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| 1 // Protocol Buffers - Google's data interchange format |
| 2 // Copyright 2008 Google Inc. All rights reserved. |
| 3 // https://developers.google.com/protocol-buffers/ |
| 4 // |
| 5 // Redistribution and use in source and binary forms, with or without |
| 6 // modification, are permitted provided that the following conditions are |
| 7 // met: |
| 8 // |
| 9 // * Redistributions of source code must retain the above copyright |
| 10 // notice, this list of conditions and the following disclaimer. |
| 11 // * Redistributions in binary form must reproduce the above |
| 12 // copyright notice, this list of conditions and the following disclaimer |
| 13 // in the documentation and/or other materials provided with the |
| 14 // distribution. |
| 15 // * Neither the name of Google Inc. nor the names of its |
| 16 // contributors may be used to endorse or promote products derived from |
| 17 // this software without specific prior written permission. |
| 18 // |
| 19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 30 |
| 31 /** |
| 32 * @fileoverview This file contains helper code used by jspb.utils to |
| 33 * handle 64-bit integer conversion to/from strings. |
| 34 * |
| 35 * @author cfallin@google.com (Chris Fallin) |
| 36 * |
| 37 * TODO(haberman): move this to javascript/closure/math? |
| 38 */ |
| 39 |
| 40 goog.provide('jspb.arith.Int64'); |
| 41 goog.provide('jspb.arith.UInt64'); |
| 42 |
| 43 /** |
| 44 * UInt64 implements some 64-bit arithmetic routines necessary for properly |
| 45 * handling 64-bit integer fields. It implements lossless integer arithmetic on |
| 46 * top of JavaScript's number type, which has only 53 bits of precision, by |
| 47 * representing 64-bit integers as two 32-bit halves. |
| 48 * |
| 49 * @param {number} lo The low 32 bits. |
| 50 * @param {number} hi The high 32 bits. |
| 51 * @constructor |
| 52 */ |
| 53 jspb.arith.UInt64 = function(lo, hi) { |
| 54 /** |
| 55 * The low 32 bits. |
| 56 * @public {number} |
| 57 */ |
| 58 this.lo = lo; |
| 59 /** |
| 60 * The high 32 bits. |
| 61 * @public {number} |
| 62 */ |
| 63 this.hi = hi; |
| 64 }; |
| 65 |
| 66 |
| 67 /** |
| 68 * Compare two 64-bit numbers. Returns -1 if the first is |
| 69 * less, +1 if the first is greater, or 0 if both are equal. |
| 70 * @param {!jspb.arith.UInt64} other |
| 71 * @return {number} |
| 72 */ |
| 73 jspb.arith.UInt64.prototype.cmp = function(other) { |
| 74 if (this.hi < other.hi || (this.hi == other.hi && this.lo < other.lo)) { |
| 75 return -1; |
| 76 } else if (this.hi == other.hi && this.lo == other.lo) { |
| 77 return 0; |
| 78 } else { |
| 79 return 1; |
| 80 } |
| 81 }; |
| 82 |
| 83 |
| 84 /** |
| 85 * Right-shift this number by one bit. |
| 86 * @return {!jspb.arith.UInt64} |
| 87 */ |
| 88 jspb.arith.UInt64.prototype.rightShift = function() { |
| 89 var hi = this.hi >>> 1; |
| 90 var lo = (this.lo >>> 1) | ((this.hi & 1) << 31); |
| 91 return new jspb.arith.UInt64(lo >>> 0, hi >>> 0); |
| 92 }; |
| 93 |
| 94 |
| 95 /** |
| 96 * Left-shift this number by one bit. |
| 97 * @return {!jspb.arith.UInt64} |
| 98 */ |
| 99 jspb.arith.UInt64.prototype.leftShift = function() { |
| 100 var lo = this.lo << 1; |
| 101 var hi = (this.hi << 1) | (this.lo >>> 31); |
| 102 return new jspb.arith.UInt64(lo >>> 0, hi >>> 0); |
| 103 }; |
| 104 |
| 105 |
| 106 /** |
| 107 * Test the MSB. |
| 108 * @return {boolean} |
| 109 */ |
| 110 jspb.arith.UInt64.prototype.msb = function() { |
| 111 return !!(this.hi & 0x80000000); |
| 112 }; |
| 113 |
| 114 |
| 115 /** |
| 116 * Test the LSB. |
| 117 * @return {boolean} |
| 118 */ |
| 119 jspb.arith.UInt64.prototype.lsb = function() { |
| 120 return !!(this.lo & 1); |
| 121 }; |
| 122 |
| 123 |
| 124 /** |
| 125 * Test whether this number is zero. |
| 126 * @return {boolean} |
| 127 */ |
| 128 jspb.arith.UInt64.prototype.zero = function() { |
| 129 return this.lo == 0 && this.hi == 0; |
| 130 }; |
| 131 |
| 132 |
| 133 /** |
| 134 * Add two 64-bit numbers to produce a 64-bit number. |
| 135 * @param {!jspb.arith.UInt64} other |
| 136 * @return {!jspb.arith.UInt64} |
| 137 */ |
| 138 jspb.arith.UInt64.prototype.add = function(other) { |
| 139 var lo = ((this.lo + other.lo) & 0xffffffff) >>> 0; |
| 140 var hi = |
| 141 (((this.hi + other.hi) & 0xffffffff) >>> 0) + |
| 142 (((this.lo + other.lo) >= 0x100000000) ? 1 : 0); |
| 143 return new jspb.arith.UInt64(lo >>> 0, hi >>> 0); |
| 144 }; |
| 145 |
| 146 |
| 147 /** |
| 148 * Subtract two 64-bit numbers to produce a 64-bit number. |
| 149 * @param {!jspb.arith.UInt64} other |
| 150 * @return {!jspb.arith.UInt64} |
| 151 */ |
| 152 jspb.arith.UInt64.prototype.sub = function(other) { |
| 153 var lo = ((this.lo - other.lo) & 0xffffffff) >>> 0; |
| 154 var hi = |
| 155 (((this.hi - other.hi) & 0xffffffff) >>> 0) - |
| 156 (((this.lo - other.lo) < 0) ? 1 : 0); |
| 157 return new jspb.arith.UInt64(lo >>> 0, hi >>> 0); |
| 158 }; |
| 159 |
| 160 |
| 161 /** |
| 162 * Multiply two 32-bit numbers to produce a 64-bit number. |
| 163 * @param {number} a The first integer: must be in [0, 2^32-1). |
| 164 * @param {number} b The second integer: must be in [0, 2^32-1). |
| 165 * @return {!jspb.arith.UInt64} |
| 166 */ |
| 167 jspb.arith.UInt64.mul32x32 = function(a, b) { |
| 168 // Directly multiplying two 32-bit numbers may produce up to 64 bits of |
| 169 // precision, thus losing precision because of the 53-bit mantissa of |
| 170 // JavaScript numbers. So we multiply with 16-bit digits (radix 65536) |
| 171 // instead. |
| 172 var aLow = (a & 0xffff); |
| 173 var aHigh = (a >>> 16); |
| 174 var bLow = (b & 0xffff); |
| 175 var bHigh = (b >>> 16); |
| 176 var productLow = |
| 177 // 32-bit result, result bits 0-31, take all 32 bits |
| 178 (aLow * bLow) + |
| 179 // 32-bit result, result bits 16-47, take bottom 16 as our top 16 |
| 180 ((aLow * bHigh) & 0xffff) * 0x10000 + |
| 181 // 32-bit result, result bits 16-47, take bottom 16 as our top 16 |
| 182 ((aHigh * bLow) & 0xffff) * 0x10000; |
| 183 var productHigh = |
| 184 // 32-bit result, result bits 32-63, take all 32 bits |
| 185 (aHigh * bHigh) + |
| 186 // 32-bit result, result bits 16-47, take top 16 as our bottom 16 |
| 187 ((aLow * bHigh) >>> 16) + |
| 188 // 32-bit result, result bits 16-47, take top 16 as our bottom 16 |
| 189 ((aHigh * bLow) >>> 16); |
| 190 |
| 191 // Carry. Note that we actually have up to *two* carries due to addition of |
| 192 // three terms. |
| 193 while (productLow >= 0x100000000) { |
| 194 productLow -= 0x100000000; |
| 195 productHigh += 1; |
| 196 } |
| 197 |
| 198 return new jspb.arith.UInt64(productLow >>> 0, productHigh >>> 0); |
| 199 }; |
| 200 |
| 201 |
| 202 /** |
| 203 * Multiply this number by a 32-bit number, producing a 96-bit number, then |
| 204 * truncate the top 32 bits. |
| 205 * @param {number} a The multiplier. |
| 206 * @return {!jspb.arith.UInt64} |
| 207 */ |
| 208 jspb.arith.UInt64.prototype.mul = function(a) { |
| 209 // Produce two parts: at bits 0-63, and 32-95. |
| 210 var lo = jspb.arith.UInt64.mul32x32(this.lo, a); |
| 211 var hi = jspb.arith.UInt64.mul32x32(this.hi, a); |
| 212 // Left-shift hi by 32 bits, truncating its top bits. The parts will then be |
| 213 // aligned for addition. |
| 214 hi.hi = hi.lo; |
| 215 hi.lo = 0; |
| 216 return lo.add(hi); |
| 217 }; |
| 218 |
| 219 |
| 220 /** |
| 221 * Divide a 64-bit number by a 32-bit number to produce a |
| 222 * 64-bit quotient and a 32-bit remainder. |
| 223 * @param {number} _divisor |
| 224 * @return {Array.<jspb.arith.UInt64>} array of [quotient, remainder], |
| 225 * unless divisor is 0, in which case an empty array is returned. |
| 226 */ |
| 227 jspb.arith.UInt64.prototype.div = function(_divisor) { |
| 228 if (_divisor == 0) { |
| 229 return []; |
| 230 } |
| 231 |
| 232 // We perform long division using a radix-2 algorithm, for simplicity (i.e., |
| 233 // one bit at a time). TODO: optimize to a radix-2^32 algorithm, taking care |
| 234 // to get the variable shifts right. |
| 235 var quotient = new jspb.arith.UInt64(0, 0); |
| 236 var remainder = new jspb.arith.UInt64(this.lo, this.hi); |
| 237 var divisor = new jspb.arith.UInt64(_divisor, 0); |
| 238 var unit = new jspb.arith.UInt64(1, 0); |
| 239 |
| 240 // Left-shift the divisor and unit until the high bit of divisor is set. |
| 241 while (!divisor.msb()) { |
| 242 divisor = divisor.leftShift(); |
| 243 unit = unit.leftShift(); |
| 244 } |
| 245 |
| 246 // Perform long division one bit at a time. |
| 247 while (!unit.zero()) { |
| 248 // If divisor < remainder, add unit to quotient and subtract divisor from |
| 249 // remainder. |
| 250 if (divisor.cmp(remainder) <= 0) { |
| 251 quotient = quotient.add(unit); |
| 252 remainder = remainder.sub(divisor); |
| 253 } |
| 254 // Right-shift the divisor and unit. |
| 255 divisor = divisor.rightShift(); |
| 256 unit = unit.rightShift(); |
| 257 } |
| 258 |
| 259 return [quotient, remainder]; |
| 260 }; |
| 261 |
| 262 |
| 263 /** |
| 264 * Convert a 64-bit number to a string. |
| 265 * @return {string} |
| 266 * @override |
| 267 */ |
| 268 jspb.arith.UInt64.prototype.toString = function() { |
| 269 var result = ''; |
| 270 var num = this; |
| 271 while (!num.zero()) { |
| 272 var divResult = num.div(10); |
| 273 var quotient = divResult[0], remainder = divResult[1]; |
| 274 result = remainder.lo + result; |
| 275 num = quotient; |
| 276 } |
| 277 if (result == '') { |
| 278 result = '0'; |
| 279 } |
| 280 return result; |
| 281 }; |
| 282 |
| 283 |
| 284 /** |
| 285 * Parse a string into a 64-bit number. Returns `null` on a parse error. |
| 286 * @param {string} s |
| 287 * @return {?jspb.arith.UInt64} |
| 288 */ |
| 289 jspb.arith.UInt64.fromString = function(s) { |
| 290 var result = new jspb.arith.UInt64(0, 0); |
| 291 // optimization: reuse this instance for each digit. |
| 292 var digit64 = new jspb.arith.UInt64(0, 0); |
| 293 for (var i = 0; i < s.length; i++) { |
| 294 if (s[i] < '0' || s[i] > '9') { |
| 295 return null; |
| 296 } |
| 297 var digit = parseInt(s[i], 10); |
| 298 digit64.lo = digit; |
| 299 result = result.mul(10).add(digit64); |
| 300 } |
| 301 return result; |
| 302 }; |
| 303 |
| 304 |
| 305 /** |
| 306 * Make a copy of the uint64. |
| 307 * @return {!jspb.arith.UInt64} |
| 308 */ |
| 309 jspb.arith.UInt64.prototype.clone = function() { |
| 310 return new jspb.arith.UInt64(this.lo, this.hi); |
| 311 }; |
| 312 |
| 313 |
| 314 /** |
| 315 * Int64 is like UInt64, but modifies string conversions to interpret the stored |
| 316 * 64-bit value as a twos-complement-signed integer. It does *not* support the |
| 317 * full range of operations that UInt64 does: only add, subtract, and string |
| 318 * conversions. |
| 319 * |
| 320 * N.B. that multiply and divide routines are *NOT* supported. They will throw |
| 321 * exceptions. (They are not necessary to implement string conversions, which |
| 322 * are the only operations we really need in jspb.) |
| 323 * |
| 324 * @param {number} lo The low 32 bits. |
| 325 * @param {number} hi The high 32 bits. |
| 326 * @constructor |
| 327 */ |
| 328 jspb.arith.Int64 = function(lo, hi) { |
| 329 /** |
| 330 * The low 32 bits. |
| 331 * @public {number} |
| 332 */ |
| 333 this.lo = lo; |
| 334 /** |
| 335 * The high 32 bits. |
| 336 * @public {number} |
| 337 */ |
| 338 this.hi = hi; |
| 339 }; |
| 340 |
| 341 |
| 342 /** |
| 343 * Add two 64-bit numbers to produce a 64-bit number. |
| 344 * @param {!jspb.arith.Int64} other |
| 345 * @return {!jspb.arith.Int64} |
| 346 */ |
| 347 jspb.arith.Int64.prototype.add = function(other) { |
| 348 var lo = ((this.lo + other.lo) & 0xffffffff) >>> 0; |
| 349 var hi = |
| 350 (((this.hi + other.hi) & 0xffffffff) >>> 0) + |
| 351 (((this.lo + other.lo) >= 0x100000000) ? 1 : 0); |
| 352 return new jspb.arith.Int64(lo >>> 0, hi >>> 0); |
| 353 }; |
| 354 |
| 355 |
| 356 /** |
| 357 * Subtract two 64-bit numbers to produce a 64-bit number. |
| 358 * @param {!jspb.arith.Int64} other |
| 359 * @return {!jspb.arith.Int64} |
| 360 */ |
| 361 jspb.arith.Int64.prototype.sub = function(other) { |
| 362 var lo = ((this.lo - other.lo) & 0xffffffff) >>> 0; |
| 363 var hi = |
| 364 (((this.hi - other.hi) & 0xffffffff) >>> 0) - |
| 365 (((this.lo - other.lo) < 0) ? 1 : 0); |
| 366 return new jspb.arith.Int64(lo >>> 0, hi >>> 0); |
| 367 }; |
| 368 |
| 369 |
| 370 /** |
| 371 * Make a copy of the int64. |
| 372 * @return {!jspb.arith.Int64} |
| 373 */ |
| 374 jspb.arith.Int64.prototype.clone = function() { |
| 375 return new jspb.arith.Int64(this.lo, this.hi); |
| 376 }; |
| 377 |
| 378 |
| 379 /** |
| 380 * Convert a 64-bit number to a string. |
| 381 * @return {string} |
| 382 * @override |
| 383 */ |
| 384 jspb.arith.Int64.prototype.toString = function() { |
| 385 // If the number is negative, find its twos-complement inverse. |
| 386 var sign = (this.hi & 0x80000000) != 0; |
| 387 var num = new jspb.arith.UInt64(this.lo, this.hi); |
| 388 if (sign) { |
| 389 num = new jspb.arith.UInt64(0, 0).sub(num); |
| 390 } |
| 391 return (sign ? '-' : '') + num.toString(); |
| 392 }; |
| 393 |
| 394 |
| 395 /** |
| 396 * Parse a string into a 64-bit number. Returns `null` on a parse error. |
| 397 * @param {string} s |
| 398 * @return {?jspb.arith.Int64} |
| 399 */ |
| 400 jspb.arith.Int64.fromString = function(s) { |
| 401 var hasNegative = (s.length > 0 && s[0] == '-'); |
| 402 if (hasNegative) { |
| 403 s = s.substring(1); |
| 404 } |
| 405 var num = jspb.arith.UInt64.fromString(s); |
| 406 if (num === null) { |
| 407 return null; |
| 408 } |
| 409 if (hasNegative) { |
| 410 num = new jspb.arith.UInt64(0, 0).sub(num); |
| 411 } |
| 412 return new jspb.arith.Int64(num.lo, num.hi); |
| 413 }; |
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