mpd/src/growing_fifo.c

91 lines
2.6 KiB
C

/*
* 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 "growing_fifo.h"
#include "fifo_buffer.h"
#include <assert.h>
#include <string.h>
/**
* Align buffer sizes at 8 kB boundaries. Must be a power of two.
*/
static const size_t GROWING_FIFO_ALIGN = 8192;
/**
* Align the specified size to the next #GROWING_FIFO_ALIGN boundary.
*/
static size_t
align(size_t size)
{
return ((size - 1) | (GROWING_FIFO_ALIGN - 1)) + 1;
}
struct fifo_buffer *
growing_fifo_new(void)
{
return fifo_buffer_new(GROWING_FIFO_ALIGN);
}
void *
growing_fifo_write(struct fifo_buffer **buffer_p, size_t length)
{
assert(buffer_p != NULL);
struct fifo_buffer *buffer = *buffer_p;
assert(buffer != NULL);
size_t max_length;
void *p = fifo_buffer_write(buffer, &max_length);
if (p != NULL && max_length >= length)
return p;
/* grow */
size_t new_size = fifo_buffer_available(buffer) + length;
assert(new_size > fifo_buffer_capacity(buffer));
*buffer_p = buffer = fifo_buffer_realloc(buffer, align(new_size));
/* try again */
p = fifo_buffer_write(buffer, &max_length);
assert(p != NULL);
assert(max_length >= length);
return p;
}
void
growing_fifo_append(struct fifo_buffer **buffer_p,
const void *data, size_t length)
{
void *p = growing_fifo_write(buffer_p, length);
memcpy(p, data, length);
fifo_buffer_append(*buffer_p, length);
}