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"use strict";
var Buffer = require("safer-buffer").Buffer;
// 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 = SBCSCodec;
function SBCSCodec(codecOptions, iconv) {
if (!codecOptions)
throw new Error("SBCS codec is called without the data.")
// Prepare char buffer for decoding.
if (!codecOptions.chars || (codecOptions.chars.length !== 128 && codecOptions.chars.length !== 256))
throw new Error("Encoding '"+codecOptions.type+"' has incorrect 'chars' (must be of len 128 or 256)");
if (codecOptions.chars.length === 128) {
var asciiString = "";
for (var i = 0; i < 128; i++)
asciiString += String.fromCharCode(i);
codecOptions.chars = asciiString + codecOptions.chars;
}
this.decodeBuf = Buffer.from(codecOptions.chars, 'ucs2');
// Encoding buffer.
var encodeBuf = Buffer.alloc(65536, iconv.defaultCharSingleByte.charCodeAt(0));
for (var i = 0; i < codecOptions.chars.length; i++)
encodeBuf[codecOptions.chars.charCodeAt(i)] = i;
this.encodeBuf = encodeBuf;
}
SBCSCodec.prototype.encoder = SBCSEncoder;
SBCSCodec.prototype.decoder = SBCSDecoder;
function SBCSEncoder(options, codec) {
this.encodeBuf = codec.encodeBuf;
}
SBCSEncoder.prototype.write = function(str) {
var buf = Buffer.alloc(str.length);
for (var i = 0; i < str.length; i++)
buf[i] = this.encodeBuf[str.charCodeAt(i)];
return buf;
}
SBCSEncoder.prototype.end = function() {
}
function SBCSDecoder(options, codec) {
this.decodeBuf = codec.decodeBuf;
}
SBCSDecoder.prototype.write = function(buf) {
// Strings are immutable in JS -> we use ucs2 buffer to speed up computations.
var decodeBuf = this.decodeBuf;
var newBuf = Buffer.alloc(buf.length*2);
var idx1 = 0, idx2 = 0;
for (var i = 0; i < buf.length; i++) {
idx1 = buf[i]*2; idx2 = i*2;
newBuf[idx2] = decodeBuf[idx1];
newBuf[idx2+1] = decodeBuf[idx1+1];
}
return newBuf.toString('ucs2');
}
SBCSDecoder.prototype.end = function() {
}
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