From 331597b9f8a7942cbcb233a328301e4d5bf94fb0 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Fri, 11 Jan 2019 23:28:47 +0200
Subject: Switch to Go modules and make other changes

---
 vendor/golang.org/x/image/vp8/reconstruct.go | 442 ---------------------------
 1 file changed, 442 deletions(-)
 delete mode 100644 vendor/golang.org/x/image/vp8/reconstruct.go

(limited to 'vendor/golang.org/x/image/vp8/reconstruct.go')

diff --git a/vendor/golang.org/x/image/vp8/reconstruct.go b/vendor/golang.org/x/image/vp8/reconstruct.go
deleted file mode 100644
index c1cc4b5..0000000
--- a/vendor/golang.org/x/image/vp8/reconstruct.go
+++ /dev/null
@@ -1,442 +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
-
-// This file implements decoding DCT/WHT residual coefficients and
-// reconstructing YCbCr data equal to predicted values plus residuals.
-//
-// There are 1*16*16 + 2*8*8 + 1*4*4 coefficients per macroblock:
-//	- 1*16*16 luma DCT coefficients,
-//	- 2*8*8 chroma DCT coefficients, and
-//	- 1*4*4 luma WHT coefficients.
-// Coefficients are read in lots of 16, and the later coefficients in each lot
-// are often zero.
-//
-// The YCbCr data consists of 1*16*16 luma values and 2*8*8 chroma values,
-// plus previously decoded values along the top and left borders. The combined
-// values are laid out as a [1+16+1+8][32]uint8 so that vertically adjacent
-// samples are 32 bytes apart. In detail, the layout is:
-//
-//	0 1 2 3 4 5 6 7  8 9 0 1 2 3 4 5  6 7 8 9 0 1 2 3  4 5 6 7 8 9 0 1
-//	. . . . . . . a  b b b b b b b b  b b b b b b b b  c c c c . . . .	0
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	1
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	2
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	3
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  c c c c . . . .	4
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	5
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	6
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	7
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  c c c c . . . .	8
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	9
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	10
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	11
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  c c c c . . . .	12
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	13
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	14
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	15
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	16
-//	. . . . . . . e  f f f f f f f f  . . . . . . . g  h h h h h h h h	17
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	18
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	19
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	20
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	21
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	22
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	23
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	24
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	25
-//
-// Y, B and R are the reconstructed luma (Y) and chroma (B, R) values.
-// The Y values are predicted (either as one 16x16 region or 16 4x4 regions)
-// based on the row above's Y values (some combination of {abc} or {dYC}) and
-// the column left's Y values (either {ad} or {bY}). Similarly, B and R values
-// are predicted on the row above and column left of their respective 8x8
-// region: {efi} for B, {ghj} for R.
-//
-// For uppermost macroblocks (i.e. those with mby == 0), the {abcefgh} values
-// are initialized to 0x81. Otherwise, they are copied from the bottom row of
-// the macroblock above. The {c} values are then duplicated from row 0 to rows
-// 4, 8 and 12 of the ybr workspace.
-// Similarly, for leftmost macroblocks (i.e. those with mbx == 0), the {adeigj}
-// values are initialized to 0x7f. Otherwise, they are copied from the right
-// column of the macroblock to the left.
-// For the top-left macroblock (with mby == 0 && mbx == 0), {aeg} is 0x81.
-//
-// When moving from one macroblock to the next horizontally, the {adeigj}
-// values can simply be copied from the workspace to itself, shifted by 8 or
-// 16 columns. When moving from one macroblock to the next vertically,
-// filtering can occur and hence the row values have to be copied from the
-// post-filtered image instead of the pre-filtered workspace.
-
-const (
-	bCoeffBase   = 1*16*16 + 0*8*8
-	rCoeffBase   = 1*16*16 + 1*8*8
-	whtCoeffBase = 1*16*16 + 2*8*8
-)
-
-const (
-	ybrYX = 8
-	ybrYY = 1
-	ybrBX = 8
-	ybrBY = 18
-	ybrRX = 24
-	ybrRY = 18
-)
-
-// prepareYBR prepares the {abcdefghij} elements of ybr.
-func (d *Decoder) prepareYBR(mbx, mby int) {
-	if mbx == 0 {
-		for y := 0; y < 17; y++ {
-			d.ybr[y][7] = 0x81
-		}
-		for y := 17; y < 26; y++ {
-			d.ybr[y][7] = 0x81
-			d.ybr[y][23] = 0x81
-		}
-	} else {
-		for y := 0; y < 17; y++ {
-			d.ybr[y][7] = d.ybr[y][7+16]
-		}
-		for y := 17; y < 26; y++ {
-			d.ybr[y][7] = d.ybr[y][15]
-			d.ybr[y][23] = d.ybr[y][31]
-		}
-	}
-	if mby == 0 {
-		for x := 7; x < 28; x++ {
-			d.ybr[0][x] = 0x7f
-		}
-		for x := 7; x < 16; x++ {
-			d.ybr[17][x] = 0x7f
-		}
-		for x := 23; x < 32; x++ {
-			d.ybr[17][x] = 0x7f
-		}
-	} else {
-		for i := 0; i < 16; i++ {
-			d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
-		}
-		for i := 0; i < 8; i++ {
-			d.ybr[17][8+i] = d.img.Cb[(8*mby-1)*d.img.CStride+8*mbx+i]
-		}
-		for i := 0; i < 8; i++ {
-			d.ybr[17][24+i] = d.img.Cr[(8*mby-1)*d.img.CStride+8*mbx+i]
-		}
-		if mbx == d.mbw-1 {
-			for i := 16; i < 20; i++ {
-				d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+15]
-			}
-		} else {
-			for i := 16; i < 20; i++ {
-				d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
-			}
-		}
-	}
-	for y := 4; y < 16; y += 4 {
-		d.ybr[y][24] = d.ybr[0][24]
-		d.ybr[y][25] = d.ybr[0][25]
-		d.ybr[y][26] = d.ybr[0][26]
-		d.ybr[y][27] = d.ybr[0][27]
-	}
-}
-
-// btou converts a bool to a 0/1 value.
-func btou(b bool) uint8 {
-	if b {
-		return 1
-	}
-	return 0
-}
-
-// pack packs four 0/1 values into four bits of a uint32.
-func pack(x [4]uint8, shift int) uint32 {
-	u := uint32(x[0])<<0 | uint32(x[1])<<1 | uint32(x[2])<<2 | uint32(x[3])<<3
-	return u << uint(shift)
-}
-
-// unpack unpacks four 0/1 values from a four-bit value.
-var unpack = [16][4]uint8{
-	{0, 0, 0, 0},
-	{1, 0, 0, 0},
-	{0, 1, 0, 0},
-	{1, 1, 0, 0},
-	{0, 0, 1, 0},
-	{1, 0, 1, 0},
-	{0, 1, 1, 0},
-	{1, 1, 1, 0},
-	{0, 0, 0, 1},
-	{1, 0, 0, 1},
-	{0, 1, 0, 1},
-	{1, 1, 0, 1},
-	{0, 0, 1, 1},
-	{1, 0, 1, 1},
-	{0, 1, 1, 1},
-	{1, 1, 1, 1},
-}
-
-var (
-	// The mapping from 4x4 region position to band is specified in section 13.3.
-	bands = [17]uint8{0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 0}
-	// Category probabilties are specified in section 13.2.
-	// Decoding categories 1 and 2 are done inline.
-	cat3456 = [4][12]uint8{
-		{173, 148, 140, 0, 0, 0, 0, 0, 0, 0, 0, 0},
-		{176, 155, 140, 135, 0, 0, 0, 0, 0, 0, 0, 0},
-		{180, 157, 141, 134, 130, 0, 0, 0, 0, 0, 0, 0},
-		{254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129, 0},
-	}
-	// The zigzag order is:
-	//	0  1  5  6
-	//	2  4  7 12
-	//	3  8 11 13
-	//	9 10 14 15
-	zigzag = [16]uint8{0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15}
-)
-
-// parseResiduals4 parses a 4x4 region of residual coefficients, as specified
-// in section 13.3, and returns a 0/1 value indicating whether there was at
-// least one non-zero coefficient.
-// r is the partition to read bits from.
-// plane and context describe which token probability table to use. context is
-// either 0, 1 or 2, and equals how many of the macroblock left and macroblock
-// above have non-zero coefficients.
-// quant are the DC/AC quantization factors.
-// skipFirstCoeff is whether the DC coefficient has already been parsed.
-// coeffBase is the base index of d.coeff to write to.
-func (d *Decoder) parseResiduals4(r *partition, plane int, context uint8, quant [2]uint16, skipFirstCoeff bool, coeffBase int) uint8 {
-	prob, n := &d.tokenProb[plane], 0
-	if skipFirstCoeff {
-		n = 1
-	}
-	p := prob[bands[n]][context]
-	if !r.readBit(p[0]) {
-		return 0
-	}
-	for n != 16 {
-		n++
-		if !r.readBit(p[1]) {
-			p = prob[bands[n]][0]
-			continue
-		}
-		var v uint32
-		if !r.readBit(p[2]) {
-			v = 1
-			p = prob[bands[n]][1]
-		} else {
-			if !r.readBit(p[3]) {
-				if !r.readBit(p[4]) {
-					v = 2
-				} else {
-					v = 3 + r.readUint(p[5], 1)
-				}
-			} else if !r.readBit(p[6]) {
-				if !r.readBit(p[7]) {
-					// Category 1.
-					v = 5 + r.readUint(159, 1)
-				} else {
-					// Category 2.
-					v = 7 + 2*r.readUint(165, 1) + r.readUint(145, 1)
-				}
-			} else {
-				// Categories 3, 4, 5 or 6.
-				b1 := r.readUint(p[8], 1)
-				b0 := r.readUint(p[9+b1], 1)
-				cat := 2*b1 + b0
-				tab := &cat3456[cat]
-				v = 0
-				for i := 0; tab[i] != 0; i++ {
-					v *= 2
-					v += r.readUint(tab[i], 1)
-				}
-				v += 3 + (8 << cat)
-			}
-			p = prob[bands[n]][2]
-		}
-		z := zigzag[n-1]
-		c := int32(v) * int32(quant[btou(z > 0)])
-		if r.readBit(uniformProb) {
-			c = -c
-		}
-		d.coeff[coeffBase+int(z)] = int16(c)
-		if n == 16 || !r.readBit(p[0]) {
-			return 1
-		}
-	}
-	return 1
-}
-
-// parseResiduals parses the residuals and returns whether inner loop filtering
-// should be skipped for this macroblock.
-func (d *Decoder) parseResiduals(mbx, mby int) (skip bool) {
-	partition := &d.op[mby&(d.nOP-1)]
-	plane := planeY1SansY2
-	quant := &d.quant[d.segment]
-
-	// Parse the DC coefficient of each 4x4 luma region.
-	if d.usePredY16 {
-		nz := d.parseResiduals4(partition, planeY2, d.leftMB.nzY16+d.upMB[mbx].nzY16, quant.y2, false, whtCoeffBase)
-		d.leftMB.nzY16 = nz
-		d.upMB[mbx].nzY16 = nz
-		d.inverseWHT16()
-		plane = planeY1WithY2
-	}
-
-	var (
-		nzDC, nzAC         [4]uint8
-		nzDCMask, nzACMask uint32
-		coeffBase          int
-	)
-
-	// Parse the luma coefficients.
-	lnz := unpack[d.leftMB.nzMask&0x0f]
-	unz := unpack[d.upMB[mbx].nzMask&0x0f]
-	for y := 0; y < 4; y++ {
-		nz := lnz[y]
-		for x := 0; x < 4; x++ {
-			nz = d.parseResiduals4(partition, plane, nz+unz[x], quant.y1, d.usePredY16, coeffBase)
-			unz[x] = nz
-			nzAC[x] = nz
-			nzDC[x] = btou(d.coeff[coeffBase] != 0)
-			coeffBase += 16
-		}
-		lnz[y] = nz
-		nzDCMask |= pack(nzDC, y*4)
-		nzACMask |= pack(nzAC, y*4)
-	}
-	lnzMask := pack(lnz, 0)
-	unzMask := pack(unz, 0)
-
-	// Parse the chroma coefficients.
-	lnz = unpack[d.leftMB.nzMask>>4]
-	unz = unpack[d.upMB[mbx].nzMask>>4]
-	for c := 0; c < 4; c += 2 {
-		for y := 0; y < 2; y++ {
-			nz := lnz[y+c]
-			for x := 0; x < 2; x++ {
-				nz = d.parseResiduals4(partition, planeUV, nz+unz[x+c], quant.uv, false, coeffBase)
-				unz[x+c] = nz
-				nzAC[y*2+x] = nz
-				nzDC[y*2+x] = btou(d.coeff[coeffBase] != 0)
-				coeffBase += 16
-			}
-			lnz[y+c] = nz
-		}
-		nzDCMask |= pack(nzDC, 16+c*2)
-		nzACMask |= pack(nzAC, 16+c*2)
-	}
-	lnzMask |= pack(lnz, 4)
-	unzMask |= pack(unz, 4)
-
-	// Save decoder state.
-	d.leftMB.nzMask = uint8(lnzMask)
-	d.upMB[mbx].nzMask = uint8(unzMask)
-	d.nzDCMask = nzDCMask
-	d.nzACMask = nzACMask
-
-	// Section 15.1 of the spec says that "Steps 2 and 4 [of the loop filter]
-	// are skipped... [if] there is no DCT coefficient coded for the whole
-	// macroblock."
-	return nzDCMask == 0 && nzACMask == 0
-}
-
-// reconstructMacroblock applies the predictor functions and adds the inverse-
-// DCT transformed residuals to recover the YCbCr data.
-func (d *Decoder) reconstructMacroblock(mbx, mby int) {
-	if d.usePredY16 {
-		p := checkTopLeftPred(mbx, mby, d.predY16)
-		predFunc16[p](d, 1, 8)
-		for j := 0; j < 4; j++ {
-			for i := 0; i < 4; i++ {
-				n := 4*j + i
-				y := 4*j + 1
-				x := 4*i + 8
-				mask := uint32(1) << uint(n)
-				if d.nzACMask&mask != 0 {
-					d.inverseDCT4(y, x, 16*n)
-				} else if d.nzDCMask&mask != 0 {
-					d.inverseDCT4DCOnly(y, x, 16*n)
-				}
-			}
-		}
-	} else {
-		for j := 0; j < 4; j++ {
-			for i := 0; i < 4; i++ {
-				n := 4*j + i
-				y := 4*j + 1
-				x := 4*i + 8
-				predFunc4[d.predY4[j][i]](d, y, x)
-				mask := uint32(1) << uint(n)
-				if d.nzACMask&mask != 0 {
-					d.inverseDCT4(y, x, 16*n)
-				} else if d.nzDCMask&mask != 0 {
-					d.inverseDCT4DCOnly(y, x, 16*n)
-				}
-			}
-		}
-	}
-	p := checkTopLeftPred(mbx, mby, d.predC8)
-	predFunc8[p](d, ybrBY, ybrBX)
-	if d.nzACMask&0x0f0000 != 0 {
-		d.inverseDCT8(ybrBY, ybrBX, bCoeffBase)
-	} else if d.nzDCMask&0x0f0000 != 0 {
-		d.inverseDCT8DCOnly(ybrBY, ybrBX, bCoeffBase)
-	}
-	predFunc8[p](d, ybrRY, ybrRX)
-	if d.nzACMask&0xf00000 != 0 {
-		d.inverseDCT8(ybrRY, ybrRX, rCoeffBase)
-	} else if d.nzDCMask&0xf00000 != 0 {
-		d.inverseDCT8DCOnly(ybrRY, ybrRX, rCoeffBase)
-	}
-}
-
-// reconstruct reconstructs one macroblock and returns whether inner loop
-// filtering should be skipped for it.
-func (d *Decoder) reconstruct(mbx, mby int) (skip bool) {
-	if d.segmentHeader.updateMap {
-		if !d.fp.readBit(d.segmentHeader.prob[0]) {
-			d.segment = int(d.fp.readUint(d.segmentHeader.prob[1], 1))
-		} else {
-			d.segment = int(d.fp.readUint(d.segmentHeader.prob[2], 1)) + 2
-		}
-	}
-	if d.useSkipProb {
-		skip = d.fp.readBit(d.skipProb)
-	}
-	// Prepare the workspace.
-	for i := range d.coeff {
-		d.coeff[i] = 0
-	}
-	d.prepareYBR(mbx, mby)
-	// Parse the predictor modes.
-	d.usePredY16 = d.fp.readBit(145)
-	if d.usePredY16 {
-		d.parsePredModeY16(mbx)
-	} else {
-		d.parsePredModeY4(mbx)
-	}
-	d.parsePredModeC8()
-	// Parse the residuals.
-	if !skip {
-		skip = d.parseResiduals(mbx, mby)
-	} else {
-		if d.usePredY16 {
-			d.leftMB.nzY16 = 0
-			d.upMB[mbx].nzY16 = 0
-		}
-		d.leftMB.nzMask = 0
-		d.upMB[mbx].nzMask = 0
-		d.nzDCMask = 0
-		d.nzACMask = 0
-	}
-	// Reconstruct the YCbCr data and copy it to the image.
-	d.reconstructMacroblock(mbx, mby)
-	for i, y := (mby*d.img.YStride+mbx)*16, 0; y < 16; i, y = i+d.img.YStride, y+1 {
-		copy(d.img.Y[i:i+16], d.ybr[ybrYY+y][ybrYX:ybrYX+16])
-	}
-	for i, y := (mby*d.img.CStride+mbx)*8, 0; y < 8; i, y = i+d.img.CStride, y+1 {
-		copy(d.img.Cb[i:i+8], d.ybr[ybrBY+y][ybrBX:ybrBX+8])
-		copy(d.img.Cr[i:i+8], d.ybr[ybrRY+y][ybrRX:ybrRX+8])
-	}
-	return skip
-}
-- 
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