Cleanup and Test: base64.js
This is the first commit in a series of commits which improve the readability of some of the code and add tests. File: base64.js Tests Added: True Changes: - Improved indentation - Fixed JSHint errors - Moved loop variables to be declared in the loop for better readability (N.B. Javascript does not have block scoping, so the variables are still technically available outside the loop -- it just makes the code clearer to place them inside the loop, since they are only used there)
This commit is contained in:
Solly Ross
parent
371a43ccad
commit
5d2d3dfc63
@ -4,112 +4,110 @@
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// From: http://hg.mozilla.org/mozilla-central/raw-file/ec10630b1a54/js/src/devtools/jint/sunspider/string-base64.js
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/*jslint white: false, bitwise: false, plusplus: false */
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/*jslint white: false */
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/*global console */
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var Base64 = {
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/* Convert data (an array of integers) to a Base64 string. */
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toBase64Table : 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='.split(''),
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base64Pad : '=',
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/* Convert data (an array of integers) to a Base64 string. */
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toBase64Table : 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='.split(''),
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base64Pad : '=',
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encode: function (data) {
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"use strict";
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var result = '';
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var toBase64Table = Base64.toBase64Table;
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var length = data.length;
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var lengthpad = (length % 3);
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// Convert every three bytes to 4 ascii characters.
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encode: function (data) {
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"use strict";
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var result = '';
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var toBase64Table = Base64.toBase64Table;
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var length = data.length
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var lengthpad = (length%3);
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var i = 0, j = 0;
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// Convert every three bytes to 4 ascii characters.
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/* BEGIN LOOP */
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for (i = 0; i < (length - 2); i += 3) {
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result += toBase64Table[data[i] >> 2];
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result += toBase64Table[((data[i] & 0x03) << 4) + (data[i+1] >> 4)];
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result += toBase64Table[((data[i+1] & 0x0f) << 2) + (data[i+2] >> 6)];
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result += toBase64Table[data[i+2] & 0x3f];
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}
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/* END LOOP */
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// Convert the remaining 1 or 2 bytes, pad out to 4 characters.
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if (lengthpad === 2) {
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j = length - lengthpad;
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result += toBase64Table[data[j] >> 2];
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result += toBase64Table[((data[j] & 0x03) << 4) + (data[j+1] >> 4)];
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result += toBase64Table[(data[j+1] & 0x0f) << 2];
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result += toBase64Table[64];
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} else if (lengthpad === 1) {
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j = length - lengthpad;
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result += toBase64Table[data[j] >> 2];
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result += toBase64Table[(data[j] & 0x03) << 4];
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result += toBase64Table[64];
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result += toBase64Table[64];
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}
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return result;
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},
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/* Convert Base64 data to a string */
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toBinaryTable : [
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-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
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-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
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-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
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52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1, 0,-1,-1,
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-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14,
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15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
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-1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
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41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
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],
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decode: function (data, offset) {
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"use strict";
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offset = typeof(offset) !== 'undefined' ? offset : 0;
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var toBinaryTable = Base64.toBinaryTable;
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var base64Pad = Base64.base64Pad;
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var result, result_length, idx, i, c, padding;
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var leftbits = 0; // number of bits decoded, but yet to be appended
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var leftdata = 0; // bits decoded, but yet to be appended
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var data_length = data.indexOf('=') - offset;
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if (data_length < 0) { data_length = data.length - offset; }
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/* Every four characters is 3 resulting numbers */
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result_length = (data_length >> 2) * 3 + Math.floor((data_length%4)/1.5);
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result = new Array(result_length);
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// Convert one by one.
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/* BEGIN LOOP */
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for (idx = 0, i = offset; i < data.length; i++) {
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c = toBinaryTable[data.charCodeAt(i) & 0x7f];
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padding = (data.charAt(i) === base64Pad);
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// Skip illegal characters and whitespace
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if (c === -1) {
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console.error("Illegal character code " + data.charCodeAt(i) + " at position " + i);
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continue;
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for (var i = 0; i < (length - 2); i += 3) {
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result += toBase64Table[data[i] >> 2];
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result += toBase64Table[((data[i] & 0x03) << 4) + (data[i + 1] >> 4)];
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result += toBase64Table[((data[i + 1] & 0x0f) << 2) + (data[i + 2] >> 6)];
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result += toBase64Table[data[i + 2] & 0x3f];
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}
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// Collect data into leftdata, update bitcount
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leftdata = (leftdata << 6) | c;
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leftbits += 6;
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// If we have 8 or more bits, append 8 bits to the result
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if (leftbits >= 8) {
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leftbits -= 8;
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// Append if not padding.
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if (!padding) {
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result[idx++] = (leftdata >> leftbits) & 0xff;
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// Convert the remaining 1 or 2 bytes, pad out to 4 characters.
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var j = 0;
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if (lengthpad === 2) {
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j = length - lengthpad;
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result += toBase64Table[data[j] >> 2];
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result += toBase64Table[((data[j] & 0x03) << 4) + (data[j + 1] >> 4)];
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result += toBase64Table[(data[j + 1] & 0x0f) << 2];
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result += toBase64Table[64];
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} else if (lengthpad === 1) {
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j = length - lengthpad;
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result += toBase64Table[data[j] >> 2];
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result += toBase64Table[(data[j] & 0x03) << 4];
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result += toBase64Table[64];
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result += toBase64Table[64];
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}
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return result;
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},
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/* Convert Base64 data to a string */
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/* jshint -W013 */
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toBinaryTable : [
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-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
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-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
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-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
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52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1, 0,-1,-1,
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-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14,
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15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
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-1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
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41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
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],
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/* jshint +W013 */
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decode: function (data, offset) {
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"use strict";
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offset = typeof(offset) !== 'undefined' ? offset : 0;
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var toBinaryTable = Base64.toBinaryTable;
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var base64Pad = Base64.base64Pad;
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var result, result_length;
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var leftbits = 0; // number of bits decoded, but yet to be appended
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var leftdata = 0; // bits decoded, but yet to be appended
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var data_length = data.indexOf('=') - offset;
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if (data_length < 0) { data_length = data.length - offset; }
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/* Every four characters is 3 resulting numbers */
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result_length = (data_length >> 2) * 3 + Math.floor((data_length % 4) / 1.5);
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result = new Array(result_length);
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// Convert one by one.
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for (var idx = 0, i = offset; i < data.length; i++) {
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var c = toBinaryTable[data.charCodeAt(i) & 0x7f];
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var padding = (data.charAt(i) === base64Pad);
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// Skip illegal characters and whitespace
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if (c === -1) {
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console.error("Illegal character code " + data.charCodeAt(i) + " at position " + i);
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continue;
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}
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// Collect data into leftdata, update bitcount
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leftdata = (leftdata << 6) | c;
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leftbits += 6;
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// If we have 8 or more bits, append 8 bits to the result
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if (leftbits >= 8) {
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leftbits -= 8;
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// Append if not padding.
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if (!padding) {
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result[idx++] = (leftdata >> leftbits) & 0xff;
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}
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leftdata &= (1 << leftbits) - 1;
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}
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leftdata &= (1 << leftbits) - 1;
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}
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// If there are any bits left, the base64 string was corrupted
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if (leftbits) {
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err = new Error('Corrupted base64 string');
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err.name = 'Base64-Error';
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throw err;
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}
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return result;
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}
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/* END LOOP */
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// If there are any bits left, the base64 string was corrupted
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if (leftbits) {
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throw {name: 'Base64-Error',
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message: 'Corrupted base64 string'};
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}
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return result;
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}
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}; /* End of Base64 namespace */
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33
tests/test.base64.js
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33
tests/test.base64.js
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@ -0,0 +1,33 @@
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// requires local modules: base64
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var assert = chai.assert;
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var expect = chai.expect;
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describe('Base64 Tools', function() {
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"use strict";
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var BIN_ARR = new Array(256);
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for (var i = 0; i < 256; i++) {
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BIN_ARR[i] = i;
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}
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var B64_STR = "AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8gISIjJCUmJygpKissLS4vMDEyMzQ1Njc4OTo7PD0+P0BBQkNERUZHSElKS0xNTk9QUVJTVFVWV1hZWltcXV5fYGFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6e3x9fn+AgYKDhIWGh4iJiouMjY6PkJGSk5SVlpeYmZqbnJ2en6ChoqOkpaanqKmqq6ytrq+wsbKztLW2t7i5uru8vb6/wMHCw8TFxsfIycrLzM3Oz9DR0tPU1dbX2Nna29zd3t/g4eLj5OXm5+jp6uvs7e7v8PHy8/T19vf4+fr7/P3+/w==";
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describe('encode', function() {
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it('should encode a binary string into Base64', function() {
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var encoded = Base64.encode(BIN_ARR);
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expect(encoded).to.equal(B64_STR);
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});
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});
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describe('decode', function() {
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it('should decode a Base64 string into a normal string', function() {
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var decoded = Base64.decode(B64_STR);
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expect(decoded).to.deep.equal(BIN_ARR);
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});
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it('should throw an error if we have extra characters at the end of the string', function() {
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expect(function () { Base64.decode(B64_STR+'abcdef'); }).to.throw(Error);
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});
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});
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});
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