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font/sfnt: rename a "stack" field to "argStack".

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This will lessen the diff in a subsequent commit, which introduces a
call stack.

Change-Id: I478857675f47b53e6bd3ee270087a00b9d1d4d34
Reviewed-on: https://go-review.googlesource.com/38279
Reviewed-by: Nigel Tao <nigeltao@golang.org>
This commit is contained in:
Nigel Tao 2017-03-19 16:22:00 +11:00
parent 88e2d806a0
commit fb59e5ba10
1 changed files with 87 additions and 87 deletions
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174
font/sfnt/postscript.go
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@ -56,11 +56,11 @@ import (
) )
const ( const (
// psStackSize is the stack size for a PostScript interpreter. 5176.CFF.pdf // psArgStackSize is the argument stack size for a PostScript interpreter.
// section 4 "DICT Data" says that "An operator may be preceded by up to a // 5176.CFF.pdf section 4 "DICT Data" says that "An operator may be
// maximum of 48 operands". Similarly, 5177.Type2.pdf Appendix B "Type 2 // preceded by up to a maximum of 48 operands". 5177.Type2.pdf Appendix B
// Charstring Implementation Limits" says that "Argument stack 48". // "Type 2 Charstring Implementation Limits" says that "Argument stack 48".
psStackSize = 48 psArgStackSize = 48
) )
func bigEndian(b []byte) uint32 { func bigEndian(b []byte) uint32 {
@ -288,8 +288,8 @@ func (d *psType2CharstringsData) initialize(segments []Segment) {
type psInterpreter struct { type psInterpreter struct {
ctx psContext ctx psContext
instructions []byte instructions []byte
stack struct { argStack struct {
a [psStackSize]int32 a [psArgStackSize]int32
top int32 top int32
} }
parseNumberBuf [maxRealNumberStrLen]byte parseNumberBuf [maxRealNumberStrLen]byte
@ -300,7 +300,7 @@ type psInterpreter struct {
func (p *psInterpreter) run(ctx psContext, instructions []byte) error { func (p *psInterpreter) run(ctx psContext, instructions []byte) error {
p.ctx = ctx p.ctx = ctx
p.instructions = instructions p.instructions = instructions
p.stack.top = 0 p.argStack.top = 0
loop: loop:
for len(p.instructions) > 0 { for len(p.instructions) > 0 {
@ -330,7 +330,7 @@ loop:
if int(b) < len(ops) { if int(b) < len(ops) {
if op := ops[b]; op.name != "" { if op := ops[b]; op.name != "" {
if p.stack.top < op.numPop { if p.argStack.top < op.numPop {
return errInvalidCFFTable return errInvalidCFFTable
} }
if op.run != nil { if op.run != nil {
@ -339,9 +339,9 @@ loop:
} }
} }
if op.numPop < 0 { if op.numPop < 0 {
p.stack.top = 0 p.argStack.top = 0
} else { } else {
p.stack.top -= op.numPop p.argStack.top -= op.numPop
} }
continue loop continue loop
} }
@ -445,11 +445,11 @@ func (p *psInterpreter) parseNumber() (hasResult bool, err error) {
} }
if hasResult { if hasResult {
if p.stack.top == psStackSize { if p.argStack.top == psArgStackSize {
return true, errInvalidCFFTable return true, errInvalidCFFTable
} }
p.stack.a[p.stack.top] = number p.argStack.a[p.argStack.top] = number
p.stack.top++ p.argStack.top++
} }
return hasResult, nil return hasResult, nil
} }
@ -506,7 +506,7 @@ var psOperators = [...][2][]psOperator{
15: {+1, "charset", nil}, 15: {+1, "charset", nil},
16: {+1, "Encoding", nil}, 16: {+1, "Encoding", nil},
17: {+1, "CharStrings", func(p *psInterpreter) error { 17: {+1, "CharStrings", func(p *psInterpreter) error {
p.topDict.charStrings = p.stack.a[p.stack.top-1] p.topDict.charStrings = p.argStack.a[p.argStack.top-1]
return nil return nil
}}, }},
18: {+2, "Private", nil}, 18: {+2, "Private", nil},
@ -597,42 +597,42 @@ func t2CReadWidth(p *psInterpreter, nArgs int32) {
p.type2Charstrings.seenWidth = true p.type2Charstrings.seenWidth = true
switch nArgs { switch nArgs {
case 0: case 0:
if p.stack.top != 1 { if p.argStack.top != 1 {
return return
} }
case 1: case 1:
if p.stack.top <= 1 { if p.argStack.top <= 1 {
return return
} }
default: default:
if p.stack.top%nArgs != 1 { if p.argStack.top%nArgs != 1 {
return return
} }
} }
// When parsing a standalone CFF, we'd save the value of p.stack.a[0] here // When parsing a standalone CFF, we'd save the value of p.argStack.a[0]
// as it defines the glyph's width (horizontal advance). Specifically, if // here as it defines the glyph's width (horizontal advance). Specifically,
// present, it is a delta to the font-global nominalWidthX value found in // if present, it is a delta to the font-global nominalWidthX value found
// the Private DICT. If absent, the glyph's width is the defaultWidthX // in the Private DICT. If absent, the glyph's width is the defaultWidthX
// value in that dict. See 5176.CFF.pdf section 15 "Private DICT Data". // value in that dict. See 5176.CFF.pdf section 15 "Private DICT Data".
// //
// For a CFF embedded in an SFNT font (i.e. an OpenType font), glyph widths // For a CFF embedded in an SFNT font (i.e. an OpenType font), glyph widths
// are already stored in the hmtx table, separate to the CFF table, and it // are already stored in the hmtx table, separate to the CFF table, and it
// is simpler to parse that table for all OpenType fonts (PostScript and // is simpler to parse that table for all OpenType fonts (PostScript and
// TrueType). We therefore ignore the width value here, and just remove it // TrueType). We therefore ignore the width value here, and just remove it
// from the bottom of the stack. // from the bottom of the argStack.
copy(p.stack.a[:p.stack.top-1], p.stack.a[1:p.stack.top]) copy(p.argStack.a[:p.argStack.top-1], p.argStack.a[1:p.argStack.top])
p.stack.top-- p.argStack.top--
} }
func t2CStem(p *psInterpreter) error { func t2CStem(p *psInterpreter) error {
t2CReadWidth(p, 2) t2CReadWidth(p, 2)
if p.stack.top%2 != 0 { if p.argStack.top%2 != 0 {
return errInvalidCFFTable return errInvalidCFFTable
} }
// We update the number of hintBits need to parse hintmask and cntrmask // We update the number of hintBits need to parse hintmask and cntrmask
// instructions, but this Type 2 Charstring implementation otherwise // instructions, but this Type 2 Charstring implementation otherwise
// ignores the stem hints. // ignores the stem hints.
p.type2Charstrings.hintBits += p.stack.top / 2 p.type2Charstrings.hintBits += p.argStack.top / 2
if p.type2Charstrings.hintBits > maxHintBits { if p.type2Charstrings.hintBits > maxHintBits {
return errUnsupportedNumberOfHints return errUnsupportedNumberOfHints
} }
@ -697,11 +697,11 @@ func t2CAppendCubeto(p *psInterpreter, dxa, dya, dxb, dyb, dxc, dyc int32) {
func t2CHmoveto(p *psInterpreter) error { func t2CHmoveto(p *psInterpreter) error {
t2CReadWidth(p, 1) t2CReadWidth(p, 1)
if p.stack.top < 1 { if p.argStack.top < 1 {
return errInvalidCFFTable return errInvalidCFFTable
} }
for i := int32(0); i < p.stack.top; i++ { for i := int32(0); i < p.argStack.top; i++ {
p.type2Charstrings.x += p.stack.a[i] p.type2Charstrings.x += p.argStack.a[i]
} }
t2CAppendMoveto(p) t2CAppendMoveto(p)
return nil return nil
@ -709,11 +709,11 @@ func t2CHmoveto(p *psInterpreter) error {
func t2CVmoveto(p *psInterpreter) error { func t2CVmoveto(p *psInterpreter) error {
t2CReadWidth(p, 1) t2CReadWidth(p, 1)
if p.stack.top < 1 { if p.argStack.top < 1 {
return errInvalidCFFTable return errInvalidCFFTable
} }
for i := int32(0); i < p.stack.top; i++ { for i := int32(0); i < p.argStack.top; i++ {
p.type2Charstrings.y += p.stack.a[i] p.type2Charstrings.y += p.argStack.a[i]
} }
t2CAppendMoveto(p) t2CAppendMoveto(p)
return nil return nil
@ -721,12 +721,12 @@ func t2CVmoveto(p *psInterpreter) error {
func t2CRmoveto(p *psInterpreter) error { func t2CRmoveto(p *psInterpreter) error {
t2CReadWidth(p, 2) t2CReadWidth(p, 2)
if p.stack.top < 2 || p.stack.top%2 != 0 { if p.argStack.top < 2 || p.argStack.top%2 != 0 {
return errInvalidCFFTable return errInvalidCFFTable
} }
for i := int32(0); i < p.stack.top; i += 2 { for i := int32(0); i < p.argStack.top; i += 2 {
p.type2Charstrings.x += p.stack.a[i+0] p.type2Charstrings.x += p.argStack.a[i+0]
p.type2Charstrings.y += p.stack.a[i+1] p.type2Charstrings.y += p.argStack.a[i+1]
} }
t2CAppendMoveto(p) t2CAppendMoveto(p)
return nil return nil
@ -736,14 +736,14 @@ func t2CHlineto(p *psInterpreter) error { return t2CLineto(p, false) }
func t2CVlineto(p *psInterpreter) error { return t2CLineto(p, true) } func t2CVlineto(p *psInterpreter) error { return t2CLineto(p, true) }
func t2CLineto(p *psInterpreter, vertical bool) error { func t2CLineto(p *psInterpreter, vertical bool) error {
if !p.type2Charstrings.seenWidth || p.stack.top < 1 { if !p.type2Charstrings.seenWidth || p.argStack.top < 1 {
return errInvalidCFFTable return errInvalidCFFTable
} }
for i := int32(0); i < p.stack.top; i, vertical = i+1, !vertical { for i := int32(0); i < p.argStack.top; i, vertical = i+1, !vertical {
if vertical { if vertical {
p.type2Charstrings.y += p.stack.a[i] p.type2Charstrings.y += p.argStack.a[i]
} else { } else {
p.type2Charstrings.x += p.stack.a[i] p.type2Charstrings.x += p.argStack.a[i]
} }
t2CAppendLineto(p) t2CAppendLineto(p)
} }
@ -751,12 +751,12 @@ func t2CLineto(p *psInterpreter, vertical bool) error {
} }
func t2CRlineto(p *psInterpreter) error { func t2CRlineto(p *psInterpreter) error {
if !p.type2Charstrings.seenWidth || p.stack.top < 2 || p.stack.top%2 != 0 { if !p.type2Charstrings.seenWidth || p.argStack.top < 2 || p.argStack.top%2 != 0 {
return errInvalidCFFTable return errInvalidCFFTable
} }
for i := int32(0); i < p.stack.top; i += 2 { for i := int32(0); i < p.argStack.top; i += 2 {
p.type2Charstrings.x += p.stack.a[i+0] p.type2Charstrings.x += p.argStack.a[i+0]
p.type2Charstrings.y += p.stack.a[i+1] p.type2Charstrings.y += p.argStack.a[i+1]
t2CAppendLineto(p) t2CAppendLineto(p)
} }
return nil return nil
@ -771,43 +771,43 @@ func t2CRlineto(p *psInterpreter) error {
// - {dxa dya}+ dxb dyb dxc dyc dxd dyd // - {dxa dya}+ dxb dyb dxc dyc dxd dyd
func t2CRcurveline(p *psInterpreter) error { func t2CRcurveline(p *psInterpreter) error {
if !p.type2Charstrings.seenWidth || p.stack.top < 8 || p.stack.top%6 != 2 { if !p.type2Charstrings.seenWidth || p.argStack.top < 8 || p.argStack.top%6 != 2 {
return errInvalidCFFTable return errInvalidCFFTable
} }
i := int32(0) i := int32(0)
for iMax := p.stack.top - 2; i < iMax; i += 6 { for iMax := p.argStack.top - 2; i < iMax; i += 6 {
t2CAppendCubeto(p, t2CAppendCubeto(p,
p.stack.a[i+0], p.argStack.a[i+0],
p.stack.a[i+1], p.argStack.a[i+1],
p.stack.a[i+2], p.argStack.a[i+2],
p.stack.a[i+3], p.argStack.a[i+3],
p.stack.a[i+4], p.argStack.a[i+4],
p.stack.a[i+5], p.argStack.a[i+5],
) )
} }
p.type2Charstrings.x += p.stack.a[i+0] p.type2Charstrings.x += p.argStack.a[i+0]
p.type2Charstrings.y += p.stack.a[i+1] p.type2Charstrings.y += p.argStack.a[i+1]
t2CAppendLineto(p) t2CAppendLineto(p)
return nil return nil
} }
func t2CRlinecurve(p *psInterpreter) error { func t2CRlinecurve(p *psInterpreter) error {
if !p.type2Charstrings.seenWidth || p.stack.top < 8 || p.stack.top%2 != 0 { if !p.type2Charstrings.seenWidth || p.argStack.top < 8 || p.argStack.top%2 != 0 {
return errInvalidCFFTable return errInvalidCFFTable
} }
i := int32(0) i := int32(0)
for iMax := p.stack.top - 6; i < iMax; i += 2 { for iMax := p.argStack.top - 6; i < iMax; i += 2 {
p.type2Charstrings.x += p.stack.a[i+0] p.type2Charstrings.x += p.argStack.a[i+0]
p.type2Charstrings.y += p.stack.a[i+1] p.type2Charstrings.y += p.argStack.a[i+1]
t2CAppendLineto(p) t2CAppendLineto(p)
} }
t2CAppendCubeto(p, t2CAppendCubeto(p,
p.stack.a[i+0], p.argStack.a[i+0],
p.stack.a[i+1], p.argStack.a[i+1],
p.stack.a[i+2], p.argStack.a[i+2],
p.stack.a[i+3], p.argStack.a[i+3],
p.stack.a[i+4], p.argStack.a[i+4],
p.stack.a[i+5], p.argStack.a[i+5],
) )
return nil return nil
} }
@ -844,12 +844,12 @@ func t2CVhcurveto(p *psInterpreter) error { return t2CCurveto(p, true, true) }
// //
// vertical is whether the first implicit constraint is vertical. // vertical is whether the first implicit constraint is vertical.
func t2CCurveto(p *psInterpreter, swap, vertical bool) error { func t2CCurveto(p *psInterpreter, swap, vertical bool) error {
if !p.type2Charstrings.seenWidth || p.stack.top < 4 { if !p.type2Charstrings.seenWidth || p.argStack.top < 4 {
return errInvalidCFFTable return errInvalidCFFTable
} }
i := int32(0) i := int32(0)
switch p.stack.top & 3 { switch p.argStack.top & 3 {
case 0: case 0:
// No-op. // No-op.
case 1: case 1:
@ -858,15 +858,15 @@ func t2CCurveto(p *psInterpreter, swap, vertical bool) error {
} }
i = 1 i = 1
if vertical { if vertical {
p.type2Charstrings.x += p.stack.a[0] p.type2Charstrings.x += p.argStack.a[0]
} else { } else {
p.type2Charstrings.y += p.stack.a[0] p.type2Charstrings.y += p.argStack.a[0]
} }
default: default:
return errInvalidCFFTable return errInvalidCFFTable
} }
for i != p.stack.top { for i != p.argStack.top {
i = t2CCurveto4(p, swap, vertical, i) i = t2CCurveto4(p, swap, vertical, i)
if i < 0 { if i < 0 {
return errInvalidCFFTable return errInvalidCFFTable
@ -879,14 +879,14 @@ func t2CCurveto(p *psInterpreter, swap, vertical bool) error {
} }
func t2CCurveto4(p *psInterpreter, swap bool, vertical bool, i int32) (j int32) { func t2CCurveto4(p *psInterpreter, swap bool, vertical bool, i int32) (j int32) {
if i+4 > p.stack.top { if i+4 > p.argStack.top {
return -1 return -1
} }
dxa := p.stack.a[i+0] dxa := p.argStack.a[i+0]
dya := int32(0) dya := int32(0)
dxb := p.stack.a[i+1] dxb := p.argStack.a[i+1]
dyb := p.stack.a[i+2] dyb := p.argStack.a[i+2]
dxc := p.stack.a[i+3] dxc := p.argStack.a[i+3]
dyc := int32(0) dyc := int32(0)
i += 4 i += 4
@ -895,8 +895,8 @@ func t2CCurveto4(p *psInterpreter, swap bool, vertical bool, i int32) (j int32)
} }
if swap { if swap {
if i+1 == p.stack.top { if i+1 == p.argStack.top {
dyc = p.stack.a[i] dyc = p.argStack.a[i]
i++ i++
} }
} }
@ -910,17 +910,17 @@ func t2CCurveto4(p *psInterpreter, swap bool, vertical bool, i int32) (j int32)
} }
func t2CRrcurveto(p *psInterpreter) error { func t2CRrcurveto(p *psInterpreter) error {
if !p.type2Charstrings.seenWidth || p.stack.top < 6 || p.stack.top%6 != 0 { if !p.type2Charstrings.seenWidth || p.argStack.top < 6 || p.argStack.top%6 != 0 {
return errInvalidCFFTable return errInvalidCFFTable
} }
for i := int32(0); i != p.stack.top; i += 6 { for i := int32(0); i != p.argStack.top; i += 6 {
t2CAppendCubeto(p, t2CAppendCubeto(p,
p.stack.a[i+0], p.argStack.a[i+0],
p.stack.a[i+1], p.argStack.a[i+1],
p.stack.a[i+2], p.argStack.a[i+2],
p.stack.a[i+3], p.argStack.a[i+3],
p.stack.a[i+4], p.argStack.a[i+4],
p.stack.a[i+5], p.argStack.a[i+5],
) )
} }
return nil return nil
@ -928,8 +928,8 @@ func t2CRrcurveto(p *psInterpreter) error {
func t2CEndchar(p *psInterpreter) error { func t2CEndchar(p *psInterpreter) error {
t2CReadWidth(p, 0) t2CReadWidth(p, 0)
if p.stack.top != 0 || len(p.instructions) != 0 { if p.argStack.top != 0 || len(p.instructions) != 0 {
if p.stack.top == 4 { if p.argStack.top == 4 {
// TODO: process the implicit "seac" command as per 5177.Type2.pdf // TODO: process the implicit "seac" command as per 5177.Type2.pdf
// Appendix C "Compatibility and Deprecated Operators". // Appendix C "Compatibility and Deprecated Operators".
return errUnsupportedType2Charstring return errUnsupportedType2Charstring