1039 lines
26 KiB
C
1039 lines
26 KiB
C
/**
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* FreeRDP: A Remote Desktop Protocol Implementation
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* Implements Microsoft Point to Point Compression (MPPC) protocol
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*
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* Copyright 2012 Laxmikant Rashinkar <LK.Rashinkar@gmail.com>
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* Copyright 2012 Jay Sorg <jay.sorg@gmail.com>
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <winpr/crt.h>
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#include <freerdp/codec/mppc_dec.h>
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#include <freerdp/codec/mppc_enc.h>
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#define MPPC_ENC_DEBUG 0
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/* local defines */
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#define RDP_40_HIST_BUF_LEN (1024 * 8) /* RDP 4.0 uses 8K history buf */
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#define RDP_50_HIST_BUF_LEN (1024 * 64) /* RDP 5.0 uses 64K history buf */
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#define CRC_INIT 0xFFFF
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#define CRC(crcval, newchar) crcval = (crcval >> 8) ^ crc_table[(crcval ^ newchar) & 0x00ff]
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/* CRC16 defs */
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static const UINT16 crc_table[256] =
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{
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0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
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0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
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0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
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0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
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0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
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0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
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0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
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0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
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0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
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0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
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0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
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0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
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0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
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0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
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0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
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0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
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0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
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0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
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0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
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0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
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0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
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0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
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0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
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0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
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0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
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0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
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0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
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0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
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0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
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0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
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0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
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0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
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};
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/*****************************************************************************
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insert 2 bits into outputBuffer
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******************************************************************************/
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#define insert_2_bits(_data) \
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do \
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{ \
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if ((bits_left >= 3) && (bits_left <= 8)) \
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{ \
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i = bits_left - 2; \
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outputBuffer[opb_index] |= _data << i; \
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bits_left = i; \
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} \
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else \
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{ \
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i = 2 - bits_left; \
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j = 8 - i; \
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outputBuffer[opb_index++] |= _data >> i; \
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outputBuffer[opb_index] |= _data << j; \
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bits_left = j; \
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} \
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} while (0)
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/*****************************************************************************
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insert 3 bits into outputBuffer
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******************************************************************************/
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#define insert_3_bits(_data) \
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do \
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{ \
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if ((bits_left >= 4) && (bits_left <= 8)) \
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{ \
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i = bits_left - 3; \
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outputBuffer[opb_index] |= _data << i; \
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bits_left = i; \
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} \
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else \
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{ \
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i = 3 - bits_left; \
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j = 8 - i; \
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outputBuffer[opb_index++] |= _data >> i; \
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outputBuffer[opb_index] |= _data << j; \
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bits_left = j; \
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} \
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} while (0)
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/*****************************************************************************
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insert 4 bits into outputBuffer
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******************************************************************************/
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#define insert_4_bits(_data) \
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do \
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{ \
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if ((bits_left >= 5) && (bits_left <= 8)) \
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{ \
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i = bits_left - 4; \
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outputBuffer[opb_index] |= _data << i; \
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bits_left = i; \
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} \
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else \
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{ \
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i = 4 - bits_left; \
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j = 8 - i; \
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outputBuffer[opb_index++] |= _data >> i; \
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outputBuffer[opb_index] |= _data << j; \
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bits_left = j; \
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} \
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} while (0)
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/*****************************************************************************
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insert 5 bits into outputBuffer
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******************************************************************************/
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#define insert_5_bits(_data) \
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do \
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{ \
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if ((bits_left >= 6) && (bits_left <= 8)) \
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{ \
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i = bits_left - 5; \
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outputBuffer[opb_index] |= _data << i; \
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bits_left = i; \
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} \
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else \
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{ \
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i = 5 - bits_left; \
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j = 8 - i; \
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outputBuffer[opb_index++] |= _data >> i; \
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outputBuffer[opb_index] |= _data << j; \
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bits_left = j; \
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} \
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} while (0)
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/*****************************************************************************
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insert 6 bits into outputBuffer
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******************************************************************************/
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#define insert_6_bits(_data) \
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do \
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{ \
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if ((bits_left >= 7) && (bits_left <= 8)) \
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{ \
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i = bits_left - 6; \
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outputBuffer[opb_index] |= (_data << i); \
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bits_left = i; \
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} \
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else \
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{ \
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i = 6 - bits_left; \
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j = 8 - i; \
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outputBuffer[opb_index++] |= (_data >> i); \
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outputBuffer[opb_index] |= (_data << j); \
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bits_left = j; \
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} \
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} while (0)
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/*****************************************************************************
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insert 7 bits into outputBuffer
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******************************************************************************/
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#define insert_7_bits(_data) \
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do \
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{ \
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if (bits_left == 8) \
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{ \
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outputBuffer[opb_index] |= _data << 1; \
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bits_left = 1; \
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} \
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else \
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{ \
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i = 7 - bits_left; \
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j = 8 - i; \
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outputBuffer[opb_index++] |= _data >> i; \
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outputBuffer[opb_index] |= _data << j; \
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bits_left = j; \
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} \
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} while (0)
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/*****************************************************************************
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insert 8 bits into outputBuffer
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******************************************************************************/
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#define insert_8_bits(_data) \
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do \
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{ \
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if (bits_left == 8) \
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{ \
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outputBuffer[opb_index++] |= _data; \
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bits_left = 8; \
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} \
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else \
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{ \
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i = 8 - bits_left; \
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j = 8 - i; \
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outputBuffer[opb_index++] |= _data >> i; \
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outputBuffer[opb_index] |= _data << j; \
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bits_left = j; \
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} \
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} while (0)
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/*****************************************************************************
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insert 9 bits into outputBuffer
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******************************************************************************/
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#define insert_9_bits(_data16) \
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do \
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{ \
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i = 9 - bits_left; \
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j = 8 - i; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index] |= (char) (_data16 << j); \
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bits_left = j; \
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if (bits_left == 0) \
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{ \
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opb_index++; \
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bits_left = 8; \
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} \
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} while (0)
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/*****************************************************************************
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insert 10 bits into outputBuffer
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******************************************************************************/
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#define insert_10_bits(_data16) \
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do \
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{ \
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i = 10 - bits_left; \
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if ((bits_left >= 3) && (bits_left <= 8)) \
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{ \
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j = 8 - i; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index] |= (char) (_data16 << j); \
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bits_left = j; \
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} \
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else \
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{ \
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j = i - 8; \
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k = 8 - j; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index++] |= (char) (_data16 >> j); \
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outputBuffer[opb_index] |= (char) (_data16 << k); \
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bits_left = k; \
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} \
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} while (0)
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/*****************************************************************************
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insert 11 bits into outputBuffer
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******************************************************************************/
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#define insert_11_bits(_data16) \
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do \
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{ \
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i = 11 - bits_left; \
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if ((bits_left >= 4) && (bits_left <= 8)) \
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{ \
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j = 8 - i; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index] |= (char) (_data16 << j); \
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bits_left = j; \
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} \
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else \
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{ \
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j = i - 8; \
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k = 8 - j; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index++] |= (char) (_data16 >> j); \
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outputBuffer[opb_index] |= (char) (_data16 << k); \
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bits_left = k; \
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} \
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} while (0)
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/*****************************************************************************
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insert 12 bits into outputBuffer
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******************************************************************************/
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#define insert_12_bits(_data16) \
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do \
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{ \
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i = 12 - bits_left; \
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if ((bits_left >= 5) && (bits_left <= 8)) \
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{ \
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j = 8 - i; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index] |= (char) (_data16 << j); \
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bits_left = j; \
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} \
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else \
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{ \
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j = i - 8; \
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k = 8 - j; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index++] |= (char) (_data16 >> j); \
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outputBuffer[opb_index] |= (char) (_data16 << k); \
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bits_left = k; \
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} \
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} while (0)
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/*****************************************************************************
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insert 13 bits into outputBuffer
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******************************************************************************/
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#define insert_13_bits(_data16) \
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do \
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{ \
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i = 13 - bits_left; \
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if ((bits_left >= 6) && (bits_left <= 8)) \
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{ \
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j = 8 - i; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index] |= (char) (_data16 << j); \
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bits_left = j; \
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} \
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else \
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{ \
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j = i - 8; \
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k = 8 - j; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index++] |= (char) (_data16 >> j); \
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outputBuffer[opb_index] |= (char) (_data16 << k); \
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bits_left = k; \
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} \
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} while (0)
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/*****************************************************************************
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insert 14 bits into outputBuffer
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******************************************************************************/
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#define insert_14_bits(_data16) \
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do \
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{ \
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i = 14 - bits_left; \
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if ((bits_left >= 7) && (bits_left <= 8)) \
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{ \
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j = 8 - i; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index] |= (char) (_data16 << j); \
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bits_left = j; \
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} \
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else \
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{ \
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j = i - 8; \
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k = 8 - j; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index++] |= (char) (_data16 >> j); \
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outputBuffer[opb_index] |= (char) (_data16 << k); \
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bits_left = k; \
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} \
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} while (0)
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/*****************************************************************************
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insert 15 bits into outputBuffer
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******************************************************************************/
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#define insert_15_bits(_data16) \
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do \
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{ \
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i = 15 - bits_left; \
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if (bits_left == 8) \
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{ \
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j = 8 - i; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index] |= (char) (_data16 << j); \
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bits_left = j; \
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} \
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else \
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{ \
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j = i - 8; \
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k = 8 - j; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index++] |= (char) (_data16 >> j); \
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outputBuffer[opb_index] |= (char) (_data16 << k); \
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bits_left = k; \
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} \
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} while (0)
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|
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/*****************************************************************************
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insert 16 bits into outputBuffer
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******************************************************************************/
|
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#define insert_16_bits(_data16) \
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do \
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{ \
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i = 16 - bits_left; \
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j = i - 8; \
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k = 8 - j; \
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outputBuffer[opb_index++] |= (char) (_data16 >> i); \
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outputBuffer[opb_index++] |= (char) (_data16 >> j); \
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outputBuffer[opb_index] |= (char) (_data16 << k); \
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bits_left = k; \
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} while (0)
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|
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#if MPPC_ENC_DEBUG
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#define DLOG(_args) printf _args
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#else
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#define DLOG(_args) do { } while (0)
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#endif
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|
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/**
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* Initialize mppc_enc structure
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*
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* @param protocol_type PROTO_RDP_40 or PROTO_RDP_50
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*
|
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* @return struct rdp_mppc_enc* or nil on failure
|
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*/
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|
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struct rdp_mppc_enc* mppc_enc_new(int protocol_type)
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{
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struct rdp_mppc_enc* enc;
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|
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enc = (struct rdp_mppc_enc*) malloc(sizeof(struct rdp_mppc_enc));
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ZeroMemory(enc, sizeof(struct rdp_mppc_enc));
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|
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if (enc == NULL)
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return NULL;
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|
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switch (protocol_type)
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{
|
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case PROTO_RDP_40:
|
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enc->protocol_type = PROTO_RDP_40;
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enc->buf_len = RDP_40_HIST_BUF_LEN;
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break;
|
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|
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case PROTO_RDP_50:
|
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enc->protocol_type = PROTO_RDP_50;
|
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enc->buf_len = RDP_50_HIST_BUF_LEN;
|
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break;
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|
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default:
|
|
free(enc);
|
|
return NULL;
|
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}
|
|
|
|
enc->first_pkt = 1;
|
|
enc->historyBuffer = (char*) malloc(enc->buf_len);
|
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ZeroMemory(enc->historyBuffer, enc->buf_len);
|
|
|
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if (enc->historyBuffer == NULL)
|
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{
|
|
free(enc);
|
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return NULL;
|
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}
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|
|
enc->outputBufferPlus = (char*) malloc(enc->buf_len + 64);
|
|
ZeroMemory(enc->outputBufferPlus, enc->buf_len + 64);
|
|
|
|
if (enc->outputBufferPlus == NULL)
|
|
{
|
|
free(enc->historyBuffer);
|
|
free(enc);
|
|
return NULL;
|
|
}
|
|
|
|
enc->outputBuffer = enc->outputBufferPlus + 64;
|
|
enc->hash_table = (UINT16*) malloc(enc->buf_len * 2);
|
|
ZeroMemory(enc->hash_table, enc->buf_len * 2);
|
|
|
|
if (enc->hash_table == NULL)
|
|
{
|
|
free(enc->historyBuffer);
|
|
free(enc->outputBufferPlus);
|
|
free(enc);
|
|
return NULL;
|
|
}
|
|
|
|
return enc;
|
|
}
|
|
|
|
/**
|
|
* deinit mppc_enc structure
|
|
*
|
|
* @param enc struct to be deinited
|
|
*/
|
|
|
|
void mppc_enc_free(struct rdp_mppc_enc* enc)
|
|
{
|
|
if (enc == NULL)
|
|
return;
|
|
free(enc->historyBuffer);
|
|
free(enc->outputBufferPlus);
|
|
free(enc->hash_table);
|
|
free(enc);
|
|
}
|
|
|
|
/**
|
|
* encode (compress) data
|
|
*
|
|
* @param enc encoder state info
|
|
* @param srcData uncompressed data
|
|
* @param len length of srcData
|
|
*
|
|
* @return TRUE on success, FALSE on failure
|
|
*/
|
|
|
|
BOOL compress_rdp(struct rdp_mppc_enc* enc, BYTE* srcData, int len)
|
|
{
|
|
if ((enc == NULL) || (srcData == NULL) || (len <= 0) || (len > enc->buf_len))
|
|
return FALSE;
|
|
|
|
switch (enc->protocol_type)
|
|
{
|
|
case PROTO_RDP_40:
|
|
return compress_rdp_4(enc, srcData, len);
|
|
break;
|
|
|
|
case PROTO_RDP_50:
|
|
return compress_rdp_5(enc, srcData, len);
|
|
break;
|
|
}
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
/**
|
|
* encode (compress) data using RDP 4.0 protocol
|
|
*
|
|
* @param enc encoder state info
|
|
* @param srcData uncompressed data
|
|
* @param len length of srcData
|
|
*
|
|
* @return TRUE on success, FALSE on failure
|
|
*/
|
|
|
|
BOOL compress_rdp_4(struct rdp_mppc_enc* enc, BYTE* srcData, int len)
|
|
{
|
|
/* RDP 4.0 encoding not yet implemented */
|
|
return FALSE;
|
|
}
|
|
|
|
/**
|
|
* encode (compress) data using RDP 5.0 protocol using hash table
|
|
*
|
|
* @param enc encoder state info
|
|
* @param srcData uncompressed data
|
|
* @param len length of srcData
|
|
*
|
|
* @return TRUE on success, FALSE on failure
|
|
*/
|
|
|
|
BOOL compress_rdp_5(struct rdp_mppc_enc* enc, BYTE* srcData, int len)
|
|
{
|
|
char* outputBuffer; /* points to enc->outputBuffer */
|
|
char* hptr_end; /* points to end of history data */
|
|
char* historyPointer; /* points to first byte of srcData in historyBuffer */
|
|
char* hbuf_start; /* points to start of history buffer */
|
|
char* cptr1;
|
|
char* cptr2;
|
|
int opb_index; /* index into outputBuffer */
|
|
int bits_left; /* unused bits in current byte in outputBuffer */
|
|
UINT32 copy_offset; /* pattern match starts here... */
|
|
UINT32 lom; /* ...and matches this many bytes */
|
|
int last_crc_index; /* don't compute CRC beyond this index */
|
|
UINT16 *hash_table; /* hash table for pattern matching */
|
|
|
|
UINT32 i;
|
|
UINT32 j;
|
|
UINT32 k;
|
|
UINT32 x;
|
|
BYTE data;
|
|
UINT16 data16;
|
|
UINT32 historyOffset;
|
|
UINT16 crc;
|
|
UINT32 ctr;
|
|
UINT32 saved_ctr;
|
|
UINT32 data_end;
|
|
BYTE byte_val;
|
|
|
|
crc = 0;
|
|
opb_index = 0;
|
|
bits_left = 8;
|
|
copy_offset = 0;
|
|
hash_table = enc->hash_table;
|
|
hbuf_start = enc->historyBuffer;
|
|
outputBuffer = enc->outputBuffer;
|
|
memset(outputBuffer, 0, len);
|
|
enc->flags = PACKET_COMPR_TYPE_64K;
|
|
if (enc->first_pkt)
|
|
{
|
|
enc->first_pkt = 0;
|
|
enc->flagsHold |= PACKET_AT_FRONT;
|
|
}
|
|
|
|
if ((enc->historyOffset + len) > enc->buf_len)
|
|
{
|
|
/* historyBuffer cannot hold srcData - rewind it */
|
|
enc->historyOffset = 0;
|
|
enc->flagsHold |= PACKET_AT_FRONT;
|
|
memset(hash_table, 0, enc->buf_len * 2);
|
|
}
|
|
|
|
/* point to next free byte in historyBuffer */
|
|
historyOffset = enc->historyOffset;
|
|
|
|
/* add / append new data to historyBuffer */
|
|
memcpy(&(enc->historyBuffer[historyOffset]), srcData, len);
|
|
|
|
/* point to start of data to be compressed */
|
|
historyPointer = &(enc->historyBuffer[historyOffset]);
|
|
|
|
ctr = copy_offset = lom = 0;
|
|
|
|
/* if we are at start of history buffer, do not attempt to compress */
|
|
/* first 2 bytes,because minimum LoM is 3 */
|
|
if (historyOffset == 0)
|
|
{
|
|
/* encode first two bytes are literals */
|
|
for (x = 0; x < 2; x++)
|
|
{
|
|
data = *(historyPointer + x);
|
|
DLOG(("%.2x ", (unsigned char) data));
|
|
if (data & 0x80)
|
|
{
|
|
/* insert encoded literal */
|
|
insert_2_bits(0x02);
|
|
data &= 0x7f;
|
|
insert_7_bits(data);
|
|
}
|
|
else
|
|
{
|
|
/* insert literal */
|
|
insert_8_bits(data);
|
|
}
|
|
}
|
|
|
|
/* store hash for first two entries in historyBuffer */
|
|
crc = CRC_INIT;
|
|
byte_val = enc->historyBuffer[0];
|
|
CRC(crc, byte_val);
|
|
byte_val = enc->historyBuffer[1];
|
|
CRC(crc, byte_val);
|
|
byte_val = enc->historyBuffer[2];
|
|
CRC(crc, byte_val);
|
|
hash_table[crc] = 0;
|
|
|
|
crc = CRC_INIT;
|
|
byte_val = enc->historyBuffer[1];
|
|
CRC(crc, byte_val);
|
|
byte_val = enc->historyBuffer[2];
|
|
CRC(crc, byte_val);
|
|
byte_val = enc->historyBuffer[3];
|
|
CRC(crc, byte_val);
|
|
hash_table[crc] = 1;
|
|
|
|
/* first two bytes have already been processed */
|
|
ctr = 2;
|
|
}
|
|
|
|
enc->historyOffset += len;
|
|
|
|
/* point to last byte in new data */
|
|
hptr_end = &(enc->historyBuffer[enc->historyOffset - 1]);
|
|
|
|
/* do not compute CRC beyond this */
|
|
last_crc_index = enc->historyOffset - 3;
|
|
|
|
/* do not search for pattern match beyond this */
|
|
data_end = len - 2;
|
|
|
|
/* start compressing data */
|
|
|
|
while (ctr < data_end)
|
|
{
|
|
cptr1 = historyPointer + ctr;
|
|
|
|
crc = CRC_INIT;
|
|
byte_val = *cptr1;
|
|
CRC(crc, byte_val);
|
|
byte_val = *(cptr1 + 1);
|
|
CRC(crc, byte_val);
|
|
byte_val = *(cptr1 + 2);
|
|
CRC(crc, byte_val);
|
|
|
|
/* cptr2 points to start of pattern match */
|
|
cptr2 = hbuf_start + hash_table[crc];
|
|
copy_offset = cptr1 - cptr2;
|
|
|
|
/* save current entry */
|
|
hash_table[crc] = cptr1 - hbuf_start;
|
|
|
|
/* double check that we have a pattern match */
|
|
if ((*cptr1 != *cptr2) ||
|
|
(*(cptr1 + 1) != *(cptr2 + 1)) ||
|
|
(*(cptr1 + 2) != *(cptr2 + 2)))
|
|
{
|
|
/* no match found; encode literal byte */
|
|
data = *cptr1;
|
|
|
|
DLOG(("%.2x ", (unsigned char) data));
|
|
if (data < 0x80)
|
|
{
|
|
/* literal byte < 0x80 */
|
|
insert_8_bits(data);
|
|
}
|
|
else
|
|
{
|
|
/* literal byte >= 0x80 */
|
|
insert_2_bits(0x02);
|
|
data &= 0x7f;
|
|
insert_7_bits(data);
|
|
}
|
|
ctr++;
|
|
continue;
|
|
}
|
|
|
|
/* we have a match - compute Length of Match */
|
|
cptr1 += 3;
|
|
cptr2 += 3;
|
|
lom = 3;
|
|
while ((cptr1 <= hptr_end) && (*(cptr1++) == *(cptr2++)))
|
|
{
|
|
lom++;
|
|
}
|
|
saved_ctr = ctr + lom;
|
|
DLOG(("<%d: %ld,%d> ", (historyPointer + ctr) - hbuf_start, copy_offset, lom));
|
|
|
|
/* compute CRC for matching segment and store in hash table */
|
|
|
|
cptr1 = historyPointer + ctr;
|
|
if (cptr1 + lom > hbuf_start + last_crc_index)
|
|
{
|
|
/* we have gone beyond last_crc_index - go back */
|
|
j = last_crc_index - (cptr1 - hbuf_start);
|
|
}
|
|
else
|
|
{
|
|
j = lom - 1;
|
|
}
|
|
ctr++;
|
|
for (i = 0; i < j; i++)
|
|
{
|
|
cptr1 = historyPointer + ctr;
|
|
|
|
/* compute CRC on triplet */
|
|
crc = CRC_INIT;
|
|
byte_val = *(cptr1++);
|
|
CRC(crc, byte_val);
|
|
byte_val = *(cptr1++);
|
|
CRC(crc, byte_val);
|
|
byte_val = *(cptr1++);
|
|
CRC(crc, byte_val);
|
|
|
|
/* save current entry */
|
|
hash_table[crc] = (cptr1 - 3) - hbuf_start;
|
|
|
|
/* point to next triplet */
|
|
ctr++;
|
|
}
|
|
ctr = saved_ctr;
|
|
|
|
/* encode copy_offset and insert into output buffer */
|
|
|
|
if (copy_offset <= 63) /* (copy_offset >= 0) is always true */
|
|
{
|
|
/* insert binary header */
|
|
data = 0x1f;
|
|
insert_5_bits(data);
|
|
|
|
/* insert 6 bits of copy_offset */
|
|
data = (char) (copy_offset & 0x3f);
|
|
insert_6_bits(data);
|
|
}
|
|
else if ((copy_offset >= 64) && (copy_offset <= 319))
|
|
{
|
|
/* insert binary header */
|
|
data = 0x1e;
|
|
insert_5_bits(data);
|
|
|
|
/* insert 8 bits of copy offset */
|
|
data = (char) (copy_offset - 64);
|
|
insert_8_bits(data);
|
|
}
|
|
else if ((copy_offset >= 320) && (copy_offset <= 2367))
|
|
{
|
|
/* insert binary header */
|
|
data = 0x0e;
|
|
insert_4_bits(data);
|
|
|
|
/* insert 11 bits of copy offset */
|
|
data16 = copy_offset - 320;;
|
|
insert_11_bits(data16);
|
|
}
|
|
else
|
|
{
|
|
/* copy_offset is 2368+ */
|
|
|
|
/* insert binary header */
|
|
data = 0x06;
|
|
insert_3_bits(data);
|
|
|
|
/* insert 16 bits of copy offset */
|
|
data16 = copy_offset - 2368;;
|
|
insert_16_bits(data16);
|
|
}
|
|
|
|
/* encode length of match and insert into output buffer */
|
|
|
|
if (lom == 3)
|
|
{
|
|
/* binary header is 'zero'; since outputBuffer is zero */
|
|
/* filled, all we have to do is update bits_left */
|
|
bits_left--;
|
|
if (bits_left == 0)
|
|
{
|
|
opb_index++;
|
|
bits_left = 8;
|
|
}
|
|
}
|
|
else if ((lom >= 4) && (lom <= 7))
|
|
{
|
|
/* insert binary header */
|
|
data = 0x02;
|
|
insert_2_bits(data);
|
|
|
|
/* insert lower 2 bits of LoM */
|
|
data = (char) (lom - 4);
|
|
insert_2_bits(data);
|
|
}
|
|
else if ((lom >= 8) && (lom <= 15))
|
|
{
|
|
/* insert binary header */
|
|
data = 0x06;
|
|
insert_3_bits(data);
|
|
|
|
/* insert lower 3 bits of LoM */
|
|
data = (char) (lom - 8);
|
|
insert_3_bits(data);
|
|
}
|
|
else if ((lom >= 16) && (lom <= 31))
|
|
{
|
|
/* insert binary header */
|
|
data = 0x0e;
|
|
insert_4_bits(data);
|
|
|
|
/* insert lower 4 bits of LoM */
|
|
data = (char) (lom - 16);
|
|
insert_4_bits(data);
|
|
}
|
|
else if ((lom >= 32) && (lom <= 63))
|
|
{
|
|
/* insert binary header */
|
|
data = 0x1e;
|
|
insert_5_bits(data);
|
|
|
|
/* insert lower 5 bits of LoM */
|
|
data = (char) (lom - 32);
|
|
insert_5_bits(data);
|
|
}
|
|
else if ((lom >= 64) && (lom <= 127))
|
|
{
|
|
/* insert binary header */
|
|
data = 0x3e;
|
|
insert_6_bits(data);
|
|
|
|
/* insert lower 6 bits of LoM */
|
|
data = (char) (lom - 64);
|
|
insert_6_bits(data);
|
|
}
|
|
else if ((lom >= 128) && (lom <= 255))
|
|
{
|
|
/* insert binary header */
|
|
data = 0x7e;
|
|
insert_7_bits(data);
|
|
|
|
/* insert lower 7 bits of LoM */
|
|
data = (char) (lom - 128);
|
|
insert_7_bits(data);
|
|
}
|
|
else if ((lom >= 256) && (lom <= 511))
|
|
{
|
|
/* insert binary header */
|
|
data = 0xfe;
|
|
insert_8_bits(data);
|
|
|
|
/* insert lower 8 bits of LoM */
|
|
data = (char) (lom - 256);
|
|
insert_8_bits(data);
|
|
}
|
|
else if ((lom >= 512) && (lom <= 1023))
|
|
{
|
|
/* insert binary header */
|
|
data16 = 0x1fe;
|
|
insert_9_bits(data16);
|
|
|
|
/* insert lower 9 bits of LoM */
|
|
data16 = lom - 512;
|
|
insert_9_bits(data16);
|
|
}
|
|
else if ((lom >= 1024) && (lom <= 2047))
|
|
{
|
|
/* insert binary header */
|
|
data16 = 0x3fe;
|
|
insert_10_bits(data16);
|
|
|
|
/* insert 10 lower bits of LoM */
|
|
data16 = lom - 1024;
|
|
insert_10_bits(data16);
|
|
}
|
|
else if ((lom >= 2048) && (lom <= 4095))
|
|
{
|
|
/* insert binary header */
|
|
data16 = 0x7fe;
|
|
insert_11_bits(data16);
|
|
|
|
/* insert 11 lower bits of LoM */
|
|
data16 = lom - 2048;
|
|
insert_11_bits(data16);
|
|
}
|
|
else if ((lom >= 4096) && (lom <= 8191))
|
|
{
|
|
/* insert binary header */
|
|
data16 = 0xffe;
|
|
insert_12_bits(data16);
|
|
|
|
/* insert 12 lower bits of LoM */
|
|
data16 = lom - 4096;
|
|
insert_12_bits(data16);
|
|
}
|
|
else if ((lom >= 8192) && (lom <= 16383))
|
|
{
|
|
/* insert binary header */
|
|
data16 = 0x1ffe;
|
|
insert_13_bits(data16);
|
|
|
|
/* insert 13 lower bits of LoM */
|
|
data16 = lom - 8192;
|
|
insert_13_bits(data16);
|
|
}
|
|
else if ((lom >= 16384) && (lom <= 32767))
|
|
{
|
|
/* insert binary header */
|
|
data16 = 0x3ffe;
|
|
insert_14_bits(data16);
|
|
|
|
/* insert 14 lower bits of LoM */
|
|
data16 = lom - 16384;
|
|
insert_14_bits(data16);
|
|
}
|
|
else if ((lom >= 32768) && (lom <= 65535))
|
|
{
|
|
/* insert binary header */
|
|
data16 = 0x7ffe;
|
|
insert_15_bits(data16);
|
|
|
|
/* insert 15 lower bits of LoM */
|
|
data16 = lom - 32768;
|
|
insert_15_bits(data16);
|
|
}
|
|
} /* end while (ctr < data_end) */
|
|
|
|
/* add remaining data to the output */
|
|
while (len - ctr > 0)
|
|
{
|
|
data = srcData[ctr];
|
|
DLOG(("%.2x ", (unsigned char) data));
|
|
if (data < 0x80)
|
|
{
|
|
/* literal byte < 0x80 */
|
|
insert_8_bits(data);
|
|
}
|
|
else
|
|
{
|
|
/* literal byte >= 0x80 */
|
|
insert_2_bits(0x02);
|
|
data &= 0x7f;
|
|
insert_7_bits(data);
|
|
}
|
|
ctr++;
|
|
}
|
|
|
|
/* if bits_left == 8, opb_index has already been incremented */
|
|
if ((bits_left == 8) && (opb_index > len))
|
|
{
|
|
/* compressed data longer than uncompressed data */
|
|
/* give up */
|
|
enc->historyOffset = 0;
|
|
memset(hash_table, 0, enc->buf_len * 2);
|
|
enc->flagsHold |= PACKET_FLUSHED;
|
|
enc->first_pkt = 1;
|
|
return TRUE;
|
|
}
|
|
else if (opb_index + 1 > len)
|
|
{
|
|
/* compressed data longer than uncompressed data */
|
|
/* give up */
|
|
enc->historyOffset = 0;
|
|
memset(hash_table, 0, enc->buf_len * 2);
|
|
enc->flagsHold |= PACKET_FLUSHED;
|
|
enc->first_pkt = 1;
|
|
return TRUE;
|
|
}
|
|
|
|
/* if bits_left != 8, increment opb_index, which is zero indexed */
|
|
if (bits_left != 8)
|
|
{
|
|
opb_index++;
|
|
}
|
|
|
|
if (opb_index > len)
|
|
{
|
|
/* give up */
|
|
enc->historyOffset = 0;
|
|
memset(hash_table, 0, enc->buf_len * 2);
|
|
enc->flagsHold |= PACKET_FLUSHED;
|
|
enc->first_pkt = 1;
|
|
return TRUE;
|
|
}
|
|
enc->flags |= PACKET_COMPRESSED;
|
|
enc->bytes_in_opb = opb_index;
|
|
|
|
enc->flags |= enc->flagsHold;
|
|
enc->flagsHold = 0;
|
|
DLOG(("\n"));
|
|
|
|
return TRUE;
|
|
}
|