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authorRichard Braun <rbraun@sceen.net>2018-01-04 21:50:05 +0100
committerRichard Braun <rbraun@sceen.net>2018-01-04 21:50:05 +0100
commitb03224b9a82a4d46fd1e469821975f9a5295ed40 (patch)
tree7830e5dc6316f4d29abb3c27c8a7ef77684446df /src/cbuf.h
parente7321910ca4d956b572a050d302a25df37ce06ab (diff)
Move sources to new src/ directory
Diffstat (limited to 'src/cbuf.h')
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+/*
+ * Copyright (c) 2015-2017 Richard Braun.
+ *
+ * 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.
+ *
+ * Upstream site with license notes :
+ * http://git.sceen.net/rbraun/librbraun.git/
+ *
+ *
+ * Circular byte buffer.
+ */
+
+#ifndef _CBUF_H
+#define _CBUF_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+/*
+ * Circular buffer descriptor.
+ *
+ * The buffer capacity must be a power-of-two. Indexes are absolute values
+ * which can overflow. Their difference cannot exceed the capacity.
+ */
+struct cbuf {
+ uint8_t *buf;
+ size_t capacity;
+ size_t start;
+ size_t end;
+};
+
+static inline size_t
+cbuf_capacity(const struct cbuf *cbuf)
+{
+ return cbuf->capacity;
+}
+
+static inline size_t
+cbuf_start(const struct cbuf *cbuf)
+{
+ return cbuf->start;
+}
+
+static inline size_t
+cbuf_end(const struct cbuf *cbuf)
+{
+ return cbuf->end;
+}
+
+static inline size_t
+cbuf_size(const struct cbuf *cbuf)
+{
+ return cbuf->end - cbuf->start;
+}
+
+static inline void
+cbuf_clear(struct cbuf *cbuf)
+{
+ cbuf->start = cbuf->end;
+}
+
+static inline bool
+cbuf_range_valid(const struct cbuf *cbuf, size_t start, size_t end)
+{
+ return (((end - start) <= cbuf_size(cbuf))
+ && ((start - cbuf->start) <= cbuf_size(cbuf))
+ && ((cbuf->end - end) <= cbuf_size(cbuf)));
+}
+
+/*
+ * Initialize a circular buffer.
+ *
+ * The descriptor is set to use the given buffer for storage. Capacity
+ * must be a power-of-two.
+ */
+void cbuf_init(struct cbuf *cbuf, void *buf, size_t capacity);
+
+/*
+ * Push data to a circular buffer.
+ *
+ * If the function isn't allowed to erase old data and the circular buffer
+ * doesn't have enough unused bytes for the new data, EAGAIN is returned.
+ */
+int cbuf_push(struct cbuf *cbuf, const void *buf, size_t size, bool erase);
+
+/*
+ * Pop data from a circular buffer.
+ *
+ * On entry, the sizep argument points to the size of the output buffer.
+ * On exit, it is updated to the number of bytes actually transferred.
+ *
+ * If the buffer is empty, EAGAIN is returned, and the size of the
+ * output buffer is undefined.
+ */
+int cbuf_pop(struct cbuf *cbuf, void *buf, size_t *sizep);
+
+/*
+ * Push a byte to a circular buffer.
+ *
+ * If the function isn't allowed to erase old data and the circular buffer
+ * is full, EAGAIN is returned.
+ */
+int cbuf_pushb(struct cbuf *cbuf, uint8_t byte, bool erase);
+
+/*
+ * Pop a byte from a circular buffer.
+ *
+ * If the buffer is empty, EAGAIN is returned.
+ */
+int cbuf_popb(struct cbuf *cbuf, void *bytep);
+
+/*
+ * Write into a circular buffer at a specific location.
+ *
+ * If the given index is outside buffer boundaries, EINVAL is returned.
+ * The given [index, size) range may extend beyond the end of the circular
+ * buffer.
+ */
+int cbuf_write(struct cbuf *cbuf, size_t index, const void *buf, size_t size);
+
+/*
+ * Read from a circular buffer at a specific location.
+ *
+ * On entry, the sizep argument points to the size of the output buffer.
+ * On exit, it is updated to the number of bytes actually transferred.
+ *
+ * If the given index is outside buffer boundaries, EINVAL is returned.
+ *
+ * The circular buffer isn't changed by this operation.
+ */
+int cbuf_read(const struct cbuf *cbuf, size_t index, void *buf, size_t *sizep);
+
+#endif /* _CBUF_H */