src/liblzma/common/alone_encoder.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       alone_decoder.c
   4 /// \brief      Decoder for LZMA_Alone files
   5 //
   6 //  Copyright (C) 2007 Lasse Collin
   7 //
   8 //  This library is free software; you can redistribute it and/or
   9 //  modify it under the terms of the GNU Lesser General Public
  10 //  License as published by the Free Software Foundation; either
  11 //  version 2.1 of the License, or (at your option) any later version.
  12 //
  13 //  This library is distributed in the hope that it will be useful,
  14 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 //  Lesser General Public License for more details.
  17 //
  18 ///////////////////////////////////////////////////////////////////////////////
  19
  20 #include "common.h"
  21 #include "lzma_encoder.h"
  22
  23
  24 #define ALONE_HEADER_SIZE (1 + 4 + 8)
  25
  26
  27 struct lzma_coder_s {
  28         lzma_next_coder next;
  29
  30         enum {
  31                 SEQ_HEADER,
  32                 SEQ_CODE,
  33         } sequence;
  34
  35         size_t header_pos;
  36         uint8_t header[ALONE_HEADER_SIZE];
  37 };
  38
  39
  40 static lzma_ret
  41 alone_encode(lzma_coder *coder,
  42                 lzma_allocator *allocator lzma_attribute((unused)),
  43                 const uint8_t *restrict in, size_t *restrict in_pos,
  44                 size_t in_size, uint8_t *restrict out,
  45                 size_t *restrict out_pos, size_t out_size,
  46                 lzma_action action)
  47 {
  48         while (*out_pos < out_size)
  49         switch (coder->sequence) {
  50         case SEQ_HEADER:
  51                 bufcpy(coder->header, &coder->header_pos,
  52                                 ALONE_HEADER_SIZE,
  53                                 out, out_pos, out_size);
  54                 if (coder->header_pos < ALONE_HEADER_SIZE)
  55                         return LZMA_OK;
  56
  57                 coder->sequence = SEQ_CODE;
  58                 break;
  59
  60         case SEQ_CODE:
  61                 return coder->next.code(coder->next.coder,
  62                                 allocator, in, in_pos, in_size,
  63                                 out, out_pos, out_size, action);
  64
  65         default:
  66                 assert(0);
  67                 return LZMA_PROG_ERROR;
  68         }
  69
  70         return LZMA_OK;
  71 }
  72
  73
  74 static void
  75 alone_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
  76 {
  77         lzma_next_coder_end(&coder->next, allocator);
  78         lzma_free(coder, allocator);
  79         return;
  80 }
  81
  82
  83 // At least for now, this is not used by any internal function.
  84 static lzma_ret
  85 alone_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
  86                 const lzma_options_lzma *options)
  87 {
  88         if (next->coder == NULL) {
  89                 next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
  90                 if (next->coder == NULL)
  91                         return LZMA_MEM_ERROR;
  92
  93                 next->code = &alone_encode;
  94                 next->end = &alone_encoder_end;
  95                 next->coder->next = LZMA_NEXT_CODER_INIT;
  96         }
  97
  98         // Basic initializations
  99         next->coder->sequence = SEQ_HEADER;
 100         next->coder->header_pos = 0;
 101
 102         // Encode the header:
 103         // - Properties (1 byte)
 104         if (lzma_lzma_encode_properties(options, next->coder->header))
 105                 return LZMA_PROG_ERROR;
 106
 107         // - Dictionary size (4 bytes)
 108         if (options->dictionary_size < LZMA_DICTIONARY_SIZE_MIN
 109                         || options->dictionary_size > LZMA_DICTIONARY_SIZE_MAX)
 110                 return LZMA_PROG_ERROR;
 111
 112         // Round up to to the next 2^n or 2^n + 2^(n - 1) depending on which
 113         // one is the next. While the header would allow any 32-bit integer,
 114         // we do this to keep the decoder of liblzma accepting the resulting
 115         // files.
 116         uint32_t d = options->dictionary_size - 1;
 117         d |= d >> 2;
 118         d |= d >> 3;
 119         d |= d >> 4;
 120         d |= d >> 8;
 121         d |= d >> 16;
 122         ++d;
 123
 124         integer_write_32(next->coder->header + 1, d);
 125
 126         // - Uncompressed size (always unknown and using EOPM)
 127         memset(next->coder->header + 1 + 4, 0xFF, 8);
 128
 129         // Initialize the LZMA encoder.
 130         const lzma_filter_info filters[2] = {
 131                 {
 132                         .init = &lzma_lzma_encoder_init,
 133                         .options = (void *)(options),
 134                 }, {
 135                         .init = NULL,
 136                 }
 137         };
 138
 139         return lzma_next_filter_init(&next->coder->next, allocator, filters);
 140 }
 141
 142
 143 /*
 144 extern lzma_ret
 145 lzma_alone_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
 146                 const lzma_options_alone *options)
 147 {
 148         lzma_next_coder_init(alone_encoder_init, next, allocator, options);
 149 }
 150 */
 151
 152
 153 extern LZMA_API lzma_ret
 154 lzma_alone_encoder(lzma_stream *strm, const lzma_options_lzma *options)
 155 {
 156         lzma_next_strm_init(strm, alone_encoder_init, options);
 157
 158         strm->internal->supported_actions[LZMA_RUN] = true;
 159         strm->internal->supported_actions[LZMA_FINISH] = true;
 160
 161         return LZMA_OK;
 162 }