[mLib] / bits.h

/* -*-c-*-
 *
 * $Id: bits.h,v 1.5 2000/06/17 10:36:06 mdw Exp $
 *
 * Portable bit-level manipulation macros
 *
 * (c) 1998 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of the mLib utilities library.
 *
 * mLib is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * mLib is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with mLib; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: bits.h,v $
 * Revision 1.5  2000/06/17 10:36:06  mdw
 * Support for 24-bit types.
 *
 * Revision 1.4  1999/12/10 23:42:04  mdw
 * Change header file guard names.
 *
 * Revision 1.3  1999/06/20 23:31:52  mdw
 * More portability enhancements.
 *
 * Revision 1.2  1999/06/17 00:12:46  mdw
 * Improve portability for shift and rotate macros.
 *
 * Revision 1.1  1999/06/01 09:46:19  mdw
 * New addition: bit manipulation macros.
 *
 */

#ifndef MLIB_BITS_H
#define MLIB_BITS_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Header files ------------------------------------------------------*/

#include <limits.h>
#include <stddef.h>

/*----- Decide on some types ----------------------------------------------*/

/* --- Decide on a 32-bit type --- *
 *
 * I want a type which is capable of expressing 32-bit numbers.  Because some
 * implementations have 64-bit @long@s (infinitely preferable to the abortion
 * that is @long long@), using @unsigned long@ regardless is wasteful.  So,
 * if @int@ appears to be good enough, then I'll go with that.
 */

#if UINT_MAX >= 0xffffffffu
  typedef unsigned int uint32;
#else
  typedef unsigned long uint32;
#endif

/* --- Decide on a 24-bit type --- */

#if UINT_MAX >= 0x00ffffffu
  typedef unsigned int uint24;
#else
  typedef unsigned long uint24;
#endif

/* --- Decide on 16-bit and 8-bit types --- *
 *
 * This is more for brevity than anything else.
 */

typedef unsigned short uint16;
typedef unsigned char octet;

/* --- WARNING! --- *
 *
 * Never lose sight of the fact that the above types may be wider than the
 * names suggest.  Some architectures have 32-bit @short@s for example.
 */

/*----- Macros ------------------------------------------------------------*/

/* --- Useful masks --- */

#define MASK8 0xffu
#define MASK16 0xffffu
#define MASK24 0xffffffu
#define MASK32 0xffffffffu

/* --- Type coercions --- */

#define U8(x) ((octet)((x) & MASK8))
#define U16(x) ((uint16)((x) & MASK16))
#define U24(x) ((uint24)((x) & MASK24))
#define U32(x) ((uint32)((x) & MASK32))

/* --- Safe shifting macros --- */

#define LSL8(v, s) U8(U8(v) << ((s) & 7u))
#define LSR8(v, s) U8(U8(v) >> ((s) & 7u))
#define LSL16(v, s) U16(U16(v) << ((s) & 15u))
#define LSR16(v, s) U16(U16(v) >> ((s) & 15u))
#define LSL24(v, s) U24(U24(v) << ((s) % 24u))
#define LSR24(v, s) U24(U24(v) >> ((s) % 24u))
#define LSL32(v, s) U32(U32(v) << ((s) & 31u))
#define LSR32(v, s) U32(U32(v) >> ((s) & 31u))

/* --- Rotation macros --- */

#define ROL8(v, s) (LSL8((v), (s)) | (LSR8((v), 8u - (s))))
#define ROR8(v, s) (LSR8((v), (s)) | (LSL8((v), 8u - (s))))
#define ROL16(v, s) (LSL16((v), (s)) | (LSR16((v), 16u - (s))))
#define ROR16(v, s) (LSR16((v), (s)) | (LSL16((v), 16u - (s))))
#define ROL24(v, s) (LSL24((v), (s)) | (LSR24((v), 24u - (s))))
#define ROR24(v, s) (LSR24((v), (s)) | (LSL24((v), 24u - (s))))
#define ROL32(v, s) (LSL32((v), (s)) | (LSR32((v), 32u - (s))))
#define ROR32(v, s) (LSR32((v), (s)) | (LSL32((v), 32u - (s))))

/* --- Storage and retrieval --- */

#define GETBYTE(p, o) (((octet *)(p))[o] & MASK8)
#define PUTBYTE(p, o, v) (((octet *)(p))[o] = U8((v)))

#define LOAD8(p) (GETBYTE((p), 0))
#define STORE8(p, v) (PUTBYTE((p), 0, (v)))

#define LOAD16_B(p)							\
  (((uint16)GETBYTE((p), 0) << 8) |					\
   ((uint16)GETBYTE((p), 1) << 0))
#define LOAD16_L(p)							\
  (((uint16)GETBYTE((p), 0) << 0) |					\
   ((uint16)GETBYTE((p), 1) << 8))
#define LOAD16(p) LOAD16_B((p))

#define STORE16_B(p, v)							\
  (PUTBYTE((p), 0, (uint16)(v) >> 8),					\
   PUTBYTE((p), 1, (uint16)(v) >> 0))
#define STORE16_L(p, v)							\
  (PUTBYTE((p), 0, (uint16)(v) >> 0),					\
   PUTBYTE((p), 1, (uint16)(v) >> 8))
#define STORE16(p, v) STORE16_B((p), (v))

#define LOAD24_B(p)							\
  (((uint24)GETBYTE((p), 0) << 16) |					\
   ((uint24)GETBYTE((p), 1) <<  8) |					\
   ((uint24)GETBYTE((p), 2) <<  0))
#define LOAD24_L(p)							\
  (((uint24)GETBYTE((p), 0) <<  0) |					\
   ((uint24)GETBYTE((p), 1) <<  8) |					\
   ((uint24)GETBYTE((p), 2) << 16))
#define LOAD24(p) LOAD24_B((p))

#define STORE24_B(p, v)							\
  (PUTBYTE((p), 0, (uint24)(v) >> 16),					\
   PUTBYTE((p), 1, (uint24)(v) >>  8),					\
   PUTBYTE((p), 2, (uint24)(v) >>  0))
#define STORE24_L(p, v)							\
  (PUTBYTE((p), 0, (uint24)(v) >>  0),					\
   PUTBYTE((p), 1, (uint24)(v) >>  8),					\
   PUTBYTE((p), 2, (uint24)(v) >> 16))
#define STORE24(p, v) STORE24_B((p), (v))

#define LOAD32_B(p)							\
  (((uint32)GETBYTE((p), 0) << 24) |					\
   ((uint32)GETBYTE((p), 1) << 16) |					\
   ((uint32)GETBYTE((p), 2) <<  8) |					\
   ((uint32)GETBYTE((p), 3) <<  0))
#define LOAD32_L(p)							\
  (((uint32)GETBYTE((p), 0) <<  0) |					\
   ((uint32)GETBYTE((p), 1) <<  8) |					\
   ((uint32)GETBYTE((p), 2) << 16) |					\
   ((uint32)GETBYTE((p), 3) << 24))
#define LOAD32(p) LOAD32_B((p))

#define STORE32_B(p, v)							\
  (PUTBYTE((p), 0, (uint32)(v) >> 24),					\
   PUTBYTE((p), 1, (uint32)(v) >> 16),					\
   PUTBYTE((p), 2, (uint32)(v) >>  8),					\
   PUTBYTE((p), 3, (uint32)(v) >>  0))
#define STORE32_L(p, v)							\
  (PUTBYTE((p), 0, (uint32)(v) >>  0),					\
   PUTBYTE((p), 1, (uint32)(v) >>  8),					\
   PUTBYTE((p), 2, (uint32)(v) >> 16),					\
   PUTBYTE((p), 3, (uint32)(v) >> 24))
#define STORE32(p, v) STORE32_B((p), (v))

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif
Commit	Line	Data
6b033bc4	1	/* --c--
6b033bc4	2	*
6a0129ea	3	* $Id: bits.h,v 1.5 2000/06/17 10:36:06 mdw Exp $
6b033bc4	4	*
	5	* Portable bit-level manipulation macros
	6	*
	7	* (c) 1998 Straylight/Edgeware
	8	*/
	9
	10	/----- Licensing notice --------------------------------------------------
	11	*
	12	* This file is part of the mLib utilities library.
	13	*
	14	* mLib is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU Library General Public License as
	16	* published by the Free Software Foundation; either version 2 of the
	17	* License, or (at your option) any later version.
	18	*
	19	* mLib is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU Library General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU Library General Public
	25	* License along with mLib; if not, write to the Free
	26	* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
	27	* MA 02111-1307, USA.
	28	*/
	29
	30	/----- Revision history --------------------------------------------------
	31	*
	32	* $Log: bits.h,v $
6a0129ea	33	* Revision 1.5 2000/06/17 10:36:06 mdw
	34	* Support for 24-bit types.
	35	*
c6e0eaf0	36	* Revision 1.4 1999/12/10 23:42:04 mdw
	37	* Change header file guard names.
	38	*
0d4e268a	39	* Revision 1.3 1999/06/20 23:31:52 mdw
	40	* More portability enhancements.
	41	*
bc9f60b6	42	* Revision 1.2 1999/06/17 00:12:46 mdw
	43	* Improve portability for shift and rotate macros.
	44	*
6b033bc4	45	* Revision 1.1 1999/06/01 09:46:19 mdw
	46	* New addition: bit manipulation macros.
	47	*
	48	*/
	49
c6e0eaf0	50	#ifndef MLIB_BITS_H
c6e0eaf0	51	#define MLIB_BITS_H
6b033bc4	52
	53	#ifdef __cplusplus
	54	extern "C" {
	55	#endif
	56
	57	/----- Header files ------------------------------------------------------/
	58
	59	#include <limits.h>
	60	#include <stddef.h>
	61
	62	/----- Decide on some types ----------------------------------------------/
	63
	64	/* --- Decide on a 32-bit type --- *
	65	*
	66	* I want a type which is capable of expressing 32-bit numbers. Because some
	67	* implementations have 64-bit @long@s (infinitely preferable to the abortion
	68	* that is @long long@), using @unsigned long@ regardless is wasteful. So,
	69	* if @int@ appears to be good enough, then I'll go with that.
	70	*/
	71
	72	#if UINT_MAX >= 0xffffffffu
	73	typedef unsigned int uint32;
	74	#else
	75	typedef unsigned long uint32;
	76	#endif
	77
6a0129ea	78	/* --- Decide on a 24-bit type --- */
	79
	80	#if UINT_MAX >= 0x00ffffffu
	81	typedef unsigned int uint24;
	82	#else
	83	typedef unsigned long uint24;
	84	#endif
	85
6b033bc4	86	/* --- Decide on 16-bit and 8-bit types --- *
	87	*
	88	* This is more for brevity than anything else.
	89	*/
	90
	91	typedef unsigned short uint16;
	92	typedef unsigned char octet;
	93
	94	/* --- WARNING! --- *
	95	*
	96	* Never lose sight of the fact that the above types may be wider than the
	97	* names suggest. Some architectures have 32-bit @short@s for example.
	98	*/
	99
	100	/----- Macros ------------------------------------------------------------/
	101
	102	/* --- Useful masks --- */
	103
	104	#define MASK8 0xffu
	105	#define MASK16 0xffffu
6a0129ea	106	#define MASK24 0xffffffu
6b033bc4	107	#define MASK32 0xffffffffu
	108
	109	/* --- Type coercions --- */
	110
	111	#define U8(x) ((octet)((x) & MASK8))
	112	#define U16(x) ((uint16)((x) & MASK16))
6a0129ea	113	#define U24(x) ((uint24)((x) & MASK24))
6b033bc4	114	#define U32(x) ((uint32)((x) & MASK32))
	115
	116	/* --- Safe shifting macros --- */
	117
bc9f60b6	118	#define LSL8(v, s) U8(U8(v) << ((s) & 7u))
	119	#define LSR8(v, s) U8(U8(v) >> ((s) & 7u))
	120	#define LSL16(v, s) U16(U16(v) << ((s) & 15u))
	121	#define LSR16(v, s) U16(U16(v) >> ((s) & 15u))
6a0129ea	122	#define LSL24(v, s) U24(U24(v) << ((s) % 24u))
6a0129ea	123	#define LSR24(v, s) U24(U24(v) >> ((s) % 24u))
bc9f60b6	124	#define LSL32(v, s) U32(U32(v) << ((s) & 31u))
bc9f60b6	125	#define LSR32(v, s) U32(U32(v) >> ((s) & 31u))
6b033bc4	126
	127	/* --- Rotation macros --- */
	128
bc9f60b6	129	#define ROL8(v, s) (LSL8((v), (s)) \| (LSR8((v), 8u - (s))))
	130	#define ROR8(v, s) (LSR8((v), (s)) \| (LSL8((v), 8u - (s))))
	131	#define ROL16(v, s) (LSL16((v), (s)) \| (LSR16((v), 16u - (s))))
	132	#define ROR16(v, s) (LSR16((v), (s)) \| (LSL16((v), 16u - (s))))
6a0129ea	133	#define ROL24(v, s) (LSL24((v), (s)) \| (LSR24((v), 24u - (s))))
6a0129ea	134	#define ROR24(v, s) (LSR24((v), (s)) \| (LSL24((v), 24u - (s))))
bc9f60b6	135	#define ROL32(v, s) (LSL32((v), (s)) \| (LSR32((v), 32u - (s))))
bc9f60b6	136	#define ROR32(v, s) (LSR32((v), (s)) \| (LSL32((v), 32u - (s))))
6b033bc4	137
	138	/* --- Storage and retrieval --- */
	139
	140	#define GETBYTE(p, o) (((octet *)(p))[o] & MASK8)
	141	#define PUTBYTE(p, o, v) (((octet *)(p))[o] = U8((v)))
	142
	143	#define LOAD8(p) (GETBYTE((p), 0))
	144	#define STORE8(p, v) (PUTBYTE((p), 0, (v)))
	145
0d4e268a	146	#define LOAD16_B(p) \
	147	(((uint16)GETBYTE((p), 0) << 8) \| \
	148	((uint16)GETBYTE((p), 1) << 0))
	149	#define LOAD16_L(p) \
	150	(((uint16)GETBYTE((p), 0) << 0) \| \
	151	((uint16)GETBYTE((p), 1) << 8))
6b033bc4	152	#define LOAD16(p) LOAD16_B((p))
6b033bc4	153
0d4e268a	154	#define STORE16_B(p, v) \
	155	(PUTBYTE((p), 0, (uint16)(v) >> 8), \
	156	PUTBYTE((p), 1, (uint16)(v) >> 0))
	157	#define STORE16_L(p, v) \
	158	(PUTBYTE((p), 0, (uint16)(v) >> 0), \
	159	PUTBYTE((p), 1, (uint16)(v) >> 8))
6b033bc4	160	#define STORE16(p, v) STORE16_B((p), (v))
6b033bc4	161
6a0129ea	162	#define LOAD24_B(p) \
	163	(((uint24)GETBYTE((p), 0) << 16) \| \
	164	((uint24)GETBYTE((p), 1) << 8) \| \
	165	((uint24)GETBYTE((p), 2) << 0))
	166	#define LOAD24_L(p) \
	167	(((uint24)GETBYTE((p), 0) << 0) \| \
	168	((uint24)GETBYTE((p), 1) << 8) \| \
	169	((uint24)GETBYTE((p), 2) << 16))
	170	#define LOAD24(p) LOAD24_B((p))
	171
	172	#define STORE24_B(p, v) \
	173	(PUTBYTE((p), 0, (uint24)(v) >> 16), \
	174	PUTBYTE((p), 1, (uint24)(v) >> 8), \
	175	PUTBYTE((p), 2, (uint24)(v) >> 0))
	176	#define STORE24_L(p, v) \
	177	(PUTBYTE((p), 0, (uint24)(v) >> 0), \
	178	PUTBYTE((p), 1, (uint24)(v) >> 8), \
	179	PUTBYTE((p), 2, (uint24)(v) >> 16))
	180	#define STORE24(p, v) STORE24_B((p), (v))
	181
6b033bc4	182	#define LOAD32_B(p) \
0d4e268a	183	(((uint32)GETBYTE((p), 0) << 24) \| \
	184	((uint32)GETBYTE((p), 1) << 16) \| \
	185	((uint32)GETBYTE((p), 2) << 8) \| \
	186	((uint32)GETBYTE((p), 3) << 0))
6b033bc4	187	#define LOAD32_L(p) \
0d4e268a	188	(((uint32)GETBYTE((p), 0) << 0) \| \
	189	((uint32)GETBYTE((p), 1) << 8) \| \
	190	((uint32)GETBYTE((p), 2) << 16) \| \
	191	((uint32)GETBYTE((p), 3) << 24))
6b033bc4	192	#define LOAD32(p) LOAD32_B((p))
	193
	194	#define STORE32_B(p, v) \
0d4e268a	195	(PUTBYTE((p), 0, (uint32)(v) >> 24), \
	196	PUTBYTE((p), 1, (uint32)(v) >> 16), \
	197	PUTBYTE((p), 2, (uint32)(v) >> 8), \
	198	PUTBYTE((p), 3, (uint32)(v) >> 0))
6b033bc4	199	#define STORE32_L(p, v) \
0d4e268a	200	(PUTBYTE((p), 0, (uint32)(v) >> 0), \
	201	PUTBYTE((p), 1, (uint32)(v) >> 8), \
	202	PUTBYTE((p), 2, (uint32)(v) >> 16), \
	203	PUTBYTE((p), 3, (uint32)(v) >> 24))
6b033bc4	204	#define STORE32(p, v) STORE32_B((p), (v))
	205
	206	/----- That's all, folks -------------------------------------------------/
	207
	208	#ifdef __cplusplus
	209	}
	210	#endif
	211
	212	#endif