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
19union tre_stack_item {
20  void *voidptr_value;
21  int int_value;
22};
23
24struct 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
33tre_stack_t *
34tre_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
55void
56tre_stack_destroy(tre_stack_t *s)
57{
58  xfree(s->stack);
59  xfree(s);
60}
61
62int
63tre_stack_num_objects(tre_stack_t *s)
64{
65  return s->ptr;
66}
67
68static reg_errcode_t
69tre_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
114define_pushf(int, int)
115define_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
122define_popf(int, int)
123define_popf(voidptr, void *)
124
125/* EOF */
126