// Copyright 2018 Ulf Adams

//

// The contents of this file may be used under the terms of the Apache License,

// Version 2.0.

//

//    (See accompanying file LICENSE-Apache or copy at

//     http://www.apache.org/licenses/LICENSE-2.0)

//

// Alternatively, the contents of this file may be used under the terms of

// the Boost Software License, Version 1.0.

//    (See accompanying file LICENSE-Boost or copy at

//     https://www.boost.org/LICENSE_1_0.txt)

//

// Unless required by applicable law or agreed to in writing, this software

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

// KIND, either express or implied.

#ifndef RYU_COMMON_H

#define RYU_COMMON_H

#include <assert.h>

#include <stdint.h>

#include <string.h>

#if defined(_M_IX86) || defined(_M_ARM)

#define RYU_32_BIT_PLATFORM

#endif

// Returns the number of decimal digits in v, which must not contain more than 9 digits.

static inline uint32_t decimalLength9(const uint32_t v) {

  // Function precondition: v is not a 10-digit number.

  // (f2s: 9 digits are sufficient for round-tripping.)

  // (d2fixed: We print 9-digit blocks.)

  assert(v >= 0);

  assert(v < 1000000000);

  if (v >= 100000000) { return 9; }

  if (v >= 10000000) { return 8; }

  if (v >= 1000000) { return 7; }

  if (v >= 100000) { return 6; }

  if (v >= 10000) { return 5; }

  if (v >= 1000) { return 4; }

  if (v >= 100) { return 3; }

  if (v >= 10) { return 2; }

  return 1;

}

// Returns e == 0 ? 1 : ceil(log_2(5^e)); requires 0 <= e <= 3528.

static inline int32_t pow5bits(const int32_t e) {

  // This approximation works up to the point that the multiplication overflows at e = 3529.

  // If the multiplication were done in 64 bits, it would fail at 5^4004 which is just greater

  // than 2^9297.

  assert(e >= 0);

  assert(e <= 3528);

  return (int32_t) (((((uint32_t) e) * 1217359) >> 19) + 1);

}

// Returns e == 0 ? 1 : ceil(log_2(5^e)); requires 0 <= e <= 3528.

static inline int32_t ceil_log2pow5(const int32_t e) {

  return pow5bits(e);

}

// Returns floor(log_10(2^e)); requires 0 <= e <= 1650.

static inline uint32_t log10Pow2(const int32_t e) {

  // The first value this approximation fails for is 2^1651 which is just greater than 10^297.

  assert(e >= 0);

  assert(e <= 1650);

  return (((uint32_t) e) * 78913) >> 18;

}

// Returns floor(log_10(5^e)); requires 0 <= e <= 2620.

static inline uint32_t log10Pow5(const int32_t e) {

  // The first value this approximation fails for is 5^2621 which is just greater than 10^1832.

  assert(e >= 0);

  assert(e <= 2620);

  return (((uint32_t) e) * 732923) >> 20;

}

static inline int copy_special_str(char * const result, const bool sign, const bool exponent, const bool mantissa) {

  if (mantissa) {

    memcpy(result, "NaN", 3);

    return 3;

  }

  if (exponent) {

  /* PostGIS: Do not print signed zero */

  if (sign) {

    result[0] = '-';

  }

    memcpy(result + sign, "Infinity", 8);

    return sign + 8;

  }

  memcpy(result, "0", 1);

  return 1;

}

static inline uint32_t float_to_bits(const float f) {

  uint32_t bits = 0;

  memcpy(&bits, &f, sizeof(float));

  return bits;

}

static inline uint64_t double_to_bits(const double d) {

  uint64_t bits = 0;

  memcpy(&bits, &d, sizeof(double));

  return bits;

}

#endif // RYU_COMMON_H