| "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() { |
| } |