mirror of
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105 lines
3.1 KiB
Go
105 lines
3.1 KiB
Go
/*
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* This file is subject to the terms and conditions defined in
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* file 'LICENSE.md', which is part of this source code package.
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*/
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package textencoding
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import (
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"fmt"
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"strconv"
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"strings"
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"github.com/unidoc/unidoc/pdf/core"
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)
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// IdentityEncoder represents an 2-byte identity encoding
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type IdentityEncoder struct {
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baseName string
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}
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// NewIdentityTextEncoder returns a new IdentityEncoder based on predefined
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// encoding `baseName` and difference map `differences`.
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func NewIdentityTextEncoder(baseName string) IdentityEncoder {
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return IdentityEncoder{baseName}
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}
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// String returns a string that describes `enc`.
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func (enc IdentityEncoder) String() string {
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return enc.baseName
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}
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// Encode converts the Go unicode string `raw` to a PDF encoded string.
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func (enc IdentityEncoder) Encode(raw string) []byte {
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return encodeString16bit(enc, raw)
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}
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// CharcodeToGlyph returns the glyph name matching character code `code`.
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// The bool return flag is true if there was a match, and false otherwise.
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func (enc IdentityEncoder) CharcodeToGlyph(code CharCode) (GlyphName, bool) {
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r, found := enc.CharcodeToRune(code)
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if found && r == 0x20 {
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return "space", true
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}
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// Returns "uniXXXX" format where XXXX is the code in hex format.
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glyph := GlyphName(fmt.Sprintf("uni%.4X", code))
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return glyph, true
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}
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// GlyphToCharcode returns the character code matching glyph `glyph`.
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// The bool return flag is true if there was a match, and false otherwise.
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func (enc IdentityEncoder) GlyphToCharcode(glyph GlyphName) (CharCode, bool) {
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r, ok := enc.GlyphToRune(glyph)
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if !ok {
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return 0, false
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}
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return enc.RuneToCharcode(r)
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}
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// RuneToCharcode converts rune `r` to a PDF character code.
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// The bool return flag is true if there was a match, and false otherwise.
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func (enc IdentityEncoder) RuneToCharcode(r rune) (CharCode, bool) {
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return CharCode(r), true
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}
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// CharcodeToRune converts PDF character code `code` to a rune.
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// The bool return flag is true if there was a match, and false otherwise.
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func (enc IdentityEncoder) CharcodeToRune(code CharCode) (rune, bool) {
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return rune(code), true
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}
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// RuneToGlyph returns the glyph name for rune `r`.
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// The bool return flag is true if there was a match, and false otherwise.
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func (enc IdentityEncoder) RuneToGlyph(r rune) (GlyphName, bool) {
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if r == ' ' {
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return "space", true
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}
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glyph := GlyphName(fmt.Sprintf("uni%.4X", r))
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return glyph, true
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}
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// GlyphToRune returns the rune corresponding to glyph name `glyph`.
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// The bool return flag is true if there was a match, and false otherwise.
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func (enc IdentityEncoder) GlyphToRune(glyph GlyphName) (rune, bool) {
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// String with "uniXXXX" format where XXXX is the hexcode.
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if glyph == "space" {
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return ' ', true
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} else if !strings.HasPrefix(string(glyph), "uni") || len(glyph) != 7 {
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return 0, false
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}
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r, err := strconv.ParseUint(string(glyph[3:]), 16, 16)
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if err != nil {
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return 0, false
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}
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return rune(r), true
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}
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// ToPdfObject returns a nil as it is not truly a PDF object and should not be attempted to store in file.
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func (enc IdentityEncoder) ToPdfObject() core.PdfObject {
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if enc.baseName != "" {
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return core.MakeName(enc.baseName)
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}
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return core.MakeNull()
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}
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