mirror of
https://github.com/unidoc/unipdf.git
synced 2025-04-27 13:48:51 +08:00
96 lines
2.3 KiB
Go
96 lines
2.3 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 strutils provides convenient functions for string processing in unidoc internally.
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package strutils
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import (
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"bytes"
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"unicode/utf16"
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"github.com/unidoc/unipdf/v3/common"
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)
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var pdfdocEncodingRuneMap map[rune]byte
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func init() {
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pdfdocEncodingRuneMap = map[rune]byte{}
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for b, r := range pdfDocEncoding {
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pdfdocEncodingRuneMap[r] = b
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}
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}
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// UTF16ToRunes decodes the UTF-16BE encoded byte slice `b` to unicode runes.
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func UTF16ToRunes(b []byte) []rune {
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if len(b) == 1 {
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return []rune{rune(b[0])}
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}
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if len(b)%2 != 0 {
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b = append(b, 0)
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common.Log.Debug("ERROR: UTF16ToRunes. Padding with zeros.")
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}
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n := len(b) >> 1
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chars := make([]uint16, n)
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for i := 0; i < n; i++ {
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chars[i] = uint16(b[i<<1])<<8 + uint16(b[i<<1+1])
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}
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runes := utf16.Decode(chars)
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return runes
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}
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// UTF16ToString decodes the UTF-16BE encoded byte slice `b` to a unicode go string.
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func UTF16ToString(b []byte) string {
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return string(UTF16ToRunes(b))
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}
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// StringToUTF16 encoded `s` to UTF16 and returns a string containing UTF16 runes.
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func StringToUTF16(s string) string {
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encoded := utf16.Encode([]rune(s))
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var buf bytes.Buffer
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for _, code := range encoded {
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buf.WriteByte(byte((code >> 8) & 0xff))
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buf.WriteByte(byte(code & 0xff))
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}
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return buf.String()
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}
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// PDFDocEncodingToRunes decodes PDFDocEncoded byte slice `b` to unicode runes.
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func PDFDocEncodingToRunes(b []byte) []rune {
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var runes []rune
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for _, bval := range b {
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rune, has := pdfDocEncoding[bval]
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if !has {
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common.Log.Debug("Error: PDFDocEncoding input mapping error %d - skipping", bval)
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continue
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}
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runes = append(runes, rune)
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}
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return runes
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}
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// PDFDocEncodingToString decodes PDFDocEncoded byte slice `b` to unicode go string.
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func PDFDocEncodingToString(b []byte) string {
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return string(PDFDocEncodingToRunes(b))
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}
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// StringToPDFDocEncoding encoded go string `s` to PdfDocEncoding.
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func StringToPDFDocEncoding(s string) []byte {
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var buf bytes.Buffer
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for _, r := range s {
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b, has := pdfdocEncodingRuneMap[r]
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if !has {
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common.Log.Debug("ERROR: PDFDocEncoding rune mapping missing %c/%X - skipping", r, r)
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continue
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}
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buf.WriteByte(b)
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}
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return buf.Bytes()
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}
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