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121 lines
3.9 KiB
121 lines
3.9 KiB
var REVERSE_SOLIDUS = 0x5c; // \ |
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var QUOTATION_MARK = 0x22; // " |
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var APOSTROPHE = 0x27; // ' |
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var TAB = 0x09; // tab |
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var WHITESPACE = 0x20; // space |
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var AMPERSAND = 0x26; |
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var LESSTHANSIGN = 0x3C; |
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var GREATERTHANSIGN = 0x3E; |
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function isHex(code) { |
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return (code >= 48 && code <= 57) || // 0 .. 9 |
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(code >= 65 && code <= 70) || // A .. F |
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(code >= 97 && code <= 102); // a .. f |
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} |
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function decodeString(str) { |
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var decoded = ''; |
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var len = str.length; |
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var firstChar = str.charCodeAt(0); |
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var start = firstChar === QUOTATION_MARK || firstChar === APOSTROPHE ? 1 : 0; |
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var end = start === 1 && len > 1 && str.charCodeAt(len - 1) === firstChar ? len - 2 : len - 1; |
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for (var i = start; i <= end; i++) { |
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var code = str.charCodeAt(i); |
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if (code === REVERSE_SOLIDUS) { |
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// special case at the ending |
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if (i === end) { |
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// if the next input code point is EOF, do nothing |
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// otherwise include last quote as escaped |
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if (i !== len - 1) { |
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decoded = str.substr(i + 1); |
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} |
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break; |
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} |
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code = str.charCodeAt(++i); |
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// ignore escaped newline |
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if (code !== 0x0A && code !== 0x0C && code !== 0x0D) { // TODO: should treat a "CR/LF" pair (U+000D/U+000A) as a single white space character |
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// https://drafts.csswg.org/css-syntax/#consume-escaped-code-point |
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for (var j = 0; j < 6 && i + j <= end;) { |
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code = str.charCodeAt(i + j); |
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if (isHex(code)) { |
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j++; |
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} else { |
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break; |
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} |
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} |
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if (j > 0) { |
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code = str.charCodeAt(i + j); |
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// include space into sequence |
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// TODO: add newline support |
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if (code === WHITESPACE || code === TAB) { |
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j++; |
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} |
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code = parseInt(str.substr(i, j), 16); |
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if ( |
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(code === 0) || // If this number is zero, |
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(code >= 0xD800 && code <= 0xDFFF) || // or is for a surrogate, |
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(code > 0x10FFFF) // or is greater than the maximum allowed code point |
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) { |
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// ... return U+FFFD REPLACEMENT CHARACTER |
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code = 0xFFFD; |
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} |
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// FIXME: code above 0xFFFF will be converted incorrectly, |
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// better to use String.fromCharPoint() but it lack of support by engines |
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decoded += String.fromCharCode(code); |
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i += j - 1; |
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} else { |
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decoded += str.charAt(i); |
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} |
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} |
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} else { |
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decoded += str.charAt(i); |
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} |
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} |
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return decoded; |
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} |
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function encodeString(str, apostrophe) { |
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var quote = apostrophe ? '\'' : '"'; |
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var quoteCode = apostrophe ? APOSTROPHE : QUOTATION_MARK; |
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var encoded = quote; |
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var wsBeforeHexIsNeeded = false; |
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for (var i = 0; i < str.length; i++) { |
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var code = str.charCodeAt(i); |
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if (code <= 0x1F || code === AMPERSAND || code === LESSTHANSIGN || code === GREATERTHANSIGN) { |
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encoded += '\\' + code.toString(16); |
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wsBeforeHexIsNeeded = true; |
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} else if (code === REVERSE_SOLIDUS || code === quoteCode) { |
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encoded += '\\' + str.charAt(i); |
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wsBeforeHexIsNeeded = false; |
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} else { |
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if (wsBeforeHexIsNeeded && isHex(code)) { |
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encoded += ' '; |
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} |
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encoded += str.charAt(i); |
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wsBeforeHexIsNeeded = false; |
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} |
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} |
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encoded += quote; |
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return encoded; |
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} |
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module.exports = { |
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decode: decodeString, |
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encode: encodeString |
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};
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