source4/lib/compression/lzxpress.c

   1 /*
   2  * Copyright (C) Matthieu Suiche 2008
   3  *
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the author nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  */
  34
  35 #include "includes.h"
  36 #include "replace.h"
  37 #include "lzxpress.h"
  38
  39
  40 #define __BUF_POS_CONST(buf,ofs)(((const uint8_t *)buf)+(ofs))
  41 #define __PULL_BYTE(buf,ofs) \
  42         ((uint8_t)((*__BUF_POS_CONST(buf,ofs)) & 0xFF))
  43
  44 #ifndef PULL_LE_UINT16
  45 #define PULL_LE_UINT16(buf,ofs) ((uint16_t)( \
  46         ((uint16_t)(((uint16_t)(__PULL_BYTE(buf,(ofs)+0))) << 0)) | \
  47         ((uint16_t)(((uint16_t)(__PULL_BYTE(buf,(ofs)+1))) << 8)) \
  48 ))
  49 #endif
  50
  51 #ifndef PULL_LE_UINT32
  52 #define PULL_LE_UINT32(buf,ofs) ((uint32_t)( \
  53         ((uint32_t)(((uint32_t)(__PULL_BYTE(buf,(ofs)+0))) <<  0)) | \
  54         ((uint32_t)(((uint32_t)(__PULL_BYTE(buf,(ofs)+1))) <<  8)) | \
  55         ((uint32_t)(((uint32_t)(__PULL_BYTE(buf,(ofs)+2))) << 16)) | \
  56         ((uint32_t)(((uint32_t)(__PULL_BYTE(buf,(ofs)+3))) << 24)) \
  57 ))
  58 #endif
  59
  60 static uint32_t xpress_decompress(uint8_t *input,
  61                                 uint32_t input_size,
  62                                 uint8_t *output,
  63                                 uint32_t output_size)
  64 {
  65         uint32_t output_index, input_index;
  66         uint32_t indicator, indicator_bit;
  67         uint32_t length;
  68         uint32_t offset;
  69         uint32_t nibble_index;
  70
  71         output_index = 0;
  72         input_index = 0;
  73         indicator = 0;
  74         indicator_bit = 0;
  75         length = 0;
  76         offset = 0;
  77         nibble_index = 0;
  78
  79         do {
  80                 if (indicator_bit == 0) {
  81                         indicator = PULL_LE_UINT32(input, input_index);
  82                         input_index += sizeof(uint32_t);
  83                         indicator_bit = 32;
  84                 }
  85                 indicator_bit--;
  86
  87                 /*
  88                  * check whether the bit specified by indicator_bit is set or not
  89                  * set in indicator. For example, if indicator_bit has value 4
  90                  * check whether the 4th bit of the value in indicator is set
  91                  */
  92                 if (((indicator >> indicator_bit) & 1) == 0) {
  93                         output[output_index] = input[input_index];
  94                         input_index += sizeof(uint8_t);
  95                         output_index += sizeof(uint8_t);
  96                 } else {
  97                         length = PULL_LE_UINT16(input, input_index);
  98                         input_index += sizeof(uint16_t);
  99                         offset = length / 8;
 100                         length = length % 8;
 101
 102                         if (length == 7) {
 103                                 if (nibble_index == 0) {
 104                                         nibble_index = input_index;
 105                                         length = input[input_index] % 16;
 106                                         input_index += sizeof(uint8_t);
 107                                 } else {
 108                                         length = input[nibble_index] / 16;
 109                                         nibble_index = 0;
 110                                 }
 111
 112                                 if (length == 15) {
 113                                         length = input[input_index];
 114                                         input_index += sizeof(uint8_t);
 115                                                 if (length == 255) {
 116                                                         length = PULL_LE_UINT16(input, input_index);
 117                                                         input_index += sizeof(uint16_t);
 118                                                         length -= (15 + 7);
 119                                                 }
 120                                         length += 15;
 121                                 }
 122                                 length += 7;
 123                         }
 124
 125                         length += 3;
 126
 127                         do {
 128                                 if (output_index >= output_size) break;
 129                                 output[output_index] = output[output_index - offset - 1];
 130                                 output_index += sizeof(uint8_t);
 131                                 length -= sizeof(uint8_t);
 132                         } while (length != 0);
 133                 }
 134
 135         } while ((output_index < output_size) && (input_index < input_size));
 136
 137         return output_index;
 138 }
 139
 140 uint32_t lzxpress_decompress(DATA_BLOB *inbuf,
 141                                 DATA_BLOB *outbuf)
 142 {
 143         return xpress_decompress(inbuf->data, inbuf->length, outbuf->data, outbuf->length);
 144 }