source: trip-planner-front/node_modules/obuf/index.js@ 6a3a178

Last change on this file since 6a3a178 was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

  • Property mode set to 100644
File size: 8.6 KB
Line 
1var Buffer = require('buffer').Buffer;
2
3function OffsetBuffer() {
4 this.offset = 0;
5 this.size = 0;
6 this.buffers = [];
7}
8module.exports = OffsetBuffer;
9
10OffsetBuffer.prototype.isEmpty = function isEmpty() {
11 return this.size === 0;
12};
13
14OffsetBuffer.prototype.clone = function clone(size) {
15 var r = new OffsetBuffer();
16 r.offset = this.offset;
17 r.size = size;
18 r.buffers = this.buffers.slice();
19 return r;
20};
21
22OffsetBuffer.prototype.toChunks = function toChunks() {
23 if (this.size === 0)
24 return [];
25
26 // We are going to slice it anyway
27 if (this.offset !== 0) {
28 this.buffers[0] = this.buffers[0].slice(this.offset);
29 this.offset = 0;
30 }
31
32 var chunks = [ ];
33 var off = 0;
34 for (var i = 0; off <= this.size && i < this.buffers.length; i++) {
35 var buf = this.buffers[i];
36 off += buf.length;
37
38 // Slice off last buffer
39 if (off > this.size) {
40 buf = buf.slice(0, buf.length - (off - this.size));
41 this.buffers[i] = buf;
42 }
43
44 chunks.push(buf);
45 }
46
47 // If some buffers were skipped - trim length
48 if (i < this.buffers.length)
49 this.buffers.length = i;
50
51 return chunks;
52};
53
54OffsetBuffer.prototype.toString = function toString(enc) {
55 return this.toChunks().map(function(c) {
56 return c.toString(enc);
57 }).join('');
58};
59
60OffsetBuffer.prototype.use = function use(buf, off, n) {
61 this.buffers = [ buf ];
62 this.offset = off;
63 this.size = n;
64};
65
66OffsetBuffer.prototype.push = function push(data) {
67 // Ignore empty writes
68 if (data.length === 0)
69 return;
70
71 this.size += data.length;
72 this.buffers.push(data);
73};
74
75OffsetBuffer.prototype.has = function has(n) {
76 return this.size >= n;
77};
78
79OffsetBuffer.prototype.skip = function skip(n) {
80 if (this.size === 0)
81 return;
82
83 this.size -= n;
84
85 // Fast case, skip bytes in a first buffer
86 if (this.offset + n < this.buffers[0].length) {
87 this.offset += n;
88 return;
89 }
90
91 var left = n - (this.buffers[0].length - this.offset);
92 this.offset = 0;
93
94 for (var shift = 1; left > 0 && shift < this.buffers.length; shift++) {
95 var buf = this.buffers[shift];
96 if (buf.length > left) {
97 this.offset = left;
98 break;
99 }
100 left -= buf.length;
101 }
102 this.buffers = this.buffers.slice(shift);
103};
104
105OffsetBuffer.prototype.copy = function copy(target, targetOff, off, n) {
106 if (this.size === 0)
107 return;
108 if (off !== 0)
109 throw new Error('Unsupported offset in .copy()');
110
111 var toff = targetOff;
112 var first = this.buffers[0];
113 var toCopy = Math.min(n, first.length - this.offset);
114 first.copy(target, toff, this.offset, this.offset + toCopy);
115
116 toff += toCopy;
117 var left = n - toCopy;
118 for (var i = 1; left > 0 && i < this.buffers.length; i++) {
119 var buf = this.buffers[i];
120 var toCopy = Math.min(left, buf.length);
121
122 buf.copy(target, toff, 0, toCopy);
123
124 toff += toCopy;
125 left -= toCopy;
126 }
127};
128
129OffsetBuffer.prototype.take = function take(n) {
130 if (n === 0)
131 return new Buffer(0);
132
133 this.size -= n;
134
135 // Fast cases
136 var first = this.buffers[0].length - this.offset;
137 if (first === n) {
138 var r = this.buffers.shift();
139 if (this.offset !== 0) {
140 r = r.slice(this.offset);
141 this.offset = 0;
142 }
143 return r;
144 } else if (first > n) {
145 var r = this.buffers[0].slice(this.offset, this.offset + n);
146 this.offset += n;
147 return r;
148 }
149
150 // Allocate and fill buffer
151 var out = new Buffer(n);
152 var toOff = 0;
153 var startOff = this.offset;
154 for (var i = 0; toOff !== n && i < this.buffers.length; i++) {
155 var buf = this.buffers[i];
156 var toCopy = Math.min(buf.length - startOff, n - toOff);
157
158 buf.copy(out, toOff, startOff, startOff + toCopy);
159 if (startOff + toCopy < buf.length) {
160 this.offset = startOff + toCopy;
161 break;
162 } else {
163 toOff += toCopy;
164 startOff = 0;
165 }
166 }
167
168 this.buffers = this.buffers.slice(i);
169 if (this.buffers.length === 0)
170 this.offset = 0;
171
172 return out;
173};
174
175OffsetBuffer.prototype.peekUInt8 = function peekUInt8() {
176 return this.buffers[0][this.offset];
177};
178
179OffsetBuffer.prototype.readUInt8 = function readUInt8() {
180 this.size -= 1;
181 var first = this.buffers[0];
182 var r = first[this.offset];
183 if (++this.offset === first.length) {
184 this.offset = 0;
185 this.buffers.shift();
186 }
187
188 return r;
189};
190
191OffsetBuffer.prototype.readUInt16LE = function readUInt16LE() {
192 var first = this.buffers[0];
193 this.size -= 2;
194
195 var r;
196 var shift;
197
198 // Fast case - first buffer has all bytes
199 if (first.length - this.offset >= 2) {
200 r = first.readUInt16LE(this.offset);
201 shift = 0;
202 this.offset += 2;
203
204 // One byte here - one byte there
205 } else {
206 r = first[this.offset] | (this.buffers[1][0] << 8);
207 shift = 1;
208 this.offset = 1;
209 }
210
211 if (this.offset === this.buffers[shift].length) {
212 this.offset = 0;
213 shift++;
214 }
215 if (shift !== 0)
216 this.buffers = this.buffers.slice(shift);
217
218 return r;
219};
220
221OffsetBuffer.prototype.readUInt24LE = function readUInt24LE() {
222 var first = this.buffers[0];
223
224 var r;
225 var shift;
226 var firstHas = first.length - this.offset;
227
228 // Fast case - first buffer has all bytes
229 if (firstHas >= 3) {
230 r = first.readUInt16LE(this.offset) | (first[this.offset + 2] << 16);
231 shift = 0;
232 this.offset += 3;
233
234 // First buffer has 2 of 3 bytes
235 } else if (firstHas >= 2) {
236 r = first.readUInt16LE(this.offset) | (this.buffers[1][0] << 16);
237 shift = 1;
238 this.offset = 1;
239
240 // Slow case: First buffer has 1 of 3 bytes
241 } else {
242 r = first[this.offset];
243 this.offset = 0;
244 this.buffers.shift();
245 this.size -= 1;
246
247 r |= this.readUInt16LE() << 8;
248 return r;
249 }
250
251 this.size -= 3;
252 if (this.offset === this.buffers[shift].length) {
253 this.offset = 0;
254 shift++;
255 }
256 if (shift !== 0)
257 this.buffers = this.buffers.slice(shift);
258
259 return r;
260};
261
262OffsetBuffer.prototype.readUInt32LE = function readUInt32LE() {
263 var first = this.buffers[0];
264
265 var r;
266 var shift;
267 var firstHas = first.length - this.offset;
268
269 // Fast case - first buffer has all bytes
270 if (firstHas >= 4) {
271 r = first.readUInt32LE(this.offset);
272 shift = 0;
273 this.offset += 4;
274
275 // First buffer has 3 of 4 bytes
276 } else if (firstHas >= 3) {
277 r = (first.readUInt16LE(this.offset) |
278 (first[this.offset + 2] << 16)) +
279 (this.buffers[1][0] * 0x1000000);
280 shift = 1;
281 this.offset = 1;
282
283 // Slow case: First buffer has 2 of 4 bytes
284 } else if (firstHas >= 2) {
285 r = first.readUInt16LE(this.offset);
286 this.offset = 0;
287 this.buffers.shift();
288 this.size -= 2;
289
290 r += this.readUInt16LE() * 0x10000;
291 return r;
292
293 // Slow case: First buffer has 1 of 4 bytes
294 } else {
295 r = first[this.offset];
296 this.offset = 0;
297 this.buffers.shift();
298 this.size -= 1;
299
300 r += this.readUInt24LE() * 0x100;
301 return r;
302 }
303
304 this.size -= 4;
305 if (this.offset === this.buffers[shift].length) {
306 this.offset = 0;
307 shift++;
308 }
309 if (shift !== 0)
310 this.buffers = this.buffers.slice(shift);
311
312 return r;
313};
314
315OffsetBuffer.prototype.readUInt16BE = function readUInt16BE() {
316 var r = this.readUInt16LE();
317
318 return ((r & 0xff) << 8) | (r >> 8);
319};
320
321OffsetBuffer.prototype.readUInt24BE = function readUInt24BE() {
322 var r = this.readUInt24LE();
323
324 return ((r & 0xff) << 16) | (((r >> 8) & 0xff) << 8) | (r >> 16);
325};
326
327OffsetBuffer.prototype.readUInt32BE = function readUInt32BE() {
328 var r = this.readUInt32LE();
329
330 return (((r & 0xff) << 24) |
331 (((r >>> 8) & 0xff) << 16) |
332 (((r >>> 16) & 0xff) << 8) |
333 (r >>> 24)) >>> 0;
334};
335
336// Signed number APIs
337
338function signedInt8(num) {
339 if (num >= 0x80)
340 return -(0xff ^ num) - 1;
341 else
342 return num;
343}
344
345OffsetBuffer.prototype.peekInt8 = function peekInt8() {
346 return signedInt8(this.peekUInt8());
347};
348
349OffsetBuffer.prototype.readInt8 = function readInt8() {
350 return signedInt8(this.readUInt8());
351};
352
353function signedInt16(num) {
354 if (num >= 0x8000)
355 return -(0xffff ^ num) - 1;
356 else
357 return num;
358}
359
360OffsetBuffer.prototype.readInt16BE = function readInt16BE() {
361 return signedInt16(this.readUInt16BE());
362};
363
364OffsetBuffer.prototype.readInt16LE = function readInt16LE() {
365 return signedInt16(this.readUInt16LE());
366};
367
368function signedInt24(num) {
369 if (num >= 0x800000)
370 return -(0xffffff ^ num) - 1;
371 else
372 return num;
373}
374
375OffsetBuffer.prototype.readInt24BE = function readInt24BE() {
376 return signedInt24(this.readUInt24BE());
377};
378
379OffsetBuffer.prototype.readInt24LE = function readInt24LE() {
380 return signedInt24(this.readUInt24LE());
381};
382
383function signedInt32(num) {
384 if (num >= 0x80000000)
385 return -(0xffffffff ^ num) - 1;
386 else
387 return num;
388}
389
390OffsetBuffer.prototype.readInt32BE = function readInt32BE() {
391 return signedInt32(this.readUInt32BE());
392};
393
394OffsetBuffer.prototype.readInt32LE = function readInt32LE() {
395 return signedInt32(this.readUInt32LE());
396};
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