formats: Use a hash table for _mesa_format_from_array_format

Going through the for loop every time has noticable overhead.  This fixes
things up so we only do that once ever and then just do a hash table lookup
which should be much cheaper.

v2 Jason Ekstrand <jason.ekstrand@intel.com>:
 - Use once_flag and call_once from c11/threads.h instead of pthreads

Reviewed-by: Neil Roberts <neil@linux.intel.com>
This commit is contained in:
Jason Ekstrand
2015-01-12 14:43:34 -08:00
parent 333226522c
commit e24d17e08c

View File

@@ -28,7 +28,8 @@
#include "formats.h"
#include "macros.h"
#include "glformats.h"
#include "c11/threads.h"
#include "util/hash_table.h"
/**
* Information about texture formats.
@@ -377,24 +378,67 @@ _mesa_format_to_array_format(mesa_format format)
return _mesa_array_format_flip_channels(info->ArrayFormat);
}
static struct hash_table *format_array_format_table;
static once_flag format_array_format_table_exists = ONCE_FLAG_INIT;
static bool
array_formats_equal(const void *a, const void *b)
{
return (intptr_t)a == (intptr_t)b;
}
static void
format_array_format_table_init()
{
const struct gl_format_info *info;
mesa_array_format array_format;
unsigned f;
format_array_format_table = _mesa_hash_table_create(NULL, NULL,
array_formats_equal);
for (f = 1; f < MESA_FORMAT_COUNT; ++f) {
info = _mesa_get_format_info(f);
if (!info->ArrayFormat)
continue;
if (_mesa_little_endian()) {
array_format = info->ArrayFormat;
} else {
array_format = _mesa_array_format_flip_channels(info->ArrayFormat);
}
/* This can happen and does for some of the BGR formats. Let's take
* the first one in the list.
*/
if (_mesa_hash_table_search_pre_hashed(format_array_format_table,
array_format,
(void *)(intptr_t)array_format))
continue;
_mesa_hash_table_insert_pre_hashed(format_array_format_table,
array_format,
(void *)(intptr_t)array_format,
(void *)(intptr_t)f);
}
}
mesa_format
_mesa_format_from_array_format(uint32_t array_format)
{
mesa_array_format af;
unsigned f;
struct hash_entry *entry;
assert(_mesa_format_is_mesa_array_format(array_format));
if (_mesa_little_endian())
af = array_format;
call_once(&format_array_format_table_exists, format_array_format_table_init);
entry = _mesa_hash_table_search_pre_hashed(format_array_format_table,
array_format,
(void *)(intptr_t)array_format);
if (entry)
return (intptr_t)entry->data;
else
af = _mesa_array_format_flip_channels(array_format);
for (f = 1; f < MESA_FORMAT_COUNT; ++f)
if (_mesa_get_format_info(f)->ArrayFormat == af)
return f;
return MESA_FORMAT_NONE;
return MESA_FORMAT_NONE;
}
/** Is the given format a compressed format? */