Add BytePtr and ConstBytePtr overloads for SecByteBlock (GH #890)

Filelist.txt

@@ -308,6 +308,7 @@ scrypt.h
 seal.cpp
 seal.h
 secblock.h
+secblockfwd.h
 seckey.h
 seed.cpp
 seed.h

asn.cpp

@@ -6,7 +6,9 @@
 
 #ifndef CRYPTOPP_IMPORTS
 
+#include "cryptlib.h"
 #include "asn.h"
+#include "misc.h"
 
 #include <iostream>
 #include <iomanip>
@@ -15,7 +17,6 @@
 
 NAMESPACE_BEGIN(CryptoPP)
 
-/// DER Length
 size_t DERLengthEncode(BufferedTransformation &bt, lword length)
 {
 	size_t i=0;
@@ -129,7 +130,7 @@ size_t BERDecodeOctetString(BufferedTransformation &bt, SecByteBlock &str)
 		BERDecodeError();
 
 	str.New(bc);
-	if (bc != bt.Get(str, bc))
+	if (bc != bt.Get(BytePtr(str), bc))
 		BERDecodeError();
 	return bc;
 }
@@ -181,7 +182,7 @@ size_t BERDecodeTextString(BufferedTransformation &bt, SecByteBlock &str, byte a
 		BERDecodeError();
 
 	str.resize(bc);
-	if (bc != bt.Get(str, str.size()))
+	if (bc != bt.Get(BytePtr(str), BytePtrSize(str)))
 		BERDecodeError();
 
 	return bc;
@@ -227,7 +228,7 @@ size_t BERDecodeDate(BufferedTransformation &bt, SecByteBlock &str, byte asnTag)
 		BERDecodeError();
 
 	str.resize(bc);
-	if (bc != bt.Get(str, str.size()))
+	if (bc != bt.Get(BytePtr(str), BytePtrSize(str)))
 		BERDecodeError();
 
 	return bc;
@@ -263,7 +264,7 @@ size_t BERDecodeBitString(BufferedTransformation &bt, SecByteBlock &str, unsigne
 		BERDecodeError();
 	unusedBits = unused;
 	str.resize(bc-1);
-	if ((bc-1) != bt.Get(str, bc-1))
+	if ((bc-1) != bt.Get(BytePtr(str), bc-1))
 		BERDecodeError();
 	return bc-1;
 }

cryptlib.vcxproj

@@ -531,6 +531,7 @@
     <ClInclude Include="scrypt.h" />
     <ClInclude Include="seal.h" />
     <ClInclude Include="secblock.h" />
+    <ClInclude Include="secblockfwd.h" />
     <ClInclude Include="seckey.h" />
     <ClInclude Include="seed.h" />
     <ClInclude Include="serpent.h" />

cryptlib.vcxproj.filters

@@ -942,6 +942,9 @@
     <ClInclude Include="secblock.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="secblockfwd.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
     <ClInclude Include="seckey.h">
       <Filter>Header Files</Filter>
     </ClInclude>

misc.cpp

@@ -20,6 +20,28 @@
 
 NAMESPACE_BEGIN(CryptoPP)
 
+byte* BytePtr(SecByteBlock& str)
+{
+	// Caller wants a writeable pointer
+	CRYPTOPP_ASSERT(str.empty() == false);
+
+	if (str.empty())
+		return NULLPTR;
+	return reinterpret_cast<byte*>(str.data());
+}
+
+const byte* ConstBytePtr(const SecByteBlock& str)
+{
+	if (str.empty())
+		return NULLPTR;
+	return reinterpret_cast<const byte*>(str.data());
+}
+
+size_t BytePtrSize(const SecByteBlock& str)
+{
+	return str.size();
+}
+
 void xorbuf(byte *buf, const byte *mask, size_t count)
 {
 	CRYPTOPP_ASSERT(buf != NULLPTR);

misc.h

@@ -7,6 +7,7 @@
 #define CRYPTOPP_MISC_H
 
 #include "cryptlib.h"
+#include "secblockfwd.h"
 #include "smartptr.h"
 #include "stdcpp.h"
 #include "trap.h"
@@ -432,6 +433,7 @@ inline size_t PtrByteDiff(const PTR pointer1, const PTR pointer2)
 /// \param str std::string
 /// \details BytePtr returns NULL pointer for an empty string.
 /// \return Pointer to the first element of a string
+/// \since Crypto++ 8.0
 inline byte* BytePtr(std::string& str)
 {
 	// Caller wants a writeable pointer
@@ -442,16 +444,32 @@ inline byte* BytePtr(std::string& str)
 	return reinterpret_cast<byte*>(&str[0]);
 }
 
+/// \brief Pointer to the first element of a string
+/// \param str SecByteBlock
+/// \details BytePtr returns NULL pointer for an empty string.
+/// \return Pointer to the first element of a string
+/// \since Crypto++ 8.3
+byte* BytePtr(SecByteBlock& str);
+
 /// \brief Const pointer to the first element of a string
 /// \param str std::string
 /// \details ConstBytePtr returns non-NULL pointer for an empty string.
 /// \return Pointer to the first element of a string
+/// \since Crypto++ 8.0
 inline const byte* ConstBytePtr(const std::string& str)
 {
-	// Use c_str() so a pointer is always available
-	return reinterpret_cast<const byte*>(str.c_str());
+	if (str.empty())
+		return NULLPTR;
+	return reinterpret_cast<const byte*>(&str[0]);
 }
 
+/// \brief Const pointer to the first element of a string
+/// \param str SecByteBlock
+/// \details ConstBytePtr returns non-NULL pointer for an empty string.
+/// \return Pointer to the first element of a string
+/// \since Crypto++ 8.3
+const byte* ConstBytePtr(const SecByteBlock& str);
+
 /// \brief Size of a string
 /// \param str std::string
 /// \return size of a string
@@ -460,6 +478,11 @@ inline size_t BytePtrSize(const std::string& str)
 	return str.size();
 }
 
+/// \brief Size of a string
+/// \param str SecByteBlock
+/// \return size of a string
+size_t BytePtrSize(const SecByteBlock& str);
+
 #if (!__STDC_WANT_SECURE_LIB__ && !defined(_MEMORY_S_DEFINED)) || defined(CRYPTOPP_WANT_SECURE_LIB)
 
 /// \brief Bounds checking replacement for memcpy()

secblockfwd.h

@@ -0,0 +1,29 @@
+// secblockfwd.h - written and placed in the public domain by Jeffrey Walton
+
+/// \file secblockfwd.h
+/// \brief Forward declarations for SecBlock
+/// \details secblock.h and misc.h have a circular dependency. secblockfwd.h
+///  allows the library to sidestep the circular dependency, and reference
+///  SecBlock classes without the full implementation.
+/// \since Crypto++ 8.3
+
+#ifndef CRYPTOPP_SECBLOCKFWD_H
+#define CRYPTOPP_SECBLOCKFWD_H
+
+#include "config.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+template <class T, class A>
+class SecBlock;
+
+template <class T, bool A>
+class AllocatorWithCleanup;
+
+typedef SecBlock<byte, AllocatorWithCleanup<byte, false> > SecByteBlock;
+typedef SecBlock<word, AllocatorWithCleanup<word, false> > SecWordBlock;
+typedef SecBlock<byte, AllocatorWithCleanup<byte,  true> > AlignedSecByteBlock;
+
+NAMESPACE_END
+
+#endif  // CRYPTOPP_SECBLOCKFWD_H