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