lib/lzma/LzmaDec.h

   1 /* LzmaDec.h -- LZMA Decoder
   2 2009-02-07 : Igor Pavlov : Public domain */
   3
   4 #ifndef __LZMA_DEC_H
   5 #define __LZMA_DEC_H
   6
   7 #include "Types.h"
   8
   9 /* #define _LZMA_PROB32 */
  10 /* _LZMA_PROB32 can increase the speed on some CPUs,
  11    but memory usage for CLzmaDec::probs will be doubled in that case */
  12
  13 #ifdef _LZMA_PROB32
  14 #define CLzmaProb UInt32
  15 #else
  16 #define CLzmaProb UInt16
  17 #endif
  18
  19 /* ---------- LZMA Properties ---------- */
  20
  21 #define LZMA_PROPS_SIZE 5
  22
  23 typedef struct _CLzmaProps
  24 {
  25   unsigned lc, lp, pb;
  26   UInt32 dicSize;
  27 } CLzmaProps;
  28
  29 /* LzmaProps_Decode - decodes properties
  30 Returns:
  31   SZ_OK
  32   SZ_ERROR_UNSUPPORTED - Unsupported properties
  33 */
  34
  35 SRes LzmaProps_Decode(CLzmaProps *p, const Byte *data, unsigned size);
  36
  37 /* ---------- LZMA Decoder state ---------- */
  38
  39 /* LZMA_REQUIRED_INPUT_MAX = number of required input bytes for worst case.
  40    Num bits = log2((2^11 / 31) ^ 22) + 26 < 134 + 26 = 160; */
  41
  42 #define LZMA_REQUIRED_INPUT_MAX 20
  43
  44 typedef struct
  45 {
  46   CLzmaProps prop;
  47   CLzmaProb *probs;
  48   Byte *dic;
  49   const Byte *buf;
  50   UInt32 range, code;
  51   SizeT dicPos;
  52   SizeT dicBufSize;
  53   UInt32 processedPos;
  54   UInt32 checkDicSize;
  55   unsigned state;
  56   UInt32 reps[4];
  57   unsigned remainLen;
  58   int needFlush;
  59   int needInitState;
  60   UInt32 numProbs;
  61   unsigned tempBufSize;
  62   Byte tempBuf[LZMA_REQUIRED_INPUT_MAX];
  63 } CLzmaDec;
  64
  65 #define LzmaDec_Construct(p) { (p)->dic = 0; (p)->probs = 0; }
  66
  67 void LzmaDec_Init(CLzmaDec *p);
  68
  69 /* There are two types of LZMA streams:
  70      0) Stream with end mark. That end mark adds about 6 bytes to compressed size.
  71      1) Stream without end mark. You must know exact uncompressed size to decompress such stream. */
  72
  73 typedef enum
  74 {
  75   LZMA_FINISH_ANY,   /* finish at any point */
  76   LZMA_FINISH_END    /* block must be finished at the end */
  77 } ELzmaFinishMode;
  78
  79 /* ELzmaFinishMode has meaning only if the decoding reaches output limit !!!
  80
  81    You must use LZMA_FINISH_END, when you know that current output buffer
  82    covers last bytes of block. In other cases you must use LZMA_FINISH_ANY.
  83
  84    If LZMA decoder sees end marker before reaching output limit, it returns SZ_OK,
  85    and output value of destLen will be less than output buffer size limit.
  86    You can check status result also.
  87
  88    You can use multiple checks to test data integrity after full decompression:
  89      1) Check Result and "status" variable.
  90      2) Check that output(destLen) = uncompressedSize, if you know real uncompressedSize.
  91      3) Check that output(srcLen) = compressedSize, if you know real compressedSize.
  92         You must use correct finish mode in that case. */
  93
  94 typedef enum
  95 {
  96   LZMA_STATUS_NOT_SPECIFIED,               /* use main error code instead */
  97   LZMA_STATUS_FINISHED_WITH_MARK,          /* stream was finished with end mark. */
  98   LZMA_STATUS_NOT_FINISHED,                /* stream was not finished */
  99   LZMA_STATUS_NEEDS_MORE_INPUT,            /* you must provide more input bytes */
 100   LZMA_STATUS_MAYBE_FINISHED_WITHOUT_MARK  /* there is probability that stream was finished without end mark */
 101 } ELzmaStatus;
 102
 103 /* ELzmaStatus is used only as output value for function call */
 104
 105 /* ---------- Interfaces ---------- */
 106
 107 /* There are 3 levels of interfaces:
 108      1) Dictionary Interface
 109      2) Buffer Interface
 110      3) One Call Interface
 111    You can select any of these interfaces, but don't mix functions from different
 112    groups for same object. */
 113
 114 /* There are two variants to allocate state for Dictionary Interface:
 115      1) LzmaDec_Allocate / LzmaDec_Free
 116      2) LzmaDec_AllocateProbs / LzmaDec_FreeProbs
 117    You can use variant 2, if you set dictionary buffer manually.
 118    For Buffer Interface you must always use variant 1.
 119
 120 LzmaDec_Allocate* can return:
 121   SZ_OK
 122   SZ_ERROR_MEM         - Memory allocation error
 123   SZ_ERROR_UNSUPPORTED - Unsupported properties
 124 */
 125
 126 SRes LzmaDec_AllocateProbs(CLzmaDec *p, const Byte *props, unsigned propsSize, ISzAlloc *alloc);
 127 void LzmaDec_FreeProbs(CLzmaDec *p, ISzAlloc *alloc);
 128
 129 SRes LzmaDec_Allocate(CLzmaDec *state, const Byte *prop, unsigned propsSize, ISzAlloc *alloc);
 130 void LzmaDec_Free(CLzmaDec *state, ISzAlloc *alloc);
 131
 132 /* ---------- Dictionary Interface ---------- */
 133
 134 /* You can use it, if you want to eliminate the overhead for data copying from
 135    dictionary to some other external buffer.
 136    You must work with CLzmaDec variables directly in this interface.
 137
 138    STEPS:
 139      LzmaDec_Constr()
 140      LzmaDec_Allocate()
 141      for (each new stream)
 142      {
 143        LzmaDec_Init()
 144        while (it needs more decompression)
 145        {
 146          LzmaDec_DecodeToDic()
 147          use data from CLzmaDec::dic and update CLzmaDec::dicPos
 148        }
 149      }
 150      LzmaDec_Free()
 151 */
 152
 153 /* LzmaDec_DecodeToDic
 154
 155    The decoding to internal dictionary buffer (CLzmaDec::dic).
 156    You must manually update CLzmaDec::dicPos, if it reaches CLzmaDec::dicBufSize !!!
 157
 158 finishMode:
 159   It has meaning only if the decoding reaches output limit (dicLimit).
 160   LZMA_FINISH_ANY - Decode just dicLimit bytes.
 161   LZMA_FINISH_END - Stream must be finished after dicLimit.
 162
 163 Returns:
 164   SZ_OK
 165     status:
 166       LZMA_STATUS_FINISHED_WITH_MARK
 167       LZMA_STATUS_NOT_FINISHED
 168       LZMA_STATUS_NEEDS_MORE_INPUT
 169       LZMA_STATUS_MAYBE_FINISHED_WITHOUT_MARK
 170   SZ_ERROR_DATA - Data error
 171 */
 172
 173 SRes LzmaDec_DecodeToDic(CLzmaDec *p, SizeT dicLimit,
 174     const Byte *src, SizeT *srcLen, ELzmaFinishMode finishMode, ELzmaStatus *status);
 175
 176 /* ---------- Buffer Interface ---------- */
 177
 178 /* It's zlib-like interface.
 179    See LzmaDec_DecodeToDic description for information about STEPS and return results,
 180    but you must use LzmaDec_DecodeToBuf instead of LzmaDec_DecodeToDic and you don't need
 181    to work with CLzmaDec variables manually.
 182
 183 finishMode:
 184   It has meaning only if the decoding reaches output limit (*destLen).
 185   LZMA_FINISH_ANY - Decode just destLen bytes.
 186   LZMA_FINISH_END - Stream must be finished after (*destLen).
 187 */
 188
 189 SRes LzmaDec_DecodeToBuf(CLzmaDec *p, Byte *dest, SizeT *destLen,
 190     const Byte *src, SizeT *srcLen, ELzmaFinishMode finishMode, ELzmaStatus *status);
 191
 192 /* ---------- One Call Interface ---------- */
 193
 194 /* LzmaDecode
 195
 196 finishMode:
 197   It has meaning only if the decoding reaches output limit (*destLen).
 198   LZMA_FINISH_ANY - Decode just destLen bytes.
 199   LZMA_FINISH_END - Stream must be finished after (*destLen).
 200
 201 Returns:
 202   SZ_OK
 203     status:
 204       LZMA_STATUS_FINISHED_WITH_MARK
 205       LZMA_STATUS_NOT_FINISHED
 206       LZMA_STATUS_MAYBE_FINISHED_WITHOUT_MARK
 207   SZ_ERROR_DATA - Data error
 208   SZ_ERROR_MEM  - Memory allocation error
 209   SZ_ERROR_UNSUPPORTED - Unsupported properties
 210   SZ_ERROR_INPUT_EOF - It needs more bytes in input buffer (src).
 211 */
 212
 213 SRes LzmaDecode(Byte *dest, SizeT *destLen, const Byte *src, SizeT *srcLen,
 214     const Byte *propData, unsigned propSize, ELzmaFinishMode finishMode,
 215     ELzmaStatus *status, ISzAlloc *alloc);
 216
 217 #endif