//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop

#include "Compress.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
//---------------------------------------------------------------------------
typedef int WINAPI (*TZLibCompress)(void *dest, DWORD *destLen, const void *source, DWORD sourceLen);
typedef int WINAPI (*TZLibUncompress)(void *dest, DWORD *destLen, const void *source, DWORD sourceLen);
//---------------------------------------------------------------------------
bool __fastcall TPCompressM(BYTE **mh, BYTE *data, int length, TCompressMethod cm)
{
  HINSTANCE hLibrary = NULL;
	TZLibCompress ZLibCompress;
  BYTE *dst = NULL;
 	DWORD ls, ld;
  int n, r;

	switch (cm) {
 		case cmZLib:
     	ld = ls = length;
		  hLibrary = LoadLibrary("zlib.dll");
	  	if (hLibrary) {
				ZLibCompress = (TZLibCompress)GetProcAddress(hLibrary, "compress");
 	      if (ZLibCompress) {
 	    	  n = 4;
   	    	while (1) {
     	    	ld = ls/n;
 	      	  if ((*mh = (BYTE *)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, ld+4))==NULL) goto fail;
	  	      r = ZLibCompress(*mh+4, &ld, data, ls);
 		        if (r==0) break;
 	      	  HeapFree(GetProcessHeap(), 0, *mh); *mh = NULL;
     		    if (n==1) {
       		  	ld = ls;
         		  break;
  	        } else n--;
	        }
   	    }
  			FreeLibrary(hLibrary); hLibrary = NULL;
      }
      if (ld<ls) {
		  	memcpy(*mh, &ld, 4);
      } else {
        *mh = (BYTE *)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, ls+4);
		  	memcpy(*mh, &ls, 4);
        memcpy(*mh ,data, ls);
      }
 	  	break;
  	case cmLZW:
     	return false;
   	default:
      if ((*mh = (BYTE *)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, length+4))==NULL) goto fail;
      memcpy(*mh, &length, 4);
      memcpy(*mh+4,data,length);
   		break;
  }
  return true;
fail:
	if (hLibrary) {
    if (dst) HeapFree(GetProcessHeap(), 0, dst);
		FreeLibrary(hLibrary);
  }
	return false;
}

//---------------------------------------------------------------------------

bool __fastcall TPUncompressM(BYTE **mh, BYTE *data, int length, TCompressMethod cm)
{
  HINSTANCE hLibrary = NULL;
	TZLibUncompress ZLibUncompress;
 	DWORD ls, ld;
  BYTE *src = NULL;

	switch (cm) {
 		case cmZLib:
	  	memcpy(&ls, *mh, 4);
	  	ld = length;
      if (ls<ld) {
			  if ((hLibrary = LoadLibrary("zlib.dll"))==0) goto fail;
				if ((ZLibUncompress = (TZLibUncompress)GetProcAddress(hLibrary, "uncompress"))==NULL) goto fail;
    	  ZLibUncompress(data, &ld, (BYTE *)*mh+4, ls);
	      HeapFree(GetProcessHeap(), 0, *mh);
        *mh = NULL;
				FreeLibrary(hLibrary);
      } else {
        memcpy(data,*mh+4,ld);
 	      HeapFree(GetProcessHeap(), 0, *mh);
      }
 	  	break;
  	case cmLZW:
     	return false;
   	default:
      memcpy(&ls, *mh, 4);
		  memcpy(data,*mh+4,ld);
      HeapFree(GetProcessHeap(), 0, *mh);
      *mh = NULL;
      break;
  }
  return true;
fail:
	if (hLibrary) {
		FreeLibrary(hLibrary);
  }
	return false;
}
//---------------------------------------------------------------------------

bool __fastcall TPCompress(HANDLE fh, void *data, int length, TCompressMethod cm)
{
  DWORD dwWrite;
  HINSTANCE hLibrary = NULL;
	TZLibCompress ZLibCompress;
  void *dst = NULL;
 	DWORD ls, ld;
  int n, r;

	switch (cm) {
 		case cmZLib:
     	ld = ls = length;
		  hLibrary = LoadLibrary("zlib.dll");
	  	if (hLibrary) {
				ZLibCompress = (TZLibCompress)GetProcAddress(hLibrary, "compress");
 	      if (ZLibCompress) {
 	    	  n = 4;
   	    	while (1) {
     	    	ld = ls/n;
 	      	  if ((dst = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, ld))==NULL) goto fail;
	  	      r = ZLibCompress(dst, &ld, data, ls);
 		        if (r==0) break;
 	      	  HeapFree(GetProcessHeap(), 0, dst); dst = NULL;
     		    if (n==1) {
       		  	ld = ls;
         		  break;
  	        } else n--;
	        }
   	    }
  			FreeLibrary(hLibrary); hLibrary = NULL;
      }
      if (ld<ls) {
		  	if (!WriteFile(fh, &ld, sizeof(DWORD), &dwWrite, NULL)) goto fail;
		  	if (!WriteFile(fh, dst, ld, &dwWrite, NULL)) goto fail;
      } else {
		  	if (!WriteFile(fh, &ls, sizeof(DWORD), &dwWrite, NULL)) goto fail;
		  	if (!WriteFile(fh, data, ls, &dwWrite, NULL)) goto fail;
      }
      if (dst) HeapFree(GetProcessHeap(), 0, dst);
 	  	break;
  	case cmLZW:
     	return false;
   	default:
	  	if (!WriteFile(fh, data, length, &dwWrite, NULL)) goto fail;
   		break;
  }
  return true;
fail:
	if (hLibrary) {
    if (dst) HeapFree(GetProcessHeap(), 0, dst);
		FreeLibrary(hLibrary);
  }
	return false;
}
//---------------------------------------------------------------------------
bool __fastcall TPUncompress(HANDLE fh, void *data, int length, TCompressMethod cm)
{
  DWORD dwRead;
  HINSTANCE hLibrary = NULL;
	TZLibUncompress ZLibUncompress;
 	DWORD ls, ld;
  void *src = NULL;

	switch (cm) {
 		case cmZLib:
	  	if (!ReadFile(fh, &ls, sizeof(DWORD), &dwRead, NULL)) goto fail;
	  	ld = length;
      if (ls<ld) {
			  if ((hLibrary = LoadLibrary("zlib.dll"))==0) goto fail;
				if ((ZLibUncompress = (TZLibUncompress)GetProcAddress(hLibrary, "uncompress"))==NULL) goto fail;
    	  if ((src = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, ls))==NULL) goto fail;
			  if (!ReadFile(fh, src, ls, &dwRead, NULL)) goto fail;
    	  ZLibUncompress(data, &ld, src, ls);
	      HeapFree(GetProcessHeap(), 0, src);
				FreeLibrary(hLibrary);
      } else {
			  if (!ReadFile(fh, data, ld, &dwRead, NULL)) goto fail;
      }
 	  	break;
  	case cmLZW:
     	return false;
   	default:
		  if (!ReadFile(fh, data, length, &dwRead, NULL)) goto fail;
      break;
  }
  return true;
fail:
	if (hLibrary) {
    if (src) HeapFree(GetProcessHeap(), 0, src);
		FreeLibrary(hLibrary);
  }
	return false;
}
//---------------------------------------------------------------------------