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-rw-r--r--vendor/golang.org/x/image/vp8/partition.go129
1 files changed, 0 insertions, 129 deletions
diff --git a/vendor/golang.org/x/image/vp8/partition.go b/vendor/golang.org/x/image/vp8/partition.go
deleted file mode 100644
index 72288bd..0000000
--- a/vendor/golang.org/x/image/vp8/partition.go
+++ /dev/null
@@ -1,129 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8
-
-// Each VP8 frame consists of between 2 and 9 bitstream partitions.
-// Each partition is byte-aligned and is independently arithmetic-encoded.
-//
-// This file implements decoding a partition's bitstream, as specified in
-// chapter 7. The implementation follows libwebp's approach instead of the
-// specification's reference C implementation. For example, we use a look-up
-// table instead of a for loop to recalibrate the encoded range.
-
-var (
- lutShift = [127]uint8{
- 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
- 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
- 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
- 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
- 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
- 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
- 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
- 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
- }
- lutRangeM1 = [127]uint8{
- 127,
- 127, 191,
- 127, 159, 191, 223,
- 127, 143, 159, 175, 191, 207, 223, 239,
- 127, 135, 143, 151, 159, 167, 175, 183, 191, 199, 207, 215, 223, 231, 239, 247,
- 127, 131, 135, 139, 143, 147, 151, 155, 159, 163, 167, 171, 175, 179, 183, 187,
- 191, 195, 199, 203, 207, 211, 215, 219, 223, 227, 231, 235, 239, 243, 247, 251,
- 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157,
- 159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189,
- 191, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219, 221,
- 223, 225, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 253,
- }
-)
-
-// uniformProb represents a 50% probability that the next bit is 0.
-const uniformProb = 128
-
-// partition holds arithmetic-coded bits.
-type partition struct {
- // buf is the input bytes.
- buf []byte
- // r is how many of buf's bytes have been consumed.
- r int
- // rangeM1 is range minus 1, where range is in the arithmetic coding sense,
- // not the Go language sense.
- rangeM1 uint32
- // bits and nBits hold those bits shifted out of buf but not yet consumed.
- bits uint32
- nBits uint8
- // unexpectedEOF tells whether we tried to read past buf.
- unexpectedEOF bool
-}
-
-// init initializes the partition.
-func (p *partition) init(buf []byte) {
- p.buf = buf
- p.r = 0
- p.rangeM1 = 254
- p.bits = 0
- p.nBits = 0
- p.unexpectedEOF = false
-}
-
-// readBit returns the next bit.
-func (p *partition) readBit(prob uint8) bool {
- if p.nBits < 8 {
- if p.r >= len(p.buf) {
- p.unexpectedEOF = true
- return false
- }
- // Expression split for 386 compiler.
- x := uint32(p.buf[p.r])
- p.bits |= x << (8 - p.nBits)
- p.r++
- p.nBits += 8
- }
- split := (p.rangeM1*uint32(prob))>>8 + 1
- bit := p.bits >= split<<8
- if bit {
- p.rangeM1 -= split
- p.bits -= split << 8
- } else {
- p.rangeM1 = split - 1
- }
- if p.rangeM1 < 127 {
- shift := lutShift[p.rangeM1]
- p.rangeM1 = uint32(lutRangeM1[p.rangeM1])
- p.bits <<= shift
- p.nBits -= shift
- }
- return bit
-}
-
-// readUint returns the next n-bit unsigned integer.
-func (p *partition) readUint(prob, n uint8) uint32 {
- var u uint32
- for n > 0 {
- n--
- if p.readBit(prob) {
- u |= 1 << n
- }
- }
- return u
-}
-
-// readInt returns the next n-bit signed integer.
-func (p *partition) readInt(prob, n uint8) int32 {
- u := p.readUint(prob, n)
- b := p.readBit(prob)
- if b {
- return -int32(u)
- }
- return int32(u)
-}
-
-// readOptionalInt returns the next n-bit signed integer in an encoding
-// where the likely result is zero.
-func (p *partition) readOptionalInt(prob, n uint8) int32 {
- if !p.readBit(prob) {
- return 0
- }
- return p.readInt(prob, n)
-}