/github.com/klauspost/compress/fse/bitreader.go b/vendor/github.com/klauspost/compress/fse/bitreader.go
index b9db204f5..f65eb3909 100644
--- a/vendor/github.com/klauspost/compress/fse/bitreader.go
+++ b/vendor/github.com/klauspost/compress/fse/bitreader.go
@@ -6,6 +6,7 @@
 package fse
 
 import (
+	"encoding/binary"
 	"errors"
 	"io"
 )
@@ -34,8 +35,12 @@ func (b *bitReader) init(in []byte) error {
 	}
 	b.bitsRead = 64
 	b.value = 0
-	b.fill()
-	b.fill()
+	if len(in) >= 8 {
+		b.fillFastStart()
+	} else {
+		b.fill()
+		b.fill()
+	}
 	b.bitsRead += 8 - uint8(highBits(uint32(v)))
 	return nil
 }
@@ -63,8 +68,9 @@ func (b *bitReader) fillFast() {
 	if b.bitsRead < 32 {
 		return
 	}
-	// Do single re-slice to avoid bounds checks.
-	v := b.in[b.off-4 : b.off]
+	// 2 bounds checks.
+	v := b.in[b.off-4:]
+	v = v[:4]
 	low := (uint32(v[0])) | (uint32(v[1]) << 8) | (uint32(v[2]) << 16) | (uint32(v[3]) << 24)
 	b.value = (b.value << 32) | uint64(low)
 	b.bitsRead -= 32
@@ -77,7 +83,8 @@ func (b *bitReader) fill() {
 		return
 	}
 	if b.off > 4 {
-		v := b.in[b.off-4 : b.off]
+		v := b.in[b.off-4:]
+		v = v[:4]
 		low := (uint32(v[0])) | (uint32(v[1]) << 8) | (uint32(v[2]) << 16) | (uint32(v[3]) << 24)
 		b.value = (b.value << 32) | uint64(low)
 		b.bitsRead -= 32
@@ -91,9 +98,17 @@ func (b *bitReader) fill() {
 	}
 }
 
+// fillFastStart() assumes the bitreader is empty and there is at least 8 bytes to read.
+func (b *bitReader) fillFastStart() {
+	// Do single re-slice to avoid bounds checks.
+	b.value = binary.LittleEndian.Uint64(b.in[b.off-8:])
+	b.bitsRead = 0
+	b.off -= 8
+}
+
 // finished returns true if all bits have been read from the bit stream.
 func (b *bitReader) finished() bool {
-	return b.off == 0 && b.bitsRead >= 64
+	return b.bitsRead >= 64 && b.off == 0
 }
 
 // close the bitstream and returns an error if out-of-buffer reads occurred.