270 lines
6.9 KiB
JavaScript
270 lines
6.9 KiB
JavaScript
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module.exports = Buffers;
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function Buffers (bufs) {
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if (!(this instanceof Buffers)) return new Buffers(bufs);
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this.buffers = bufs || [];
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this.length = this.buffers.reduce(function (size, buf) {
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return size + buf.length
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}, 0);
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}
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Buffers.prototype.push = function () {
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for (var i = 0; i < arguments.length; i++) {
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if (!Buffer.isBuffer(arguments[i])) {
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throw new TypeError('Tried to push a non-buffer');
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}
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}
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for (var i = 0; i < arguments.length; i++) {
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var buf = arguments[i];
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this.buffers.push(buf);
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this.length += buf.length;
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}
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return this.length;
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};
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Buffers.prototype.unshift = function () {
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for (var i = 0; i < arguments.length; i++) {
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if (!Buffer.isBuffer(arguments[i])) {
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throw new TypeError('Tried to unshift a non-buffer');
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}
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}
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for (var i = 0; i < arguments.length; i++) {
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var buf = arguments[i];
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this.buffers.unshift(buf);
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this.length += buf.length;
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}
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return this.length;
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};
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Buffers.prototype.copy = function (dst, dStart, start, end) {
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return this.slice(start, end).copy(dst, dStart, 0, end - start);
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};
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Buffers.prototype.splice = function (i, howMany) {
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var buffers = this.buffers;
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var index = i >= 0 ? i : this.length - i;
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var reps = [].slice.call(arguments, 2);
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if (howMany === undefined) {
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howMany = this.length - index;
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}
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else if (howMany > this.length - index) {
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howMany = this.length - index;
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}
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for (var i = 0; i < reps.length; i++) {
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this.length += reps[i].length;
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}
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var removed = new Buffers();
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var bytes = 0;
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var startBytes = 0;
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for (
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var ii = 0;
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ii < buffers.length && startBytes + buffers[ii].length < index;
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ii ++
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) { startBytes += buffers[ii].length }
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if (index - startBytes > 0) {
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var start = index - startBytes;
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if (start + howMany < buffers[ii].length) {
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removed.push(buffers[ii].slice(start, start + howMany));
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var orig = buffers[ii];
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//var buf = new Buffer(orig.length - howMany);
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var buf0 = new Buffer(start);
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for (var i = 0; i < start; i++) {
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buf0[i] = orig[i];
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}
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var buf1 = new Buffer(orig.length - start - howMany);
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for (var i = start + howMany; i < orig.length; i++) {
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buf1[ i - howMany - start ] = orig[i]
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}
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if (reps.length > 0) {
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var reps_ = reps.slice();
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reps_.unshift(buf0);
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reps_.push(buf1);
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buffers.splice.apply(buffers, [ ii, 1 ].concat(reps_));
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ii += reps_.length;
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reps = [];
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}
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else {
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buffers.splice(ii, 1, buf0, buf1);
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//buffers[ii] = buf;
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ii += 2;
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}
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}
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else {
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removed.push(buffers[ii].slice(start));
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buffers[ii] = buffers[ii].slice(0, start);
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ii ++;
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}
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}
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if (reps.length > 0) {
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buffers.splice.apply(buffers, [ ii, 0 ].concat(reps));
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ii += reps.length;
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}
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while (removed.length < howMany) {
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var buf = buffers[ii];
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var len = buf.length;
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var take = Math.min(len, howMany - removed.length);
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if (take === len) {
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removed.push(buf);
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buffers.splice(ii, 1);
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}
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else {
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removed.push(buf.slice(0, take));
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buffers[ii] = buffers[ii].slice(take);
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}
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}
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this.length -= removed.length;
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return removed;
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};
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Buffers.prototype.slice = function (i, j) {
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var buffers = this.buffers;
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if (j === undefined) j = this.length;
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if (i === undefined) i = 0;
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if (j > this.length) j = this.length;
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var startBytes = 0;
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for (
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var si = 0;
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si < buffers.length && startBytes + buffers[si].length <= i;
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si ++
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) { startBytes += buffers[si].length }
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var target = new Buffer(j - i);
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var ti = 0;
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for (var ii = si; ti < j - i && ii < buffers.length; ii++) {
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var len = buffers[ii].length;
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var start = ti === 0 ? i - startBytes : 0;
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var end = ti + len >= j - i
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? Math.min(start + (j - i) - ti, len)
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: len
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;
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buffers[ii].copy(target, ti, start, end);
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ti += end - start;
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}
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return target;
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};
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Buffers.prototype.pos = function (i) {
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if (i < 0 || i >= this.length) throw new Error('oob');
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var l = i, bi = 0, bu = null;
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for (;;) {
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bu = this.buffers[bi];
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if (l < bu.length) {
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return {buf: bi, offset: l};
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} else {
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l -= bu.length;
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}
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bi++;
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}
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};
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Buffers.prototype.get = function get (i) {
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var pos = this.pos(i);
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return this.buffers[pos.buf].get(pos.offset);
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};
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Buffers.prototype.set = function set (i, b) {
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var pos = this.pos(i);
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return this.buffers[pos.buf].set(pos.offset, b);
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};
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Buffers.prototype.indexOf = function (needle, offset) {
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if ("string" === typeof needle) {
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needle = new Buffer(needle);
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} else if (needle instanceof Buffer) {
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// already a buffer
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} else {
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throw new Error('Invalid type for a search string');
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}
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if (!needle.length) {
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return 0;
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}
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if (!this.length) {
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return -1;
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}
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var i = 0, j = 0, match = 0, mstart, pos = 0;
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// start search from a particular point in the virtual buffer
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if (offset) {
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var p = this.pos(offset);
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i = p.buf;
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j = p.offset;
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pos = offset;
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}
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// for each character in virtual buffer
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for (;;) {
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while (j >= this.buffers[i].length) {
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j = 0;
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i++;
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if (i >= this.buffers.length) {
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// search string not found
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return -1;
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}
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}
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var char = this.buffers[i][j];
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if (char == needle[match]) {
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// keep track where match started
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if (match == 0) {
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mstart = {
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i: i,
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j: j,
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pos: pos
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};
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}
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match++;
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if (match == needle.length) {
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// full match
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return mstart.pos;
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}
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} else if (match != 0) {
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// a partial match ended, go back to match starting position
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// this will continue the search at the next character
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i = mstart.i;
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j = mstart.j;
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pos = mstart.pos;
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match = 0;
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}
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j++;
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pos++;
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}
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};
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Buffers.prototype.toBuffer = function() {
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return this.slice();
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}
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Buffers.prototype.toString = function(encoding, start, end) {
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return this.slice(start, end).toString(encoding);
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}
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