4.3BSD - /usr/ingres/source/libq/IIatoi.c

   1: # include   <sccs.h>
   2: 
   3: SCCSID(@(#)IIatoi.c	8.1	12/31/84)
   4: 
   5: 
   6: /*
   7: **  IIatoi()
   8: **  ASCII CHARACTER STRING TO 16-BIT INTEGER CONVERSION
   9: **
  10: **	`a' is a pointer to the character string, `i' is a
  11: **	pointer to the word which is to contain the result.
  12: **
  13: **	The return value of the function is:
  14: **		zero:	succesful conversion; `i' contains the integer
  15: **		+1:	numeric overflow; `i' is unchanged
  16: **		-1:	syntax error; `i' is unchanged
  17: **
  18: **	A valid string is of the form:
  19: **		<space>* [+-] <space>* <digit>* <space>*
  20: **
  21: **		Eric's utility routine.
  22: **
  23: */
  24: 
  25: IIatoi(a1, i)
  26: char    *a1;
  27: int *i;
  28: {
  29:     int     sign;       /* flag to indicate the sign */
  30:     register int    x;      /* holds the integer being formed */
  31:     register char   c;
  32:     register char   *a;
  33: 
  34:     a = a1;
  35:     sign = 0;
  36:     /* skip leading blanks */
  37:     while (*a == ' ')
  38:         a++;
  39:     /* check for sign */
  40:     switch (*a)
  41:     {
  42: 
  43:       case '-':
  44:         sign = -1;
  45: 
  46:       case '+':
  47:         while (*++a == ' ');
  48:     }
  49: 
  50:     /* at this point everything had better be numeric */
  51:     x = 0;
  52:     while ((c = *a) <= '9' && c >= '0')
  53:     {
  54:         if (x > 3276 || (x == 3276 && c > '7'))
  55:             return (1);     /* overflow */
  56:         x = x * 10 + c - '0';
  57:         a++;
  58:     }
  59: 
  60:     /* eaten all the numerics; better be all blanks */
  61:     while (c = *a++)
  62:         if(c != ' ')            /* syntax error */
  63:             return (-1);
  64:     *i = sign ? -x : x;
  65:     return (0);     /* successful termination */
  66: }

Defined functions