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author | Ryan Dahl <ry@tinyclouds.org> | 2019-10-04 20:28:51 -0400 |
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committer | GitHub <noreply@github.com> | 2019-10-04 20:28:51 -0400 |
commit | b81e5db17aa8b3088d6034ddf86b79c69410f012 (patch) | |
tree | 579e4c23d60d1b0d038156bc28a04f74ea87b2f0 /cli/js/base64.ts | |
parent | 9049213867d30f7df090a83b6baf3e0717a4d2d2 (diff) |
Merge deno_cli_snapshots into deno_cli (#3064)
Diffstat (limited to 'cli/js/base64.ts')
-rw-r--r-- | cli/js/base64.ts | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/cli/js/base64.ts b/cli/js/base64.ts new file mode 100644 index 000000000..4d30e00f1 --- /dev/null +++ b/cli/js/base64.ts @@ -0,0 +1,150 @@ +// Forked from https://github.com/beatgammit/base64-js +// Copyright (c) 2014 Jameson Little. MIT License. + +const lookup: string[] = []; +const revLookup: number[] = []; + +const code = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; +for (let i = 0, len = code.length; i < len; ++i) { + lookup[i] = code[i]; + revLookup[code.charCodeAt(i)] = i; +} + +// Support decoding URL-safe base64 strings, as Node.js does. +// See: https://en.wikipedia.org/wiki/Base64#URL_applications +revLookup["-".charCodeAt(0)] = 62; +revLookup["_".charCodeAt(0)] = 63; + +function getLens(b64: string): [number, number] { + const len = b64.length; + + if (len % 4 > 0) { + throw new Error("Invalid string. Length must be a multiple of 4"); + } + + // Trim off extra bytes after placeholder bytes are found + // See: https://github.com/beatgammit/base64-js/issues/42 + let validLen = b64.indexOf("="); + if (validLen === -1) validLen = len; + + const placeHoldersLen = validLen === len ? 0 : 4 - (validLen % 4); + + return [validLen, placeHoldersLen]; +} + +// base64 is 4/3 + up to two characters of the original data +export function byteLength(b64: string): number { + const lens = getLens(b64); + const validLen = lens[0]; + const placeHoldersLen = lens[1]; + return ((validLen + placeHoldersLen) * 3) / 4 - placeHoldersLen; +} + +function _byteLength( + b64: string, + validLen: number, + placeHoldersLen: number +): number { + return ((validLen + placeHoldersLen) * 3) / 4 - placeHoldersLen; +} + +export function toByteArray(b64: string): Uint8Array { + let tmp; + const lens = getLens(b64); + const validLen = lens[0]; + const placeHoldersLen = lens[1]; + + const arr = new Uint8Array(_byteLength(b64, validLen, placeHoldersLen)); + + let curByte = 0; + + // if there are placeholders, only get up to the last complete 4 chars + const len = placeHoldersLen > 0 ? validLen - 4 : validLen; + + let i; + for (i = 0; i < len; i += 4) { + tmp = + (revLookup[b64.charCodeAt(i)] << 18) | + (revLookup[b64.charCodeAt(i + 1)] << 12) | + (revLookup[b64.charCodeAt(i + 2)] << 6) | + revLookup[b64.charCodeAt(i + 3)]; + arr[curByte++] = (tmp >> 16) & 0xff; + arr[curByte++] = (tmp >> 8) & 0xff; + arr[curByte++] = tmp & 0xff; + } + + if (placeHoldersLen === 2) { + tmp = + (revLookup[b64.charCodeAt(i)] << 2) | + (revLookup[b64.charCodeAt(i + 1)] >> 4); + arr[curByte++] = tmp & 0xff; + } + + if (placeHoldersLen === 1) { + tmp = + (revLookup[b64.charCodeAt(i)] << 10) | + (revLookup[b64.charCodeAt(i + 1)] << 4) | + (revLookup[b64.charCodeAt(i + 2)] >> 2); + arr[curByte++] = (tmp >> 8) & 0xff; + arr[curByte++] = tmp & 0xff; + } + + return arr; +} + +function tripletToBase64(num: number): string { + return ( + lookup[(num >> 18) & 0x3f] + + lookup[(num >> 12) & 0x3f] + + lookup[(num >> 6) & 0x3f] + + lookup[num & 0x3f] + ); +} + +function encodeChunk(uint8: Uint8Array, start: number, end: number): string { + let tmp; + const output = []; + for (let i = start; i < end; i += 3) { + tmp = + ((uint8[i] << 16) & 0xff0000) + + ((uint8[i + 1] << 8) & 0xff00) + + (uint8[i + 2] & 0xff); + output.push(tripletToBase64(tmp)); + } + return output.join(""); +} + +export function fromByteArray(uint8: Uint8Array): string { + let tmp; + const len = uint8.length; + const extraBytes = len % 3; // if we have 1 byte left, pad 2 bytes + const parts = []; + const maxChunkLength = 16383; // must be multiple of 3 + + // go through the array every three bytes, we'll deal with trailing stuff later + for (let i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) { + parts.push( + encodeChunk( + uint8, + i, + i + maxChunkLength > len2 ? len2 : i + maxChunkLength + ) + ); + } + + // pad the end with zeros, but make sure to not forget the extra bytes + if (extraBytes === 1) { + tmp = uint8[len - 1]; + parts.push(lookup[tmp >> 2] + lookup[(tmp << 4) & 0x3f] + "=="); + } else if (extraBytes === 2) { + tmp = (uint8[len - 2] << 8) + uint8[len - 1]; + parts.push( + lookup[tmp >> 10] + + lookup[(tmp >> 4) & 0x3f] + + lookup[(tmp << 2) & 0x3f] + + "=" + ); + } + + return parts.join(""); +} |