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Diffstat (limited to 'vendor/github.com/klauspost/compress/fse/bitreader.go')
-rw-r--r--vendor/github.com/klauspost/compress/fse/bitreader.go27
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.