Extract simple integer math into its own module

src/common/util.c

@@ -166,105 +166,6 @@ tor_llround(double d)
 #endif /* defined(HAVE_LLROUND) || ... */
 }
 
-/** Returns floor(log2(u64)).  If u64 is 0, (incorrectly) returns 0. */
-int
-tor_log2(uint64_t u64)
-{
-  int r = 0;
-  if (u64 >= (U64_LITERAL(1)<<32)) {
-    u64 >>= 32;
-    r = 32;
-  }
-  if (u64 >= (U64_LITERAL(1)<<16)) {
-    u64 >>= 16;
-    r += 16;
-  }
-  if (u64 >= (U64_LITERAL(1)<<8)) {
-    u64 >>= 8;
-    r += 8;
-  }
-  if (u64 >= (U64_LITERAL(1)<<4)) {
-    u64 >>= 4;
-    r += 4;
-  }
-  if (u64 >= (U64_LITERAL(1)<<2)) {
-    u64 >>= 2;
-    r += 2;
-  }
-  if (u64 >= (U64_LITERAL(1)<<1)) {
-    // u64 >>= 1; // not using this any more.
-    r += 1;
-  }
-  return r;
-}
-
-/** Return the power of 2 in range [1,UINT64_MAX] closest to <b>u64</b>.  If
- * there are two powers of 2 equally close, round down. */
-uint64_t
-round_to_power_of_2(uint64_t u64)
-{
-  int lg2;
-  uint64_t low;
-  uint64_t high;
-  if (u64 == 0)
-    return 1;
-
-  lg2 = tor_log2(u64);
-  low = U64_LITERAL(1) << lg2;
-
-  if (lg2 == 63)
-    return low;
-
-  high = U64_LITERAL(1) << (lg2+1);
-  if (high - u64 < u64 - low)
-    return high;
-  else
-    return low;
-}
-
-/** Return the lowest x such that x is at least <b>number</b>, and x modulo
- * <b>divisor</b> == 0.  If no such x can be expressed as an unsigned, return
- * UINT_MAX. Asserts if divisor is zero. */
-unsigned
-round_to_next_multiple_of(unsigned number, unsigned divisor)
-{
-  tor_assert(divisor > 0);
-  if (UINT_MAX - divisor + 1 < number)
-    return UINT_MAX;
-  number += divisor - 1;
-  number -= number % divisor;
-  return number;
-}
-
-/** Return the lowest x such that x is at least <b>number</b>, and x modulo
- * <b>divisor</b> == 0. If no such x can be expressed as a uint32_t, return
- * UINT32_MAX. Asserts if divisor is zero. */
-uint32_t
-round_uint32_to_next_multiple_of(uint32_t number, uint32_t divisor)
-{
-  tor_assert(divisor > 0);
-  if (UINT32_MAX - divisor + 1 < number)
-    return UINT32_MAX;
-
-  number += divisor - 1;
-  number -= number % divisor;
-  return number;
-}
-
-/** Return the lowest x such that x is at least <b>number</b>, and x modulo
- * <b>divisor</b> == 0. If no such x can be expressed as a uint64_t, return
- * UINT64_MAX. Asserts if divisor is zero. */
-uint64_t
-round_uint64_to_next_multiple_of(uint64_t number, uint64_t divisor)
-{
-  tor_assert(divisor > 0);
-  if (UINT64_MAX - divisor + 1 < number)
-    return UINT64_MAX;
-  number += divisor - 1;
-  number -= number % divisor;
-  return number;
-}
-
 /** Transform a random value <b>p</b> from the uniform distribution in
  * [0.0, 1.0[ into a Laplace distributed value with location parameter
  * <b>mu</b> and scale parameter <b>b</b>. Truncate the final result
@@ -319,68 +220,6 @@ add_laplace_noise(int64_t signal_, double random_, double delta_f,
     return signal_ + noise;
 }
 
-/* Helper: safely add two uint32_t's, capping at UINT32_MAX rather
- * than overflow */
-uint32_t
-tor_add_u32_nowrap(uint32_t a, uint32_t b)
-{
-  /* a+b > UINT32_MAX check, without overflow */
-  if (PREDICT_UNLIKELY(a > UINT32_MAX - b)) {
-    return UINT32_MAX;
-  } else {
-    return a+b;
-  }
-}
-
-/* Helper: return greatest common divisor of a,b */
-static uint64_t
-gcd64(uint64_t a, uint64_t b)
-{
-  while (b) {
-    uint64_t t = b;
-    b = a % b;
-    a = t;
-  }
-  return a;
-}
-
-/* Given a fraction *<b>numer</b> / *<b>denom</b>, simplify it.
- * Requires that the denominator is greater than 0. */
-void
-simplify_fraction64(uint64_t *numer, uint64_t *denom)
-{
-  tor_assert(denom);
-  uint64_t gcd = gcd64(*numer, *denom);
-  *numer /= gcd;
-  *denom /= gcd;
-}
-
-/** Return the number of bits set in <b>v</b>. */
-int
-n_bits_set_u8(uint8_t v)
-{
-  static const int nybble_table[] = {
-    0, /* 0000 */
-    1, /* 0001 */
-    1, /* 0010 */
-    2, /* 0011 */
-    1, /* 0100 */
-    2, /* 0101 */
-    2, /* 0110 */
-    3, /* 0111 */
-    1, /* 1000 */
-    2, /* 1001 */
-    2, /* 1010 */
-    3, /* 1011 */
-    2, /* 1100 */
-    3, /* 1101 */
-    3, /* 1110 */
-    4, /* 1111 */
-  };
-
-  return nybble_table[v & 15] + nybble_table[v>>4];
-}
-
 /* =====
  * String manipulation
  * ===== */