#include "iwconv.h"
#include <math.h>
#include <string.h>
#include <assert.h>

// mapping of ASCII characters to hex values
const uint8_t ascii2hex[] = {
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //  !"#$%&'
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ()*+,-./
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, // 01234567
  0x08, 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 89:;<=>?
  0x00, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x00, // @ABCDEFG
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // HIJKLMNO
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // PQRSTUVW
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // XYZ[\]^_
  0x00, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x00, // `abcdefg
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // hijklmno
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // pqrstuvw
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // xyz{|}~.
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // ........
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00  // ........
};

size_t iwhex2bin(const char *hex, int hexlen, char *out, int max) {
  size_t pos = 0, vpos = 0;
  uint8_t idx0, idx1;
  while (pos < hexlen) {
    if (!pos && (hexlen % 2)) { // first iteration + odd chars in hex
      idx0 = '0';               // add '0' prefix
      idx1 = hex[0];
      pos += 1;
    } else {                    // even chars in hex
      idx0 = hex[pos];
      idx1 = hex[pos + 1];
      pos += 2;
    }
    out[vpos++] = (uint8_t)(ascii2hex[idx0] << 4) | ascii2hex[idx1];
    if (vpos >= max) {
      return vpos;
    }
  };
  return vpos;
}

int iwitoa(int64_t v, char *buf, int max) {
#define ITOA_SZSTEP(_step) if ((ret += (_step)) >= max) { \
    *ptr = 0; \
    return ret; \
  }
  int ret = 0;
  char c, *ptr = buf, *p, *p1;
  if (!v) {
    ITOA_SZSTEP(1);
    *ptr++ = '0';
    *ptr = 0;
    return ret;
  }
  // sign stuff
  if (v < 0) {
    v = -v;
    ITOA_SZSTEP(1)
    *ptr++ = '-';
  }
  // save start pointer
  p = ptr;
  while (v) {
    if (++ret >= max) { //overflow condition
      memmove(ptr, ptr + 1, p - ptr);
      p--;
    }
    *p++ = '0' + v % 10;
    v /= 10;
  }
  // save end pos
  p1 = p;
  // reverse result
  while (p > ptr) {
    c = *--p;
    *p = *ptr;
    *ptr++ = c;
  }
  ptr = p1;
  *ptr = 0;
  return ret;

#undef ITOA_SZSTEP
}

char *iwftoa(long double n, char s[static IWFTOA_BUFSIZE]) {
  static double PRECISION = 0.00000000000001;
  // handle special cases
  if (isnan(n)) {
    strcpy(s, "nan");
  } else if (isinf(n)) {
    strcpy(s, "inf");
  } else if (n == 0.0) { // -V550
    strcpy(s, "0");
  } else {
    int digit, m, m1;
    char *c = s;
    int neg = (n < 0);
    if (neg) {
      n = -n;
    }
    // calculate magnitude
    m = (int) log10l(n);
    int useExp = (m >= 14 || (neg && m >= 9) || m <= -9);
    if (neg) {
      *(c++) = '-';
    }
    // set up for scientific notation
    if (useExp) {
      if (m < 0) {
        m -= 1;
      }
      n = n / pow(10.0, m);
      m1 = m;
      m = 0;
    }
    if (m < 1) {
      m = 0;
    }
    // convert the number
    while (n > PRECISION || m >= 0) {
      double weight = pow(10.0, m);
      if (weight > 0 && !isinf(weight)) {
        digit = (int) floorl(n / weight);
        n -= (digit * weight);
        *(c++) = '0' + digit;
      }
      if (m == 0 && n > 0) {
        *(c++) = '.';
      }
      m--;
    }
    if (useExp) {
      // convert the exponent
      int i, j;
      *(c++) = 'e';
      if (m1 > 0) {
        *(c++) = '+';
      } else {
        *(c++) = '-';
        m1 = -m1;
      }
      m = 0;
      while (m1 > 0) {
        *(c++) = '0' + m1 % 10;
        m1 /= 10;
        m++;
      }
      c -= m;
      for (i = 0, j = m - 1; i < j; i++, j--) {
        c[i] ^= c[j];
        c[j] ^= c[i];
        c[i] ^= c[j];
      }
      c += m;
    }
    *(c) = '\0';
  }
  return s;
}

int64_t iwatoi(const char *str) {
  assert(str);
  while (*str > '\0' && *str <= ' ') {
    str++;
  }
  int sign = 1;
  int64_t num = 0;
  if (*str == '-') {
    str++;
    sign = -1;
  } else if (*str == '+') {
    str++;
  }
  if (!strcmp(str, "inf")) return (INT64_MAX * sign);
  while (*str != '\0') {
    if (*str < '0' || *str > '9') break;
    num = num * 10 + *str - '0';
    str++;
  }
  return num * sign;
}

long double iwatof(const char *str) {
  assert(str);
  while (*str > '\0' && *str <= ' ') {
    str++;
  }
  int sign = 1;
  if (*str == '-') {
    str++;
    sign = -1;
  } else if (*str == '+') {
    str++;
  }
  if (!strcmp(str, "inf")) {
    return HUGE_VAL * sign;
  }
  long double num = 0;
  while (*str != '\0') {
    if (*str < '0' || *str > '9') {
      break;
    }
    num = num * 10 + *str - '0';
    str++;
  }
  if (*str == '.') {
    str++;
    long double fract = 0.0;
    long double base = 10;
    while (*str != '\0') {
      if (*str < '0' || *str > '9') {
        break;
      }
      fract += (*str - '0') / base;
      str++;
      base *= 10;
    }
    num += fract;
  }
  if (*str == 'e' || *str == 'E') {
    str++;
    num *= pow(10, iwatoi(str));
  }
  return num * sign;
}

/**
 * Compare two strings as real numbers
 */
int iwafcmp(const char *aptr, int asiz, const char *bptr, int bsiz) {
  const unsigned char *arp = (const unsigned char *) aptr;
  const unsigned char *brp = (const unsigned char *) bptr;
  int alen = asiz, blen = bsiz;
  int64_t anum = 0, bnum = 0;
  int asign = 1, bsign = 1;

  // A part
  while (alen > 0 && (*arp <= ' ' || *arp == 0x7f)) {
    arp++;
    alen--;
  }
  if (alen > 0 && *arp == '-') {
    arp++;
    alen--;
    asign = -1;
  }
  while (alen > 0) {
    int c = *arp;
    if (c < '0' || c > '9') break;
    anum = anum * 10 + c - '0';
    arp++;
    alen--;
  }
  anum *= asign;

  // B part
  while (blen > 0 && (*brp <= ' ' || *brp == 0x7f)) {
    brp++;
    blen--;
  }
  if (blen > 0 && *brp == '-') {
    brp++;
    blen--;
    bsign = -1;
  }
  while (blen > 0) {
    int c = *brp;
    if (c < '0' || c > '9') break;
    bnum = bnum * 10 + c - '0';
    brp++;
    blen--;
  }
  bnum *= bsign;
  if (anum < bnum) return -1;
  if (anum > bnum) return 1;
  if ((alen > 1 && *arp == '.') || (blen > 1 && *brp == '.')) {
    long double aflt = 0;
    long double bflt = 0;
    if (alen > 1 && *arp == '.') {
      arp++;
      alen--;
      if (alen > IWFTOA_BUFSIZE) alen = IWFTOA_BUFSIZE;
      long double base = 10;
      while (alen > 0) {
        if (*arp < '0' || *arp > '9') break;
        aflt += (*arp - '0') / base;
        arp++;
        alen--;
        base *= 10;
      }
      aflt *= asign;
    }
    if (blen > 1 && *brp == '.') {
      brp++;
      blen--;
      if (blen > IWFTOA_BUFSIZE) blen = IWFTOA_BUFSIZE;
      long double base = 10;
      while (blen > 0) {
        if (*brp < '0' || *brp > '9') break;
        bflt += (*brp - '0') / base;
        brp++;
        blen--;
        base *= 10;
      }
      bflt *= bsign;
    }
    if (aflt < bflt) return -1;
    if (aflt > bflt) return 1;
  }
  int rv = strncmp(aptr, bptr, MIN(asiz, bsiz));
  if (!rv) {
    return (asiz - bsiz);
  } else {
    return rv;
  }
}