Function freq

src/simplicity/rsort.c:36–47

Given an array of midstate pointers, * count the frequencies of the values of the 'j'th character of each midstate's internal representation. * Returns 'true' if the 'j'th character of every entry is the same, otherwise returns 'false'. * * The time complexity of 'freq' is O('len'). * * Precondition: uint32_t result[CHAR_COUNT]; * for all 0 <= i < len, NULL != a[i]; *

 *               j < sizeof((*a)->s)
 */
static bool freq(uint32_t* result, const sha256_midstate * const * a, uint_fast32_t len, unsigned int j) {
  memset(result, 0, CHAR_COUNT * sizeof(uint32_t));

  if (0 == len) return true;

  for (size_t i = 0; i < len - 1; ++i) {
    result[readIndex(a[i],j)]++;
  }

  /* Check the final iteration to see if the frequency is equal to 'len'. */
  return len == ++result[readIndex(a[len-1],j)];
}

/* Given an array of bucket sizes, and an initial value 'bucketEdge[0]',
 * add subsequent bucket edges of the given bucket sizes.