scan.c

Go to the documentation of this file.

#include "scan.h"

 
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;
}
 
// Octal input
 
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;
}
 
// Decimal unsigned input -> _Generic: scan_dnum
 
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_uint(const char *s,unsigned int *u)
{
  unsigned int pos; 
  unsigned long result;
 
  pos = scan_ulong(s,&result);
  *u = result; 
  return pos;
}
 
// Decimal signed input -> _Generic: scan_dnum
 
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;
}
 
// Hexadecimal unsigned input -> _Generic scan_xnum
 
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_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);
}
 
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;
}