kc3-lang/brotli/research/read_dist.h

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• Hash : 8544ae85
  Author :
  Date : 2018-06-09T11:17:13
  

  Update (#680)
  
   * fix MSVC warnings
   * cleanups

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• research/read_dist.h

• /* 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_ */
  

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