/*****************************************************************************
*  Copyright 2005 Alt-N Technologies, Ltd. 
*
*  Licensed under the Apache License, Version 2.0 (the "License"); 
*  you may not use this file except in compliance with the License. 
*  You may obtain a copy of the License at 
*
*      http://www.apache.org/licenses/LICENSE-2.0 
*
*  This code incorporates intellectual property owned by Yahoo! and licensed 
*  pursuant to the Yahoo! DomainKeys Patent License Agreement.
*
*  Unless required by applicable law or agreed to in writing, software 
*  distributed under the License is distributed on an "AS IS" BASIS, 
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
*  See the License for the specific language governing permissions and 
*  limitations under the License.
*
*  Changes done by ¢feh@fehcom.de obeying the above license
*
*****************************************************************************/
#include <string.h>
#include <algorithm>
#include "dkim.h"
#include "dkimbase.h"


CDKIMBase::CDKIMBase()
{
  m_From = NULL;
  m_Sender = NULL;
  m_hTag = NULL;
  m_hTagSize = 0;
  m_hTagPos = 0;
  m_Line = NULL;
  m_LineSize = 0;
  m_LinePos = 0;
  m_InHeaders = true;
}

CDKIMBase::~CDKIMBase()  // delete
{
  Free(m_Line);
  Free(m_From);
  Free(m_Sender);
  Free(m_hTag);
}

int CDKIMBase::Init(void)
{
  return DKIM_SUCCESS;
}

////////////////////////////////////////////////////////////////////////////////
// 
// Alloc - allocate buffer
//
////////////////////////////////////////////////////////////////////////////////
int CDKIMBase::Alloc(char*& szBuffer,int nRequiredSize)
{
  szBuffer = new char[nRequiredSize];

  return (szBuffer == NULL) ? DKIM_OUT_OF_MEMORY : DKIM_SUCCESS;
}

////////////////////////////////////////////////////////////////////////////////
// 
// ReAlloc - extend buffer if necessary, leaving room for future expansion
//
////////////////////////////////////////////////////////////////////////////////
int CDKIMBase::ReAlloc(char*& szBuffer,int& nBufferSize,int nRequiredSize)
{
  if (nRequiredSize > nBufferSize) {
    char* newp;
    int nNewSize = nRequiredSize + BUFFER_ALLOC_INCREMENT; 

    if (Alloc(newp,nNewSize) == DKIM_SUCCESS) {
      if (szBuffer != NULL && nBufferSize > 0) {
        memcpy(newp,szBuffer,nBufferSize);
        delete[] szBuffer;
      }
      szBuffer = newp;
      nBufferSize  = nNewSize;
    } else {
      return DKIM_OUT_OF_MEMORY; // memory alloc error!
    }
  }

  return DKIM_SUCCESS;
}

////////////////////////////////////////////////////////////////////////////////
// 
// Process - split buffers into lines without any CRs or LFs at the end.
//
////////////////////////////////////////////////////////////////////////////////
void CDKIMBase::Free(char* szBuffer)
{
  if (szBuffer)
    delete[] szBuffer;
}

////////////////////////////////////////////////////////////////////////////////
// 
// Process - split buffers into lines without any CRs or LFs at the end.
//
////////////////////////////////////////////////////////////////////////////////
int CDKIMBase::Process(const char* szBuffer,int nBufLength,bool bEOF)
{ const char* p = szBuffer;
  const char* e = szBuffer + nBufLength;

  while (p < e) {
    if (*p != '\n' || m_LinePos == 0 || m_Line[m_LinePos - 1] != '\r') {
      // add char to line
      if (m_LinePos >= m_LineSize) {
        int nRet = ReAlloc(m_Line,m_LineSize,m_LinePos + 1);
        if (nRet != DKIM_SUCCESS) return nRet;
      }
      m_Line[m_LinePos++] = *p;
    } else {
      // back up past the CR
      m_LinePos--;

      if (m_InHeaders) {
        // process header line
        if (m_LinePos == 0) {
          m_InHeaders = false;
          int Result = ProcessHeaders();
          if (Result != DKIM_SUCCESS)
            return Result;
        } else {
          // append the header to the headers list
          if (m_Line[0] != ' ' && m_Line[0] != '\t') {
            HeaderList.push_back(string(m_Line,m_LinePos));
//            fprintf(stderr," dkimbase.cpp:Process:Input:  %s \n",m_Line);
          } else {
            if (!HeaderList.empty()) {
              HeaderList.back().append("\r\n",2).append(m_Line,m_LinePos);
            } else {
              // no header to append to...
            }
          }
        }
      } else {
        // process body line
        int Result = ProcessBody(m_Line,m_LinePos,bEOF);
        if (Result != DKIM_SUCCESS) {
          m_LinePos = 0;
          return Result;
        }
      }

      m_LinePos = 0;
    }

    p++;
  }

  return DKIM_SUCCESS;
}

////////////////////////////////////////////////////////////////////////////////
// 
// ProcessFinal - process leftovers if stopping before the body or mid-line
//
////////////////////////////////////////////////////////////////////////////////
int CDKIMBase::ProcessFinal(void)
{
  if (m_LinePos > 0) {
    Process("\r\n",2,true);
  }

  if (m_InHeaders) {
    m_InHeaders = false;
    ProcessHeaders();
    /* type conversion should be safe as length is zero */
    ProcessBody((char *)"",0,true);
  }

  return DKIM_SUCCESS;
}

////////////////////////////////////////////////////////////////////////////////
// 
// ProcessHeaders - process the headers (to be implemented by derived class)
//
////////////////////////////////////////////////////////////////////////////////
int CDKIMBase::ProcessHeaders()
{
  return DKIM_SUCCESS;
}

////////////////////////////////////////////////////////////////////////////////
// 
// ProcessBody - process body line (to be implemented by derived class)
//
////////////////////////////////////////////////////////////////////////////////
int CDKIMBase::ProcessBody(char* szBuffer, int nBufLength, bool bEOF)
{
  return DKIM_SUCCESS;
}

////////////////////////////////////////////////////////////////////////////////
// 
// RemoveSWSP - remove streaming white space from buffer/string inline
//
////////////////////////////////////////////////////////////////////////////////

struct isswsp
{
  bool operator()(char ch) { return(ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n'); }
};

void CDKIMBase::RemoveSWSP(char* szBuffer)
{
  *remove_if(szBuffer,szBuffer + strlen(szBuffer),isswsp()) = '\0';
}

void CDKIMBase::RemoveSWSP(char* pBuffer,int& nBufLength)
{
  nBufLength = remove_if(pBuffer,pBuffer+nBufLength,isswsp()) - pBuffer;
}

void CDKIMBase::RemoveSWSP(string& sBuffer)
{
  sBuffer.erase(remove_if(sBuffer.begin(),sBuffer.end(),isswsp()),sBuffer.end());
}

//////////////////////////////////////////////////////////////////////////////////////////
// 
// CompressSWSP - compress streaming white space into single spaces from buffer/string inline
//
//////////////////////////////////////////////////////////////////////////////////////////

void CDKIMBase::CompressSWSP(char* pBuffer,int& nBufLength)
{
  char* pSrc = pBuffer;
  char* pDst = pBuffer;
  char* pEnd = pBuffer + nBufLength;

  while (pSrc != pEnd) {
    if (isswsp()(*pSrc)) {

      do {
        ++pSrc;
      } while (pSrc != pEnd && isswsp()(*pSrc));

      if (pSrc == pEnd)
        break;

      *pDst++ = ' ';
    }

    *pDst++ = *pSrc++;
  }

  nBufLength = pDst - pBuffer;
}

void CDKIMBase::CompressSWSP(string& sBuffer)
{
  string::iterator iSrc = sBuffer.begin();
  string::iterator iDst = sBuffer.begin();
  string::iterator iEnd = sBuffer.end();

  while (iSrc != iEnd) {
    if (isswsp()(*iSrc)) {

      do {
        ++iSrc;
      } while (iSrc != iEnd && isswsp()(*iSrc));

      if (iSrc == iEnd)
        break;

      *iDst++ = ' ';
    }

    *iDst++ = *iSrc++;
  }

  sBuffer.erase(iDst, iEnd);
}

//////////////////////////////////////////////////////////////////////////////////////////
// 
// RelaxHeader - relax a header field (lower case the name, remove swsp before and after :)
//
// modified 4/21/06 STB to remove white space before colon
//
//////////////////////////////////////////////////////////////////////////////////////////

string CDKIMBase::RelaxHeader(const string& sHeader)
{
  string sTemp = sHeader;

  CompressSWSP(sTemp);

  string::size_type cpos = sTemp.find(':');

  if (cpos == string::npos) {
    // no colon?!
  } else {
    // lower case the header field name
    for (unsigned i = 0; i < cpos; i++) {
      if (sTemp[i] >= 'A' && sTemp[i] <= 'Z')
        sTemp[i] += 'a'-'A';
    }

    // remove the space after the :
    if (cpos + 1 < sTemp.length() && sTemp[cpos+1] == ' ')
      sTemp.erase(cpos + 1, 1);

    // remove the space before the :
    if (cpos > 0 && sTemp[cpos - 1] == ' ')
      sTemp.erase(cpos - 1,1);
  }

  return sTemp;
}