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                 lzma_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_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         lzma_next_coder_init(alone_encoder_init, next, allocator);
  89
  90         if (next->coder == NULL) {
  91                 next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
  92                 if (next->coder == NULL)
  93                         return LZMA_MEM_ERROR;
  94
  95                 next->code = &alone_encode;
  96                 next->end = &alone_encoder_end;
  97                 next->coder->next = LZMA_NEXT_CODER_INIT;
  98         }
  99
 100         // Basic initializations
 101         next->coder->sequence = SEQ_HEADER;
 102         next->coder->header_pos = 0;
 103
 104         // Encode the header:
 105         // - Properties (1 byte)
 106         if (lzma_lzma_lclppb_encode(options, next->coder->header))
 107                 return LZMA_PROG_ERROR;
 108
 109         // - Dictionary size (4 bytes); limit to 1 GiB since that's what
 110         //   LZMA SDK currently does for encoding.
 111         if (options->dict_size < LZMA_DICT_SIZE_MIN
 112                         || options->dict_size > (UINT32_C(1) << 30))
 113                 return LZMA_PROG_ERROR;
 114
 115         // Round up to to the next 2^n or 2^n + 2^(n - 1) depending on which
 116         // one is the next. While the header would allow any 32-bit integer,
 117         // we do this to keep the decoder of liblzma accepting the resulting
 118         // files.
 119         //
 120         // FIXME Maybe LZMA_Alone needs some lower limit for maximum
 121         // dictionary size? Must check decoders from old LZMA SDK version.
 122         uint32_t d = options->dict_size - 1;
 123         d |= d >> 2;
 124         d |= d >> 3;
 125         d |= d >> 4;
 126         d |= d >> 8;
 127         d |= d >> 16;
 128         ++d;
 129
 130         integer_write_32(next->coder->header + 1, d);
 131
 132         // - Uncompressed size (always unknown and using EOPM)
 133         memset(next->coder->header + 1 + 4, 0xFF, 8);
 134
 135         // Initialize the LZMA encoder.
 136         const lzma_filter_info filters[2] = {
 137                 {
 138                         .init = &lzma_lzma_encoder_init,
 139                         .options = (void *)(options),
 140                 }, {
 141                         .init = NULL,
 142                 }
 143         };
 144
 145         return lzma_next_filter_init(&next->coder->next, allocator, filters);
 146 }
 147
 148
 149 /*
 150 extern lzma_ret
 151 lzma_alone_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
 152                 const lzma_options_alone *options)
 153 {
 154         lzma_next_coder_init(alone_encoder_init, next, allocator, options);
 155 }
 156 */
 157
 158
 159 extern LZMA_API lzma_ret
 160 lzma_alone_encoder(lzma_stream *strm, const lzma_options_lzma *options)
 161 {
 162         lzma_next_strm_init(alone_encoder_init, strm, options);
 163
 164         strm->internal->supported_actions[LZMA_RUN] = true;
 165         strm->internal->supported_actions[LZMA_FINISH] = true;
 166
 167         return LZMA_OK;
 168 }