/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying

   file LICENSE.rst or https://cmake.org/licensing for details.  */

#include "cmHexFileConverter.h"

#include <cctype>

#include <cstdio>

#include <cstring>

#include "cmSystemTools.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)

static unsigned int ChompStrlen(char const* line)

{

  if (!line) {

    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, char const* 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(char const* 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;

  }

  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(char const* 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(

  std::string const& inFileName)

{

  char buf[1024];

  FILE* inFile = cmsys::SystemTools::Fopen(inFileName, "rb");

  if (!inFile) {

    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 (!isxdigit(buf[i])) {

      return Binary;

    }

  }

  return type;

}

bool cmHexFileConverter::TryConvert(std::string const& inFileName,

                                    std::string const& 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 || !outFile) {

    if (inFile) {

      fclose(inFile);

    }

    if (outFile) {

      fclose(outFile);

    }

    return false;

  }

  // convert them line by line

  bool success = false;

  char buf[1024];

  while (fgets(buf, 1024, inFile)) {

    if (type == MotorolaSrec) {

      success = ConvertMotorolaSrecLine(buf, outFile);

    } else if (type == IntelHex) {

      success = ConvertIntelHexLine(buf, outFile);

    }

    if (!success) {

      break;

    }

  }

  // close them again

  fclose(inFile);

  fclose(outFile);

  return success;

}