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94 lines
4.2 KiB
JavaScript
94 lines
4.2 KiB
JavaScript
import { decoderError } from "../../encoding/encodings";
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import { finished } from "../../encoding/finished";
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import { index, indexCodePointFor } from "../../encoding/indexes";
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import { end_of_stream, isASCIIByte } from "../../encoding/terminology";
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import { inRange } from "../../encoding/utilities";
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/**
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* @constructor
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* @implements {Decoder}
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* @param {{fatal: boolean}} options
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*/
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var EUCJPDecoder = /** @class */ (function () {
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function EUCJPDecoder(options) {
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this.fatal = options.fatal;
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// euc-jp's decoder has an associated euc-jp jis0212 flag
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// (initially unset) and euc-jp lead (initially 0x00).
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/** @type {boolean} */ this.eucjp_jis0212_flag = false,
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/** @type {number} */ this.eucjp_lead = 0x00;
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}
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/**
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* @param {Stream} stream The stream of bytes being decoded.
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* @param {number} bite The next byte read from the stream.
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* @return {?(number|!Array.<number>)} The next code point(s)
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* decoded, or null if not enough data exists in the input
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* stream to decode a complete code point.
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*/
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EUCJPDecoder.prototype.handler = function (stream, bite) {
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// 1. If byte is end-of-stream and euc-jp lead is not 0x00, set
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// euc-jp lead to 0x00, and return error.
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if (bite === end_of_stream && this.eucjp_lead !== 0x00) {
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this.eucjp_lead = 0x00;
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return decoderError(this.fatal);
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}
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// 2. If byte is end-of-stream and euc-jp lead is 0x00, return
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// finished.
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if (bite === end_of_stream && this.eucjp_lead === 0x00)
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return finished;
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// 3. If euc-jp lead is 0x8E and byte is in the range 0xA1 to
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// 0xDF, inclusive, set euc-jp lead to 0x00 and return a code
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// point whose value is 0xFF61 − 0xA1 + byte.
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if (this.eucjp_lead === 0x8E && inRange(bite, 0xA1, 0xDF)) {
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this.eucjp_lead = 0x00;
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return 0xFF61 - 0xA1 + bite;
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}
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// 4. If euc-jp lead is 0x8F and byte is in the range 0xA1 to
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// 0xFE, inclusive, set the euc-jp jis0212 flag, set euc-jp lead
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// to byte, and return continue.
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if (this.eucjp_lead === 0x8F && inRange(bite, 0xA1, 0xFE)) {
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this.eucjp_jis0212_flag = true;
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this.eucjp_lead = bite;
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return null;
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}
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// 5. If euc-jp lead is not 0x00, let lead be euc-jp lead, set
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// euc-jp lead to 0x00, and run these substeps:
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if (this.eucjp_lead !== 0x00) {
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var lead = this.eucjp_lead;
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this.eucjp_lead = 0x00;
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// 1. Let code point be null.
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var code_point = null;
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// 2. If lead and byte are both in the range 0xA1 to 0xFE,
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// inclusive, set code point to the index code point for (lead
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// − 0xA1) × 94 + byte − 0xA1 in index jis0208 if the euc-jp
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// jis0212 flag is unset and in index jis0212 otherwise.
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if (inRange(lead, 0xA1, 0xFE) && inRange(bite, 0xA1, 0xFE)) {
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code_point = indexCodePointFor((lead - 0xA1) * 94 + (bite - 0xA1), index(!this.eucjp_jis0212_flag ? 'jis0208' : 'jis0212'));
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}
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// 3. Unset the euc-jp jis0212 flag.
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this.eucjp_jis0212_flag = false;
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// 4. If byte is not in the range 0xA1 to 0xFE, inclusive,
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// prepend byte to stream.
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if (!inRange(bite, 0xA1, 0xFE))
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stream.prepend(bite);
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// 5. If code point is null, return error.
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if (code_point === null)
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return decoderError(this.fatal);
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// 6. Return a code point whose value is code point.
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return code_point;
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}
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// 6. If byte is an ASCII byte, return a code point whose value
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// is byte.
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if (isASCIIByte(bite))
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return bite;
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// 7. If byte is 0x8E, 0x8F, or in the range 0xA1 to 0xFE,
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// inclusive, set euc-jp lead to byte and return continue.
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if (bite === 0x8E || bite === 0x8F || inRange(bite, 0xA1, 0xFE)) {
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this.eucjp_lead = bite;
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return null;
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}
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// 8. Return error.
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return decoderError(this.fatal);
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};
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return EUCJPDecoder;
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}());
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export { EUCJPDecoder };
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//# sourceMappingURL=EUCJPDecoder.js.map
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