LzmaDec.h

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/* LzmaDec.h -- LZMA Decoder
   2009-02-07 : Igor Pavlov : Public domain */

#ifndef __LZMA_DEC_H
#define __LZMA_DEC_H

#include "7zTypes.h"

#ifdef __cplusplus
extern "C" {
#endif

/* ---------- LZMA Properties ---------- */

#define LZMA_PROPS_SIZE 5

   typedef struct _CLzmaProps
   {
      unsigned lc, lp, pb;
      uint32_t dicSize;
   } CLzmaProps;

   /* LzmaProps_Decode - decodes properties
Returns:
SZ_OK
SZ_ERROR_UNSUPPORTED - Unsupported properties
*/

   SRes LzmaProps_Decode(CLzmaProps *p, const uint8_t *data, unsigned size);


   /* ---------- LZMA Decoder state ---------- */

   /* LZMA_REQUIRED_INPUT_MAX = number of required input bytes for worst case.
      Num bits = log2((2^11 / 31) ^ 22) + 26 < 134 + 26 = 160; */

#define LZMA_REQUIRED_INPUT_MAX 20

   typedef struct
   {
      CLzmaProps prop;
      uint16_t *probs;
      uint8_t *dic;
      const uint8_t *buf;
      uint32_t range, code;
      size_t dicPos;
      size_t dicBufSize;
      uint32_t processedPos;
      uint32_t checkDicSize;
      unsigned state;
      uint32_t reps[4];
      unsigned remainLen;
      int needFlush;
      int needInitState;
      uint32_t numProbs;
      unsigned tempBufSize;
      uint8_t tempBuf[LZMA_REQUIRED_INPUT_MAX];
   } CLzmaDec;

#define LzmaDec_Construct(p) { (p)->dic = 0; (p)->probs = 0; }

   void LzmaDec_Init(CLzmaDec *p);

   /* There are two types of LZMA streams:
      0) Stream with end mark. That end mark adds about 6 bytes to compressed size.
      1) Stream without end mark. You must know exact uncompressed size to decompress such stream. */

   typedef enum
   {
      LZMA_FINISH_ANY,   /* finish at any point */
      LZMA_FINISH_END    /* block must be finished at the end */
   } ELzmaFinishMode;

   /* ELzmaFinishMode has meaning only if the decoding reaches output limit !!!

      You must use LZMA_FINISH_END, when you know that current output buffer
      covers last bytes of block. In other cases you must use LZMA_FINISH_ANY.

      If LZMA decoder sees end marker before reaching output limit, it returns SZ_OK,
      and output value of destLen will be less than output buffer size limit.
      You can check status result also.

      You can use multiple checks to test data integrity after full decompression:
      1) Check Result and "status" variable.
      2) Check that output(destLen) = uncompressedSize, if you know real uncompressedSize.
      3) Check that output(srcLen) = compressedSize, if you know real compressedSize.
      You must use correct finish mode in that case. */

   typedef enum
   {
      LZMA_STATUS_NOT_SPECIFIED,               /* use main error code instead */
      LZMA_STATUS_FINISHED_WITH_MARK,          /* stream was finished with end mark. */
      LZMA_STATUS_NOT_FINISHED,                /* stream was not finished */
      LZMA_STATUS_NEEDS_MORE_INPUT,            /* you must provide more input bytes */
      LZMA_STATUS_MAYBE_FINISHED_WITHOUT_MARK  /* there is probability that stream was finished without end mark */
   } ELzmaStatus;

   /* ELzmaStatus is used only as output value for function call */


   /* ---------- Interfaces ---------- */

   /* There are 3 levels of interfaces:
      1) Dictionary Interface
      2) Buffer Interface
      3) One Call Interface
      You can select any of these interfaces, but don't mix functions from different
      groups for same object. */


   /* There are two variants to allocate state for Dictionary Interface:
      1) LzmaDec_Allocate / LzmaDec_Free
      2) LzmaDec_AllocateProbs / LzmaDec_FreeProbs
      You can use variant 2, if you set dictionary buffer manually.
      For Buffer Interface you must always use variant 1.

      LzmaDec_Allocate* can return:
      SZ_OK
      SZ_ERROR_MEM         - Memory allocation error
      SZ_ERROR_UNSUPPORTED - Unsupported properties
      */

   SRes LzmaDec_AllocateProbs(CLzmaDec *p, const uint8_t *props, unsigned propsSize, ISzAlloc *alloc);
   void LzmaDec_FreeProbs(CLzmaDec *p, ISzAlloc *alloc);

   SRes LzmaDec_Allocate(CLzmaDec *state, const uint8_t *prop, unsigned propsSize, ISzAlloc *alloc);
   void LzmaDec_Free(CLzmaDec *state, ISzAlloc *alloc);

   /* ---------- Dictionary Interface ---------- */

   /* You can use it, if you want to eliminate the overhead for data copying from
      dictionary to some other external buffer.
      You must work with CLzmaDec variables directly in this interface.

STEPS:
LzmaDec_Constr()
LzmaDec_Allocate()
for (each new stream)
{
LzmaDec_Init()
while (it needs more decompression)
{
LzmaDec_DecodeToDic()
use data from CLzmaDec::dic and update CLzmaDec::dicPos
}
}
LzmaDec_Free()
*/

   /* LzmaDec_DecodeToDic

      The decoding to internal dictionary buffer (CLzmaDec::dic).
      You must manually update CLzmaDec::dicPos, if it reaches CLzmaDec::dicBufSize !!!

finishMode:
It has meaning only if the decoding reaches output limit (dicLimit).
LZMA_FINISH_ANY - Decode just dicLimit bytes.
LZMA_FINISH_END - Stream must be finished after dicLimit.

Returns:
SZ_OK
status:
LZMA_STATUS_FINISHED_WITH_MARK
LZMA_STATUS_NOT_FINISHED
LZMA_STATUS_NEEDS_MORE_INPUT
LZMA_STATUS_MAYBE_FINISHED_WITHOUT_MARK
SZ_ERROR_DATA - Data error
*/

   SRes LzmaDec_DecodeToDic(CLzmaDec *p, size_t dicLimit,
         const uint8_t *src, size_t *srcLen, ELzmaFinishMode finishMode, ELzmaStatus *status);


/* ---------- Buffer Interface ---------- */

/* It's zlib-like interface.
   See LzmaDec_DecodeToDic description for information about STEPS and return results,
   but you must use LzmaDec_DecodeToBuf instead of LzmaDec_DecodeToDic and you don't need
   to work with CLzmaDec variables manually.

finishMode:
It has meaning only if the decoding reaches output limit (*destLen).
LZMA_FINISH_ANY - Decode just destLen bytes.
LZMA_FINISH_END - Stream must be finished after (*destLen).
*/

SRes LzmaDec_DecodeToBuf(CLzmaDec *p, uint8_t *dest, size_t *destLen,
      const uint8_t *src, size_t *srcLen, ELzmaFinishMode finishMode, ELzmaStatus *status);


/* ---------- One Call Interface ---------- */

/* LzmaDecode

finishMode:
It has meaning only if the decoding reaches output limit (*destLen).
LZMA_FINISH_ANY - Decode just destLen bytes.
LZMA_FINISH_END - Stream must be finished after (*destLen).

Returns:
SZ_OK
status:
LZMA_STATUS_FINISHED_WITH_MARK
LZMA_STATUS_NOT_FINISHED
LZMA_STATUS_MAYBE_FINISHED_WITHOUT_MARK
SZ_ERROR_DATA - Data error
SZ_ERROR_MEM  - Memory allocation error
SZ_ERROR_UNSUPPORTED - Unsupported properties
SZ_ERROR_INPUT_EOF - It needs more bytes in input buffer (src).
*/

SRes LzmaDecode(uint8_t *dest, size_t *destLen, const uint8_t *src, size_t *srcLen,
      const uint8_t *propData, unsigned propSize, ELzmaFinishMode finishMode,
      ELzmaStatus *status, ISzAlloc *alloc);

#ifdef __cplusplus
}
#endif

#endif