rockbox/lib/skin_parser/skin_buffer.c

83 lines
2.2 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id: skin_buffer.c 25962 2010-05-12 09:31:40Z jdgordon $
*
* Copyright (C) 2002 by Linus Nielsen Feltzing
* Copyright (C) 2009 Jonathan Gordon
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "skin_buffer.h"
#ifdef ROCKBOX
static size_t buf_size;
static unsigned char *buffer_start = NULL;
static unsigned char *buffer_front = NULL;
#endif
void skin_buffer_init(char* buffer, size_t size)
{
#if defined(ROCKBOX)
buffer_start = buffer_front = buffer;
buf_size = size;
#endif
}
/* Allocate size bytes from the buffer */
void* skin_buffer_alloc(size_t size)
{
void *retval = NULL;
#ifdef ROCKBOX
if (size > skin_buffer_freespace())
return NULL;
retval = buffer_front;
buffer_front += size;
/* 32-bit aligned */
buffer_front = (void *)(((unsigned long)buffer_front + 3) & ~3);
#else
retval = malloc(size);
#endif
return retval;
}
#ifdef ROCKBOX
/* get the number of bytes currently being used */
size_t skin_buffer_usage(void)
{
return buffer_front - buffer_start;
}
size_t skin_buffer_freespace(void)
{
return buf_size - skin_buffer_usage();
}
static unsigned char *saved_buffer_pos = NULL;
void skin_buffer_save_position(void)
{
saved_buffer_pos = buffer_front;
}
void skin_buffer_restore_position(void)
{
if (saved_buffer_pos)
buffer_front = saved_buffer_pos;
}
#endif