pd.if.org Git - zpackage/blob - lzma/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 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,
  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         lzma_alone_coder *coder = coder_ptr;
  42
  43         while (*out_pos < out_size)
  44         switch (coder->sequence) {
  45         case SEQ_HEADER:
  46                 lzma_bufcpy(coder->header, &coder->header_pos,
  47                                 ALONE_HEADER_SIZE,
  48                                 out, out_pos, out_size);
  49                 if (coder->header_pos < ALONE_HEADER_SIZE)
  50                         return LZMA_OK;
  51
  52                 coder->sequence = SEQ_CODE;
  53                 break;
  54
  55         case SEQ_CODE:
  56                 return coder->next.code(coder->next.coder,
  57                                 allocator, in, in_pos, in_size,
  58                                 out, out_pos, out_size, action);
  59
  60         default:
  61                 assert(0);
  62                 return LZMA_PROG_ERROR;
  63         }
  64
  65         return LZMA_OK;
  66 }
  67
  68
  69 static void
  70 alone_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
  71 {
  72         lzma_alone_coder *coder = coder_ptr;
  73         lzma_next_end(&coder->next, allocator);
  74         lzma_free(coder, allocator);
  75         return;
  76 }
  77
  78
  79 // At least for now, this is not used by any internal function.
  80 static lzma_ret
  81 alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
  82                 const lzma_options_lzma *options)
  83 {
  84         lzma_next_coder_init(&alone_encoder_init, next, allocator);
  85
  86         lzma_alone_coder *coder = next->coder;
  87
  88         if (coder == NULL) {
  89                 coder = lzma_alloc(sizeof(lzma_alone_coder), allocator);
  90                 if (coder == NULL)
  91                         return LZMA_MEM_ERROR;
  92
  93                 next->coder = coder;
  94                 next->code = &alone_encode;
  95                 next->end = &alone_encoder_end;
  96                 coder->next = LZMA_NEXT_CODER_INIT;
  97         }
  98
  99         // Basic initializations
 100         coder->sequence = SEQ_HEADER;
 101         coder->header_pos = 0;
 102
 103         // Encode the header:
 104         // - Properties (1 byte)
 105         if (lzma_lzma_lclppb_encode(options, coder->header))
 106                 return LZMA_OPTIONS_ERROR;
 107
 108         // - Dictionary size (4 bytes)
 109         if (options->dict_size < LZMA_DICT_SIZE_MIN)
 110                 return LZMA_OPTIONS_ERROR;
 111
 112         // Round up to the next 2^n or 2^n + 2^(n - 1) depending on which
 113         // one is the next unless it is UINT32_MAX. While the header would
 114         // allow any 32-bit integer, we do this to keep the decoder of liblzma
 115         // accepting the resulting files.
 116         uint32_t d = options->dict_size - 1;
 117         d |= d >> 2;
 118         d |= d >> 3;
 119         d |= d >> 4;
 120         d |= d >> 8;
 121         d |= d >> 16;
 122         if (d != UINT32_MAX)
 123                 ++d;
 124
 125         unaligned_write32le(coder->header + 1, d);
 126
 127         // - Uncompressed size (always unknown and using EOPM)
 128         memset(coder->header + 1 + 4, 0xFF, 8);
 129
 130         // Initialize the LZMA encoder.
 131         const lzma_filter_info filters[2] = {
 132                 {
 133                         .init = &lzma_lzma_encoder_init,
 134                         .options = (void *)(options),
 135                 }, {
 136                         .init = NULL,
 137                 }
 138         };
 139
 140         return lzma_next_filter_init(&coder->next, allocator, filters);
 141 }
 142
 143
 144 /*
 145 extern lzma_ret
 146 lzma_alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 147                 const lzma_options_alone *options)
 148 {
 149         lzma_next_coder_init(&alone_encoder_init, next, allocator, options);
 150 }
 151 */
 152
 153
 154 extern LZMA_API(lzma_ret)
 155 lzma_alone_encoder(lzma_stream *strm, const lzma_options_lzma *options)
 156 {
 157         lzma_next_strm_init(alone_encoder_init, strm, options);
 158
 159         strm->internal->supported_actions[LZMA_RUN] = true;
 160         strm->internal->supported_actions[LZMA_FINISH] = true;
 161
 162         return LZMA_OK;
 163 }