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/*
* ngtcp2
*
* Copyright (c) 2017 ngtcp2 contributors
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "ngtcp2_ringbuf.h"
#include <assert.h>
#ifdef WIN32
# include <intrin.h>
#endif
#include "ngtcp2_macro.h"
#if defined(_MSC_VER) && !defined(__clang__) && \
(defined(_M_ARM) || defined(_M_ARM64))
static unsigned int __popcnt(unsigned int x) {
unsigned int c = 0;
for (; x; ++c) {
x &= x - 1;
}
return c;
}
#endif
int ngtcp2_ringbuf_init(ngtcp2_ringbuf *rb, size_t nmemb, size_t size,
const ngtcp2_mem *mem) {
uint8_t *buf = ngtcp2_mem_malloc(mem, nmemb * size);
if (buf == NULL) {
return NGTCP2_ERR_NOMEM;
}
ngtcp2_ringbuf_buf_init(rb, nmemb, size, buf, mem);
return 0;
}
void ngtcp2_ringbuf_buf_init(ngtcp2_ringbuf *rb, size_t nmemb, size_t size,
uint8_t *buf, const ngtcp2_mem *mem) {
#ifdef WIN32
assert(1 == __popcnt((unsigned int)nmemb));
#else
assert(1 == __builtin_popcount((unsigned int)nmemb));
#endif
rb->buf = buf;
rb->mem = mem;
rb->mask = nmemb - 1;
rb->size = size;
rb->first = 0;
rb->len = 0;
}
void ngtcp2_ringbuf_free(ngtcp2_ringbuf *rb) {
if (rb == NULL) {
return;
}
ngtcp2_mem_free(rb->mem, rb->buf);
}
void *ngtcp2_ringbuf_push_front(ngtcp2_ringbuf *rb) {
rb->first = (rb->first - 1) & rb->mask;
if (rb->len < rb->mask + 1) {
++rb->len;
}
return (void *)&rb->buf[rb->first * rb->size];
}
void *ngtcp2_ringbuf_push_back(ngtcp2_ringbuf *rb) {
size_t offset = (rb->first + rb->len) & rb->mask;
if (rb->len == rb->mask + 1) {
rb->first = (rb->first + 1) & rb->mask;
} else {
++rb->len;
}
return (void *)&rb->buf[offset * rb->size];
}
void ngtcp2_ringbuf_pop_front(ngtcp2_ringbuf *rb) {
rb->first = (rb->first + 1) & rb->mask;
--rb->len;
}
void ngtcp2_ringbuf_pop_back(ngtcp2_ringbuf *rb) {
assert(rb->len);
--rb->len;
}
void ngtcp2_ringbuf_resize(ngtcp2_ringbuf *rb, size_t len) {
assert(len <= rb->mask + 1);
rb->len = len;
}
void *ngtcp2_ringbuf_get(ngtcp2_ringbuf *rb, size_t offset) {
assert(offset < rb->len);
offset = (rb->first + offset) & rb->mask;
return &rb->buf[offset * rb->size];
}
int ngtcp2_ringbuf_full(ngtcp2_ringbuf *rb) { return rb->len == rb->mask + 1; }
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