/*============================================================================
  CMake - Cross Platform Makefile Generator
  Copyright 2000-2009 Kitware, Inc., Insight Software Consortium

  Distributed under the OSI-approved BSD License (the "License");
  see accompanying file Copyright.txt for details.

  This software is distributed WITHOUT ANY WARRANTY; without even the
  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the License for more information.
============================================================================*/
#include "cmCryptoHash.h"

#include <cmsys/MD5.h>
#include <cmsys/FStream.hxx>
#include "cm_sha2.h"

//----------------------------------------------------------------------------
cmsys::auto_ptr<cmCryptoHash> cmCryptoHash::New(const char* algo)
{
  if(strcmp(algo,"MD5") == 0)
    { return cmsys::auto_ptr<cmCryptoHash>(new cmCryptoHashMD5); }
  else if(strcmp(algo,"SHA1") == 0)
    { return cmsys::auto_ptr<cmCryptoHash>(new cmCryptoHashSHA1); }
  else if(strcmp(algo,"SHA224") == 0)
    { return cmsys::auto_ptr<cmCryptoHash>(new cmCryptoHashSHA224); }
  else if(strcmp(algo,"SHA256") == 0)
    { return cmsys::auto_ptr<cmCryptoHash>(new cmCryptoHashSHA256); }
  else if(strcmp(algo,"SHA384") == 0)
    { return cmsys::auto_ptr<cmCryptoHash>(new cmCryptoHashSHA384); }
  else if(strcmp(algo,"SHA512") == 0)
    { return cmsys::auto_ptr<cmCryptoHash>(new cmCryptoHashSHA512); }
  else
    { return cmsys::auto_ptr<cmCryptoHash>(0); }
}

//----------------------------------------------------------------------------
std::string cmCryptoHash::HashString(const char* input)
{
  this->Initialize();
  this->Append(reinterpret_cast<unsigned char const*>(input),
               static_cast<int>(strlen(input)));
  return this->Finalize();
}

//----------------------------------------------------------------------------
std::string cmCryptoHash::HashFile(const char* file)
{
  cmsys::ifstream fin(file, std::ios::in | cmsys_ios_binary);
  if(!fin)
    {
    return "";
    }

  this->Initialize();

  // Should be efficient enough on most system:
  cm_sha2_uint64_t buffer[512];
  char* buffer_c = reinterpret_cast<char*>(buffer);
  unsigned char const* buffer_uc =
    reinterpret_cast<unsigned char const*>(buffer);
  // This copy loop is very sensitive on certain platforms with
  // slightly broken stream libraries (like HPUX).  Normally, it is
  // incorrect to not check the error condition on the fin.read()
  // before using the data, but the fin.gcount() will be zero if an
  // error occurred.  Therefore, the loop should be safe everywhere.
  while(fin)
    {
    fin.read(buffer_c, sizeof(buffer));
    if(int gcount = static_cast<int>(fin.gcount()))
      {
      this->Append(buffer_uc, gcount);
      }
    }
  if(fin.eof())
    {
    return this->Finalize();
    }
  return "";
}

//----------------------------------------------------------------------------
cmCryptoHashMD5::cmCryptoHashMD5(): MD5(cmsysMD5_New())
{
}

//----------------------------------------------------------------------------
cmCryptoHashMD5::~cmCryptoHashMD5()
{
  cmsysMD5_Delete(this->MD5);
}

//----------------------------------------------------------------------------
void cmCryptoHashMD5::Initialize()
{
  cmsysMD5_Initialize(this->MD5);
}

//----------------------------------------------------------------------------
void cmCryptoHashMD5::Append(unsigned char const* buf, int sz)
{
  cmsysMD5_Append(this->MD5, buf, sz);
}

//----------------------------------------------------------------------------
std::string cmCryptoHashMD5::Finalize()
{
  char md5out[32];
  cmsysMD5_FinalizeHex(this->MD5, md5out);
  return std::string(md5out, 32);
}


#define cmCryptoHash_SHA_CLASS_IMPL(SHA) \
cmCryptoHash##SHA::cmCryptoHash##SHA(): SHA(new SHA_CTX) {} \
cmCryptoHash##SHA::~cmCryptoHash##SHA() { delete this->SHA; } \
void cmCryptoHash##SHA::Initialize() { SHA##_Init(this->SHA); } \
void cmCryptoHash##SHA::Append(unsigned char const* buf, int sz) \
{ SHA##_Update(this->SHA, buf, sz); } \
std::string cmCryptoHash##SHA::Finalize() \
{ \
  char out[SHA##_DIGEST_STRING_LENGTH]; \
  SHA##_End(this->SHA, out); \
  return std::string(out, SHA##_DIGEST_STRING_LENGTH-1); \
}

cmCryptoHash_SHA_CLASS_IMPL(SHA1)
cmCryptoHash_SHA_CLASS_IMPL(SHA224)
cmCryptoHash_SHA_CLASS_IMPL(SHA256)
cmCryptoHash_SHA_CLASS_IMPL(SHA384)
cmCryptoHash_SHA_CLASS_IMPL(SHA512)