1 /*
2 * buffer.c -- generic memory buffer .
3 *
4 * Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
5 *
6 * See LICENSE for the license.
7 *
8 */
9
10 #include "config.h"
11 #include <stdlib.h>
12 #include <stdio.h>
13
14 #include "buffer.h"
15
16 static void
buffer_cleanup(void * arg)17 buffer_cleanup(void *arg)
18 {
19 buffer_type *buffer = (buffer_type *) arg;
20 assert(!buffer->_fixed);
21 free(buffer->_data);
22 }
23
24 buffer_type *
buffer_create(region_type * region,size_t capacity)25 buffer_create(region_type *region, size_t capacity)
26 {
27 buffer_type *buffer
28 = (buffer_type *) region_alloc(region, sizeof(buffer_type));
29 if (!buffer)
30 return NULL;
31
32 buffer->_data = (uint8_t *) xalloc(capacity);
33 buffer->_position = 0;
34 buffer->_limit = buffer->_capacity = capacity;
35 buffer->_fixed = 0;
36 buffer_invariant(buffer);
37
38 region_add_cleanup(region, buffer_cleanup, buffer);
39
40 return buffer;
41 }
42
43 void
buffer_create_from(buffer_type * buffer,void * data,size_t size)44 buffer_create_from(buffer_type *buffer, void *data, size_t size)
45 {
46 assert(data);
47
48 buffer->_position = 0;
49 buffer->_limit = buffer->_capacity = size;
50 buffer->_data = (uint8_t *) data;
51 buffer->_fixed = 1;
52
53 buffer_invariant(buffer);
54 }
55
56 void
buffer_clear(buffer_type * buffer)57 buffer_clear(buffer_type *buffer)
58 {
59 buffer_invariant(buffer);
60
61 buffer->_position = 0;
62 buffer->_limit = buffer->_capacity;
63 }
64
65 void
buffer_flip(buffer_type * buffer)66 buffer_flip(buffer_type *buffer)
67 {
68 buffer_invariant(buffer);
69
70 buffer->_limit = buffer->_position;
71 buffer->_position = 0;
72 }
73
74 void
buffer_rewind(buffer_type * buffer)75 buffer_rewind(buffer_type *buffer)
76 {
77 buffer_invariant(buffer);
78
79 buffer->_position = 0;
80 }
81
82 void
buffer_set_capacity(buffer_type * buffer,size_t capacity)83 buffer_set_capacity(buffer_type *buffer, size_t capacity)
84 {
85 buffer_invariant(buffer);
86 assert(buffer->_position <= capacity);
87 buffer->_data = (uint8_t *) xrealloc(buffer->_data, capacity);
88 buffer->_limit = buffer->_capacity = capacity;
89 }
90
91 void
buffer_reserve(buffer_type * buffer,size_t amount)92 buffer_reserve(buffer_type *buffer, size_t amount)
93 {
94 buffer_invariant(buffer);
95 assert(!buffer->_fixed);
96 if (buffer->_capacity < buffer->_position + amount) {
97 size_t new_capacity = buffer->_capacity * 3 / 2;
98 if (new_capacity < buffer->_position + amount) {
99 new_capacity = buffer->_position + amount;
100 }
101 buffer_set_capacity(buffer, new_capacity);
102 }
103 buffer->_limit = buffer->_capacity;
104 }
105
106 int
buffer_printf(buffer_type * buffer,const char * format,...)107 buffer_printf(buffer_type *buffer, const char *format, ...)
108 {
109 va_list args;
110 int written;
111 size_t remaining;
112
113 buffer_invariant(buffer);
114 assert(buffer->_limit == buffer->_capacity);
115
116 remaining = buffer_remaining(buffer);
117 va_start(args, format);
118 written = vsnprintf((char *) buffer_current(buffer), remaining,
119 format, args);
120 va_end(args);
121 if (written >= 0 && (size_t) written >= remaining) {
122 buffer_reserve(buffer, written + 1);
123 va_start(args, format);
124 written = vsnprintf((char *) buffer_current(buffer),
125 buffer_remaining(buffer),
126 format, args);
127 va_end(args);
128 }
129 buffer->_position += written;
130 return written;
131 }
132