write_pdfdocenc.go

package model

import (
	"bytes"
	"strings"
)

var reversed = map[rune]byte{}

func init() {
	for b, r := range PDFDocEncoding {
		reversed[r] = byte(b)
	}
}

// PdfDocEncodingToString decodes a PDFDocEncoded byte slice `b` to a UTF-8 string.
func PdfDocEncodingToString(b []byte) string {
	var buf strings.Builder
	for _, bval := range b {
		r := PDFDocEncoding[bval]
		if r == 0 {
			continue
		}
		buf.WriteRune(r)
	}
	return buf.String()
}

// stringToPDFDocEncoding encode go string `s` to PdfDocEncoding,
// and return true only if all the runes have been encoded
func stringToPDFDocEncoding(s string) ([]byte, bool) {
	var buf bytes.Buffer
	ok := true
	for _, r := range s {
		b := reversed[r]
		if b == 0 {
			ok = false
			continue
		}
		buf.WriteByte(b)
	}

	return buf.Bytes(), ok
}

// PDFDocEncoding maps the PDFDocEncoding bytes (used to represent text values such as document
// metadata or annotation text) to Unicode codepoints. Not all 8-bit values in
// PDFDocEncoding are defined; undefined bytes are mapped to 0
var PDFDocEncoding = [256]rune{
	0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, // 00
	0x0008, 0x0009, 0x000a, 0x000b, 0x000c, 0x000d, 0x000e, 0x000f, 0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017, // 10
	0x02d8, 0x02c7, 0x02c6, 0x02d9, 0x02dd, 0x02db, 0x02da, 0x02dc, 0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027, // 20
	0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x002f, 0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, // 30
	0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x003e, 0x003f, 0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, // 40
	0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f, 0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, // 50
	0x0058, 0x0059, 0x005a, 0x005b, 0x005c, 0x005d, 0x005e, 0x005f, 0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067, // 60
	0x0068, 0x0069, 0x006a, 0x006b, 0x006c, 0x006d, 0x006e, 0x006f, 0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, // 70
	0x0078, 0x0079, 0x007a, 0x007b, 0x007c, 0x007d, 0x007e, 0, 0x2022, 0x2020, 0x2021, 0x2026, 0x2014, 0x2013, 0x0192, 0x2044, // 80
	0x2039, 0x203a, 0x2212, 0x2030, 0x201e, 0x201c, 0x201d, 0x2018, 0x2019, 0x201a, 0x2122, 0xfb01, 0xfb02, 0x0141, 0x0152, 0x0160, // 90
	0x0178, 0x017d, 0x0131, 0x0142, 0x0153, 0x0161, 0x017e, 0, 0x20ac, 0x00a1, 0x00a2, 0x00a3, 0x00a4, 0x00a5, 0x00a6, 0x00a7, // a0
	0x00a8, 0x00a9, 0x00aa, 0x00ab, 0x00ac, 0, 0x00ae, 0x00af, 0x00b0, 0x00b1, 0x00b2, 0x00b3, 0x00b4, 0x00b5, 0x00b6, 0x00b7, // b0
	0x00b8, 0x00b9, 0x00ba, 0x00bb, 0x00bc, 0x00bd, 0x00be, 0x00bf, 0x00c0, 0x00c1, 0x00c2, 0x00c3, 0x00c4, 0x00c5, 0x00c6, 0x00c7, // c0
	0x00c8, 0x00c9, 0x00ca, 0x00cb, 0x00cc, 0x00cd, 0x00ce, 0x00cf, 0x00d0, 0x00d1, 0x00d2, 0x00d3, 0x00d4, 0x00d5, 0x00d6, 0x00d7, // d0
	0x00d8, 0x00d9, 0x00da, 0x00db, 0x00dc, 0x00dd, 0x00de, 0x00df, 0x00e0, 0x00e1, 0x00e2, 0x00e3, 0x00e4, 0x00e5, 0x00e6, 0x00e7, // e0
	0x00e8, 0x00e9, 0x00ea, 0x00eb, 0x00ec, 0x00ed, 0x00ee, 0x00ef, 0x00f0, 0x00f1, 0x00f2, 0x00f3, 0x00f4, 0x00f5, 0x00f6, 0x00f7, // f0
	0x00f8, 0x00f9, 0x00fa, 0x00fb, 0x00fc, 0x00fd, 0x00fe, 0x00ff,
}