1 /*
2  * Copyright (c) 2007-2014, Lloyd Hilaiel <me@lloyd.io>
3  *
4  * Permission to use, copy, modify, and/or distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /*
18  * A header only implementation of a simple stack of bytes, used in YAJL
19  * to maintain parse state.
20  */
21 
22 #ifndef __YAJL_BYTESTACK_H__
23 #define __YAJL_BYTESTACK_H__
24 
25 #include "api/yajl_common.h"
26 
27 #define YAJL_BS_INC 128
28 
29 typedef struct yajl_bytestack_t
30 {
31     unsigned char * stack;
32     size_t size;
33     size_t used;
34     yajl_alloc_funcs * yaf;
35 } yajl_bytestack;
36 
37 /* initialize a bytestack */
38 #define yajl_bs_init(obs, _yaf) {               \
39         (obs).stack = NULL;                     \
40         (obs).size = 0;                         \
41         (obs).used = 0;                         \
42         (obs).yaf = (_yaf);                     \
43     }                                           \
44 
45 
46 /* initialize a bytestack */
47 #define yajl_bs_free(obs)                 \
48     if ((obs).stack) (obs).yaf->free((obs).yaf->ctx, (obs).stack);
49 
50 #define yajl_bs_current(obs)               \
51     (assert((obs).used > 0), (obs).stack[(obs).used - 1])
52 
53 #define yajl_bs_push(obs, byte) {                       \
54     if (((obs).size - (obs).used) == 0) {               \
55         (obs).size += YAJL_BS_INC;                      \
56         (obs).stack = (unsigned char *)(obs).yaf->realloc((obs).yaf->ctx,\
57                                          (void *) (obs).stack, (obs).size);\
58     }                                                   \
59     (obs).stack[((obs).used)++] = (byte);               \
60 }
61 
62 
63 /* removes the top item of the stack, returns nothing */
64 #define yajl_bs_pop(obs) { ((obs).used)--; }
65 
66 #define yajl_bs_set(obs, byte)                          \
67     (obs).stack[((obs).used) - 1] = (byte);
68 
69 
70 #endif
71