From 23b06ec0945cfc9c09e27584f9dfb4f6f6483f01 Mon Sep 17 00:00:00 2001
From: Tomasz Sowa <t.sowa@ttmath.org>
Date: Fri, 30 Mar 2012 04:24:52 +0000
Subject: [PATCH] changed: in Crypto::Crypt()          MSVC compiler in debug
 mode reports accessing to vector[0] element (assertion)          when the
 vector was empty          (we took only a pointer without dereferencing)     
     now we are using a dummy char object in such a case

git-svn-id: svn://ttmath.org/publicrep/tito/trunk@398 e52654a7-88a9-db11-a3e9-0013d4bc506e
---
 src/crypto.cpp | 38 +++++++++++++++++++++++++++++++++-----
 src/crypto.h   |  4 ++++
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/src/crypto.cpp b/src/crypto.cpp
index 6e8634b..2666c2c 100755
--- a/src/crypto.cpp
+++ b/src/crypto.cpp
@@ -86,6 +86,14 @@ void Crypto::AssignString(const std::wstring & src, std::string & dst, bool clea
 
 
 
+
+Crypto::Crypto()
+{
+	dummy_char = 0;
+}
+
+
+
 bool Crypto::SetAESKey(unsigned char aes_key[32])
 {
 	if( !aes.Key(aes_key, 32) )
@@ -102,7 +110,11 @@ return true;
 void Crypto::Crypt(const std::wstring & in, std::wstring & out)
 {
 	PT::WideToUTF8(in, utf8_str);
-	aes.Encode((const unsigned char*)utf8_str.c_str(), utf8_str.size(), aes_name, uint8_tab);
+
+	if( utf8_str.empty() )
+		aes.Encode(&dummy_char, 0, aes_name, uint8_tab);
+	else
+		aes.Encode((const unsigned char*)utf8_str.c_str(), utf8_str.size(), aes_name, uint8_tab);
 	
 	base64_str.clear();
 
@@ -116,16 +128,32 @@ void Crypto::Crypt(const std::wstring & in, std::wstring & out)
 
 void Crypto::Crypt(const std::string & in, std::string & out)
 {
-	aes.Encode((const unsigned char*)&in[0], in.size(), aes_name, uint8_tab);
-	base64.Encode((const char*)&uint8_tab[0], uint8_tab.size(), out);
+	if( in.empty() )
+		aes.Encode(&dummy_char, 0, aes_name, uint8_tab);
+	else
+		aes.Encode((const unsigned char*)&in[0], in.size(), aes_name, uint8_tab);
+
+	out.clear();
+
+	if( !uint8_tab.empty() )
+		base64.Encode((const char*)&uint8_tab[0], uint8_tab.size(), out);
+
 	Clear();
 }
 
 
 void Crypto::Crypt(const std::vector<char> & in, std::string & out)
 {
-	aes.Encode((const unsigned char*)&in[0], in.size(), aes_name, uint8_tab);
-	base64.Encode((const char*)&uint8_tab[0], uint8_tab.size(), out);
+	if( in.empty() )
+		aes.Encode(&dummy_char, 0, aes_name, uint8_tab);
+	else
+		aes.Encode((const unsigned char*)&in[0], in.size(), aes_name, uint8_tab);
+
+	out.clear();
+
+	if( !uint8_tab.empty() )
+		base64.Encode((const char*)&uint8_tab[0], uint8_tab.size(), out);
+
 	Clear();
 }
 
diff --git a/src/crypto.h b/src/crypto.h
index cadfb7d..d6288b3 100755
--- a/src/crypto.h
+++ b/src/crypto.h
@@ -51,6 +51,7 @@ class Crypto
 {
 public:
 
+	Crypto();
 
 	/*
 		setting AES256 key
@@ -106,6 +107,9 @@ private:
 	std::string base64_str;
 	std::string aes_str;
 
+	// a dummy character used when an input string is empty
+	unsigned char dummy_char;
+
 	void Clear();