font/sfnt: rename a "stack" field to "argStack".
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>
diff --git a/font/sfnt/postscript.go b/font/sfnt/postscript.go
index c92ea4a..19186be 100644
--- a/font/sfnt/postscript.go
+++ b/font/sfnt/postscript.go
@@ -56,11 +56,11 @@
)
const (
- // psStackSize is the stack size for a PostScript interpreter. 5176.CFF.pdf
- // section 4 "DICT Data" says that "An operator may be preceded by up to a
- // maximum of 48 operands". Similarly, 5177.Type2.pdf Appendix B "Type 2
- // Charstring Implementation Limits" says that "Argument stack 48".
- psStackSize = 48
+ // psArgStackSize is the argument stack size for a PostScript interpreter.
+ // 5176.CFF.pdf section 4 "DICT Data" says that "An operator may be
+ // preceded by up to a maximum of 48 operands". 5177.Type2.pdf Appendix B
+ // "Type 2 Charstring Implementation Limits" says that "Argument stack 48".
+ psArgStackSize = 48
)
func bigEndian(b []byte) uint32 {
@@ -288,8 +288,8 @@
type psInterpreter struct {
ctx psContext
instructions []byte
- stack struct {
- a [psStackSize]int32
+ argStack struct {
+ a [psArgStackSize]int32
top int32
}
parseNumberBuf [maxRealNumberStrLen]byte
@@ -300,7 +300,7 @@
func (p *psInterpreter) run(ctx psContext, instructions []byte) error {
p.ctx = ctx
p.instructions = instructions
- p.stack.top = 0
+ p.argStack.top = 0
loop:
for len(p.instructions) > 0 {
@@ -330,7 +330,7 @@
if int(b) < len(ops) {
if op := ops[b]; op.name != "" {
- if p.stack.top < op.numPop {
+ if p.argStack.top < op.numPop {
return errInvalidCFFTable
}
if op.run != nil {
@@ -339,9 +339,9 @@
}
}
if op.numPop < 0 {
- p.stack.top = 0
+ p.argStack.top = 0
} else {
- p.stack.top -= op.numPop
+ p.argStack.top -= op.numPop
}
continue loop
}
@@ -445,11 +445,11 @@
}
if hasResult {
- if p.stack.top == psStackSize {
+ if p.argStack.top == psArgStackSize {
return true, errInvalidCFFTable
}
- p.stack.a[p.stack.top] = number
- p.stack.top++
+ p.argStack.a[p.argStack.top] = number
+ p.argStack.top++
}
return hasResult, nil
}
@@ -506,7 +506,7 @@
15: {+1, "charset", nil},
16: {+1, "Encoding", nil},
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
}},
18: {+2, "Private", nil},
@@ -597,42 +597,42 @@
p.type2Charstrings.seenWidth = true
switch nArgs {
case 0:
- if p.stack.top != 1 {
+ if p.argStack.top != 1 {
return
}
case 1:
- if p.stack.top <= 1 {
+ if p.argStack.top <= 1 {
return
}
default:
- if p.stack.top%nArgs != 1 {
+ if p.argStack.top%nArgs != 1 {
return
}
}
- // When parsing a standalone CFF, we'd save the value of p.stack.a[0] here
- // as it defines the glyph's width (horizontal advance). Specifically, if
- // present, it is a delta to the font-global nominalWidthX value found in
- // the Private DICT. If absent, the glyph's width is the defaultWidthX
+ // When parsing a standalone CFF, we'd save the value of p.argStack.a[0]
+ // here as it defines the glyph's width (horizontal advance). Specifically,
+ // if present, it is a delta to the font-global nominalWidthX value found
+ // 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".
//
// 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
// is simpler to parse that table for all OpenType fonts (PostScript and
// TrueType). We therefore ignore the width value here, and just remove it
- // from the bottom of the stack.
- copy(p.stack.a[:p.stack.top-1], p.stack.a[1:p.stack.top])
- p.stack.top--
+ // from the bottom of the argStack.
+ copy(p.argStack.a[:p.argStack.top-1], p.argStack.a[1:p.argStack.top])
+ p.argStack.top--
}
func t2CStem(p *psInterpreter) error {
t2CReadWidth(p, 2)
- if p.stack.top%2 != 0 {
+ if p.argStack.top%2 != 0 {
return errInvalidCFFTable
}
// We update the number of hintBits need to parse hintmask and cntrmask
// instructions, but this Type 2 Charstring implementation otherwise
// ignores the stem hints.
- p.type2Charstrings.hintBits += p.stack.top / 2
+ p.type2Charstrings.hintBits += p.argStack.top / 2
if p.type2Charstrings.hintBits > maxHintBits {
return errUnsupportedNumberOfHints
}
@@ -697,11 +697,11 @@
func t2CHmoveto(p *psInterpreter) error {
t2CReadWidth(p, 1)
- if p.stack.top < 1 {
+ if p.argStack.top < 1 {
return errInvalidCFFTable
}
- for i := int32(0); i < p.stack.top; i++ {
- p.type2Charstrings.x += p.stack.a[i]
+ for i := int32(0); i < p.argStack.top; i++ {
+ p.type2Charstrings.x += p.argStack.a[i]
}
t2CAppendMoveto(p)
return nil
@@ -709,11 +709,11 @@
func t2CVmoveto(p *psInterpreter) error {
t2CReadWidth(p, 1)
- if p.stack.top < 1 {
+ if p.argStack.top < 1 {
return errInvalidCFFTable
}
- for i := int32(0); i < p.stack.top; i++ {
- p.type2Charstrings.y += p.stack.a[i]
+ for i := int32(0); i < p.argStack.top; i++ {
+ p.type2Charstrings.y += p.argStack.a[i]
}
t2CAppendMoveto(p)
return nil
@@ -721,12 +721,12 @@
func t2CRmoveto(p *psInterpreter) error {
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
}
- for i := int32(0); i < p.stack.top; i += 2 {
- p.type2Charstrings.x += p.stack.a[i+0]
- p.type2Charstrings.y += p.stack.a[i+1]
+ for i := int32(0); i < p.argStack.top; i += 2 {
+ p.type2Charstrings.x += p.argStack.a[i+0]
+ p.type2Charstrings.y += p.argStack.a[i+1]
}
t2CAppendMoveto(p)
return nil
@@ -736,14 +736,14 @@
func t2CVlineto(p *psInterpreter) error { return t2CLineto(p, true) }
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
}
- 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 {
- p.type2Charstrings.y += p.stack.a[i]
+ p.type2Charstrings.y += p.argStack.a[i]
} else {
- p.type2Charstrings.x += p.stack.a[i]
+ p.type2Charstrings.x += p.argStack.a[i]
}
t2CAppendLineto(p)
}
@@ -751,12 +751,12 @@
}
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
}
- for i := int32(0); i < p.stack.top; i += 2 {
- p.type2Charstrings.x += p.stack.a[i+0]
- p.type2Charstrings.y += p.stack.a[i+1]
+ for i := int32(0); i < p.argStack.top; i += 2 {
+ p.type2Charstrings.x += p.argStack.a[i+0]
+ p.type2Charstrings.y += p.argStack.a[i+1]
t2CAppendLineto(p)
}
return nil
@@ -771,43 +771,43 @@
// - {dxa dya}+ dxb dyb dxc dyc dxd dyd
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
}
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,
- p.stack.a[i+0],
- p.stack.a[i+1],
- p.stack.a[i+2],
- p.stack.a[i+3],
- p.stack.a[i+4],
- p.stack.a[i+5],
+ p.argStack.a[i+0],
+ p.argStack.a[i+1],
+ p.argStack.a[i+2],
+ p.argStack.a[i+3],
+ p.argStack.a[i+4],
+ p.argStack.a[i+5],
)
}
- p.type2Charstrings.x += p.stack.a[i+0]
- p.type2Charstrings.y += p.stack.a[i+1]
+ p.type2Charstrings.x += p.argStack.a[i+0]
+ p.type2Charstrings.y += p.argStack.a[i+1]
t2CAppendLineto(p)
return nil
}
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
}
i := int32(0)
- for iMax := p.stack.top - 6; i < iMax; i += 2 {
- p.type2Charstrings.x += p.stack.a[i+0]
- p.type2Charstrings.y += p.stack.a[i+1]
+ for iMax := p.argStack.top - 6; i < iMax; i += 2 {
+ p.type2Charstrings.x += p.argStack.a[i+0]
+ p.type2Charstrings.y += p.argStack.a[i+1]
t2CAppendLineto(p)
}
t2CAppendCubeto(p,
- p.stack.a[i+0],
- p.stack.a[i+1],
- p.stack.a[i+2],
- p.stack.a[i+3],
- p.stack.a[i+4],
- p.stack.a[i+5],
+ p.argStack.a[i+0],
+ p.argStack.a[i+1],
+ p.argStack.a[i+2],
+ p.argStack.a[i+3],
+ p.argStack.a[i+4],
+ p.argStack.a[i+5],
)
return nil
}
@@ -844,12 +844,12 @@
//
// vertical is whether the first implicit constraint is vertical.
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
}
i := int32(0)
- switch p.stack.top & 3 {
+ switch p.argStack.top & 3 {
case 0:
// No-op.
case 1:
@@ -858,15 +858,15 @@
}
i = 1
if vertical {
- p.type2Charstrings.x += p.stack.a[0]
+ p.type2Charstrings.x += p.argStack.a[0]
} else {
- p.type2Charstrings.y += p.stack.a[0]
+ p.type2Charstrings.y += p.argStack.a[0]
}
default:
return errInvalidCFFTable
}
- for i != p.stack.top {
+ for i != p.argStack.top {
i = t2CCurveto4(p, swap, vertical, i)
if i < 0 {
return errInvalidCFFTable
@@ -879,14 +879,14 @@
}
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
}
- dxa := p.stack.a[i+0]
+ dxa := p.argStack.a[i+0]
dya := int32(0)
- dxb := p.stack.a[i+1]
- dyb := p.stack.a[i+2]
- dxc := p.stack.a[i+3]
+ dxb := p.argStack.a[i+1]
+ dyb := p.argStack.a[i+2]
+ dxc := p.argStack.a[i+3]
dyc := int32(0)
i += 4
@@ -895,8 +895,8 @@
}
if swap {
- if i+1 == p.stack.top {
- dyc = p.stack.a[i]
+ if i+1 == p.argStack.top {
+ dyc = p.argStack.a[i]
i++
}
}
@@ -910,17 +910,17 @@
}
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
}
- for i := int32(0); i != p.stack.top; i += 6 {
+ for i := int32(0); i != p.argStack.top; i += 6 {
t2CAppendCubeto(p,
- p.stack.a[i+0],
- p.stack.a[i+1],
- p.stack.a[i+2],
- p.stack.a[i+3],
- p.stack.a[i+4],
- p.stack.a[i+5],
+ p.argStack.a[i+0],
+ p.argStack.a[i+1],
+ p.argStack.a[i+2],
+ p.argStack.a[i+3],
+ p.argStack.a[i+4],
+ p.argStack.a[i+5],
)
}
return nil
@@ -928,8 +928,8 @@
func t2CEndchar(p *psInterpreter) error {
t2CReadWidth(p, 0)
- if p.stack.top != 0 || len(p.instructions) != 0 {
- if p.stack.top == 4 {
+ if p.argStack.top != 0 || len(p.instructions) != 0 {
+ if p.argStack.top == 4 {
// TODO: process the implicit "seac" command as per 5177.Type2.pdf
// Appendix C "Compatibility and Deprecated Operators".
return errUnsupportedType2Charstring
