lib/skin_parser/skin_buffer.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id: skin_buffer.c 25962 2010-05-12 09:31:40Z jdgordon $
   9  *
  10  * Copyright (C) 2002 by Linus Nielsen Feltzing
  11  * Copyright (C) 2010 Jonathan Gordon
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19  * KIND, either express or implied.
  20  *
  21  ****************************************************************************/
  22
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <stdlib.h>
  26
  27 #include "skin_buffer.h"
  28 #include "skin_parser.h"
  29
  30 /****************************************************************************
  31  *
  32  *  This code handles buffer allocation for the entire skin system.
  33  *  This needs to work in 3 different situations:
  34  *    1) as a stand alone library. ROCKBOX isnt defined, alloc using malloc()
  35  *       and free the skin elements only (no callbacks doing more allocation)
  36  *    2) ROCKBOX builds for normal targets, alloc from a single big buffer
  37  *       which origionally came from the audio buffer, likely to run out of
  38  *       room with large themes. No need to free anything, just restore to
  39  *       the start of our buffer
  40  *    3) ROCKBOX "application/hosted" builds, alloc using the hosts malloc().
  41  *       We need to keep track of all allocations so they can be free()'d easily
  42  *
  43  *
  44  ****************************************************************************/
  45
  46
  47 #ifdef ROCKBOX
  48 #include "config.h"
  49 #include "skin_debug.h"
  50 static size_t buf_size;
  51 static unsigned char *buffer_start = NULL;
  52 static unsigned char *buffer_front = NULL;
  53
  54 #ifndef __PCTOOL__
  55 long skin_buffer_to_offset(void *pointer)
  56 {
  57     return pointer == NULL ? -1 : (void*)pointer - (void*)buffer_start;
  58 }
  59
  60 void* skin_buffer_from_offset(long offset)
  61 {
  62     return offset < 0 ? NULL : buffer_start + offset;
  63 }
  64 #endif
  65
  66 void skin_buffer_init(char* buffer, size_t size)
  67 {
  68     buffer_start = buffer_front = buffer;
  69     buf_size = size;
  70 }
  71
  72 /* Allocate size bytes from the buffer */
  73 #ifdef DEBUG_SKIN_ALLOCATIONS
  74 void* skin_buffer_alloc_ex(size_t size, char* debug)
  75 {
  76     void *retval = NULL;
  77     printf("%d %s\n", size, debug);
  78 #else
  79 void* skin_buffer_alloc(size_t size)
  80 {
  81     void *retval = NULL;
  82 #endif
  83     /* 32-bit aligned */
  84     size = (size + 3) & ~3;
  85     if (size > skin_buffer_freespace())
  86     {
  87         skin_error(MEMORY_LIMIT_EXCEEDED, NULL);
  88         return NULL;
  89     }
  90     retval = buffer_front;
  91     buffer_front += size;
  92     return retval;
  93 }
  94
  95 /* get the number of bytes currently being used */
  96 size_t skin_buffer_usage(void)
  97 {
  98     return buffer_front - buffer_start;
  99 }
 100 size_t skin_buffer_freespace(void)
 101 {
 102     return buf_size - skin_buffer_usage();
 103 }
 104 #else
 105 void* skin_buffer_alloc(size_t size)
 106 {
 107     return malloc(size);
 108 }
 109 #endif