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-
- // Single-byte codec. Needs a 'chars' string parameter that contains 256 or 128 chars that
- // correspond to encoded bytes (if 128 - then lower half is ASCII).
-
- exports._sbcs = function(options) {
- if (!options)
- throw new Error("SBCS codec is called without the data.")
-
- // Prepare char buffer for decoding.
- if (!options.chars || (options.chars.length !== 128 && options.chars.length !== 256))
- throw new Error("Encoding '"+options.type+"' has incorrect 'chars' (must be of len 128 or 256)");
-
- if (options.chars.length === 128) {
- var asciiString = "";
- for (var i = 0; i < 128; i++)
- asciiString += String.fromCharCode(i);
- options.chars = asciiString + options.chars;
- }
-
- var decodeBuf = new Buffer(options.chars, 'ucs2');
-
- // Encoding buffer.
- var encodeBuf = new Buffer(65536);
- encodeBuf.fill(options.iconv.defaultCharSingleByte.charCodeAt(0));
-
- for (var i = 0; i < options.chars.length; i++)
- encodeBuf[options.chars.charCodeAt(i)] = i;
-
- return {
- encoder: encoderSBCS,
- decoder: decoderSBCS,
-
- encodeBuf: encodeBuf,
- decodeBuf: decodeBuf,
- };
- }
-
- function encoderSBCS(options) {
- return {
- write: encoderSBCSWrite,
- end: function() {},
-
- encodeBuf: this.encodeBuf,
- };
- }
-
- function encoderSBCSWrite(str) {
- var buf = new Buffer(str.length);
- for (var i = 0; i < str.length; i++)
- buf[i] = this.encodeBuf[str.charCodeAt(i)];
-
- return buf;
- }
-
-
- function decoderSBCS(options) {
- return {
- write: decoderSBCSWrite,
- end: function() {},
-
- decodeBuf: this.decodeBuf,
- };
- }
-
- function decoderSBCSWrite(buf) {
- // Strings are immutable in JS -> we use ucs2 buffer to speed up computations.
- var decodeBuf = this.decodeBuf;
- var newBuf = new Buffer(buf.length*2);
- var idx1 = 0, idx2 = 0;
- for (var i = 0, _len = buf.length; i < _len; i++) {
- idx1 = buf[i]*2; idx2 = i*2;
- newBuf[idx2] = decodeBuf[idx1];
- newBuf[idx2+1] = decodeBuf[idx1+1];
- }
- return newBuf.toString('ucs2');
- }
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