third_party/tcmalloc/chromium/src/tests/realloc_unittest.cc

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  29
  30 // ---
  31 // Author: Sanjay Ghemawat
  32 //
  33 // Test realloc() functionality
  34
  35 #include "config_for_unittests.h"
  36 #include <assert.h>                     // for assert
  37 #include <stdio.h>
  38 #include <stddef.h>                     // for size_t, NULL
  39 #include <stdlib.h>                     // for free, malloc, realloc
  40 #include <algorithm>                    // for min
  41 #include "base/logging.h"
  42
  43 using std::min;
  44
  45
  46 // Fill a buffer of the specified size with a predetermined pattern
  47 static void Fill(unsigned char* buffer, int n) {
  48   for (int i = 0; i < n; i++) {
  49     buffer[i] = (i & 0xff);
  50   }
  51 }
  52
  53 // Check that the specified buffer has the predetermined pattern
  54 // generated by Fill()
  55 static bool Valid(unsigned char* buffer, int n) {
  56   for (int i = 0; i < n; i++) {
  57     if (buffer[i] != (i & 0xff)) {
  58       return false;
  59     }
  60   }
  61   return true;
  62 }
  63
  64 // Return the next interesting size/delta to check.  Returns -1 if no more.
  65 static int NextSize(int size) {
  66   if (size < 100) {
  67     return size+1;
  68   } else if (size < 100000) {
  69     // Find next power of two
  70     int power = 1;
  71     while (power < size) {
  72       power <<= 1;
  73     }
  74
  75     // Yield (power-1, power, power+1)
  76     if (size < power-1) {
  77       return power-1;
  78     } else if (size == power-1) {
  79       return power;
  80     } else {
  81       assert(size == power);
  82       return power+1;
  83     }
  84   } else {
  85     return -1;
  86   }
  87 }
  88
  89 int main(int argc, char** argv) {
  90   for (int src_size = 0; src_size >= 0; src_size = NextSize(src_size)) {
  91     for (int dst_size = 0; dst_size >= 0; dst_size = NextSize(dst_size)) {
  92       unsigned char* src = (unsigned char*) malloc(src_size);
  93       Fill(src, src_size);
  94       unsigned char* dst = (unsigned char*) realloc(src, dst_size);
  95       CHECK(Valid(dst, min(src_size, dst_size)));
  96       Fill(dst, dst_size);
  97       CHECK(Valid(dst, dst_size));
  98       if (dst != NULL) free(dst);
  99     }
 100   }
 101
 102   // Now make sure realloc works correctly even when we overflow the
 103   // packed cache, so some entries are evicted from the cache.
 104   // The cache has 2^12 entries, keyed by page number.
 105   const int kNumEntries = 1 << 14;
 106   int** p = (int**)malloc(sizeof(*p) * kNumEntries);
 107   int sum = 0;
 108   for (int i = 0; i < kNumEntries; i++) {
 109     p[i] = (int*)malloc(8192);   // no page size is likely to be bigger
 110     p[i][1000] = i;              // use memory deep in the heart of p
 111   }
 112   for (int i = 0; i < kNumEntries; i++) {
 113     p[i] = (int*)realloc(p[i], 9000);
 114   }
 115   for (int i = 0; i < kNumEntries; i++) {
 116     sum += p[i][1000];
 117     free(p[i]);
 118   }
 119   CHECK_EQ(kNumEntries/2 * (kNumEntries - 1), sum);  // assume kNE is even
 120   free(p);
 121
 122   printf("PASS\n");
 123   return 0;
 124 }