1 files changed, 132 insertions, 0 deletions
diff --git a/lib/ngtcp2_ringbuf.h b/lib/ngtcp2_ringbuf.h
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+++ b/lib/ngtcp2_ringbuf.h
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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.
+ */
+#ifndef NGTCP2_RINGBUF_H
+#define NGTCP2_RINGBUF_H
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif /* HAVE_CONFIG_H */
+
+#include <ngtcp2/ngtcp2.h>
+
+#include "ngtcp2_mem.h"
+
+typedef struct ngtcp2_ringbuf {
+  /* buf points to the underlying buffer. */
+  uint8_t *buf;
+  const ngtcp2_mem *mem;
+  /* nmemb is the number of elements that can be stored in this ring
+     buffer. */
+  size_t nmemb;
+  /* size is the size of each element. */
+  size_t size;
+  /* first is the offset to the first element. */
+  size_t first;
+  /* len is the number of elements actually stored. */
+  size_t len;
+} ngtcp2_ringbuf;
+
+/*
+ * ngtcp2_ringbuf_init initializes |rb|.  |nmemb| is the number of
+ * elements that can be stored in this buffer.  |size| is the size of
+ * each element.  |size| must be power of 2.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_NOMEM
+ *     Out of memory.
+ */
+int ngtcp2_ringbuf_init(ngtcp2_ringbuf *rb, size_t nmemb, size_t size,
+                        const ngtcp2_mem *mem);
+
+/*
+ * ngtcp2_ringbuf_buf_init initializes |rb| with given buffer and
+ * size.
+ */
+void ngtcp2_ringbuf_buf_init(ngtcp2_ringbuf *rb, size_t nmemb, size_t size,
+                             uint8_t *buf, const ngtcp2_mem *mem);
+
+/*
+ * ngtcp2_ringbuf_free frees resources allocated for |rb|.  This
+ * function does not free the memory pointed by |rb|.
+ */
+void ngtcp2_ringbuf_free(ngtcp2_ringbuf *rb);
+
+/* ngtcp2_ringbuf_push_front moves the offset to the first element in
+   the buffer backward, and returns the pointer to the element.
+   Caller can store data to the buffer pointed by the returned
+   pointer.  If this action exceeds the capacity of the ring buffer,
+   the last element is silently overwritten, and rb->len remains
+   unchanged. */
+void *ngtcp2_ringbuf_push_front(ngtcp2_ringbuf *rb);
+
+/* ngtcp2_ringbuf_push_back moves the offset to the last element in
+   the buffer forward, and returns the pointer to the element.  Caller
+   can store data to the buffer pointed by the returned pointer.  If
+   this action exceeds the capacity of the ring buffer, the first
+   element is silently overwritten, and rb->len remains unchanged. */
+void *ngtcp2_ringbuf_push_back(ngtcp2_ringbuf *rb);
+
+/*
+ * ngtcp2_ringbuf_pop_front removes first element in |rb|.
+ */
+void ngtcp2_ringbuf_pop_front(ngtcp2_ringbuf *rb);
+
+/*
+ * ngtcp2_ringbuf_pop_back removes the last element in |rb|.
+ */
+void ngtcp2_ringbuf_pop_back(ngtcp2_ringbuf *rb);
+
+/* ngtcp2_ringbuf_resize changes the number of elements stored.  This
+   does not change the capacity of the underlying buffer. */
+void ngtcp2_ringbuf_resize(ngtcp2_ringbuf *rb, size_t len);
+
+/* ngtcp2_ringbuf_get returns the pointer to the element at
+   |offset|. */
+void *ngtcp2_ringbuf_get(ngtcp2_ringbuf *rb, size_t offset);
+
+/* ngtcp2_ringbuf_len returns the number of elements stored. */
+#define ngtcp2_ringbuf_len(RB) ((RB)->len)
+
+/* ngtcp2_ringbuf_full returns nonzero if |rb| is full. */
+int ngtcp2_ringbuf_full(ngtcp2_ringbuf *rb);
+
+/* ngtcp2_static_ringbuf_def defines ngtcp2_ringbuf struct wrapper
+   which uses a statically allocated buffer that is suitable for a
+   usage that does not change buffer size with ngtcp2_ringbuf_resize.
+   ngtcp2_ringbuf_free should never be called for rb field. */
+#define ngtcp2_static_ringbuf_def(NAME, NMEMB, SIZE)                           \
+  typedef struct ngtcp2_static_ringbuf_##NAME {                                \
+    ngtcp2_ringbuf rb;                                                         \
+    uint8_t buf[(NMEMB) * (SIZE)];                                             \
+  } ngtcp2_static_ringbuf_##NAME;                                              \
+                                                                               \
+  static inline void ngtcp2_static_ringbuf_##NAME##_init(                      \
+      ngtcp2_static_ringbuf_##NAME *srb) {                                     \
+    ngtcp2_ringbuf_buf_init(&srb->rb, (NMEMB), (SIZE), srb->buf, NULL);        \
+  }
+
+#endif /* NGTCP2_RINGBUF_H */