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Diffstat (limited to 'middleware/node_modules/iconv-lite/encodings/dbcs-codec.js')
| -rw-r--r-- | middleware/node_modules/iconv-lite/encodings/dbcs-codec.js | 555 |
1 files changed, 555 insertions, 0 deletions
diff --git a/middleware/node_modules/iconv-lite/encodings/dbcs-codec.js b/middleware/node_modules/iconv-lite/encodings/dbcs-codec.js new file mode 100644 index 0000000..1fe3e16 --- /dev/null +++ b/middleware/node_modules/iconv-lite/encodings/dbcs-codec.js @@ -0,0 +1,555 @@ +"use strict"; +var Buffer = require("safer-buffer").Buffer; + +// Multibyte codec. In this scheme, a character is represented by 1 or more bytes. +// Our codec supports UTF-16 surrogates, extensions for GB18030 and unicode sequences. +// To save memory and loading time, we read table files only when requested. + +exports._dbcs = DBCSCodec; + +var UNASSIGNED = -1, + GB18030_CODE = -2, + SEQ_START = -10, + NODE_START = -1000, + UNASSIGNED_NODE = new Array(0x100), + DEF_CHAR = -1; + +for (var i = 0; i < 0x100; i++) + UNASSIGNED_NODE[i] = UNASSIGNED; + + +// Class DBCSCodec reads and initializes mapping tables. +function DBCSCodec(codecOptions, iconv) { + this.encodingName = codecOptions.encodingName; + if (!codecOptions) + throw new Error("DBCS codec is called without the data.") + if (!codecOptions.table) + throw new Error("Encoding '" + this.encodingName + "' has no data."); + + // Load tables. + var mappingTable = codecOptions.table(); + + + // Decode tables: MBCS -> Unicode. + + // decodeTables is a trie, encoded as an array of arrays of integers. Internal arrays are trie nodes and all have len = 256. + // Trie root is decodeTables[0]. + // Values: >= 0 -> unicode character code. can be > 0xFFFF + // == UNASSIGNED -> unknown/unassigned sequence. + // == GB18030_CODE -> this is the end of a GB18030 4-byte sequence. + // <= NODE_START -> index of the next node in our trie to process next byte. + // <= SEQ_START -> index of the start of a character code sequence, in decodeTableSeq. + this.decodeTables = []; + this.decodeTables[0] = UNASSIGNED_NODE.slice(0); // Create root node. + + // Sometimes a MBCS char corresponds to a sequence of unicode chars. We store them as arrays of integers here. + this.decodeTableSeq = []; + + // Actual mapping tables consist of chunks. Use them to fill up decode tables. + for (var i = 0; i < mappingTable.length; i++) + this._addDecodeChunk(mappingTable[i]); + + this.defaultCharUnicode = iconv.defaultCharUnicode; + + + // Encode tables: Unicode -> DBCS. + + // `encodeTable` is array mapping from unicode char to encoded char. All its values are integers for performance. + // Because it can be sparse, it is represented as array of buckets by 256 chars each. Bucket can be null. + // Values: >= 0 -> it is a normal char. Write the value (if <=256 then 1 byte, if <=65536 then 2 bytes, etc.). + // == UNASSIGNED -> no conversion found. Output a default char. + // <= SEQ_START -> it's an index in encodeTableSeq, see below. The character starts a sequence. + this.encodeTable = []; + + // `encodeTableSeq` is used when a sequence of unicode characters is encoded as a single code. We use a tree of + // objects where keys correspond to characters in sequence and leafs are the encoded dbcs values. A special DEF_CHAR key + // means end of sequence (needed when one sequence is a strict subsequence of another). + // Objects are kept separately from encodeTable to increase performance. + this.encodeTableSeq = []; + + // Some chars can be decoded, but need not be encoded. + var skipEncodeChars = {}; + if (codecOptions.encodeSkipVals) + for (var i = 0; i < codecOptions.encodeSkipVals.length; i++) { + var val = codecOptions.encodeSkipVals[i]; + if (typeof val === 'number') + skipEncodeChars[val] = true; + else + for (var j = val.from; j <= val.to; j++) + skipEncodeChars[j] = true; + } + + // Use decode trie to recursively fill out encode tables. + this._fillEncodeTable(0, 0, skipEncodeChars); + + // Add more encoding pairs when needed. + if (codecOptions.encodeAdd) { + for (var uChar in codecOptions.encodeAdd) + if (Object.prototype.hasOwnProperty.call(codecOptions.encodeAdd, uChar)) + this._setEncodeChar(uChar.charCodeAt(0), codecOptions.encodeAdd[uChar]); + } + + this.defCharSB = this.encodeTable[0][iconv.defaultCharSingleByte.charCodeAt(0)]; + if (this.defCharSB === UNASSIGNED) this.defCharSB = this.encodeTable[0]['?']; + if (this.defCharSB === UNASSIGNED) this.defCharSB = "?".charCodeAt(0); + + + // Load & create GB18030 tables when needed. + if (typeof codecOptions.gb18030 === 'function') { + this.gb18030 = codecOptions.gb18030(); // Load GB18030 ranges. + + // Add GB18030 decode tables. + var thirdByteNodeIdx = this.decodeTables.length; + var thirdByteNode = this.decodeTables[thirdByteNodeIdx] = UNASSIGNED_NODE.slice(0); + + var fourthByteNodeIdx = this.decodeTables.length; + var fourthByteNode = this.decodeTables[fourthByteNodeIdx] = UNASSIGNED_NODE.slice(0); + + for (var i = 0x81; i <= 0xFE; i++) { + var secondByteNodeIdx = NODE_START - this.decodeTables[0][i]; + var secondByteNode = this.decodeTables[secondByteNodeIdx]; + for (var j = 0x30; j <= 0x39; j++) + secondByteNode[j] = NODE_START - thirdByteNodeIdx; + } + for (var i = 0x81; i <= 0xFE; i++) + thirdByteNode[i] = NODE_START - fourthByteNodeIdx; + for (var i = 0x30; i <= 0x39; i++) + fourthByteNode[i] = GB18030_CODE + } +} + +DBCSCodec.prototype.encoder = DBCSEncoder; +DBCSCodec.prototype.decoder = DBCSDecoder; + +// Decoder helpers +DBCSCodec.prototype._getDecodeTrieNode = function(addr) { + var bytes = []; + for (; addr > 0; addr >>= 8) + bytes.push(addr & 0xFF); + if (bytes.length == 0) + bytes.push(0); + + var node = this.decodeTables[0]; + for (var i = bytes.length-1; i > 0; i--) { // Traverse nodes deeper into the trie. + var val = node[bytes[i]]; + + if (val == UNASSIGNED) { // Create new node. + node[bytes[i]] = NODE_START - this.decodeTables.length; + this.decodeTables.push(node = UNASSIGNED_NODE.slice(0)); + } + else if (val <= NODE_START) { // Existing node. + node = this.decodeTables[NODE_START - val]; + } + else + throw new Error("Overwrite byte in " + this.encodingName + ", addr: " + addr.toString(16)); + } + return node; +} + + +DBCSCodec.prototype._addDecodeChunk = function(chunk) { + // First element of chunk is the hex mbcs code where we start. + var curAddr = parseInt(chunk[0], 16); + + // Choose the decoding node where we'll write our chars. + var writeTable = this._getDecodeTrieNode(curAddr); + curAddr = curAddr & 0xFF; + + // Write all other elements of the chunk to the table. + for (var k = 1; k < chunk.length; k++) { + var part = chunk[k]; + if (typeof part === "string") { // String, write as-is. + for (var l = 0; l < part.length;) { + var code = part.charCodeAt(l++); + if (0xD800 <= code && code < 0xDC00) { // Decode surrogate + var codeTrail = part.charCodeAt(l++); + if (0xDC00 <= codeTrail && codeTrail < 0xE000) + writeTable[curAddr++] = 0x10000 + (code - 0xD800) * 0x400 + (codeTrail - 0xDC00); + else + throw new Error("Incorrect surrogate pair in " + this.encodingName + " at chunk " + chunk[0]); + } + else if (0x0FF0 < code && code <= 0x0FFF) { // Character sequence (our own encoding used) + var len = 0xFFF - code + 2; + var seq = []; + for (var m = 0; m < len; m++) + seq.push(part.charCodeAt(l++)); // Simple variation: don't support surrogates or subsequences in seq. + + writeTable[curAddr++] = SEQ_START - this.decodeTableSeq.length; + this.decodeTableSeq.push(seq); + } + else + writeTable[curAddr++] = code; // Basic char + } + } + else if (typeof part === "number") { // Integer, meaning increasing sequence starting with prev character. + var charCode = writeTable[curAddr - 1] + 1; + for (var l = 0; l < part; l++) + writeTable[curAddr++] = charCode++; + } + else + throw new Error("Incorrect type '" + typeof part + "' given in " + this.encodingName + " at chunk " + chunk[0]); + } + if (curAddr > 0xFF) + throw new Error("Incorrect chunk in " + this.encodingName + " at addr " + chunk[0] + ": too long" + curAddr); +} + +// Encoder helpers +DBCSCodec.prototype._getEncodeBucket = function(uCode) { + var high = uCode >> 8; // This could be > 0xFF because of astral characters. + if (this.encodeTable[high] === undefined) + this.encodeTable[high] = UNASSIGNED_NODE.slice(0); // Create bucket on demand. + return this.encodeTable[high]; +} + +DBCSCodec.prototype._setEncodeChar = function(uCode, dbcsCode) { + var bucket = this._getEncodeBucket(uCode); + var low = uCode & 0xFF; + if (bucket[low] <= SEQ_START) + this.encodeTableSeq[SEQ_START-bucket[low]][DEF_CHAR] = dbcsCode; // There's already a sequence, set a single-char subsequence of it. + else if (bucket[low] == UNASSIGNED) + bucket[low] = dbcsCode; +} + +DBCSCodec.prototype._setEncodeSequence = function(seq, dbcsCode) { + + // Get the root of character tree according to first character of the sequence. + var uCode = seq[0]; + var bucket = this._getEncodeBucket(uCode); + var low = uCode & 0xFF; + + var node; + if (bucket[low] <= SEQ_START) { + // There's already a sequence with - use it. + node = this.encodeTableSeq[SEQ_START-bucket[low]]; + } + else { + // There was no sequence object - allocate a new one. + node = {}; + if (bucket[low] !== UNASSIGNED) node[DEF_CHAR] = bucket[low]; // If a char was set before - make it a single-char subsequence. + bucket[low] = SEQ_START - this.encodeTableSeq.length; + this.encodeTableSeq.push(node); + } + + // Traverse the character tree, allocating new nodes as needed. + for (var j = 1; j < seq.length-1; j++) { + var oldVal = node[uCode]; + if (typeof oldVal === 'object') + node = oldVal; + else { + node = node[uCode] = {} + if (oldVal !== undefined) + node[DEF_CHAR] = oldVal + } + } + + // Set the leaf to given dbcsCode. + uCode = seq[seq.length-1]; + node[uCode] = dbcsCode; +} + +DBCSCodec.prototype._fillEncodeTable = function(nodeIdx, prefix, skipEncodeChars) { + var node = this.decodeTables[nodeIdx]; + for (var i = 0; i < 0x100; i++) { + var uCode = node[i]; + var mbCode = prefix + i; + if (skipEncodeChars[mbCode]) + continue; + + if (uCode >= 0) + this._setEncodeChar(uCode, mbCode); + else if (uCode <= NODE_START) + this._fillEncodeTable(NODE_START - uCode, mbCode << 8, skipEncodeChars); + else if (uCode <= SEQ_START) + this._setEncodeSequence(this.decodeTableSeq[SEQ_START - uCode], mbCode); + } +} + + + +// == Encoder ================================================================== + +function DBCSEncoder(options, codec) { + // Encoder state + this.leadSurrogate = -1; + this.seqObj = undefined; + + // Static data + this.encodeTable = codec.encodeTable; + this.encodeTableSeq = codec.encodeTableSeq; + this.defaultCharSingleByte = codec.defCharSB; + this.gb18030 = codec.gb18030; +} + +DBCSEncoder.prototype.write = function(str) { + var newBuf = Buffer.alloc(str.length * (this.gb18030 ? 4 : 3)), + leadSurrogate = this.leadSurrogate, + seqObj = this.seqObj, nextChar = -1, + i = 0, j = 0; + + while (true) { + // 0. Get next character. + if (nextChar === -1) { + if (i == str.length) break; + var uCode = str.charCodeAt(i++); + } + else { + var uCode = nextChar; + nextChar = -1; + } + + // 1. Handle surrogates. + if (0xD800 <= uCode && uCode < 0xE000) { // Char is one of surrogates. + if (uCode < 0xDC00) { // We've got lead surrogate. + if (leadSurrogate === -1) { + leadSurrogate = uCode; + continue; + } else { + leadSurrogate = uCode; + // Double lead surrogate found. + uCode = UNASSIGNED; + } + } else { // We've got trail surrogate. + if (leadSurrogate !== -1) { + uCode = 0x10000 + (leadSurrogate - 0xD800) * 0x400 + (uCode - 0xDC00); + leadSurrogate = -1; + } else { + // Incomplete surrogate pair - only trail surrogate found. + uCode = UNASSIGNED; + } + + } + } + else if (leadSurrogate !== -1) { + // Incomplete surrogate pair - only lead surrogate found. + nextChar = uCode; uCode = UNASSIGNED; // Write an error, then current char. + leadSurrogate = -1; + } + + // 2. Convert uCode character. + var dbcsCode = UNASSIGNED; + if (seqObj !== undefined && uCode != UNASSIGNED) { // We are in the middle of the sequence + var resCode = seqObj[uCode]; + if (typeof resCode === 'object') { // Sequence continues. + seqObj = resCode; + continue; + + } else if (typeof resCode == 'number') { // Sequence finished. Write it. + dbcsCode = resCode; + + } else if (resCode == undefined) { // Current character is not part of the sequence. + + // Try default character for this sequence + resCode = seqObj[DEF_CHAR]; + if (resCode !== undefined) { + dbcsCode = resCode; // Found. Write it. + nextChar = uCode; // Current character will be written too in the next iteration. + + } else { + // TODO: What if we have no default? (resCode == undefined) + // Then, we should write first char of the sequence as-is and try the rest recursively. + // Didn't do it for now because no encoding has this situation yet. + // Currently, just skip the sequence and write current char. + } + } + seqObj = undefined; + } + else if (uCode >= 0) { // Regular character + var subtable = this.encodeTable[uCode >> 8]; + if (subtable !== undefined) + dbcsCode = subtable[uCode & 0xFF]; + + if (dbcsCode <= SEQ_START) { // Sequence start + seqObj = this.encodeTableSeq[SEQ_START-dbcsCode]; + continue; + } + + if (dbcsCode == UNASSIGNED && this.gb18030) { + // Use GB18030 algorithm to find character(s) to write. + var idx = findIdx(this.gb18030.uChars, uCode); + if (idx != -1) { + var dbcsCode = this.gb18030.gbChars[idx] + (uCode - this.gb18030.uChars[idx]); + newBuf[j++] = 0x81 + Math.floor(dbcsCode / 12600); dbcsCode = dbcsCode % 12600; + newBuf[j++] = 0x30 + Math.floor(dbcsCode / 1260); dbcsCode = dbcsCode % 1260; + newBuf[j++] = 0x81 + Math.floor(dbcsCode / 10); dbcsCode = dbcsCode % 10; + newBuf[j++] = 0x30 + dbcsCode; + continue; + } + } + } + + // 3. Write dbcsCode character. + if (dbcsCode === UNASSIGNED) + dbcsCode = this.defaultCharSingleByte; + + if (dbcsCode < 0x100) { + newBuf[j++] = dbcsCode; + } + else if (dbcsCode < 0x10000) { + newBuf[j++] = dbcsCode >> 8; // high byte + newBuf[j++] = dbcsCode & 0xFF; // low byte + } + else { + newBuf[j++] = dbcsCode >> 16; + newBuf[j++] = (dbcsCode >> 8) & 0xFF; + newBuf[j++] = dbcsCode & 0xFF; + } + } + + this.seqObj = seqObj; + this.leadSurrogate = leadSurrogate; + return newBuf.slice(0, j); +} + +DBCSEncoder.prototype.end = function() { + if (this.leadSurrogate === -1 && this.seqObj === undefined) + return; // All clean. Most often case. + + var newBuf = Buffer.alloc(10), j = 0; + + if (this.seqObj) { // We're in the sequence. + var dbcsCode = this.seqObj[DEF_CHAR]; + if (dbcsCode !== undefined) { // Write beginning of the sequence. + if (dbcsCode < 0x100) { + newBuf[j++] = dbcsCode; + } + else { + newBuf[j++] = dbcsCode >> 8; // high byte + newBuf[j++] = dbcsCode & 0xFF; // low byte + } + } else { + // See todo above. + } + this.seqObj = undefined; + } + + if (this.leadSurrogate !== -1) { + // Incomplete surrogate pair - only lead surrogate found. + newBuf[j++] = this.defaultCharSingleByte; + this.leadSurrogate = -1; + } + + return newBuf.slice(0, j); +} + +// Export for testing +DBCSEncoder.prototype.findIdx = findIdx; + + +// == Decoder ================================================================== + +function DBCSDecoder(options, codec) { + // Decoder state + this.nodeIdx = 0; + this.prevBuf = Buffer.alloc(0); + + // Static data + this.decodeTables = codec.decodeTables; + this.decodeTableSeq = codec.decodeTableSeq; + this.defaultCharUnicode = codec.defaultCharUnicode; + this.gb18030 = codec.gb18030; +} + +DBCSDecoder.prototype.write = function(buf) { + var newBuf = Buffer.alloc(buf.length*2), + nodeIdx = this.nodeIdx, + prevBuf = this.prevBuf, prevBufOffset = this.prevBuf.length, + seqStart = -this.prevBuf.length, // idx of the start of current parsed sequence. + uCode; + + if (prevBufOffset > 0) // Make prev buf overlap a little to make it easier to slice later. + prevBuf = Buffer.concat([prevBuf, buf.slice(0, 10)]); + + for (var i = 0, j = 0; i < buf.length; i++) { + var curByte = (i >= 0) ? buf[i] : prevBuf[i + prevBufOffset]; + + // Lookup in current trie node. + var uCode = this.decodeTables[nodeIdx][curByte]; + + if (uCode >= 0) { + // Normal character, just use it. + } + else if (uCode === UNASSIGNED) { // Unknown char. + // TODO: Callback with seq. + //var curSeq = (seqStart >= 0) ? buf.slice(seqStart, i+1) : prevBuf.slice(seqStart + prevBufOffset, i+1 + prevBufOffset); + i = seqStart; // Try to parse again, after skipping first byte of the sequence ('i' will be incremented by 'for' cycle). + uCode = this.defaultCharUnicode.charCodeAt(0); + } + else if (uCode === GB18030_CODE) { + var curSeq = (seqStart >= 0) ? buf.slice(seqStart, i+1) : prevBuf.slice(seqStart + prevBufOffset, i+1 + prevBufOffset); + var ptr = (curSeq[0]-0x81)*12600 + (curSeq[1]-0x30)*1260 + (curSeq[2]-0x81)*10 + (curSeq[3]-0x30); + var idx = findIdx(this.gb18030.gbChars, ptr); + uCode = this.gb18030.uChars[idx] + ptr - this.gb18030.gbChars[idx]; + } + else if (uCode <= NODE_START) { // Go to next trie node. + nodeIdx = NODE_START - uCode; + continue; + } + else if (uCode <= SEQ_START) { // Output a sequence of chars. + var seq = this.decodeTableSeq[SEQ_START - uCode]; + for (var k = 0; k < seq.length - 1; k++) { + uCode = seq[k]; + newBuf[j++] = uCode & 0xFF; + newBuf[j++] = uCode >> 8; + } + uCode = seq[seq.length-1]; + } + else + throw new Error("iconv-lite internal error: invalid decoding table value " + uCode + " at " + nodeIdx + "/" + curByte); + + // Write the character to buffer, handling higher planes using surrogate pair. + if (uCode > 0xFFFF) { + uCode -= 0x10000; + var uCodeLead = 0xD800 + Math.floor(uCode / 0x400); + newBuf[j++] = uCodeLead & 0xFF; + newBuf[j++] = uCodeLead >> 8; + + uCode = 0xDC00 + uCode % 0x400; + } + newBuf[j++] = uCode & 0xFF; + newBuf[j++] = uCode >> 8; + + // Reset trie node. + nodeIdx = 0; seqStart = i+1; + } + + this.nodeIdx = nodeIdx; + this.prevBuf = (seqStart >= 0) ? buf.slice(seqStart) : prevBuf.slice(seqStart + prevBufOffset); + return newBuf.slice(0, j).toString('ucs2'); +} + +DBCSDecoder.prototype.end = function() { + var ret = ''; + + // Try to parse all remaining chars. + while (this.prevBuf.length > 0) { + // Skip 1 character in the buffer. + ret += this.defaultCharUnicode; + var buf = this.prevBuf.slice(1); + + // Parse remaining as usual. + this.prevBuf = Buffer.alloc(0); + this.nodeIdx = 0; + if (buf.length > 0) + ret += this.write(buf); + } + + this.nodeIdx = 0; + return ret; +} + +// Binary search for GB18030. Returns largest i such that table[i] <= val. +function findIdx(table, val) { + if (table[0] > val) + return -1; + + var l = 0, r = table.length; + while (l < r-1) { // always table[l] <= val < table[r] + var mid = l + Math.floor((r-l+1)/2); + if (table[mid] <= val) + l = mid; + else + r = mid; + } + return l; +} + |