1 /*
2 tre-stack.c - Simple stack implementation
3
4 This software is released under a BSD-style license.
5 See the file LICENSE for details and copyright.
6
7 */
8
9 #ifdef HAVE_CONFIG_H
10 #include <config.h>
11 #endif /* HAVE_CONFIG_H */
12 #include <stdlib.h>
13 #include <assert.h>
14
15 #include "tre-internal.h"
16 #include "tre-stack.h"
17 #include "xmalloc.h"
18
19 union tre_stack_item {
20 void *voidptr_value;
21 long long_value;
22 };
23
24 struct tre_stack_rec {
25 int size;
26 int max_size;
27 int increment;
28 int ptr;
29 union tre_stack_item *stack;
30 };
31
32
33 tre_stack_t *
tre_stack_new(int size,int max_size,int increment)34 tre_stack_new(int size, int max_size, int increment)
35 {
36 tre_stack_t *s;
37
38 s = xmalloc(sizeof(*s));
39 if (s != NULL)
40 {
41 s->stack = xmalloc(sizeof(*s->stack) * size);
42 if (s->stack == NULL)
43 {
44 xfree(s);
45 return NULL;
46 }
47 s->size = size;
48 s->max_size = max_size;
49 s->increment = increment;
50 s->ptr = 0;
51 }
52 return s;
53 }
54
55 void
tre_stack_destroy(tre_stack_t * s)56 tre_stack_destroy(tre_stack_t *s)
57 {
58 xfree(s->stack);
59 xfree(s);
60 }
61
62 int
tre_stack_num_objects(tre_stack_t * s)63 tre_stack_num_objects(tre_stack_t *s)
64 {
65 return s->ptr;
66 }
67
68 static reg_errcode_t
tre_stack_push(tre_stack_t * s,union tre_stack_item value)69 tre_stack_push(tre_stack_t *s, union tre_stack_item value)
70 {
71 if (s->ptr < s->size)
72 {
73 s->stack[s->ptr] = value;
74 s->ptr++;
75 }
76 else
77 {
78 if (s->size >= s->max_size)
79 {
80 DPRINT(("tre_stack_push: stack full\n"));
81 return REG_ESPACE;
82 }
83 else
84 {
85 union tre_stack_item *new_buffer;
86 int new_size;
87 DPRINT(("tre_stack_push: trying to realloc more space\n"));
88 new_size = s->size + s->increment;
89 if (new_size > s->max_size)
90 new_size = s->max_size;
91 new_buffer = xrealloc(s->stack, sizeof(*new_buffer) * new_size);
92 if (new_buffer == NULL)
93 {
94 DPRINT(("tre_stack_push: realloc failed.\n"));
95 return REG_ESPACE;
96 }
97 DPRINT(("tre_stack_push: realloc succeeded.\n"));
98 assert(new_size > s->size);
99 s->size = new_size;
100 s->stack = new_buffer;
101 tre_stack_push(s, value);
102 }
103 }
104 return REG_OK;
105 }
106
107 #define define_pushf(typetag, type) \
108 declare_pushf(typetag, type) { \
109 union tre_stack_item item; \
110 item.typetag ## _value = value; \
111 return tre_stack_push(s, item); \
112 }
113
114 define_pushf(long, long)
115 define_pushf(voidptr, void *)
116
117 #define define_popf(typetag, type) \
118 declare_popf(typetag, type) { \
119 return s->stack[--s->ptr].typetag ## _value; \
120 }
121
122 define_popf(long, long)
123 define_popf(voidptr, void *)
124
125 /* EOF */
126