( base: Uint8Array, delta: Uint8Array, limits: Pick<ParsePackLimits, "maxDeltaResultBytes"> = DEFAULT_LIMITS, )
| 345 | } |
| 346 | |
| 347 | function applyDelta( |
| 348 | base: Uint8Array, |
| 349 | delta: Uint8Array, |
| 350 | limits: Pick<ParsePackLimits, "maxDeltaResultBytes"> = DEFAULT_LIMITS, |
| 351 | ): Uint8Array { |
| 352 | let p = 0; |
| 353 | const baseSize = readDeltaVarint(delta, p, "delta base size"); |
| 354 | p = baseSize.pos; |
| 355 | if (baseSize.value !== base.length) { |
| 356 | throw new PackParseError("delta base size does not match base object"); |
| 357 | } |
| 358 | const resSize = readDeltaVarint(delta, p, "delta result size"); |
| 359 | p = resSize.pos; |
| 360 | if (resSize.value > limits.maxDeltaResultBytes) { |
| 361 | throw repositoryTooLarge(`delta result exceeds ${limits.maxDeltaResultBytes} bytes`); |
| 362 | } |
| 363 | const out = new Uint8Array(resSize.value); |
| 364 | let o = 0; |
| 365 | while (p < delta.length) { |
| 366 | const op = delta[p++]; |
| 367 | if (op & 0x80) { |
| 368 | // copy from base |
| 369 | let cpOff = 0, |
| 370 | cpLen = 0; |
| 371 | if (op & 0x01) { |
| 372 | requireAvailable(delta, p, 1, "delta copy offset"); |
| 373 | cpOff += delta[p++]!; |
| 374 | } |
| 375 | if (op & 0x02) { |
| 376 | requireAvailable(delta, p, 1, "delta copy offset"); |
| 377 | cpOff += delta[p++]! * 256; |
| 378 | } |
| 379 | if (op & 0x04) { |
| 380 | requireAvailable(delta, p, 1, "delta copy offset"); |
| 381 | cpOff += delta[p++]! * 65536; |
| 382 | } |
| 383 | if (op & 0x08) { |
| 384 | requireAvailable(delta, p, 1, "delta copy offset"); |
| 385 | cpOff += delta[p++]! * 16777216; |
| 386 | } |
| 387 | if (op & 0x10) { |
| 388 | requireAvailable(delta, p, 1, "delta copy length"); |
| 389 | cpLen += delta[p++]!; |
| 390 | } |
| 391 | if (op & 0x20) { |
| 392 | requireAvailable(delta, p, 1, "delta copy length"); |
| 393 | cpLen += delta[p++]! * 256; |
| 394 | } |
| 395 | if (op & 0x40) { |
| 396 | requireAvailable(delta, p, 1, "delta copy length"); |
| 397 | cpLen += delta[p++]! * 65536; |
| 398 | } |
| 399 | if (cpLen === 0) cpLen = 0x10000; |
| 400 | requireAvailable(base, cpOff, cpLen, "delta copy source"); |
| 401 | requireAvailable(out, o, cpLen, "delta copy target"); |
| 402 | out.set(base.subarray(cpOff, cpOff + cpLen), o); |
| 403 | o += cpLen; |
| 404 | } else if (op) { |
no test coverage detected