UncompressLoader.c

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#include                "libFireBird.h"
#include                "FBLib_compression.h"
 
// UncompressLoader() is a function wrapper that decodes data blocks
// encoded with AR002 algorithm until the uncompressed size field
// is set to 0xfefe. This is normaly used for the Loader or the Firmware
// inside of the flash memory.
// The expected block structure is as follows:
// 0 - uncompressed size (word)
// 2 - compressed size (word)
// 4 .. - compressed data (byte array)
dword UncompressLoader(byte *pSrc, byte *pDest, void *pPercentFinishedCallback)
{
  TRACEENTER();
 
  word                  compSize, uncompSize;
  dword                 outSize = 0, NrBlocks = 0, CurrentBlock = 0;
  byte                  *OrigpSrc;
 
  if(!pSrc || !pDest)
  {
    TRACEEXIT();
    return 0;
  }
 
  //PercentFinishedCallback is called for every block. PercentFinished contains a number between 0 and 100
  void (*PercentFinishedCallback) (dword PercentFinished) = pPercentFinishedCallback;
 
  OrigpSrc   = pSrc;
  uncompSize = LOAD_WORDLE(pSrc + 0);
  compSize   = LOAD_WORDLE(pSrc + 2);
 
  //Count the number of blocks
  while(uncompSize != 0xfefe)
  {
    NrBlocks++;
 
    if(uncompSize > 0x8000)
    {
      //Uncompressed data block size too large
      TRACEEXIT();
 
      return 0;
    }
 
    pSrc += 4;
    pSrc += compSize;
 
    uncompSize = LOAD_WORDLE(pSrc + 0);
    compSize   = LOAD_WORDLE(pSrc + 2);
  }
 
  pSrc = OrigpSrc;
  uncompSize = LOAD_WORDLE(pSrc + 0);
  compSize   = LOAD_WORDLE(pSrc + 2);
 
  while(uncompSize != 0xfefe)
  {
    if(PercentFinishedCallback) PercentFinishedCallback(CurrentBlock * 100 / NrBlocks);
    CurrentBlock++;
 
    if(uncompSize > 0x8000)
    {
      //Uncompressed data block size too large
      TRACEEXIT();
 
      return 0;
    }
 
    pSrc += 4;
 
    if(compSize == uncompSize)
    {
      //data not compressed, copy it directly
      if(pDest) memcpy(pDest, pSrc, uncompSize);
    }
    else
    {
      // compressed data, uncompress it
      if(!UncompressBlock(pSrc, compSize, pDest, uncompSize))
      {
        //Uncompress has failed
        TRACEEXIT();
        return 0;
      }
    }
 
    if(pDest) pDest += uncompSize;
    pSrc += compSize;
    outSize += uncompSize;
 
    uncompSize = LOAD_WORDLE(pSrc + 0);
    compSize   = LOAD_WORDLE(pSrc + 2);
  }
  if(PercentFinishedCallback) PercentFinishedCallback(100);
 
  TRACEEXIT();
  return outSize;
}