/*
  itoa.c

  Copyleft (C) 2022 Taiji Yamada <taiji@aihara.co.jp>
*/
#include <stdio.h>
#include <inttypes.h>
#include <string.h>

char *itoa(int v, char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  b[0] = '\0';
  if (r == 8)
    snprintf(b, 256-1, "%o", v);
  else if (r == 10)
    snprintf(b, 256-1, "%d", v);
  else if (r == 16)
    snprintf(b, 256-1, "%x", v);
  else {
    const unsigned long long radix = (unsigned long long)r;
    const int sign = (r == 10 && v < 0) ? -1 : 1;
    unsigned long long value = (r == 10 && v < 0) ? (unsigned int)-v : (unsigned int)v;
    unsigned long long ub = 1, previous_ub = ub;
    while (!0) {
      ub *= radix;
      if (ub < previous_ub)
	break;
      if (value < ub)
	break;
      previous_ub = ub;
    }
    ub = previous_ub;
    if (sign == -1)
      strcat(b, "-");
    while (0 < ub) {
      const unsigned long long n = value / ub;
      char s[] = { digits[n], '\0' };
      strcat(b, s);
      value -= n*ub;
      ub /= radix;
    }
  }
  return b;
}
int stoi(const char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  const unsigned long long radix = (unsigned long long)r;
  const size_t l = strlen(b);
  int sign = 1;
  unsigned long long e = 1, value = 0;
  for (size_t i=l-1; ; --i) {
    const unsigned long long n = strchr(digits, b[i]) - digits;
    value += e*n;
    if (i == 0) break;
    if (b[i-1] == '-') { sign = -1; break; }
    e *= radix;
  }
  return (sign != -1) ? (int)value : -(int)value;
}
char *i16toa(int16_t v, char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  b[0] = '\0';
  if (r == 8)
    snprintf(b, 256-1, "%" PRIo16, v);
  else if (r == 10)
    snprintf(b, 256-1, "%" PRId16, v);
  else if (r == 16)
    snprintf(b, 256-1, "%" PRIx16, v);
  else {
    const unsigned long long radix = (unsigned long long)r;
    const int sign = (r == 10 && v < 0) ? -1 : 1;
    unsigned long long value = (r == 10 && v < 0) ? (uint16_t)-v : (uint16_t)v;
    unsigned long long ub = 1, previous_ub = ub;
    while (!0) {
      ub *= radix;
      if (ub < previous_ub)
	break;
      if (value < ub)
	break;
      previous_ub = ub;
    }
    ub = previous_ub;
    if (sign == -1)
      strcat(b, "-");
    while (0 < ub) {
      const unsigned long long n = value / ub;
      char s[] = { digits[n], '\0' };
      strcat(b, s);
      value -= n*ub;
      ub /= radix;
    }
  }
  return b;
}
int16_t stoi16(const char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  const unsigned long long radix = (unsigned long long)r;
  const size_t l = strlen(b);
  int sign = 1;
  unsigned long long e = 1, value = 0;
  for (size_t i=l-1; ; --i) {
    const unsigned long long n = strchr(digits, b[i]) - digits;
    value += e*n;
    if (i == 0) break;
    if (b[i-1] == '-') { sign = -1; break; }
    e *= radix;
  }
  return (sign != -1) ? (int16_t)value : -(int16_t)value;
}
char *ui16toa(uint16_t v, char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  b[0] = '\0';
  if (r == 8)
    snprintf(b, 256-1, "%" PRIo16, v);
  else if (r == 10)
    snprintf(b, 256-1, "%" PRIu16, v);
  else if (r == 16)
    snprintf(b, 256-1, "%" PRIx16, v);
  else {
    const unsigned long long radix = (unsigned long long)r;
    unsigned long long value = v;
    unsigned long long ub = 1, previous_ub = ub;
    while (!0) {
      ub *= radix;
      if (ub < previous_ub)
	break;
      if (value < ub)
	break;
      previous_ub = ub;
    }
    ub = previous_ub;
    while (0 < ub) {
      const unsigned long long n = value / ub;
      char s[] = { digits[n], '\0' };
      strcat(b, s);
      value -= n*ub;
      ub /= radix;
    }
  }
  return b;
}
int16_t stoui16(const char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  const unsigned long long radix = (unsigned long long)r;
  const size_t l = strlen(b);
  int sign = 1;
  unsigned long long e = 1, value = 0;
  for (size_t i=l-1; ; --i) {
    const unsigned long long n = strchr(digits, b[i]) - digits;
    value += e*n;
    if (i == 0) break;
    if (b[i-1] == '-') { sign = -1; break; }
    e *= radix;
  }
  return (sign != -1) ? (uint16_t)value : -(uint16_t)value;
}
char *i32toa(int32_t v, char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  b[0] = '\0';
  if (r == 8)
    snprintf(b, 256-1, "%" PRIo32, v);
  else if (r == 10)
    snprintf(b, 256-1, "%" PRId32, v);
  else if (r == 16)
    snprintf(b, 256-1, "%" PRIx32, v);
  else {
    const unsigned long long radix = (unsigned long long)r;
    const int sign = (r == 10 && v < 0) ? -1 : 1;
    unsigned long long value = (r == 10 && v < 0) ? (uint32_t)-v : (uint32_t)v;
    unsigned long long ub = 1, previous_ub = ub;
    while (!0) {
      ub *= radix;
      if (ub < previous_ub)
	break;
      if (value < ub)
	break;
      previous_ub = ub;
    }
    ub = previous_ub;
    if (sign == -1)
      strcat(b, "-");
    while (0 < ub) {
      const unsigned long long n = value / ub;
      char s[] = { digits[n], '\0' };
      strcat(b, s);
      value -= n*ub;
      ub /= radix;
    }
  }
  return b;
}
int32_t stoi32(const char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  const unsigned long long radix = (unsigned long long)r;
  const size_t l = strlen(b);
  int sign = 1;
  unsigned long long e = 1, value = 0;
  for (size_t i=l-1; ; --i) {
    const unsigned long long n = strchr(digits, b[i]) - digits;
    value += e*n;
    if (i == 0) break;
    if (b[i-1] == '-') { sign = -1; break; }
    e *= radix;
  }
  return (sign != -1) ? (int32_t)value : -(int32_t)value;
}
char *ui32toa(uint32_t v, char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  b[0] = '\0';
  if (r == 8)
    snprintf(b, 256-1, "%" PRIo32, v);
  else if (r == 10)
    snprintf(b, 256-1, "%" PRIu32, v);
  else if (r == 16)
    snprintf(b, 256-1, "%" PRIx32, v);
  else {
    const unsigned long long radix = (unsigned long long)r;
    unsigned long long value = v;
    unsigned long long ub = 1, previous_ub = ub;
    while (!0) {
      ub *= radix;
      if (ub < previous_ub)
	break;
      if (value < ub)
	break;
      previous_ub = ub;
    }
    ub = previous_ub;
    while (0 < ub) {
      const unsigned long long n = value / ub;
      char s[] = { digits[n], '\0' };
      strcat(b, s);
      value -= n*ub;
      ub /= radix;
    }
  }
  return b;
}
uint32_t stoui32(const char *b, const int r)
{
  const char digits[] = "0123456789abcdefghijklmnopqrstuv";
  const unsigned long long radix = (unsigned long long)r;
  const size_t l = strlen(b);
  int sign = 1;
  unsigned long long e = 1, value = 0;
  for (size_t i=l-1; ; --i) {
    const unsigned long long n = strchr(digits, b[i]) - digits;
    value += e*n;
    if (i == 0) break;
    if (b[i-1] == '-') { sign = -1; break; }
    e *= radix;
  }
  return (sign != -1) ? (uint32_t)value : -(uint32_t)value;
}