From dfc517b05395d925a4d7b1ce9633a849f9468e70 Mon Sep 17 00:00:00 2001 From: Jelmer Vernooij Date: Thu, 23 Feb 2006 15:52:24 +0000 Subject: r13658: More moving around of files: - Collect the generic utility functions into a lib/util/ (a la GLib is for the GNOME folks) - Remove even more files from include/ (This used to be commit ba62880f5b05c2a505dc7f54676b231197a7e707) --- source4/lib/util/byteorder.h | 224 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 224 insertions(+) create mode 100644 source4/lib/util/byteorder.h (limited to 'source4/lib/util/byteorder.h') diff --git a/source4/lib/util/byteorder.h b/source4/lib/util/byteorder.h new file mode 100644 index 0000000000..941dee9e88 --- /dev/null +++ b/source4/lib/util/byteorder.h @@ -0,0 +1,224 @@ +/* + Unix SMB/CIFS implementation. + SMB Byte handling + Copyright (C) Andrew Tridgell 1992-1998 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#ifndef _BYTEORDER_H +#define _BYTEORDER_H + +/* + This file implements macros for machine independent short and + int manipulation + +Here is a description of this file that I emailed to the samba list once: + +> I am confused about the way that byteorder.h works in Samba. I have +> looked at it, and I would have thought that you might make a distinction +> between LE and BE machines, but you only seem to distinguish between 386 +> and all other architectures. +> +> Can you give me a clue? + +sure. + +The distinction between 386 and other architectures is only there as +an optimisation. You can take it out completely and it will make no +difference. The routines (macros) in byteorder.h are totally byteorder +independent. The 386 optimsation just takes advantage of the fact that +the x86 processors don't care about alignment, so we don't have to +align ints on int boundaries etc. If there are other processors out +there that aren't alignment sensitive then you could also define +CAREFUL_ALIGNMENT=0 on those processors as well. + +Ok, now to the macros themselves. I'll take a simple example, say we +want to extract a 2 byte integer from a SMB packet and put it into a +type called uint16_t that is in the local machines byte order, and you +want to do it with only the assumption that uint16_t is _at_least_ 16 +bits long (this last condition is very important for architectures +that don't have any int types that are 2 bytes long) + +You do this: + +#define CVAL(buf,pos) (((uint8_t *)(buf))[pos]) +#define PVAL(buf,pos) ((uint_t)CVAL(buf,pos)) +#define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8) + +then to extract a uint16_t value at offset 25 in a buffer you do this: + +char *buffer = foo_bar(); +uint16_t xx = SVAL(buffer,25); + +We are using the byteoder independence of the ANSI C bitshifts to do +the work. A good optimising compiler should turn this into efficient +code, especially if it happens to have the right byteorder :-) + +I know these macros can be made a bit tidier by removing some of the +casts, but you need to look at byteorder.h as a whole to see the +reasoning behind them. byteorder.h defines the following macros: + +SVAL(buf,pos) - extract a 2 byte SMB value +IVAL(buf,pos) - extract a 4 byte SMB value +SVALS(buf,pos) signed version of SVAL() +IVALS(buf,pos) signed version of IVAL() + +SSVAL(buf,pos,val) - put a 2 byte SMB value into a buffer +SIVAL(buf,pos,val) - put a 4 byte SMB value into a buffer +SSVALS(buf,pos,val) - signed version of SSVAL() +SIVALS(buf,pos,val) - signed version of SIVAL() + +RSVAL(buf,pos) - like SVAL() but for NMB byte ordering +RSVALS(buf,pos) - like SVALS() but for NMB byte ordering +RIVAL(buf,pos) - like IVAL() but for NMB byte ordering +RIVALS(buf,pos) - like IVALS() but for NMB byte ordering +RSSVAL(buf,pos,val) - like SSVAL() but for NMB ordering +RSIVAL(buf,pos,val) - like SIVAL() but for NMB ordering +RSIVALS(buf,pos,val) - like SIVALS() but for NMB ordering + +it also defines lots of intermediate macros, just ignore those :-) + +*/ + + +/* + on powerpc we can use the magic instructions to load/store + in little endian +*/ +#if (defined(__powerpc__) && defined(__GNUC__)) +static __inline__ uint16_t ld_le16(const uint16_t *addr) +{ + uint16_t val; + __asm__ ("lhbrx %0,0,%1" : "=r" (val) : "r" (addr), "m" (*addr)); + return val; +} + +static __inline__ void st_le16(uint16_t *addr, const uint16_t val) +{ + __asm__ ("sthbrx %1,0,%2" : "=m" (*addr) : "r" (val), "r" (addr)); +} + +static __inline__ uint32_t ld_le32(const uint32_t *addr) +{ + uint32_t val; + __asm__ ("lwbrx %0,0,%1" : "=r" (val) : "r" (addr), "m" (*addr)); + return val; +} + +static __inline__ void st_le32(uint32_t *addr, const uint32_t val) +{ + __asm__ ("stwbrx %1,0,%2" : "=m" (*addr) : "r" (val), "r" (addr)); +} +#define HAVE_ASM_BYTEORDER 1 +#endif + + + +#undef CAREFUL_ALIGNMENT + +/* we know that the 386 can handle misalignment and has the "right" + byteorder */ +#if defined(__i386__) +#define CAREFUL_ALIGNMENT 0 +#endif + +#ifndef CAREFUL_ALIGNMENT +#define CAREFUL_ALIGNMENT 1 +#endif + +#define CVAL(buf,pos) ((uint_t)(((const uint8_t *)(buf))[pos])) +#define CVAL_NC(buf,pos) (((uint8_t *)(buf))[pos]) /* Non-const version of CVAL */ +#define PVAL(buf,pos) (CVAL(buf,pos)) +#define SCVAL(buf,pos,val) (CVAL_NC(buf,pos) = (val)) + +#if HAVE_ASM_BYTEORDER + +#define _PTRPOS(buf,pos) (((const uint8_t *)buf)+(pos)) +#define SVAL(buf,pos) ld_le16((const uint16_t *)_PTRPOS(buf,pos)) +#define IVAL(buf,pos) ld_le32((const uint32_t *)_PTRPOS(buf,pos)) +#define SSVAL(buf,pos,val) st_le16((uint16_t *)_PTRPOS(buf,pos), val) +#define SIVAL(buf,pos,val) st_le32((uint32_t *)_PTRPOS(buf,pos), val) +#define SVALS(buf,pos) ((int16_t)SVAL(buf,pos)) +#define IVALS(buf,pos) ((int32_t)IVAL(buf,pos)) +#define SSVALS(buf,pos,val) SSVAL((buf),(pos),((int16_t)(val))) +#define SIVALS(buf,pos,val) SIVAL((buf),(pos),((int32_t)(val))) + +#elif CAREFUL_ALIGNMENT + +#define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8) +#define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16) +#define SSVALX(buf,pos,val) (CVAL_NC(buf,pos)=(uint8_t)((val)&0xFF),CVAL_NC(buf,pos+1)=(uint8_t)((val)>>8)) +#define SIVALX(buf,pos,val) (SSVALX(buf,pos,val&0xFFFF),SSVALX(buf,pos+2,val>>16)) +#define SVALS(buf,pos) ((int16_t)SVAL(buf,pos)) +#define IVALS(buf,pos) ((int32_t)IVAL(buf,pos)) +#define SSVAL(buf,pos,val) SSVALX((buf),(pos),((uint16_t)(val))) +#define SIVAL(buf,pos,val) SIVALX((buf),(pos),((uint32_t)(val))) +#define SSVALS(buf,pos,val) SSVALX((buf),(pos),((int16_t)(val))) +#define SIVALS(buf,pos,val) SIVALX((buf),(pos),((int32_t)(val))) + +#else /* CAREFUL_ALIGNMENT */ + +/* this handles things for architectures like the 386 that can handle + alignment errors */ +/* + WARNING: This section is dependent on the length of int16_t and int32_t + being correct +*/ + +/* get single value from an SMB buffer */ +#define SVAL(buf,pos) (*(const uint16_t *)((const char *)(buf) + (pos))) +#define SVAL_NC(buf,pos) (*(uint16_t *)((char *)(buf) + (pos))) /* Non const version of above. */ +#define IVAL(buf,pos) (*(const uint32_t *)((const char *)(buf) + (pos))) +#define IVAL_NC(buf,pos) (*(uint32_t *)((char *)(buf) + (pos))) /* Non const version of above. */ +#define SVALS(buf,pos) (*(const int16_t *)((const char *)(buf) + (pos))) +#define SVALS_NC(buf,pos) (*(int16_t *)((char *)(buf) + (pos))) /* Non const version of above. */ +#define IVALS(buf,pos) (*(const int32_t *)((const char *)(buf) + (pos))) +#define IVALS_NC(buf,pos) (*(int32_t *)((char *)(buf) + (pos))) /* Non const version of above. */ + +/* store single value in an SMB buffer */ +#define SSVAL(buf,pos,val) SVAL_NC(buf,pos)=((uint16_t)(val)) +#define SIVAL(buf,pos,val) IVAL_NC(buf,pos)=((uint32_t)(val)) +#define SSVALS(buf,pos,val) SVALS_NC(buf,pos)=((int16_t)(val)) +#define SIVALS(buf,pos,val) IVALS_NC(buf,pos)=((int32_t)(val)) + +#endif /* CAREFUL_ALIGNMENT */ + +/* now the reverse routines - these are used in nmb packets (mostly) */ +#define SREV(x) ((((x)&0xFF)<<8) | (((x)>>8)&0xFF)) +#define IREV(x) ((SREV(x)<<16) | (SREV((x)>>16))) + +#define RSVAL(buf,pos) SREV(SVAL(buf,pos)) +#define RSVALS(buf,pos) SREV(SVALS(buf,pos)) +#define RIVAL(buf,pos) IREV(IVAL(buf,pos)) +#define RIVALS(buf,pos) IREV(IVALS(buf,pos)) +#define RSSVAL(buf,pos,val) SSVAL(buf,pos,SREV(val)) +#define RSSVALS(buf,pos,val) SSVALS(buf,pos,SREV(val)) +#define RSIVAL(buf,pos,val) SIVAL(buf,pos,IREV(val)) +#define RSIVALS(buf,pos,val) SIVALS(buf,pos,IREV(val)) + +/* Alignment macros. */ +#define ALIGN4(p,base) ((p) + ((4 - (PTR_DIFF((p), (base)) & 3)) & 3)) +#define ALIGN2(p,base) ((p) + ((2 - (PTR_DIFF((p), (base)) & 1)) & 1)) + + +/* macros for accessing SMB protocol elements */ +#define VWV(vwv) ((vwv)*2) + +/* 64 bit macros */ +#define SBVAL(p, ofs, v) (SIVAL(p,ofs,(v)&0xFFFFFFFF), SIVAL(p,(ofs)+4,((uint64_t)(v))>>32)) +#define BVAL(p, ofs) (IVAL(p,ofs) | (((uint64_t)IVAL(p,(ofs)+4)) << 32)) + +#endif /* _BYTEORDER_H */ -- cgit