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
  29 /****************************************************************************
  30  *
  31  *  This code handles buffer allocation for the entire skin system.
  32  *  This needs to work in 3 different situations:
  33  *    1) as a stand alone library. ROCKBOX isnt defined, alloc using malloc()
  34  *       and free the skin elements only (no callbacks doing more allocation)
  35  *    2) ROCKBOX builds for normal targets, alloc from a single big buffer
  36  *       which origionally came from the audio buffer, likely to run out of
  37  *       room with large themes. No need to free anything, just restore to
  38  *       the start of our buffer
  39  *    3) ROCKBOX "application/hosted" builds, alloc using the hosts malloc().
  40  *       We need to keep track of all allocations so they can be free()'d easily
  41  *
  42  *
  43  ****************************************************************************/
  44
  45
  46 #ifdef ROCKBOX
  47 #include "config.h"
  48
  49 #ifdef APPLICATION
  50 #   define USE_HOST_MALLOC
  51 #else
  52 #   define USE_ROCKBOX_ALLOC
  53 #endif
  54
  55 #endif
  56
  57 #ifdef USE_ROCKBOX_ALLOC
  58 static size_t buf_size;
  59 static unsigned char *buffer_start = NULL;
  60 static unsigned char *buffer_front = NULL;
  61 #endif
  62
  63 #ifdef USE_HOST_MALLOC
  64
  65 struct malloc_object {
  66     struct malloc_object *next;
  67     char buf[0];
  68 };
  69 static struct malloc_object *malloced_head = NULL, *malloced_tail = NULL;
  70
  71 static void skin_free_malloced(void)
  72 {
  73     struct malloc_object *obj = malloced_head;
  74     struct malloc_object *this;
  75     while (obj)
  76     {
  77         this = obj;
  78         obj = this->next;
  79         free(this);
  80     }
  81     malloced_head = NULL;
  82     malloced_tail = NULL;
  83 }
  84
  85 #endif
  86
  87 void skin_buffer_init(char* buffer, size_t size)
  88 {
  89 #ifdef USE_ROCKBOX_ALLOC
  90     buffer_start = buffer_front = buffer;
  91     buf_size = size;
  92 #elif defined(USE_HOST_MALLOC)
  93     (void)buffer; (void)size;
  94     skin_free_malloced();
  95 #endif
  96 }
  97
  98 /* Allocate size bytes from the buffer */
  99 void* skin_buffer_alloc(size_t size)
 100 {
 101     void *retval = NULL;
 102 #ifdef USE_ROCKBOX_ALLOC
 103     /* 32-bit aligned */
 104     size = (size + 3) & ~3;
 105     if (size > skin_buffer_freespace())
 106         return NULL;
 107     retval = buffer_front;
 108     buffer_front += size;
 109 #elif defined(USE_HOST_MALLOC)
 110     size_t malloc_size = sizeof(struct malloc_object) + size;
 111     struct malloc_object *obj = malloc(malloc_size);
 112     retval = &obj->buf;
 113     obj->next = NULL;
 114     if (malloced_tail == NULL)
 115         malloced_head = malloced_tail = obj;
 116     else
 117         malloced_tail->next = obj;
 118     malloced_tail = obj;
 119
 120 #else
 121     retval = malloc(size);
 122 #endif
 123     return retval;
 124 }
 125
 126
 127 #ifdef USE_ROCKBOX_ALLOC
 128 /* get the number of bytes currently being used */
 129 size_t skin_buffer_usage(void)
 130 {
 131     return buffer_front - buffer_start;
 132 }
 133 size_t skin_buffer_freespace(void)
 134 {
 135     return buf_size - skin_buffer_usage();
 136 }
 137
 138 static unsigned char *saved_buffer_pos = NULL;
 139 void skin_buffer_save_position(void)
 140 {
 141     saved_buffer_pos = buffer_front;
 142 }
 143
 144 void skin_buffer_restore_position(void)
 145 {
 146     if (saved_buffer_pos)
 147         buffer_front = saved_buffer_pos;
 148 }
 149 #endif