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-rw-r--r--lib/ngtcp2_ringbuf.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/lib/ngtcp2_ringbuf.c b/lib/ngtcp2_ringbuf.c
new file mode 100644
index 0000000..a6b3f73
--- /dev/null
+++ b/lib/ngtcp2_ringbuf.c
@@ -0,0 +1,120 @@
+/*
+ * 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(_M_ARM64)
+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->nmemb = nmemb;
+ 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->nmemb - 1);
+ rb->len = ngtcp2_min(rb->nmemb, rb->len + 1);
+
+ return (void *)&rb->buf[rb->first * rb->size];
+}
+
+void *ngtcp2_ringbuf_push_back(ngtcp2_ringbuf *rb) {
+ size_t offset = (rb->first + rb->len) & (rb->nmemb - 1);
+
+ if (rb->len == rb->nmemb) {
+ rb->first = (rb->first + 1) & (rb->nmemb - 1);
+ } else {
+ ++rb->len;
+ }
+
+ return (void *)&rb->buf[offset * rb->size];
+}
+
+void ngtcp2_ringbuf_pop_front(ngtcp2_ringbuf *rb) {
+ rb->first = (rb->first + 1) & (rb->nmemb - 1);
+ --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->nmemb);
+ rb->len = len;
+}
+
+void *ngtcp2_ringbuf_get(ngtcp2_ringbuf *rb, size_t offset) {
+ assert(offset < rb->len);
+ offset = (rb->first + offset) & (rb->nmemb - 1);
+ return &rb->buf[offset * rb->size];
+}
+
+int ngtcp2_ringbuf_full(ngtcp2_ringbuf *rb) { return rb->len == rb->nmemb; }