VPatch 3.0

git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@4271 212acab6-be3b-0410-9dea-997c60f758d6

Contrib/VPatch/Source/GenPat/ChunkedFile.cpp

@@ -0,0 +1,95 @@
+//---------------------------------------------------------------------------
+// ChunkedFile.cpp
+//---------------------------------------------------------------------------
+//                           -=* VPatch *=-
+//---------------------------------------------------------------------------
+// Copyright (C) 2001-2005 Koen van de Sande / Van de Sande Productions
+//---------------------------------------------------------------------------
+// Website: http://www.tibed.net/vpatch
+//
+// This software is provided 'as-is', without any express or implied
+// warranty.  In no event will the authors be held liable for any damages
+// arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented; you must not
+//    claim that you wrote the original software. If you use this software
+//    in a product, an acknowledgment in the product documentation would be
+//    appreciated but is not required.
+// 2. Altered source versions must be plainly marked as such, and must not be
+//    misrepresented as being the original software.
+// 3. This notice may not be removed or altered from any source distribution.
+
+
+#include "ChunkedFile.h"
+
+using namespace std;
+
+      ChunkedFile::ChunkedFile(bistream& f, TFileOffset fSize, TFileOffset chunkSize) :
+        chunks(NULL) {
+
+        chunkCount = fSize / chunkSize;
+        cout << "[ChunkedFile] Filesize of " << static_cast<unsigned int>(fSize) << " gives " << static_cast<unsigned int>(chunkCount) << " chunks.\n";
+
+        cout << "[ChunkedFile] Memory to be used by those chunks: " << sizeof(FileChunk) * chunkCount << " bytes...";
+        if(chunkCount == 0) {
+          chunks = NULL;
+          return;
+        }
+        chunks = new FileChunk[chunkCount];
+        cout << " allocated.\n";
+
+        unsigned char* data = new unsigned char[chunkSize];
+        for(TFileOffset i = 0; i < chunkCount; i++) {
+          f.read(reinterpret_cast<char*>(data),chunkSize);
+          chunks[i].offset = i * chunkSize;
+          calculateChecksum(data,chunkSize,chunks[i].checksum);
+        }
+        delete[] data;
+
+        cout << "[ChunkedFile] Sorting chunks... ";
+        std::sort(chunks,chunks + chunkCount);
+        cout << "done.\n";
+      }
+
+
+bool ChunkedFile::search(TChunkChecksum key, TFileOffset* start) {
+   // function:
+   //   Searches sortedArray[first]..sortedArray[last] for key.
+   // returns: index of the matching element if it finds key,
+   //         otherwise  -(index where it could be inserted)-1.
+   // parameters:
+   //   sortedArray in  array of sorted (ascending) values.
+   //   first, last in  lower and upper subscript bounds
+   //   key         in  value to search for.
+   // returns:
+   //   index of key, or -insertion_position -1 if key is not
+   //                 in the array. This value can easily be
+   //                 transformed into the position to insert it.
+  if(chunkCount == 0) return false;
+  int first = 0;
+  int last = chunkCount - 1;
+  while (first <= last) {
+    int mid = (first + last) / 2;  // compute mid point.
+    if(key == chunks[mid].checksum) {
+      while(true) {
+        if(mid == 0) break;
+        mid--;
+        if(!(key == chunks[mid].checksum)) {
+          mid++;
+          break;
+        }
+      }
+      *start = mid;
+      return true;     // found it. return position
+    }
+    if (key < chunks[mid].checksum)
+      last = mid - 1; // repeat search in bottom half.
+    else
+      first = mid + 1;  // repeat search in top half.
+  }
+  return false;    // failed to find key
+}