xref: /php-src/ext/bcmath/libbcmath/src/num2str.c (revision 90a5b871)
1 /* num2str.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 "bcmath.h"
33 #include "convert.h"
34 #include "zend_string.h"
35 
36 /* Convert a numbers to a string.  Base 10 only.*/
bc_num2str_ex(bc_num num,size_t scale)37 zend_string *bc_num2str_ex(bc_num num, size_t scale)
38 {
39 	zend_string *str;
40 	char *sptr;
41 	size_t index;
42 	bool signch;
43 	size_t min_scale = MIN(num->n_scale, scale);
44 
45 	/* Number of sign chars. */
46 	signch = num->n_sign != PLUS && !bc_is_zero_for_scale(num, min_scale);
47 	/* Allocate the string memory. */
48 	if (scale > 0) {
49 		str = zend_string_alloc(num->n_len + scale + signch + 1, 0);
50 	} else {
51 		str = zend_string_alloc(num->n_len + signch, 0);
52 	}
53 
54 	/* The negative sign if needed. */
55 	sptr = ZSTR_VAL(str);
56 	if (signch) *sptr++ = '-';
57 
58 	/* Load the whole number. */
59 	const char *nptr = num->n_value;
60 	sptr = bc_copy_and_toggle_bcd(sptr, nptr, nptr + num->n_len);
61 	nptr += num->n_len;
62 
63 	/* Now the fraction. */
64 	if (scale > 0) {
65 		*sptr++ = '.';
66 		sptr = bc_copy_and_toggle_bcd(sptr, nptr, nptr + min_scale);
67 		for (index = num->n_scale; index < scale; index++) {
68 			*sptr++ = BCD_CHAR(0);
69 		}
70 	}
71 
72 	/* Terminate the string and return it! */
73 	*sptr = '\0';
74 	ZSTR_LEN(str) = sptr - (char *)ZSTR_VAL(str);
75 	return str;
76 }
77