1 /*
2 * nghttp3
3 *
4 * Copyright (c) 2019 nghttp3 contributors
5 * Copyright (c) 2017 ngtcp2 contributors
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining
8 * a copy of this software and associated documentation files (the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sublicense, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be
16 * included in all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
22 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 */
26 #include "nghttp3_ringbuf.h"
27
28 #include <assert.h>
29 #include <string.h>
30 #ifdef WIN32
31 # include <intrin.h>
32 #endif
33
34 #include "nghttp3_macro.h"
35
36 #if defined(_MSC_VER) && defined(_M_ARM64)
__popcnt(unsigned int x)37 unsigned int __popcnt(unsigned int x) {
38 unsigned int c = 0;
39 for (; x; ++c) {
40 x &= x - 1;
41 }
42 return c;
43 }
44 #endif
45
nghttp3_ringbuf_init(nghttp3_ringbuf * rb,size_t nmemb,size_t size,const nghttp3_mem * mem)46 int nghttp3_ringbuf_init(nghttp3_ringbuf *rb, size_t nmemb, size_t size,
47 const nghttp3_mem *mem) {
48 if (nmemb) {
49 #ifdef WIN32
50 assert(1 == __popcnt((unsigned int)nmemb));
51 #else
52 assert(1 == __builtin_popcount((unsigned int)nmemb));
53 #endif
54
55 rb->buf = nghttp3_mem_malloc(mem, nmemb * size);
56 if (rb->buf == NULL) {
57 return NGHTTP3_ERR_NOMEM;
58 }
59 } else {
60 rb->buf = NULL;
61 }
62
63 rb->mem = mem;
64 rb->nmemb = nmemb;
65 rb->size = size;
66 rb->first = 0;
67 rb->len = 0;
68
69 return 0;
70 }
71
nghttp3_ringbuf_free(nghttp3_ringbuf * rb)72 void nghttp3_ringbuf_free(nghttp3_ringbuf *rb) {
73 if (rb == NULL) {
74 return;
75 }
76
77 nghttp3_mem_free(rb->mem, rb->buf);
78 }
79
nghttp3_ringbuf_push_front(nghttp3_ringbuf * rb)80 void *nghttp3_ringbuf_push_front(nghttp3_ringbuf *rb) {
81 rb->first = (rb->first - 1) & (rb->nmemb - 1);
82 rb->len = nghttp3_min(rb->nmemb, rb->len + 1);
83
84 return (void *)&rb->buf[rb->first * rb->size];
85 }
86
nghttp3_ringbuf_push_back(nghttp3_ringbuf * rb)87 void *nghttp3_ringbuf_push_back(nghttp3_ringbuf *rb) {
88 size_t offset = (rb->first + rb->len) & (rb->nmemb - 1);
89
90 if (rb->len == rb->nmemb) {
91 rb->first = (rb->first + 1) & (rb->nmemb - 1);
92 } else {
93 ++rb->len;
94 }
95
96 return (void *)&rb->buf[offset * rb->size];
97 }
98
nghttp3_ringbuf_pop_front(nghttp3_ringbuf * rb)99 void nghttp3_ringbuf_pop_front(nghttp3_ringbuf *rb) {
100 rb->first = (rb->first + 1) & (rb->nmemb - 1);
101 --rb->len;
102 }
103
nghttp3_ringbuf_pop_back(nghttp3_ringbuf * rb)104 void nghttp3_ringbuf_pop_back(nghttp3_ringbuf *rb) {
105 assert(rb->len);
106 --rb->len;
107 }
108
nghttp3_ringbuf_resize(nghttp3_ringbuf * rb,size_t len)109 void nghttp3_ringbuf_resize(nghttp3_ringbuf *rb, size_t len) {
110 assert(len <= rb->nmemb);
111 rb->len = len;
112 }
113
nghttp3_ringbuf_get(nghttp3_ringbuf * rb,size_t offset)114 void *nghttp3_ringbuf_get(nghttp3_ringbuf *rb, size_t offset) {
115 assert(offset < rb->len);
116 offset = (rb->first + offset) & (rb->nmemb - 1);
117 return &rb->buf[offset * rb->size];
118 }
119
nghttp3_ringbuf_full(nghttp3_ringbuf * rb)120 int nghttp3_ringbuf_full(nghttp3_ringbuf *rb) { return rb->len == rb->nmemb; }
121
nghttp3_ringbuf_reserve(nghttp3_ringbuf * rb,size_t nmemb)122 int nghttp3_ringbuf_reserve(nghttp3_ringbuf *rb, size_t nmemb) {
123 uint8_t *buf;
124
125 if (rb->nmemb >= nmemb) {
126 return 0;
127 }
128
129 #ifdef WIN32
130 assert(1 == __popcnt((unsigned int)nmemb));
131 #else
132 assert(1 == __builtin_popcount((unsigned int)nmemb));
133 #endif
134
135 buf = nghttp3_mem_malloc(rb->mem, nmemb * rb->size);
136 if (buf == NULL) {
137 return NGHTTP3_ERR_NOMEM;
138 }
139
140 if (rb->buf != NULL) {
141 if (rb->first + rb->len <= rb->nmemb) {
142 memcpy(buf, rb->buf + rb->first * rb->size, rb->len * rb->size);
143 rb->first = 0;
144 } else {
145 memcpy(buf, rb->buf + rb->first * rb->size,
146 (rb->nmemb - rb->first) * rb->size);
147 memcpy(buf + (rb->nmemb - rb->first) * rb->size, rb->buf,
148 (rb->len - (rb->nmemb - rb->first)) * rb->size);
149 rb->first = 0;
150 }
151
152 nghttp3_mem_free(rb->mem, rb->buf);
153 }
154
155 rb->buf = buf;
156 rb->nmemb = nmemb;
157
158 return 0;
159 }
160