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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
*
* Copyright (C) 2003 Tat Tang
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <string.h>
#include "font_cache.h"
#include "debug.h"
/*******************************************************************************
* font_cache_lru_init
******************************************************************************/
void font_cache_lru_init(void* data)
{
struct font_cache_entry* p = data;
p->_char_code = 0xffff; /* assume invalid char */
}
/*******************************************************************************
* font_cache_create
******************************************************************************/
void font_cache_create(
struct font_cache* fcache,
void *buf,
int buf_size,
int bitmap_bytes_size)
{
int font_cache_entry_size =
sizeof(struct font_cache_entry) + bitmap_bytes_size;
/* make sure font cache entries are a multiple of 16 bits */
if (font_cache_entry_size % 2 != 0)
font_cache_entry_size++;
int cache_size = buf_size /
(font_cache_entry_size + LRU_SLOT_OVERHEAD + sizeof(short));
fcache->_size = 1;
fcache->_capacity = cache_size;
/* set up index */
fcache->_index = buf;
/* set up lru list */
unsigned char* lru_buf = buf;
lru_buf += sizeof(short) * cache_size;
lru_create(&fcache->_lru, lru_buf, cache_size, font_cache_entry_size);
/* initialise cache */
lru_traverse(&fcache->_lru, font_cache_lru_init);
short i;
for (i = 0; i < cache_size; i++)
fcache->_index[i] = i; /* small cheat here */
}
/*******************************************************************************
* font_cache_index_of
******************************************************************************/
int font_cache_index_of(
struct font_cache* fcache,
unsigned short char_code)
{
struct font_cache_entry* p;
int left, right, mid, c;
left = 0;
right = fcache->_size - 1;
do
{
mid = (left + right) / 2;
p = lru_data(&fcache->_lru, fcache->_index[mid]);
c = p->_char_code - char_code;
if (c == 0)
return mid;
if (c < 0)
left = mid + 1;
else
right = mid - 1;
}
while (left <= right);
return -1;
}
/*******************************************************************************
* font_cache_insertion_point
******************************************************************************/
int font_cache_insertion_point(
struct font_cache* fcache,
unsigned short char_code)
{
struct font_cache_entry* p;
short *index = fcache->_index;
p = lru_data(&fcache->_lru, index[0]);
if (char_code < p->_char_code)
return -1;
p = lru_data(&fcache->_lru, index[fcache->_capacity - 1]);
if (char_code > p->_char_code)
return fcache->_capacity - 1;
int left, right, mid, c;
left = 0;
right = fcache->_capacity - 1;
do
{
mid = (left + right) / 2;
p = lru_data(&fcache->_lru, index[mid]);
c = char_code - p->_char_code;
if (c >= 0)
{
p = lru_data(&fcache->_lru, index[mid+1]);
int z = char_code - p->_char_code;
if (z < 0)
return mid;
if (z == 0)
return mid + 1;
}
if (c > 0)
left = mid + 1;
else
right = mid - 1;
}
while (left <= right);
/* not found */
return -2;
}
/*******************************************************************************
* font_cache_get
******************************************************************************/
struct font_cache_entry* font_cache_get(
struct font_cache* fcache,
unsigned short char_code,
void (*callback) (struct font_cache_entry* p, void *callback_data),
void *callback_data)
{
int insertion_point = font_cache_insertion_point(fcache, char_code);
if (insertion_point >= 0)
{
short lru_handle = fcache->_index[insertion_point];
struct font_cache_entry* p = lru_data(&fcache->_lru, lru_handle);
if (p->_char_code == char_code)
{
lru_touch(&fcache->_lru, lru_handle);
return lru_data(&fcache->_lru, lru_handle);
}
}
/* not found */
short lru_handle_to_replace = fcache->_lru._head;
struct font_cache_entry* p =
lru_data(&fcache->_lru, lru_handle_to_replace);
int index_to_replace = font_cache_index_of(fcache, p->_char_code);
if (insertion_point < index_to_replace)
{
/* shift memory down */
int dest = insertion_point+2;
int src = insertion_point+1;
int len = index_to_replace - insertion_point - 1;
int desti = dest + len - 1;
int srci = src + len - 1;
int i;
for (i = 0; i < len; i++)
fcache->_index[desti--] = fcache->_index[srci--];
/* add to index */
fcache->_index[insertion_point + 1] = lru_handle_to_replace;
}
else if (insertion_point > index_to_replace)
{
/* shift memory up */
int dest = index_to_replace;
int src = index_to_replace + 1;
int len = insertion_point - index_to_replace;
int i;
for (i=0; i < len; i++)
fcache->_index[dest++] = fcache->_index[src++];
/* add to index */
fcache->_index[insertion_point] = lru_handle_to_replace;
}
/* load new entry into cache */
lru_touch(&fcache->_lru, lru_handle_to_replace);
if (fcache->_size < fcache->_capacity)
fcache->_size++;
p->_char_code = char_code;
callback(p, callback_data);
return p;
}
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