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-rw-r--r--src/util/fifo_buffer.c218
1 files changed, 218 insertions, 0 deletions
diff --git a/src/util/fifo_buffer.c b/src/util/fifo_buffer.c
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index 000000000..162ddf946
--- /dev/null
+++ b/src/util/fifo_buffer.c
@@ -0,0 +1,218 @@
+/*
+ * Copyright (C) 2003-2011 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "fifo_buffer.h"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <string.h>
+
+struct fifo_buffer {
+ size_t size, start, end;
+ unsigned char buffer[sizeof(size_t)];
+};
+
+struct fifo_buffer *
+fifo_buffer_new(size_t size)
+{
+ struct fifo_buffer *buffer;
+
+ assert(size > 0);
+
+ buffer = (struct fifo_buffer *)g_malloc(sizeof(*buffer) -
+ sizeof(buffer->buffer) + size);
+
+ buffer->size = size;
+ buffer->start = 0;
+ buffer->end = 0;
+
+ return buffer;
+}
+
+void
+fifo_buffer_init(struct fifo_buffer *buffer, size_t size)
+{
+ buffer->size = size - (sizeof(*buffer) - sizeof(buffer->buffer));
+ buffer->start = 0;
+ buffer->end = 0;
+}
+
+static void
+fifo_buffer_move(struct fifo_buffer *buffer);
+
+struct fifo_buffer *
+fifo_buffer_realloc(struct fifo_buffer *buffer, size_t new_size)
+{
+ if (buffer == NULL)
+ return new_size > 0
+ ? fifo_buffer_new(new_size)
+ : NULL;
+
+ /* existing data must fit in new size */
+ assert(new_size >= buffer->end - buffer->start);
+
+ if (new_size == 0) {
+ fifo_buffer_free(buffer);
+ return NULL;
+ }
+
+ /* compress the buffer when we're shrinking and the tail of
+ the buffer would exceed the new size */
+ if (buffer->end > new_size)
+ fifo_buffer_move(buffer);
+
+ /* existing data must fit in new size: second check */
+ assert(buffer->end <= new_size);
+
+ buffer = g_realloc(buffer, sizeof(*buffer) - sizeof(buffer->buffer) +
+ new_size);
+ buffer->size = new_size;
+ return buffer;
+}
+
+void
+fifo_buffer_free(struct fifo_buffer *buffer)
+{
+ assert(buffer != NULL);
+
+ g_free(buffer);
+}
+
+size_t
+fifo_buffer_capacity(const struct fifo_buffer *buffer)
+{
+ assert(buffer != NULL);
+
+ return buffer->size;
+}
+
+size_t
+fifo_buffer_available(const struct fifo_buffer *buffer)
+{
+ assert(buffer != NULL);
+
+ return buffer->end - buffer->start;
+}
+
+void
+fifo_buffer_clear(struct fifo_buffer *buffer)
+{
+ assert(buffer != NULL);
+
+ buffer->start = 0;
+ buffer->end = 0;
+}
+
+const void *
+fifo_buffer_read(const struct fifo_buffer *buffer, size_t *length_r)
+{
+ assert(buffer != NULL);
+ assert(buffer->end >= buffer->start);
+ assert(length_r != NULL);
+
+ if (buffer->start == buffer->end)
+ /* the buffer is empty */
+ return NULL;
+
+ *length_r = buffer->end - buffer->start;
+ return buffer->buffer + buffer->start;
+}
+
+void
+fifo_buffer_consume(struct fifo_buffer *buffer, size_t length)
+{
+ assert(buffer != NULL);
+ assert(buffer->end >= buffer->start);
+ assert(buffer->start + length <= buffer->end);
+
+ buffer->start += length;
+}
+
+/**
+ * Move data to the beginning of the buffer, to make room at the end.
+ */
+static void
+fifo_buffer_move(struct fifo_buffer *buffer)
+{
+ if (buffer->start == 0)
+ return;
+
+ if (buffer->end > buffer->start)
+ memmove(buffer->buffer,
+ buffer->buffer + buffer->start,
+ buffer->end - buffer->start);
+
+ buffer->end -= buffer->start;
+ buffer->start = 0;
+}
+
+void *
+fifo_buffer_write(struct fifo_buffer *buffer, size_t *max_length_r)
+{
+ assert(buffer != NULL);
+ assert(buffer->end <= buffer->size);
+ assert(max_length_r != NULL);
+
+ if (buffer->end == buffer->size) {
+ fifo_buffer_move(buffer);
+ if (buffer->end == buffer->size)
+ return NULL;
+ } else if (buffer->start > 0 && buffer->start == buffer->end) {
+ buffer->start = 0;
+ buffer->end = 0;
+ }
+
+ *max_length_r = buffer->size - buffer->end;
+ return buffer->buffer + buffer->end;
+}
+
+void
+fifo_buffer_append(struct fifo_buffer *buffer, size_t length)
+{
+ assert(buffer != NULL);
+ assert(buffer->end >= buffer->start);
+ assert(buffer->end + length <= buffer->size);
+
+ buffer->end += length;
+}
+
+bool
+fifo_buffer_is_empty(struct fifo_buffer *buffer)
+{
+ return buffer->start == buffer->end;
+}
+
+bool
+fifo_buffer_is_full(struct fifo_buffer *buffer)
+{
+ return buffer->start == 0 && buffer->end == buffer->size;
+}