| /* Copyright 2016 Google Inc. All Rights Reserved. |
| Author: zip753@gmail.com (Ivan Nikulin) |
| |
| Distributed under MIT license. |
| See file LICENSE for detail or copy at https://opensource.org/licenses/MIT |
| */ |
| |
| /* API for reading distances from *.dist file. |
| The format of *.dist file is as follows: for each backward reference there is |
| a position-distance pair, also a copy length may be specified. Copy length is |
| prefixed with flag byte 0, position-distance pair is prefixed with flag |
| byte 1. Each number is a 32-bit integer. Copy length always comes before |
| position-distance pair. Standalone copy length is allowed, in this case it is |
| ignored. */ |
| |
| #ifndef BROTLI_RESEARCH_READ_DIST_H_ |
| #define BROTLI_RESEARCH_READ_DIST_H_ |
| |
| #include <cstdio> |
| #include <cstdlib> /* exit, EXIT_FAILURE */ |
| |
| #if !defined(CHECK) |
| #define CHECK(X) if (!(X)) exit(EXIT_FAILURE); |
| #endif |
| |
| /* Reads backwards reference from .dist file. Sets all missing fields to -1. |
| Returns false when EOF is met or input is corrupt. */ |
| bool ReadBackwardReference(FILE* fin, int* copy, int* pos, int* dist) { |
| int c = getc(fin); |
| if (c == EOF) return false; |
| if (c == 0) { |
| CHECK(fread(copy, sizeof(int), 1, fin) == 1); |
| if ((c = getc(fin)) != 1) { |
| ungetc(c, fin); |
| *pos = *dist = -1; |
| } else { |
| CHECK(fread(pos, sizeof(int), 1, fin) == 1); |
| CHECK(fread(dist, sizeof(int), 1, fin) == 1); |
| } |
| } else if (c != 1) { |
| return false; |
| } else { |
| CHECK(fread(pos, sizeof(int), 1, fin) == 1); |
| CHECK(fread(dist, sizeof(int), 1, fin) == 1); |
| *copy = -1; |
| } |
| return true; |
| } |
| |
| #endif /* BROTLI_RESEARCH_READ_DIST_H_ */ |