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General cleanup and direct export of bitreversal-array for faster access.

This commit is contained in:
Morten Rolland 1999-04-18 18:03:02 +00:00
parent 63f4c0b517
commit 28c2aeecd6
2 changed files with 63 additions and 15 deletions
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38
include/ifax/bitreverse.h
View File

@ -1,8 +1,32 @@
/* bitreverse.h
*
* Mirror the bits of an unsigned character so that b0 -> b7, b1 -> b6 etc.
*
* (C) 1998 Morten Rolland
*/
/* $Id$
******************************************************************************
unsigned char bitrev(unsigned char v);
Fax program for ISDN.
Lookup tables to handle bit-reversal of 8-bits
Copyright (C) 1998 Morten Rolland [Morten.Rolland@asker.mail.telia.com]
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
******************************************************************************
*/
#include <ifax/types.h>
extern ifax_uint8 bitreverse[256];
ifax_uint8 bitrev(ifax_uint8);

40
lib/bitreverse.c
View File

@ -1,11 +1,35 @@
/* bitreverse.c
*
* Mirror the bits of an unsigned character so that b0 -> b7, b1 -> b6 etc.
*
* (C) 1998 Morten Rolland
*/
/* $Id$
******************************************************************************
static unsigned char bitreverse[256] = {
Fax program for ISDN.
Lookup tables to handle bit-reversal of 8-bits
Copyright (C) 1998 Morten Rolland [Morten.Rolland@asker.mail.telia.com]
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
******************************************************************************
*/
#include <ifax/types.h>
#include <ifax/bitreverse.h>
ifax_uint8 bitreverse[256] = {
0x00,0x80,0x40,0xc0,0x20,0xa0,0x60,0xe0,
0x10,0x90,0x50,0xd0,0x30,0xb0,0x70,0xf0,
0x08,0x88,0x48,0xc8,0x28,0xa8,0x68,0xe8,
@ -40,7 +64,7 @@ static unsigned char bitreverse[256] = {
0x1f,0x9f,0x5f,0xdf,0x3f,0xbf,0x7f,0xff
};
unsigned char bitrev(unsigned char v)
ifax_uint8 bitrev(ifax_uint8 v)
{
return bitreverse[v];
}