From 6023520b8150f43f68c9a3454b4afecd4ea2ac1a Mon Sep 17 00:00:00 2001
From: Kirill Volinsky <mataes2007@gmail.com>
Date: Mon, 11 Feb 2013 15:47:08 +0000
Subject: added checking crc sum

git-svn-id: http://svn.miranda-ng.org/main/trunk@3555 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c
---
 plugins/PluginUpdater/src/Utils.cpp | 86 +++++++++++++++++++++++++++++++++++--
 1 file changed, 82 insertions(+), 4 deletions(-)

(limited to 'plugins/PluginUpdater/src/Utils.cpp')

diff --git a/plugins/PluginUpdater/src/Utils.cpp b/plugins/PluginUpdater/src/Utils.cpp
index 1946babfca..38d46a6c75 100644
--- a/plugins/PluginUpdater/src/Utils.cpp
+++ b/plugins/PluginUpdater/src/Utils.cpp
@@ -122,7 +122,73 @@ void LoadOptions()
 	opts.bUpdateIcons = DBGetContactSettingByte(NULL, MODNAME, "UpdateIcons", DEFAULT_UPDATEICONS);
 }
 
-BOOL DownloadFile(LPCTSTR tszURL, LPCTSTR tszLocal)
+ULONG crc32_table[256];
+ULONG ulPolynomial = 0x04c11db7;
+
+//////////////////////////////////////////////////////////////
+// Reflection is a requirement for the official CRC-32 standard.
+// You can create CRCs without it, but they won't conform to the standard.
+//////////////////////////////////////////////////////////////////////////
+
+ULONG Reflect(ULONG ref, char ch)
+{
+	// Used only by Init_CRC32_Table()
+	ULONG value(0);
+
+	// Swap bit 0 for bit 7
+	// bit 1 for bit 6, etc.
+	for(int i = 1; i < (ch + 1); i++)
+	{
+		if(ref & 1)
+			value |= 1 << (ch - i);
+		ref >>= 1;
+	}
+	return value;
+}
+
+void InitCrcTable()
+{
+	// 256 values representing ASCII character codes.
+	for(int i = 0; i <= 0xFF; i++)
+	{
+		crc32_table[i] = Reflect(i, 8) << 24;
+		for (int j = 0; j < 8; j++)
+			crc32_table[i] = (crc32_table[i] << 1) ^ (crc32_table[i] & (1 << 31) ? ulPolynomial : 0);
+		crc32_table[i] = Reflect(crc32_table[i], 32);
+	}
+}
+
+int Get_CRC(unsigned char* buffer, ULONG bufsize)
+{
+	ULONG  crc(0xffffffff);
+	int len;
+	len = bufsize;
+	// Save the text in the buffer.
+
+	// Perform the algorithm on each character
+	// in the string, using the lookup table values.
+
+	for(int i = 0; i < len; i++)
+		crc = (crc >> 8) ^ crc32_table[(crc & 0xFF) ^ buffer[i]];
+    
+	// Exclusive OR the result with the beginning value.
+	return crc^0xffffffff;
+}
+
+long FileSize(FILE *input)
+{
+
+  long fileSizeBytes;
+  fseek(input, 0, SEEK_END);
+  fileSizeBytes = ftell(input);
+  fseek(input, 0, SEEK_SET);
+
+  return fileSizeBytes;
+ 
+
+}
+
+BOOL DownloadFile(LPCTSTR tszURL, LPCTSTR tszLocal, int CRCsum)
 {
 	DWORD dwBytes;
 
@@ -156,7 +222,13 @@ BOOL DownloadFile(LPCTSTR tszURL, LPCTSTR tszLocal)
 				// write the downloaded file firectly
 				WriteFile(hFile, pReply->pData, (DWORD)pReply->dataLength, &dwBytes, NULL);
 				CloseHandle(hFile);
-				ret = true;
+				if (CRCsum) {
+					InitCrcTable();
+					int crc = Get_CRC((unsigned char*)pReply->pData, (long)dwBytes);
+					if (crc == CRCsum)
+						ret = true;
+				} else
+					ret = true;
 			}
 			else {
 				// try to write it via PU stub
@@ -167,11 +239,17 @@ BOOL DownloadFile(LPCTSTR tszURL, LPCTSTR tszLocal)
 					WriteFile(hFile, pReply->pData, (DWORD)pReply->dataLength, &dwBytes, NULL);
 					CloseHandle(hFile);
 					SafeMoveFile(tszTempFile, tszLocal);
-					ret = true;
+					if (CRCsum) {
+						InitCrcTable();
+						int crc = Get_CRC((unsigned char*)pReply->pData, (long)dwBytes);
+						if (crc == CRCsum)
+							ret = true;
+					} else
+						ret = true;
 				}
 			}
 		}
-		CallService(MS_NETLIB_FREEHTTPREQUESTSTRUCT,0,(LPARAM)pReply);
+		CallService(MS_NETLIB_FREEHTTPREQUESTSTRUCT, 0, (LPARAM)pReply);
 	}
 
 	mir_free(szUrl);
-- 
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