wallet-core/packages/web-util/src/utils/base64.ts
2023-02-08 17:36:26 -03:00

244 lines
7.1 KiB
TypeScript

/*
This file is part of GNU Taler
(C) 2021-2023 Taler Systems S.A.
GNU Taler is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
export function base64encode(str: string): string {
return base64EncArr(strToUTF8Arr(str))
}
export function base64decode(str: string): string {
return UTF8ArrToStr(base64DecToArr(str))
}
// from https://developer.mozilla.org/en-US/docs/Glossary/Base64
// Array of bytes to Base64 string decoding
function b64ToUint6(nChr: number): number {
return nChr > 64 && nChr < 91
? nChr - 65
: nChr > 96 && nChr < 123
? nChr - 71
: nChr > 47 && nChr < 58
? nChr + 4
: nChr === 43
? 62
: nChr === 47
? 63
: 0;
}
function base64DecToArr(sBase64: string, nBlocksSize?: number): Uint8Array {
const sB64Enc = sBase64.replace(/[^A-Za-z0-9+/]/g, ""); // Only necessary if the base64 includes whitespace such as line breaks.
const nInLen = sB64Enc.length;
const nOutLen = nBlocksSize
? Math.ceil(((nInLen * 3 + 1) >> 2) / nBlocksSize) * nBlocksSize
: (nInLen * 3 + 1) >> 2;
const taBytes = new Uint8Array(nOutLen);
let nMod3;
let nMod4;
let nUint24 = 0;
let nOutIdx = 0;
for (let nInIdx = 0; nInIdx < nInLen; nInIdx++) {
nMod4 = nInIdx & 3;
nUint24 |= b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << (6 * (3 - nMod4));
if (nMod4 === 3 || nInLen - nInIdx === 1) {
nMod3 = 0;
while (nMod3 < 3 && nOutIdx < nOutLen) {
taBytes[nOutIdx] = (nUint24 >>> ((16 >>> nMod3) & 24)) & 255;
nMod3++;
nOutIdx++;
}
nUint24 = 0;
}
}
return taBytes;
}
/* Base64 string to array encoding */
function uint6ToB64(nUint6: number): number {
return nUint6 < 26
? nUint6 + 65
: nUint6 < 52
? nUint6 + 71
: nUint6 < 62
? nUint6 - 4
: nUint6 === 62
? 43
: nUint6 === 63
? 47
: 65;
}
function base64EncArr(aBytes: Uint8Array): string {
let nMod3 = 2;
let sB64Enc = "";
const nLen = aBytes.length;
let nUint24 = 0;
for (let nIdx = 0; nIdx < nLen; nIdx++) {
nMod3 = nIdx % 3;
// To break your base64 into several 80-character lines, add:
// if (nIdx > 0 && ((nIdx * 4) / 3) % 76 === 0) {
// sB64Enc += "\r\n";
// }
nUint24 |= aBytes[nIdx] << ((16 >>> nMod3) & 24);
if (nMod3 === 2 || aBytes.length - nIdx === 1) {
sB64Enc += String.fromCodePoint(
uint6ToB64((nUint24 >>> 18) & 63),
uint6ToB64((nUint24 >>> 12) & 63),
uint6ToB64((nUint24 >>> 6) & 63),
uint6ToB64(nUint24 & 63)
);
nUint24 = 0;
}
}
return (
sB64Enc.substring(0, sB64Enc.length - 2 + nMod3) +
(nMod3 === 2 ? "" : nMod3 === 1 ? "=" : "==")
);
}
/* UTF-8 array to JS string and vice versa */
function UTF8ArrToStr(aBytes: Uint8Array): string {
let sView = "";
let nPart;
const nLen = aBytes.length;
for (let nIdx = 0; nIdx < nLen; nIdx++) {
nPart = aBytes[nIdx];
sView += String.fromCodePoint(
nPart > 251 && nPart < 254 && nIdx + 5 < nLen /* six bytes */
? /* (nPart - 252 << 30) may be not so safe in ECMAScript! So…: */
(nPart - 252) * 1073741824 +
((aBytes[++nIdx] - 128) << 24) +
((aBytes[++nIdx] - 128) << 18) +
((aBytes[++nIdx] - 128) << 12) +
((aBytes[++nIdx] - 128) << 6) +
aBytes[++nIdx] -
128
: nPart > 247 && nPart < 252 && nIdx + 4 < nLen /* five bytes */
? ((nPart - 248) << 24) +
((aBytes[++nIdx] - 128) << 18) +
((aBytes[++nIdx] - 128) << 12) +
((aBytes[++nIdx] - 128) << 6) +
aBytes[++nIdx] -
128
: nPart > 239 && nPart < 248 && nIdx + 3 < nLen /* four bytes */
? ((nPart - 240) << 18) +
((aBytes[++nIdx] - 128) << 12) +
((aBytes[++nIdx] - 128) << 6) +
aBytes[++nIdx] -
128
: nPart > 223 && nPart < 240 && nIdx + 2 < nLen /* three bytes */
? ((nPart - 224) << 12) +
((aBytes[++nIdx] - 128) << 6) +
aBytes[++nIdx] -
128
: nPart > 191 && nPart < 224 && nIdx + 1 < nLen /* two bytes */
? ((nPart - 192) << 6) + aBytes[++nIdx] - 128
: /* nPart < 127 ? */ /* one byte */
nPart
);
}
return sView;
}
function strToUTF8Arr(sDOMStr: string): Uint8Array {
let nChr;
const nStrLen = sDOMStr.length;
let nArrLen = 0;
/* mapping… */
for (let nMapIdx = 0; nMapIdx < nStrLen; nMapIdx++) {
nChr = sDOMStr.codePointAt(nMapIdx);
if (nChr === undefined) {
throw Error(`No char at ${nMapIdx} on string with length: ${sDOMStr.length}`)
}
if (nChr >= 0x10000) {
nMapIdx++;
}
nArrLen +=
nChr < 0x80
? 1
: nChr < 0x800
? 2
: nChr < 0x10000
? 3
: nChr < 0x200000
? 4
: nChr < 0x4000000
? 5
: 6;
}
const aBytes = new Uint8Array(nArrLen);
/* transcription… */
let nIdx = 0;
let nChrIdx = 0;
while (nIdx < nArrLen) {
nChr = sDOMStr.codePointAt(nChrIdx);
if (nChr === undefined) {
throw Error(`No char at ${nChrIdx} on string with length: ${sDOMStr.length}`)
}
if (nChr < 128) {
/* one byte */
aBytes[nIdx++] = nChr;
} else if (nChr < 0x800) {
/* two bytes */
aBytes[nIdx++] = 192 + (nChr >>> 6);
aBytes[nIdx++] = 128 + (nChr & 63);
} else if (nChr < 0x10000) {
/* three bytes */
aBytes[nIdx++] = 224 + (nChr >>> 12);
aBytes[nIdx++] = 128 + ((nChr >>> 6) & 63);
aBytes[nIdx++] = 128 + (nChr & 63);
} else if (nChr < 0x200000) {
/* four bytes */
aBytes[nIdx++] = 240 + (nChr >>> 18);
aBytes[nIdx++] = 128 + ((nChr >>> 12) & 63);
aBytes[nIdx++] = 128 + ((nChr >>> 6) & 63);
aBytes[nIdx++] = 128 + (nChr & 63);
nChrIdx++;
} else if (nChr < 0x4000000) {
/* five bytes */
aBytes[nIdx++] = 248 + (nChr >>> 24);
aBytes[nIdx++] = 128 + ((nChr >>> 18) & 63);
aBytes[nIdx++] = 128 + ((nChr >>> 12) & 63);
aBytes[nIdx++] = 128 + ((nChr >>> 6) & 63);
aBytes[nIdx++] = 128 + (nChr & 63);
nChrIdx++;
} /* if (nChr <= 0x7fffffff) */ else {
/* six bytes */
aBytes[nIdx++] = 252 + (nChr >>> 30);
aBytes[nIdx++] = 128 + ((nChr >>> 24) & 63);
aBytes[nIdx++] = 128 + ((nChr >>> 18) & 63);
aBytes[nIdx++] = 128 + ((nChr >>> 12) & 63);
aBytes[nIdx++] = 128 + ((nChr >>> 6) & 63);
aBytes[nIdx++] = 128 + (nChr & 63);
nChrIdx++;
}
nChrIdx++;
}
return aBytes;
}