#include "scan.h"

/**
  @file   scan.c
  @author djb
  @ref    qmail, ucspi-tcp
  @brief  scanning/conversion of strings to different variable types
*/

static long int fromhex(unsigned char c)
{
  if (c >= '0' && c <= '9')
    return c - '0';
  else if (c >= 'A' && c <= 'F')
    return c - 'A' + 10;
  else if (c >= 'a' && c <= 'f')
    return c - 'a' + 10;
  return -1;
}

unsigned int scan_0x(const char *s, unsigned int *u)
{
  unsigned int pos = 0;
  unsigned long result = 0;
  long int c;

  while ((c = fromhex((unsigned char)(s[pos]))) >= 0) {
    result = (result << 4) + c;
    ++pos;
  }
  *u = result;
  return pos;
}

unsigned int scan_8long(const char *s, unsigned long *u)
{
  unsigned int pos = 0;
  unsigned long result = 0;
  unsigned long c;

  while ((c = (unsigned long)(unsigned char)(s[pos] - '0')) < 8) {
    result = result * 8 + c;
    ++pos;
  }
  *u = result;
  return pos;
}

unsigned int scan_uint(const char *s, unsigned int *u)
{
  unsigned int pos;
  unsigned long result;

  pos = scan_ulong(s, &result);
  *u = result;
  return pos;
}

static unsigned int scan_plusminus(const char *s, int *sign)
{
  if (*s == '+') {
    *sign = 1;
    return 1;
  }
  if (*s == '-') {
    *sign = -1;
    return 1;
  }
  *sign = 1;
  return 0;
}

unsigned int scan_long(const char *s, long *i)
{
  int sign;
  unsigned long u;
  unsigned int len;

  len = scan_plusminus(s, &sign);
  s += len;
  len += scan_ulong(s, &u);
  if (sign < 0)
    *i = -u;
  else
    *i = u;
  return len;
}


unsigned int scan_ulong(const char *s, unsigned long *u)
{
  unsigned int pos = 0;
  unsigned long result = 0;
  unsigned long c;

  while ((c = (unsigned long)(unsigned char)(s[pos] - '0')) < 10) {
    result = result * 10 + c;
    ++pos;
  }
  *u = result;
  return pos;
}

unsigned int scan_xlong(const char *s, unsigned long *u)
{
  const char *t = s;
  int l = 0;
  unsigned char c;

  while ((c = fromhex(*t)) < 16) {
    l = (l << 4) + c;
    ++t;
  }
  *u = l;
  return t - s;
}

unsigned int scan_xint(const char *s, unsigned int *i)
{
  const char *t = s;
  unsigned int l = 0;
  unsigned char c;

  while ((l >> (sizeof(l) * 8 - 4)) == 0 && (c = (unsigned char)fromhex((unsigned char)*t)) < 16) {
    l = (l << 4) + c;
    ++t;
  }
  *i = l;
  return (unsigned int)(t - s);
}