262 lines
8.2 KiB
JavaScript
262 lines
8.2 KiB
JavaScript
'use strict';
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const charCodeDefinitions = require('./char-code-definitions.cjs');
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function getCharCode(source, offset) {
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return offset < source.length ? source.charCodeAt(offset) : 0;
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}
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function getNewlineLength(source, offset, code) {
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if (code === 13 /* \r */ && getCharCode(source, offset + 1) === 10 /* \n */) {
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return 2;
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}
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return 1;
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}
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function cmpChar(testStr, offset, referenceCode) {
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let code = testStr.charCodeAt(offset);
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// code.toLowerCase() for A..Z
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if (charCodeDefinitions.isUppercaseLetter(code)) {
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code = code | 32;
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}
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return code === referenceCode;
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}
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function cmpStr(testStr, start, end, referenceStr) {
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if (end - start !== referenceStr.length) {
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return false;
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}
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if (start < 0 || end > testStr.length) {
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return false;
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}
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for (let i = start; i < end; i++) {
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const referenceCode = referenceStr.charCodeAt(i - start);
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let testCode = testStr.charCodeAt(i);
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// testCode.toLowerCase() for A..Z
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if (charCodeDefinitions.isUppercaseLetter(testCode)) {
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testCode = testCode | 32;
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}
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if (testCode !== referenceCode) {
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return false;
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}
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}
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return true;
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}
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function findWhiteSpaceStart(source, offset) {
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for (; offset >= 0; offset--) {
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if (!charCodeDefinitions.isWhiteSpace(source.charCodeAt(offset))) {
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break;
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}
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}
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return offset + 1;
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}
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function findWhiteSpaceEnd(source, offset) {
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for (; offset < source.length; offset++) {
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if (!charCodeDefinitions.isWhiteSpace(source.charCodeAt(offset))) {
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break;
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}
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}
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return offset;
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}
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function findDecimalNumberEnd(source, offset) {
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for (; offset < source.length; offset++) {
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if (!charCodeDefinitions.isDigit(source.charCodeAt(offset))) {
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break;
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}
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}
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return offset;
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}
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// § 4.3.7. Consume an escaped code point
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function consumeEscaped(source, offset) {
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// It assumes that the U+005C REVERSE SOLIDUS (\) has already been consumed and
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// that the next input code point has already been verified to be part of a valid escape.
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offset += 2;
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// hex digit
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if (charCodeDefinitions.isHexDigit(getCharCode(source, offset - 1))) {
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// Consume as many hex digits as possible, but no more than 5.
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// Note that this means 1-6 hex digits have been consumed in total.
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for (const maxOffset = Math.min(source.length, offset + 5); offset < maxOffset; offset++) {
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if (!charCodeDefinitions.isHexDigit(getCharCode(source, offset))) {
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break;
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}
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}
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// If the next input code point is whitespace, consume it as well.
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const code = getCharCode(source, offset);
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if (charCodeDefinitions.isWhiteSpace(code)) {
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offset += getNewlineLength(source, offset, code);
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}
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}
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return offset;
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}
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// §4.3.11. Consume a name
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// Note: This algorithm does not do the verification of the first few code points that are necessary
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// to ensure the returned code points would constitute an <ident-token>. If that is the intended use,
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// ensure that the stream starts with an identifier before calling this algorithm.
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function consumeName(source, offset) {
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// Let result initially be an empty string.
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// Repeatedly consume the next input code point from the stream:
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for (; offset < source.length; offset++) {
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const code = source.charCodeAt(offset);
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// name code point
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if (charCodeDefinitions.isName(code)) {
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// Append the code point to result.
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continue;
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}
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// the stream starts with a valid escape
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if (charCodeDefinitions.isValidEscape(code, getCharCode(source, offset + 1))) {
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// Consume an escaped code point. Append the returned code point to result.
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offset = consumeEscaped(source, offset) - 1;
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continue;
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}
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// anything else
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// Reconsume the current input code point. Return result.
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break;
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}
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return offset;
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}
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// §4.3.12. Consume a number
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function consumeNumber(source, offset) {
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let code = source.charCodeAt(offset);
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// 2. If the next input code point is U+002B PLUS SIGN (+) or U+002D HYPHEN-MINUS (-),
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// consume it and append it to repr.
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if (code === 0x002B || code === 0x002D) {
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code = source.charCodeAt(offset += 1);
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}
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// 3. While the next input code point is a digit, consume it and append it to repr.
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if (charCodeDefinitions.isDigit(code)) {
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offset = findDecimalNumberEnd(source, offset + 1);
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code = source.charCodeAt(offset);
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}
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// 4. If the next 2 input code points are U+002E FULL STOP (.) followed by a digit, then:
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if (code === 0x002E && charCodeDefinitions.isDigit(source.charCodeAt(offset + 1))) {
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// 4.1 Consume them.
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// 4.2 Append them to repr.
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offset += 2;
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// 4.3 Set type to "number".
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// TODO
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// 4.4 While the next input code point is a digit, consume it and append it to repr.
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offset = findDecimalNumberEnd(source, offset);
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}
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// 5. If the next 2 or 3 input code points are U+0045 LATIN CAPITAL LETTER E (E)
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// or U+0065 LATIN SMALL LETTER E (e), ... , followed by a digit, then:
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if (cmpChar(source, offset, 101 /* e */)) {
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let sign = 0;
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code = source.charCodeAt(offset + 1);
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// ... optionally followed by U+002D HYPHEN-MINUS (-) or U+002B PLUS SIGN (+) ...
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if (code === 0x002D || code === 0x002B) {
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sign = 1;
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code = source.charCodeAt(offset + 2);
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}
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// ... followed by a digit
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if (charCodeDefinitions.isDigit(code)) {
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// 5.1 Consume them.
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// 5.2 Append them to repr.
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// 5.3 Set type to "number".
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// TODO
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// 5.4 While the next input code point is a digit, consume it and append it to repr.
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offset = findDecimalNumberEnd(source, offset + 1 + sign + 1);
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}
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}
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return offset;
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}
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// § 4.3.14. Consume the remnants of a bad url
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// ... its sole use is to consume enough of the input stream to reach a recovery point
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// where normal tokenizing can resume.
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function consumeBadUrlRemnants(source, offset) {
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// Repeatedly consume the next input code point from the stream:
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for (; offset < source.length; offset++) {
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const code = source.charCodeAt(offset);
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// U+0029 RIGHT PARENTHESIS ())
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// EOF
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if (code === 0x0029) {
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// Return.
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offset++;
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break;
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}
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if (charCodeDefinitions.isValidEscape(code, getCharCode(source, offset + 1))) {
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// Consume an escaped code point.
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// Note: This allows an escaped right parenthesis ("\)") to be encountered
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// without ending the <bad-url-token>. This is otherwise identical to
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// the "anything else" clause.
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offset = consumeEscaped(source, offset);
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}
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}
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return offset;
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}
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// § 4.3.7. Consume an escaped code point
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// Note: This algorithm assumes that escaped is valid without leading U+005C REVERSE SOLIDUS (\)
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function decodeEscaped(escaped) {
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// Single char escaped that's not a hex digit
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if (escaped.length === 1 && !charCodeDefinitions.isHexDigit(escaped.charCodeAt(0))) {
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return escaped[0];
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}
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// Interpret the hex digits as a hexadecimal number.
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let code = parseInt(escaped, 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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// Otherwise, return the code point with that value.
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return String.fromCodePoint(code);
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}
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exports.cmpChar = cmpChar;
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exports.cmpStr = cmpStr;
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exports.consumeBadUrlRemnants = consumeBadUrlRemnants;
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exports.consumeEscaped = consumeEscaped;
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exports.consumeName = consumeName;
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exports.consumeNumber = consumeNumber;
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exports.decodeEscaped = decodeEscaped;
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exports.findDecimalNumberEnd = findDecimalNumberEnd;
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exports.findWhiteSpaceEnd = findWhiteSpaceEnd;
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exports.findWhiteSpaceStart = findWhiteSpaceStart;
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exports.getNewlineLength = getNewlineLength;
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