1 files changed, 20 insertions, 10 deletions
diff --git a/research/read_dist.h b/research/read_dist.h
index dd5ade3..3cac473 100644
--- a/research/read_dist.h
+++ b/research/read_dist.h
@@ -1,37 +1,47 @@
 /* Copyright 2016 Google Inc. All Rights Reserved.
-   Author: vanickulin@google.com (Ivan Nikulin)
+   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. */
-
-#include <cassert>
-#include <cstdio>
+/* 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 */
+
+#ifndef 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) {
-    assert(fread(copy, sizeof(int), 1, fin) == 1);
+    CHECK(fread(copy, sizeof(int), 1, fin) == 1);
     if ((c = getc(fin)) != 1) {
       ungetc(c, fin);
       *pos = *dist = -1;
     } else {
-      assert(fread(pos, sizeof(int), 1, fin) == 1);
-      assert(fread(dist, sizeof(int), 1, fin) == 1);
+      CHECK(fread(pos, sizeof(int), 1, fin) == 1);
+      CHECK(fread(dist, sizeof(int), 1, fin) == 1);
     }
   } else if (c != 1) {
     return false;
   } else {
-    assert(fread(pos, sizeof(int), 1, fin) == 1);
-    assert(fread(dist, sizeof(int), 1, fin) == 1);
+    CHECK(fread(pos, sizeof(int), 1, fin) == 1);
+    CHECK(fread(dist, sizeof(int), 1, fin) == 1);
     *copy = -1;
   }
   return true;