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
  51 #ifdef APPLICATION
  52 #   define USE_HOST_MALLOC
  53 #else
  54 #   define USE_ROCKBOX_ALLOC
  55 #endif
  56
  57 #endif
  58
  59 #ifdef USE_ROCKBOX_ALLOC
  60 static size_t buf_size;
  61 static unsigned char *buffer_start = NULL;
  62 static unsigned char *buffer_front = NULL;
  63 #endif
  64
  65 #ifdef USE_HOST_MALLOC
  66
  67 struct malloc_object {
  68     struct malloc_object *next;
  69     char buf[0];
  70 };
  71 static struct malloc_object *malloced_head = NULL, *malloced_tail = NULL;
  72
  73 static void skin_free_malloced(void)
  74 {
  75     struct malloc_object *obj = malloced_head;
  76     struct malloc_object *this;
  77     while (obj)
  78     {
  79         this = obj;
  80         obj = this->next;
  81         free(this);
  82     }
  83     malloced_head = NULL;
  84     malloced_tail = NULL;
  85 }
  86
  87 #endif
  88
  89 void skin_buffer_init(char* buffer, size_t size)
  90 {
  91 #ifdef USE_ROCKBOX_ALLOC
  92     buffer_start = buffer_front = buffer;
  93     buf_size = size;
  94 #elif defined(USE_HOST_MALLOC)
  95     (void)buffer; (void)size;
  96     skin_free_malloced();
  97 #endif
  98 }
  99
 100 /* Allocate size bytes from the buffer */
 101 void* skin_buffer_alloc(size_t size)
 102 {
 103     void *retval = NULL;
 104 #ifdef USE_ROCKBOX_ALLOC
 105     /* 32-bit aligned */
 106     size = (size + 3) & ~3;
 107     if (size > skin_buffer_freespace())
 108     {
 109         skin_error(MEMORY_LIMIT_EXCEEDED, NULL);
 110         return NULL;
 111     }
 112     retval = buffer_front;
 113     buffer_front += size;
 114 #elif defined(USE_HOST_MALLOC)
 115     size_t malloc_size = sizeof(struct malloc_object) + size;
 116     struct malloc_object *obj = malloc(malloc_size);
 117     retval = &obj->buf;
 118     obj->next = NULL;
 119     if (malloced_tail == NULL)
 120         malloced_head = malloced_tail = obj;
 121     else
 122         malloced_tail->next = obj;
 123     malloced_tail = obj;
 124
 125 #else
 126     retval = malloc(size);
 127 #endif
 128     return retval;
 129 }
 130
 131
 132 #ifdef USE_ROCKBOX_ALLOC
 133 /* get the number of bytes currently being used */
 134 size_t skin_buffer_usage(void)
 135 {
 136     return buffer_front - buffer_start;
 137 }
 138 size_t skin_buffer_freespace(void)
 139 {
 140     return buf_size - skin_buffer_usage();
 141 }
 142
 143 static unsigned char *saved_buffer_pos = NULL;
 144 void skin_buffer_save_position(void)
 145 {
 146     saved_buffer_pos = buffer_front;
 147 }
 148
 149 void skin_buffer_restore_position(void)
 150 {
 151     if (saved_buffer_pos)
 152         buffer_front = saved_buffer_pos;
 153 }
 154 #endif