xref: /PHP-8.4/ext/bcmath/libbcmath/src/init.c (revision 70b5a4d5)
1 /* init.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 <stdbool.h>
34 #include <stddef.h>
35 #include <string.h>
36 #include "zend_alloc.h"
37 
_bc_new_num_nonzeroed_ex_internal(size_t length,size_t scale,bool persistent)38 static bc_num _bc_new_num_nonzeroed_ex_internal(size_t length, size_t scale, bool persistent)
39 {
40 	size_t required_size = zend_safe_address_guarded(1, sizeof(bc_struct) + (ZEND_MM_ALIGNMENT - 1) + length, scale);
41 	required_size &= -ZEND_MM_ALIGNMENT;
42 	bc_num temp;
43 
44 	if (!persistent && BCG(arena) && required_size <= BC_ARENA_SIZE - BCG(arena_offset)) {
45 		temp = (bc_num) (BCG(arena) + BCG(arena_offset));
46 		BCG(arena_offset) += required_size;
47 		temp->n_refs = 2; /* prevent freeing */
48 	} else {
49 		/* PHP Change: malloc() -> pemalloc(), removed free_list code, merged n_ptr and n_value */
50 		temp = pemalloc(required_size, persistent);
51 		temp->n_refs = 1;
52 	}
53 
54 	temp->n_sign = PLUS;
55 	temp->n_len = length;
56 	temp->n_scale = scale;
57 	temp->n_value = (char *) temp + sizeof(bc_struct);
58 	return temp;
59 }
60 
61 /* new_num allocates a number and sets fields to known values. */
_bc_new_num_ex(size_t length,size_t scale,bool persistent)62 bc_num _bc_new_num_ex(size_t length, size_t scale, bool persistent)
63 {
64 	bc_num temp = _bc_new_num_nonzeroed_ex_internal(length, scale, persistent);
65 	memset(temp->n_value, 0, length + scale);
66 	return temp;
67 }
68 
_bc_new_num_nonzeroed_ex(size_t length,size_t scale,bool persistent)69 bc_num _bc_new_num_nonzeroed_ex(size_t length, size_t scale, bool persistent)
70 {
71 	return _bc_new_num_nonzeroed_ex_internal(length, scale, persistent);
72 }
73 
74 /* "Frees" a bc_num NUM.  Actually decreases reference count and only
75    frees the storage if reference count is zero. */
_bc_free_num_ex(bc_num * num,bool persistent)76 void _bc_free_num_ex(bc_num *num, bool persistent)
77 {
78 	if (*num == NULL) {
79 		return;
80 	}
81 	(*num)->n_refs--;
82 	if ((*num)->n_refs == 0) {
83 		pefree(*num, persistent);
84 	}
85 	*num = NULL;
86 }
87 
88 
89 /* Initialize the number package! */
90 
bc_init_numbers(void)91 void bc_init_numbers(void)
92 {
93 	BCG(_zero_) = _bc_new_num_ex(1, 0, 1);
94 	BCG(_one_) = _bc_new_num_ex(1, 0, 1);
95 	BCG(_one_)->n_value[0] = 1;
96 	BCG(_two_) = _bc_new_num_ex(1, 0, 1);
97 	BCG(_two_)->n_value[0] = 2;
98 }
99 
100 
101 /* Initialize a number NUM by making it a copy of zero. */
bc_init_num(bc_num * num)102 void bc_init_num(bc_num *num)
103 {
104 	*num = bc_copy_num(BCG(_zero_));
105 }
106