/*============================================================================
  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 "cmHexFileConverter.h"

#include <stdio.h>
#include <string.h>

#define INTEL_HEX_MIN_LINE_LENGTH     (1+8        +2)
#define INTEL_HEX_MAX_LINE_LENGTH     (1+8+(256*2)+2)
#define MOTOROLA_SREC_MIN_LINE_LENGTH (2+2+4        +2)
#define MOTOROLA_SREC_MAX_LINE_LENGTH (2+2+8+(256*2)+2)

// might go to SystemTools ?
static bool cm_IsHexChar(char c)
{
  return (((c >= '0') && (c <= '9'))
         || ((c >= 'a') && (c <= 'f'))
         || ((c >= 'A') && (c <= 'F')));
}

static unsigned int ChompStrlen(const char* line)
{
  if (line == 0)
    {
    return 0;
    }
  unsigned int  length = static_cast<unsigned int>(strlen(line));
  if ((line[length-1] == '\n') || (line[length-1] == '\r'))
    {
    length--;
    }
  if ((line[length-1] == '\n') || (line[length-1] == '\r'))
    {
    length--;
    }
  return length;
}

static bool OutputBin(FILE* file, const char * buf,
                      unsigned int startIndex, unsigned int stopIndex)
{
  bool success = true;
  char hexNumber[3];
  hexNumber[2] = '\0';
  char outBuf[256];
  unsigned int outBufCount = 0;
  for (unsigned int i = startIndex; i < stopIndex; i += 2)
    {
    hexNumber[0] = buf[i];
    hexNumber[1] = buf[i+1];
    unsigned int convertedByte = 0;
    if (sscanf(hexNumber, "%x", &convertedByte) != 1)
      {
      success = false;
      break;
      }
    outBuf[outBufCount] = static_cast<char>(convertedByte & 0xff);
    outBufCount++;
    }
  if (success)
    {
    success = (fwrite(outBuf, 1, outBufCount, file)==outBufCount);
    }
  return success;
}

// see http://www.die.net/doc/linux/man/man5/srec.5.html
static bool ConvertMotorolaSrecLine(const char* buf, FILE* outFile)
{
  unsigned int slen = ChompStrlen(buf);
  if ((slen < MOTOROLA_SREC_MIN_LINE_LENGTH)
       || (slen > MOTOROLA_SREC_MAX_LINE_LENGTH))
    {
    return false;
    }

  // line length must be even
  if (slen % 2 == 1)
    {
    return false;
    }

  if (buf[0] != 'S')
    {
    return false;
    }

  unsigned int dataStart = 0;
  // ignore extra address records
  if ((buf[1] == '5') || (buf[1] == '7') || (buf[1] == '8') || (buf[1] == '9'))
    {
    return true;
    }
  else if (buf[1] == '1')
    {
    dataStart = 8;
    }
  else if (buf[1] == '2')
    {
    dataStart = 10;
    }
  else if (buf[1] == '3')
    {
    dataStart = 12;
    }
  else // unknown record type
    {
    return false;
    }

  // ignore the last two bytes  (checksum)
  return OutputBin(outFile, buf, dataStart, slen - 2);
}

// see http://en.wikipedia.org/wiki/Intel_hex
static bool ConvertIntelHexLine(const char* buf, FILE* outFile)
{
  unsigned int slen = ChompStrlen(buf);
  if ((slen < INTEL_HEX_MIN_LINE_LENGTH)
       || (slen > INTEL_HEX_MAX_LINE_LENGTH))
    {
    return false;
    }

  // line length must be odd
  if (slen % 2 == 0)
    {
    return false;
    }

  if ((buf[0] != ':') || (buf[7] != '0'))
    {
    return false;
    }

  unsigned int dataStart = 0;
  if ((buf[8] == '0') || (buf[8] == '1'))
    {
    dataStart = 9;
    }
  // ignore extra address records
  else if ((buf[8] == '2') || (buf[8] == '3') || (buf[8] == '4')
            || (buf[8] == '5'))
    {
    return true;
    }
  else  // unknown record type
    {
    return false;
    }

// ignore the last two bytes  (checksum)
  return OutputBin(outFile, buf, dataStart, slen - 2);
}

cmHexFileConverter::FileType cmHexFileConverter::DetermineFileType(
                                                        const char* inFileName)
{
  char buf[1024];
  FILE* inFile = cmsys::SystemTools::Fopen(inFileName, "rb");
  if (inFile == 0)
    {
    return Binary;
    }

  if(!fgets(buf, 1024, inFile))
    {
    buf[0] = 0;
    }
  fclose(inFile);
  FileType type = Binary;
  unsigned int minLineLength = 0;
  unsigned int maxLineLength = 0;
  if (buf[0] == ':') // might be an intel hex file
    {
    type = IntelHex;
    minLineLength = INTEL_HEX_MIN_LINE_LENGTH;
    maxLineLength = INTEL_HEX_MAX_LINE_LENGTH;
    }
  else if (buf[0] == 'S') // might be a motorola srec file
    {
    type = MotorolaSrec;
    minLineLength = MOTOROLA_SREC_MIN_LINE_LENGTH;
    maxLineLength = MOTOROLA_SREC_MAX_LINE_LENGTH;
    }
  else
    {
    return Binary;
    }

  unsigned int slen = ChompStrlen(buf);
  if ((slen < minLineLength) || (slen > maxLineLength))
    {
    return Binary;
    }

  for (unsigned int i = 1; i < slen; i++)
    {
    if (!cm_IsHexChar(buf[i]))
      {
      return Binary;
      }
    }
  return type;
}

bool cmHexFileConverter::TryConvert(const char* inFileName,
                                    const char* outFileName)
{
  FileType type = DetermineFileType(inFileName);
  if (type == Binary)
    {
    return false;
    }

  // try to open the file
  FILE* inFile = cmsys::SystemTools::Fopen(inFileName, "rb");
  FILE* outFile = cmsys::SystemTools::Fopen(outFileName, "wb");
  if ((inFile == 0) || (outFile == 0))
    {
    if (inFile != 0)
      {
      fclose(inFile);
      }
    if (outFile != 0)
      {
      fclose(outFile);
      }
    return false;
    }

  // convert them line by line
  bool success = false;
  char buf[1024];
  while (fgets(buf, 1024, inFile) != 0)
    {
    if (type == MotorolaSrec)
      {
      success = ConvertMotorolaSrecLine(buf, outFile);
      }
    else if (type == IntelHex)
      {
      success = ConvertIntelHexLine(buf, outFile);
      }
    if (success == false)
      {
      break;
      }
    }

  // close them again
  fclose(inFile);
  fclose(outFile);
  return success;
}