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-rw-r--r-- | lib/util/byteorder.h | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/lib/util/byteorder.h b/lib/util/byteorder.h new file mode 100644 index 0000000..7f7dc79 --- /dev/null +++ b/lib/util/byteorder.h @@ -0,0 +1,169 @@ +/* + 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 3 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, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef _BYTEORDER_H +#define _BYTEORDER_H + +#include "bytearray.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. + +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) ((unsigned int)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 +BVAL(buf,pos) - extract a 8 byte SMB value +SVALS(buf,pos) - signed version of SVAL() +IVALS(buf,pos) - signed version of IVAL() +BVALS(buf,pos) - signed version of BVAL() + +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 +SBVAL(buf,pos,val) - put a 8 byte SMB value into a buffer +SSVALS(buf,pos,val) - signed version of SSVAL() +SIVALS(buf,pos,val) - signed version of SIVAL() +SBVALS(buf,pos,val) - signed version of SBVAL() + +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 :-) + +*/ + + +/**************************************************************************** + * + * ATTENTION: Do not use those macros anymore, use the ones from bytearray.h + * + ****************************************************************************/ + +#define CVAL(buf,pos) ((uint32_t)_DATA_BYTE_CONST(buf, pos)) +#define CVAL_NC(buf,pos) _DATA_BYTE(buf, pos) /* Non-const version of CVAL */ +#define PVAL(buf,pos) (CVAL(buf,pos)) +#define SCVAL(buf,pos,val) (CVAL_NC(buf,pos) = (val)) + +/**************************************************************************** + * + * ATTENTION: Do not use those macros anymore, use the ones from bytearray.h + * + ****************************************************************************/ + +#define SVAL(buf,pos) (uint32_t)PULL_LE_U16(buf, pos) +#define IVAL(buf,pos) PULL_LE_U32(buf, pos) +#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) PUSH_LE_U16(buf, pos, val) +#define SIVAL(buf,pos,val) PUSH_LE_U32(buf, pos, val) +#define SSVALS(buf,pos,val) PUSH_LE_U16(buf, pos, val) +#define SIVALS(buf,pos,val) PUSH_LE_U32(buf, pos, val) + +/**************************************************************************** + * + * ATTENTION: Do not use those macros anymore, use the ones from bytearray.h + * + ****************************************************************************/ + +/* 64 bit macros */ +#define BVAL(p, ofs) PULL_LE_U64(p, ofs) +#define BVALS(p, ofs) ((int64_t)BVAL(p,ofs)) +#define SBVAL(p, ofs, v) PUSH_LE_U64(p, ofs, v) +#define SBVALS(p, ofs, v) (SBVAL(p,ofs,(uint64_t)v)) + +/**************************************************************************** + * + * ATTENTION: Do not use those macros anymore, use the ones from bytearray.h + * + ****************************************************************************/ + +/* 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 BREV(x) ((IREV((uint64_t)x)<<32) | (IREV(((uint64_t)x)>>32))) + +/**************************************************************************** + * + * ATTENTION: Do not use those macros anymore, use the ones from bytearray.h + * + ****************************************************************************/ + +#define RSVAL(buf,pos) (uint32_t)PULL_BE_U16(buf, pos) +#define RSVALS(buf,pos) PULL_BE_U16(buf, pos) +#define RIVAL(buf,pos) PULL_BE_U32(buf, pos) +#define RIVALS(buf,pos) PULL_BE_U32(buf, pos) +#define RBVAL(buf,pos) PULL_BE_U64(buf, pos) +#define RBVALS(buf,pos) PULL_BE_U64(buf, pos) +#define RSSVAL(buf,pos,val) PUSH_BE_U16(buf, pos, val) +#define RSSVALS(buf,pos,val) PUSH_BE_U16(buf, pos, val) +#define RSIVAL(buf,pos,val) PUSH_BE_U32(buf, pos, val) +#define RSIVALS(buf,pos,val) PUSH_BE_U32(buf, pos, val) +#define RSBVAL(buf,pos,val) PUSH_BE_U64(buf, pos, val) +#define RSBVALS(buf,pos,val) PUSH_BE_U64(buf, pos, val) + +/**************************************************************************** + * + * ATTENTION: Do not use those macros anymore, use the ones from bytearray.h + * + ****************************************************************************/ + +#endif /* _BYTEORDER_H */ |