xref: /PHP-8.0/ext/bcmath/libbcmath/src/str2num.c (revision eb23c600)
1 /* str2num.c: bcmath library file. */
2 /*
3     Copyright (C) 1991, 1992, 1993, 1994, 1997 Free Software Foundation, Inc.
4     Copyright (C) 2000 Philip A. Nelson
5 
6     This library is free software; you can redistribute it and/or
7     modify it under the terms of the GNU Lesser General Public
8     License as published by the Free Software Foundation; either
9     version 2 of the License, or (at your option) any later version.
10 
11     This library is distributed in the hope that it will be useful,
12     but WITHOUT ANY WARRANTY; without even the implied warranty of
13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14     Lesser General Public License for more details.  (LICENSE)
15 
16     You should have received a copy of the GNU Lesser General Public
17     License along with this library; if not, write to:
18 
19       The Free Software Foundation, Inc.
20       59 Temple Place, Suite 330
21       Boston, MA 02111-1307 USA.
22 
23     You may contact the author by:
24        e-mail:  philnelson@acm.org
25       us-mail:  Philip A. Nelson
26                 Computer Science Department, 9062
27                 Western Washington University
28                 Bellingham, WA 98226-9062
29 
30 *************************************************************************/
31 
32 #include <config.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <ctype.h>
36 #include <stdarg.h>
37 #include "bcmath.h"
38 #include "private.h"
39 
40 /* Convert strings to bc numbers.  Base 10 only.*/
41 
42 int
bc_str2num(bc_num * num,char * str,int scale)43 bc_str2num (bc_num *num, char *str, int scale)
44 {
45   int digits, strscale;
46   char *ptr, *nptr;
47   char zero_int;
48 
49   /* Prepare num. */
50   bc_free_num (num);
51 
52   /* Check for valid number and count digits. */
53   ptr = str;
54   digits = 0;
55   strscale = 0;
56   zero_int = FALSE;
57   if ( (*ptr == '+') || (*ptr == '-'))  ptr++;  /* Sign */
58   while (*ptr == '0') ptr++;			/* Skip leading zeros. */
59   while (*ptr >= '0' && *ptr <= '9') ptr++, digits++;	/* digits */
60   if (*ptr == '.') ptr++;			/* decimal point */
61   while (*ptr >= '0' && *ptr <= '9') ptr++, strscale++;	/* digits */
62   if ((*ptr != '\0') || (digits+strscale == 0))
63     {
64       *num = bc_copy_num (BCG(_zero_));
65       return *ptr == '\0';
66     }
67 
68   /* Adjust numbers and allocate storage and initialize fields. */
69   strscale = MIN(strscale, scale);
70   if (digits == 0)
71     {
72       zero_int = TRUE;
73       digits = 1;
74     }
75   *num = bc_new_num (digits, strscale);
76 
77   /* Build the whole number. */
78   ptr = str;
79   if (*ptr == '-')
80     {
81       (*num)->n_sign = MINUS;
82       ptr++;
83     }
84   else
85     {
86       (*num)->n_sign = PLUS;
87       if (*ptr == '+') ptr++;
88     }
89   while (*ptr == '0') ptr++;			/* Skip leading zeros. */
90   nptr = (*num)->n_value;
91   if (zero_int)
92     {
93       *nptr++ = 0;
94       digits = 0;
95     }
96   for (;digits > 0; digits--)
97     *nptr++ = CH_VAL(*ptr++);
98 
99 
100   /* Build the fractional part. */
101   if (strscale > 0)
102     {
103       ptr++;  /* skip the decimal point! */
104       for (;strscale > 0; strscale--)
105 	*nptr++ = CH_VAL(*ptr++);
106     }
107 
108   if (bc_is_zero (*num))
109     (*num)->n_sign = PLUS;
110 
111   return 1;
112 }
113