lshpack.h revision 229fce07 
1/* Copyright (c) 2017 - 2019 LiteSpeed Technologies Inc.  See LICENSE. */
2/*
3MIT License
4
5Copyright (c) 2018 LiteSpeed Technologies Inc
6
7Permission is hereby granted, free of charge, to any person obtaining a copy
8of this software and associated documentation files (the "Software"), to deal
9in the Software without restriction, including without limitation the rights
10to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11copies of the Software, and to permit persons to whom the Software is
12furnished to do so, subject to the following conditions:
13
14The above copyright notice and this permission notice shall be included in all
15copies or substantial portions of the Software.
16
17THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23SOFTWARE.
24*/
25
26#ifndef LITESPEED_HPACK_H
27#define LITESPEED_HPACK_H 1
28
29#ifdef __cplusplus
30extern "C" {
31#endif
32
33#include <stdint.h>
34
35/**
36 * Strings up to 65535 characters in length are supported.
37 */
38typedef uint16_t lshpack_strlen_t;
39
40/** Maximum length is defined for convenience */
41#define LSHPACK_MAX_STRLEN UINT16_MAX
42
43struct lshpack_enc;
44struct lshpack_dec;
45
46/**
47 * Initialization routine allocates memory.  -1 is returned if memory
48 * could not be allocated.  0 is returned on success.
49 */
50int
51lshpack_enc_init (struct lshpack_enc *);
52
53/**
54 * Clean up HPACK encoder, freeing all allocated memory.
55 */
56void
57lshpack_enc_cleanup (struct lshpack_enc *);
58
59/**
60 * @brief Encode one name/value pair
61 *
62 * @param[in,out] henc - A pointer to a valid HPACK API struct
63 * @param[out] dst - A pointer to destination buffer
64 * @param[out] dst_end - A pointer to end of destination buffer
65 * @param[in] name - A pointer to the item name
66 * @param[in] name_len - The item name's length
67 * @param[in] value - A pointer to the item value
68 * @param[in] value_len - The item value's length
69 * @param[in] indexed_type - 0, Add, 1,: without, 2: never
70 *
71 * @return The (possibly advanced) dst pointer.  If the destination
72 * pointer was not advanced, an error must have occurred.
73 */
74unsigned char *
75lshpack_enc_encode (struct lshpack_enc *henc, unsigned char *dst,
76    unsigned char *dst_end, const char *name, lshpack_strlen_t name_len,
77    const char *value, lshpack_strlen_t value_len, int indexed_type);
78
79void
80lshpack_enc_set_max_capacity (struct lshpack_enc *, unsigned);
81
82/**
83 * Initialize HPACK decoder structure.
84 */
85void
86lshpack_dec_init (struct lshpack_dec *);
87
88/**
89 * Clean up HPACK decoder structure, freeing all allocated memory.
90 */
91void
92lshpack_dec_cleanup (struct lshpack_dec *);
93
94/*
95 * Returns 0 on success, a negative value on failure.
96 *
97 * If 0 is returned, `src' is advanced.  Calling with a zero-length input
98 * buffer results in an error.
99 */
100int
101lshpack_dec_decode (struct lshpack_dec *dec,
102    const unsigned char **src, const unsigned char *src_end,
103    char *dst, char *const dst_end, lshpack_strlen_t *name_len,
104    lshpack_strlen_t *val_len, uint32_t *name_idx);
105
106void
107lshpack_dec_set_max_capacity (struct lshpack_dec *, unsigned);
108
109/* Some internals follow.  Struct definitions are exposed to save a malloc.
110 * These structures are not very complicated.
111 */
112
113#include <sys/queue.h>
114
115struct lshpack_enc_table_entry;
116
117STAILQ_HEAD(lshpack_enc_head, lshpack_enc_table_entry);
118struct lshpack_double_enc_head;
119
120struct lshpack_enc
121{
122    unsigned            hpe_cur_capacity;
123    unsigned            hpe_max_capacity;
124
125    /* Each new dynamic table entry gets the next number.  It is used to
126     * calculate the entry's position in the decoder table without having
127     * to maintain an actual array.
128     */
129    unsigned            hpe_next_id;
130
131    /* Dynamic table entries (struct enc_table_entry) live in two hash
132     * tables: name/value hash table and name hash table.  These tables
133     * are the same size.
134     */
135    unsigned            hpe_nelem;
136    unsigned            hpe_nbits;
137    struct lshpack_enc_head
138                        hpe_all_entries;
139    struct lshpack_double_enc_head
140                       *hpe_buckets;
141};
142
143struct lshpack_arr
144{
145    unsigned        nalloc,
146                    nelem,
147                    off;
148    uintptr_t      *els;
149};
150
151struct lshpack_dec
152{
153    unsigned           hpd_max_capacity;       /* Maximum set by caller */
154    unsigned           hpd_cur_max_capacity;   /* Adjusted at runtime */
155    unsigned           hpd_cur_capacity;
156    struct lshpack_arr hpd_dyn_table;
157};
158
159unsigned
160lshpack_enc_get_stx_tab_id (const char *name, lshpack_strlen_t name_len,
161                const char *val, lshpack_strlen_t val_len, int *val_matched);
162
163#ifdef __cplusplus
164}
165#endif
166
167#endif
168