396 lines
14 KiB
C
396 lines
14 KiB
C
/*
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* Copyright (c) 2000 Hans Petter Selasky. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*---------------------------------------------------------------------------
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*
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* i4b_hdlc.h - software-HDLC header file
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* --------------------------------------
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*
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* $Id: i4b_hdlc.h,v 1.5 2000/08/28 07:41:19 hm Exp $
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*
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* $FreeBSD$
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*
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* last edit-date: [Wed Jul 19 09:41:13 2000]
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*
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* NOTE:
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* - October 19th: made minor changes to HDLC_ENCODE macro
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* Please conform "ihfc/i4b_ihfc_drv.c" (ihfc_hdlc_Bwrite)
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* for correct usage! (-hp)
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*
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*---------------------------------------------------------------------------*/
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#ifndef _I4B_HDLC_H_
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#define _I4B_HDLC_H_
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/*---------------------------------------------------------------------------*
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* HDLC CRC table
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*
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* Usage:
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* crc = (HDLC_FCS_TAB[(u_char)(crc ^ byte of data)] ^ (u_char)(crc >> 8));
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*
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* For more information see RFC 1662 (p. 10)
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*---------------------------------------------------------------------------*/
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const u_short HDLC_FCS_TAB[256] = { 0x0000,
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0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, 0x8c48,
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0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, 0x1081,
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0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, 0x9cc9,
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0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, 0x2102,
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0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, 0xad4a,
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0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, 0x3183,
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0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, 0xbdcb,
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0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, 0x4204,
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0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, 0xce4c,
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0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, 0x5285,
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0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, 0xdecd,
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0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, 0x6306,
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0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, 0xef4e,
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0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, 0x7387,
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0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, 0xffcf,
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0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, 0x8408,
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0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, 0x0840,
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0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, 0x9489,
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0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, 0x18c1,
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0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, 0xa50a,
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0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, 0x2942,
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0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, 0xb58b,
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0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, 0x39c3,
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0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, 0xc60c,
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0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, 0x4a44,
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0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, 0xd68d,
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0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, 0x5ac5,
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0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, 0xe70e,
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0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, 0x6b46,
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0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, 0xf78f,
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0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, 0x7bc7,
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0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
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};
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/*---------------------------------------------------------------------------*
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* HDLC bit table
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* ==============
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*
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* bits[0..3]: A value which tells how many set bits there are at the
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* beginning of the byte.
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*
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* bits[4..7]: Special bytes like 0x7e, 0x7d, 0xfd ... are flagged here
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* NOTE: Special bytes also means 'abort' bytes (7 or more
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* continious set bits)
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*
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* bits[8..11]: A copy of bits[0..3] but only incremented by one.
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* NOTE: 0x7e has value '8' instead of '0'. Internal reasons.
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*
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* bits[12..15]: A value which tells how many set bits there are at the
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* end of the byte.
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* NOTE: 0xff has both '8' incoming and '8' outgoing bits.
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*
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*---------------------------------------------------------------------------*/
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const u_short HDLC_BIT_TAB[256] = { 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0504, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0605, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0504, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0160, 0x0706, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0504, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0605, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0504, 0x0100,
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0x0201, 0x0100, 0x0302, 0x0100, 0x0201, 0x0100, 0x0403, 0x0100,
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0x0201, 0x0100, 0x0302, 0x01a0, 0x02a1, 0x0860, 0x0807, 0x1100,
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0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1403, 0x1100,
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0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1504, 0x1100,
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0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1403, 0x1100,
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0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1605, 0x1100,
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0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1403, 0x1100,
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0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1504, 0x1100,
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0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1100, 0x1403, 0x1100,
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0x1201, 0x1100, 0x1302, 0x1100, 0x1201, 0x1160, 0x1706, 0x2100,
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0x2201, 0x2100, 0x2302, 0x2100, 0x2201, 0x2100, 0x2403, 0x2100,
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0x2201, 0x2100, 0x2302, 0x2100, 0x2201, 0x2100, 0x2504, 0x2100,
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0x2201, 0x2100, 0x2302, 0x2100, 0x2201, 0x2100, 0x2403, 0x2100,
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0x2201, 0x2100, 0x2302, 0x2100, 0x2201, 0x2100, 0x2605, 0x3100,
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0x3201, 0x3100, 0x3302, 0x3100, 0x3201, 0x3100, 0x3403, 0x3100,
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0x3201, 0x3100, 0x3302, 0x3100, 0x3201, 0x3100, 0x3504, 0x4100,
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0x4201, 0x4100, 0x4302, 0x4100, 0x4201, 0x4100, 0x4403, 0x5100,
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0x5201, 0x5100, 0x5302, 0x6180, 0x6281, 0x7150, 0x8908
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};
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/*---------------------------------------------------------------------------*
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* HDLC_DECODE
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* ===========
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*
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* u_char: flag, blevel
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* u_short: crc, ib, tmp, tmp2, len
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*
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* next: 'continue' or 'goto xxx'
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*
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* cfr: complet frame
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* nfr: new frame
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* NOTE: must setup 'len' and 'dst', so that 'dst' may be written
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* at most 'len' times.
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*
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* rab: abort
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* rdd: read data (read byte is stored in 'tmp2')
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* rdo: overflow
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*
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* d: dummy
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*
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* NOTE: setting flag to '0' and len to '0' => recover from rdu
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* NOTE: bits[8 .. ] of tmp2 may be used to store custom data/flags
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* NOTE: these variables have to be 'suspended' / 'resumed' somehow:
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* flag, blevel, crc, ib, tmp, len
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* NOTE: zero is default value for all variables.
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* NOTE: each time 'dst' is written, 'len' is decremented by one.
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*---------------------------------------------------------------------------*/
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#define HDLC_DECODE(dst, len, tmp, tmp2, blevel, ib, crc, flag, rddcmd, nfrcmd, \
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cfrcmd, rabcmd, rdocmd, nextcmd, d) \
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\
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rddcmd; \
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\
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ib += HDLC_BIT_TAB[(u_char)tmp2]; \
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\
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if ((u_char)ib >= 5) \
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{ \
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if (ib & 0x20) /* de-stuff (msb) */ \
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{ \
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if ((u_char)tmp2 == 0x7e) goto j0##d; \
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tmp2 += tmp2 & 0x7f; \
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blevel--; \
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\
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if ((ib += 0x100) & 0xc) tmp2 |= 1; /* */ \
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} \
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\
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ib &= ~0xe0; \
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\
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if ((u_char)ib == 6) /* flag seq (lsb) */ \
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{ \
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j0##d: if (flag >= 2) \
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{ \
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len += (4 - flag) & 3; /* remove CRC bytes */ \
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crc ^= 0xf0b8; \
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cfrcmd; \
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len = 0; \
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} \
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\
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flag = 1; \
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\
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blevel = (ib >> 8) & 0xf; \
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tmp = ((u_char)tmp2) >> blevel; \
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blevel = 8 - blevel; \
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\
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ib >>= 12; \
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\
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nextcmd; \
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} \
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if ((u_char)ib >= 7) /* abort (msb & lsb) */ \
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{ \
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if (flag >= 2) \
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{ \
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rabcmd; \
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len = 0; \
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} \
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\
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flag = 0; \
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\
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ib >>= 12; \
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\
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nextcmd; \
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} \
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if ((u_char)ib == 5) /* de-stuff (lsb) */ \
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{ \
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tmp2 = (tmp2 | (tmp2 + 1)) & ~0x1; \
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blevel--; \
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} \
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if (blevel > 7) /* EO - bits */ \
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{ \
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tmp |= (u_char)tmp2 >> (8 - (blevel &= 7)); \
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\
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ib >>= 12; \
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\
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nextcmd; \
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} \
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} \
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\
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tmp |= (u_char)tmp2 << blevel; \
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\
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if (!len--) \
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{ \
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len++; \
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\
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if (!flag++) { flag--; goto j5##d;} /* hunt mode */ \
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\
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switch (flag) \
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{ case 2: /* new frame */ \
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nfrcmd; \
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crc = -1; \
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if (!len--) { len++; flag++; goto j4##d; } \
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goto j3##d; \
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case 3: /* CRC (lsb's) */ \
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case 4: /* CRC (msb's) */ \
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goto j4##d; \
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case 5: /* RDO */ \
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rdocmd; \
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flag = 0; \
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break; \
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} \
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} \
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else \
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{ \
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j3##d: dst = (u_char)tmp; \
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j4##d: crc = (HDLC_FCS_TAB[(u_char)(tmp ^ crc)] ^ (u_char)(crc >> 8)); \
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} \
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\
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j5##d: ib >>= 12; \
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tmp >>= 8; \
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/*------ end of HDLC_DECODE -------------------------------------------------*/
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/*---------------------------------------------------------------------------*
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* HDLC_ENCODE
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* ===========
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*
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* u_char: flag, src
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* u_short: tmp2, blevel, ib, crc, len
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* u_int: tmp
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*
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* gfr: get new frame, free old, and exit if no frame
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* NOTE: must setup 'len' and 'src', so that 'src' can be read
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* 'len' times.
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*
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* wrd: write data (output = (u_char)tmp)
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*
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* d: dummy
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*
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* NOTE: setting flag to '-1' and len to '0' => abort byte will be sent
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* NOTE: these variables have to be 'suspended' / 'resumed' somehow:
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* flag, blevel, crc, ib, tmp, len
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* NOTE: zero is default value for all variables.
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* NOTE: each time 'src' is read, 'len' is decremented by one.
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* NOTE: gfr must setup 'len'.
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*---------------------------------------------------------------------------*/
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#define HDLC_ENCODE(src, len, tmp, tmp2, blevel, ib, crc, flag, gfrcmd, wrdcmd, d) \
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\
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if (blevel >= 0x800) { blevel -= 0x800; goto j4##d; } \
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\
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if (!len--) \
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{ \
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len++; \
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\
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switch(++flag) \
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{ case 0: /* abort */ \
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tmp = blevel = 0; /* zero is default */ \
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tmp2 = 0xff; \
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goto j3##d; \
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case 1: /* 1st time FS */ \
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case 2: /* 2nd time FS */ \
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tmp2 = 0x7e; \
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goto j3##d; \
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case 3: /* get new frame */ \
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gfrcmd; \
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if (!len--) \
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{ \
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len++; \
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flag--; /* don't proceed */ \
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tmp2 = 0x7e; \
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goto j3##d; /* final FS */ \
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} \
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else \
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{ \
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crc = -1; \
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ib = 0; \
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goto j1##d; /* first byte */ \
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} \
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case 4: /* CRC (lsb's) */ \
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crc ^= -1; \
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case 5: /* CRC (msb's) */ \
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tmp2 = (u_char)crc; \
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crc >>= 8; \
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flag = 1; \
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goto j2##d; /* CRC stuff */ \
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} \
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} \
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else \
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{ j1##d : \
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tmp2 = (u_char)src; \
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crc =(HDLC_FCS_TAB[(u_char)(crc ^ tmp2)] ^ (u_char)(crc >> 8)); \
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j2##d: \
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\
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ib >>= 12; \
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ib += HDLC_BIT_TAB[(u_char)tmp2]; \
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\
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if ((u_char)ib >= 5) /* stuffing */ \
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{ \
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blevel &= ~0xff; \
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\
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if (ib & 0xc0) /* bit stuff (msb) */ \
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{ \
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tmp2 += tmp2 & (0xff * (ib & 0xc0)); \
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ib %= 0x5000; \
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blevel++; \
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} \
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\
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ib &= ~0xf0; \
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\
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if ((u_char)ib >= 5) /* bit stuff (lsb) */ \
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{ \
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tmp2 += tmp2 & ~0x1f >> ((ib - (ib >> 8) + 1) \
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& 7); \
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blevel++; \
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\
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if ((u_char)ib >= 10) /* bit stuff (msb) */ \
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{ \
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tmp2 += tmp2 & ~0x7ff >> ((ib - \
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(ib >> 8) + 1) & 7); \
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blevel++; \
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} \
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if (ib & 0x8000) /* bit walk */ \
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{ \
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ib = ((u_char)ib % 5) << 12; \
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} \
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} \
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\
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tmp |= tmp2 << (u_char)(blevel >> 8); \
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blevel += (u_char)blevel << 8; \
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} \
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else /* no stuffing */ \
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{ \
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j3##d:tmp |= tmp2 << (u_char)(blevel >> 8); \
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} \
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} \
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\
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j4##d: wrdcmd; \
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tmp >>= 8; \
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/*------ end of HDLC_ENCODE -------------------------------------------------*/
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#endif /* _I4B_HDLC_H_ */
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