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Diffstat (limited to 'packages/web-util/src/utils/base64.ts')
| -rw-r--r-- | packages/web-util/src/utils/base64.ts | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/packages/web-util/src/utils/base64.ts b/packages/web-util/src/utils/base64.ts new file mode 100644 index 000000000..0e075880f --- /dev/null +++ b/packages/web-util/src/utils/base64.ts @@ -0,0 +1,243 @@ +/* + 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; +} |