external/public-domain/xz/dist/src/liblzma/common/alone_encoder.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       alone_decoder.c
   4 /// \brief      Decoder 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 struct lzma_coder_s {
  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 };
  31
  32
  33 static lzma_ret
  34 alone_encode(lzma_coder *coder,
  35                 const lzma_allocator *allocator lzma_attribute((__unused__)),
  36                 const uint8_t *restrict in, size_t *restrict in_pos,
  37                 size_t in_size, uint8_t *restrict out,
  38                 size_t *restrict out_pos, size_t out_size,
  39                 lzma_action action)
  40 {
  41         while (*out_pos < out_size)
  42         switch (coder->sequence) {
  43         case SEQ_HEADER:
  44                 lzma_bufcpy(coder->header, &coder->header_pos,
  45                                 ALONE_HEADER_SIZE,
  46                                 out, out_pos, out_size);
  47                 if (coder->header_pos < ALONE_HEADER_SIZE)
  48                         return LZMA_OK;
  49
  50                 coder->sequence = SEQ_CODE;
  51                 break;
  52
  53         case SEQ_CODE:
  54                 return coder->next.code(coder->next.coder,
  55                                 allocator, in, in_pos, in_size,
  56                                 out, out_pos, out_size, action);
  57
  58         default:
  59                 assert(0);
  60                 return LZMA_PROG_ERROR;
  61         }
  62
  63         return LZMA_OK;
  64 }
  65
  66
  67 static void
  68 alone_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
  69 {
  70         lzma_next_end(&coder->next, allocator);
  71         lzma_free(coder, allocator);
  72         return;
  73 }
  74
  75
  76 // At least for now, this is not used by any internal function.
  77 static lzma_ret
  78 alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
  79                 const lzma_options_lzma *options)
  80 {
  81         lzma_next_coder_init(&alone_encoder_init, next, allocator);
  82
  83         if (next->coder == NULL) {
  84                 next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
  85                 if (next->coder == NULL)
  86                         return LZMA_MEM_ERROR;
  87
  88                 next->code = &alone_encode;
  89                 next->end = &alone_encoder_end;
  90                 next->coder->next = LZMA_NEXT_CODER_INIT;
  91         }
  92
  93         // Basic initializations
  94         next->coder->sequence = SEQ_HEADER;
  95         next->coder->header_pos = 0;
  96
  97         // Encode the header:
  98         // - Properties (1 byte)
  99         if (lzma_lzma_lclppb_encode(options, next->coder->header))
 100                 return LZMA_OPTIONS_ERROR;
 101
 102         // - Dictionary size (4 bytes)
 103         if (options->dict_size < LZMA_DICT_SIZE_MIN)
 104                 return LZMA_OPTIONS_ERROR;
 105
 106         // Round up to the next 2^n or 2^n + 2^(n - 1) depending on which
 107         // one is the next unless it is UINT32_MAX. While the header would
 108         // allow any 32-bit integer, we do this to keep the decoder of liblzma
 109         // accepting the resulting files.
 110         uint32_t d = options->dict_size - 1;
 111         d |= d >> 2;
 112         d |= d >> 3;
 113         d |= d >> 4;
 114         d |= d >> 8;
 115         d |= d >> 16;
 116         if (d != UINT32_MAX)
 117                 ++d;
 118
 119         unaligned_write32le(next->coder->header + 1, d);
 120
 121         // - Uncompressed size (always unknown and using EOPM)
 122         memset(next->coder->header + 1 + 4, 0xFF, 8);
 123
 124         // Initialize the LZMA encoder.
 125         const lzma_filter_info filters[2] = {
 126                 {
 127                         .init = &lzma_lzma_encoder_init,
 128                         .options = (void *)(options),
 129                 }, {
 130                         .init = NULL,
 131                 }
 132         };
 133
 134         return lzma_next_filter_init(&next->coder->next, allocator, filters);
 135 }
 136
 137
 138 /*
 139 extern lzma_ret
 140 lzma_alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 141                 const lzma_options_alone *options)
 142 {
 143         lzma_next_coder_init(&alone_encoder_init, next, allocator, options);
 144 }
 145 */
 146
 147
 148 extern LZMA_API(lzma_ret)
 149 lzma_alone_encoder(lzma_stream *strm, const lzma_options_lzma *options)
 150 {
 151         lzma_next_strm_init(alone_encoder_init, strm, options);
 152
 153         strm->internal->supported_actions[LZMA_RUN] = true;
 154         strm->internal->supported_actions[LZMA_FINISH] = true;
 155
 156         return LZMA_OK;
 157 }