src/liblzma/common/alone_encoder.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       alone_encoder.c
   4 /// \brief      Encoder for LZMA_Alone files
   5 //
   6 //  Author:     Lasse Collin
   7 //
   8 //  This file has been put into the public domain.
   9 //  You can do whatever you want with this file.
  10 //
  11 ///////////////////////////////////////////////////////////////////////////////
  12
  13 #include "common.h"
  14 #include "lzma_encoder.h"
  15
  16
  17 #define ALONE_HEADER_SIZE (1 + 4 + 8)
  18
  19
  20 typedef struct {
  21         lzma_next_coder next;
  22
  23         enum {
  24                 SEQ_HEADER,
  25                 SEQ_CODE,
  26         } sequence;
  27
  28         size_t header_pos;
  29         uint8_t header[ALONE_HEADER_SIZE];
  30 } lzma_alone_coder;
  31
  32
  33 static lzma_ret
  34 alone_encode(void *coder_ptr, const lzma_allocator *allocator,
  35                 const uint8_t *restrict in, size_t *restrict in_pos,
  36                 size_t in_size, uint8_t *restrict out,
  37                 size_t *restrict out_pos, size_t out_size,
  38                 lzma_action action)
  39 {
  40         lzma_alone_coder *coder = coder_ptr;
  41
  42         while (*out_pos < out_size)
  43         switch (coder->sequence) {
  44         case SEQ_HEADER:
  45                 lzma_bufcpy(coder->header, &coder->header_pos,
  46                                 ALONE_HEADER_SIZE,
  47                                 out, out_pos, out_size);
  48                 if (coder->header_pos < ALONE_HEADER_SIZE)
  49                         return LZMA_OK;
  50
  51                 coder->sequence = SEQ_CODE;
  52                 break;
  53
  54         case SEQ_CODE:
  55                 return coder->next.code(coder->next.coder,
  56                                 allocator, in, in_pos, in_size,
  57                                 out, out_pos, out_size, action);
  58
  59         default:
  60                 assert(0);
  61                 return LZMA_PROG_ERROR;
  62         }
  63
  64         return LZMA_OK;
  65 }
  66
  67
  68 static void
  69 alone_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
  70 {
  71         lzma_alone_coder *coder = coder_ptr;
  72         lzma_next_end(&coder->next, allocator);
  73         lzma_free(coder, allocator);
  74         return;
  75 }
  76
  77
  78 static lzma_ret
  79 alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
  80                 const lzma_options_lzma *options)
  81 {
  82         lzma_next_coder_init(&alone_encoder_init, next, allocator);
  83
  84         lzma_alone_coder *coder = next->coder;
  85
  86         if (coder == NULL) {
  87                 coder = lzma_alloc(sizeof(lzma_alone_coder), allocator);
  88                 if (coder == NULL)
  89                         return LZMA_MEM_ERROR;
  90
  91                 next->coder = coder;
  92                 next->code = &alone_encode;
  93                 next->end = &alone_encoder_end;
  94                 coder->next = LZMA_NEXT_CODER_INIT;
  95         }
  96
  97         // Basic initializations
  98         coder->sequence = SEQ_HEADER;
  99         coder->header_pos = 0;
 100
 101         // Encode the header:
 102         // - Properties (1 byte)
 103         if (lzma_lzma_lclppb_encode(options, coder->header))
 104                 return LZMA_OPTIONS_ERROR;
 105
 106         // - Dictionary size (4 bytes)
 107         if (options->dict_size < LZMA_DICT_SIZE_MIN)
 108                 return LZMA_OPTIONS_ERROR;
 109
 110         // Round up to the next 2^n or 2^n + 2^(n - 1) depending on which
 111         // one is the next unless it is UINT32_MAX. While the header would
 112         // allow any 32-bit integer, we do this to keep the decoder of liblzma
 113         // accepting the resulting files.
 114         uint32_t d = options->dict_size - 1;
 115         d |= d >> 2;
 116         d |= d >> 3;
 117         d |= d >> 4;
 118         d |= d >> 8;
 119         d |= d >> 16;
 120         if (d != UINT32_MAX)
 121                 ++d;
 122
 123         write32le(coder->header + 1, d);
 124
 125         // - Uncompressed size (always unknown and using EOPM)
 126         memset(coder->header + 1 + 4, 0xFF, 8);
 127
 128         // Initialize the LZMA encoder.
 129         const lzma_filter_info filters[2] = {
 130                 {
 131                         .id = LZMA_FILTER_LZMA1,
 132                         .init = &lzma_lzma_encoder_init,
 133                         .options = (void *)(options),
 134                 }, {
 135                         .init = NULL,
 136                 }
 137         };
 138
 139         return lzma_next_filter_init(&coder->next, allocator, filters);
 140 }
 141
 142
 143 extern LZMA_API(lzma_ret)
 144 lzma_alone_encoder(lzma_stream *strm, const lzma_options_lzma *options)
 145 {
 146         lzma_next_strm_init(alone_encoder_init, strm, options);
 147
 148         strm->internal->supported_actions[LZMA_RUN] = true;
 149         strm->internal->supported_actions[LZMA_FINISH] = true;
 150
 151         return LZMA_OK;
 152 }