/*

 * Copyright 2001-2004 Unicode, Inc.

 *

 * Disclaimer

 *

 * This source code is provided as is by Unicode, Inc. No claims are

 * made as to fitness for any particular purpose. No warranties of any

 * kind are expressed or implied. The recipient agrees to determine

 * applicability of information provided. If this file has been

 * purchased on magnetic or optical media from Unicode, Inc., the

 * sole remedy for any claim will be exchange of defective media

 * within 90 days of receipt.

 *

 * Limitations on Rights to Redistribute This Code

 *

 * Unicode, Inc. hereby grants the right to freely use the information

 * supplied in this file in the creation of products supporting the

 * Unicode Standard, and to make copies of this file in any form

 * for internal or external distribution as long as this notice

 * remains attached.

 */

/* ---------------------------------------------------------------------

Conversions between UTF32, UTF-16, and UTF-8. Source code file.

Author: Mark E. Davis, 1994.

Rev History: Rick McGowan, fixes & updates May 2001.

Sept 2001: fixed const & error conditions per

mods suggested by S. Parent & A. Lillich.

June 2002: Tim Dodd added detection and handling of incomplete

source sequences, enhanced error detection, added casts

to eliminate compiler warnings.

July 2003: slight mods to back out aggressive FFFE detection.

Jan 2004: updated switches in from-UTF8 conversions.

Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions.

See the header file "utf.h" for complete documentation.

------------------------------------------------------------------------ */

#include <winpr/wtypes.h>

#include <winpr/string.h>

#include <winpr/assert.h>

#include "unicode.h"

#include "../log.h"

#define TAG WINPR_TAG("unicode")

/*

 * Character Types:

 *

 * UTF8:    uint8_t   8 bits

 * UTF16: uint16_t  16 bits

 * UTF32: uint32_t  32 bits

 */

/* Some fundamental constants */

#define UNI_REPLACEMENT_CHAR (uint32_t)0x0000FFFD

#define UNI_MAX_BMP (uint32_t)0x0000FFFF

#define UNI_MAX_UTF16 (uint32_t)0x0010FFFF

#define UNI_MAX_UTF32 (uint32_t)0x7FFFFFFF

#define UNI_MAX_LEGAL_UTF32 (uint32_t)0x0010FFFF

typedef enum

{

  conversionOK,    /* conversion successful */

  sourceExhausted, /* partial character in source, but hit end */

  targetExhausted, /* insuff. room in target for conversion */

  sourceIllegal    /* source sequence is illegal/malformed */

} ConversionResult;

typedef enum

{

  strictConversion = 0,

  lenientConversion

} ConversionFlags;

static const int halfShift = 10; /* used for shifting by 10 bits */

static const uint32_t halfBase = 0x0010000UL;

static const uint32_t halfMask = 0x3FFUL;

#define UNI_SUR_HIGH_START (uint32_t)0xD800

#define UNI_SUR_HIGH_END (uint32_t)0xDBFF

#define UNI_SUR_LOW_START (uint32_t)0xDC00

#define UNI_SUR_LOW_END (uint32_t)0xDFFF

/* --------------------------------------------------------------------- */

/*

 * Index into the table below with the first byte of a UTF-8 sequence to

 * get the number of trailing bytes that are supposed to follow it.

 * Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is

 * left as-is for anyone who may want to do such conversion, which was

 * allowed in earlier algorithms.

 */

static const char trailingBytesForUTF8[256] = {

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,

  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5

};

/*

 * Magic values subtracted from a buffer value during UTF8 conversion.

 * This table contains as many values as there might be trailing bytes

 * in a UTF-8 sequence.

 */

static const uint32_t offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL,

                                           0x03C82080UL, 0xFA082080UL, 0x82082080UL };

/*

 * Once the bits are split out into bytes of UTF-8, this is a mask OR-ed

 * into the first byte, depending on how many bytes follow.  There are

 * as many entries in this table as there are UTF-8 sequence types.

 * (I.e., one byte sequence, two byte... etc.). Remember that sequencs

 * for *legal* UTF-8 will be 4 or fewer bytes total.

 */

static const uint8_t firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };

/* --------------------------------------------------------------------- */

/* The interface converts a whole buffer to avoid function-call overhead.

 * Constants have been gathered. Loops & conditionals have been removed as

 * much as possible for efficiency, in favor of drop-through switches.

 * (See "Note A" at the bottom of the file for equivalent code.)

 * If your compiler supports it, the "isLegalUTF8" call can be turned

 * into an inline function.

 */

/* --------------------------------------------------------------------- */

static ConversionResult winpr_ConvertUTF16toUTF8_Internal(const uint16_t** sourceStart,

                                                          const uint16_t* sourceEnd,

                                                          uint8_t** targetStart, uint8_t* targetEnd,

                                                          ConversionFlags flags)

{

  bool computeLength = (!targetEnd) ? true : false;

  const uint16_t* source = *sourceStart;

  uint8_t* target = *targetStart;

  ConversionResult result = conversionOK;

  while (source < sourceEnd)

  {

    uint32_t ch = 0;

    unsigned short bytesToWrite = 0;

    const uint32_t byteMask = 0xBF;

    const uint32_t byteMark = 0x80;

    const uint16_t* oldSource =

        source; /* In case we have to back up because of target overflow. */

    ch = *source++;

    /* If we have a surrogate pair, convert to UTF32 first. */

    if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END)

    {

      /* If the 16 bits following the high surrogate are in the source buffer... */

      if (source < sourceEnd)

      {

        uint32_t ch2 = *source;

        /* If it's a low surrogate, convert to UTF32. */

        if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END)

        {

          ch = ((ch - UNI_SUR_HIGH_START) << halfShift) + (ch2 - UNI_SUR_LOW_START) +

               halfBase;

          ++source;

        }

        else if (flags == strictConversion)

        {

          /* it's an unpaired high surrogate */

          --source; /* return to the illegal value itself */

          result = sourceIllegal;

          break;

        }

      }

      else

      {

        /* We don't have the 16 bits following the high surrogate. */

        --source; /* return to the high surrogate */

        result = sourceExhausted;

        break;

      }

    }

    else if (flags == strictConversion)

    {

      /* UTF-16 surrogate values are illegal in UTF-32 */

      if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END)

      {

        --source; /* return to the illegal value itself */

        result = sourceIllegal;

        break;

      }

    }

    /* Figure out how many bytes the result will require */

    if (ch < (uint32_t)0x80)

    {

      bytesToWrite = 1;

    }

    else if (ch < (uint32_t)0x800)

    {

      bytesToWrite = 2;

    }

    else if (ch < (uint32_t)0x10000)

    {

      bytesToWrite = 3;

    }

    else if (ch < (uint32_t)0x110000)

    {

      bytesToWrite = 4;

    }

    else

    {

      bytesToWrite = 3;

      ch = UNI_REPLACEMENT_CHAR;

    }

    target += bytesToWrite;

    if ((target > targetEnd) && (!computeLength))

    {

      source = oldSource; /* Back up source pointer! */

      target -= bytesToWrite;

      result = targetExhausted;

      break;

    }

    if (!computeLength)

    {

      switch (bytesToWrite)

      {

          /* note: everything falls through. */

        case 4:

          *--target = (uint8_t)((ch | byteMark) & byteMask);

          ch >>= 6;

          /* fallthrough */

          WINPR_FALLTHROUGH

        case 3:

          *--target = (uint8_t)((ch | byteMark) & byteMask);

          ch >>= 6;

          /* fallthrough */

          WINPR_FALLTHROUGH

        case 2:

          *--target = (uint8_t)((ch | byteMark) & byteMask);

          ch >>= 6;

          /* fallthrough */

          WINPR_FALLTHROUGH

        case 1:

          *--target = (uint8_t)(ch | firstByteMark[bytesToWrite]);

      }

    }

    else

    {

      switch (bytesToWrite)

      {

          /* note: everything falls through. */

        case 4:

          --target;

          /* fallthrough */

          WINPR_FALLTHROUGH

        case 3:

          --target;

          /* fallthrough */

          WINPR_FALLTHROUGH

        case 2:

          --target;

          /* fallthrough */

          WINPR_FALLTHROUGH

        case 1:

          --target;

      }

    }

    target += bytesToWrite;

  }

  *sourceStart = source;

  *targetStart = target;

  return result;

}

/* --------------------------------------------------------------------- */

/*

 * Utility routine to tell whether a sequence of bytes is legal UTF-8.

 * This must be called with the length pre-determined by the first byte.

 * If not calling this from ConvertUTF8to*, then the length can be set by:

 *  length = trailingBytesForUTF8[*source]+1;

 * and the sequence is illegal right away if there aren't that many bytes

 * available.

 * If presented with a length > 4, this returns false.  The Unicode

 * definition of UTF-8 goes up to 4-byte sequences.

 */

static bool isLegalUTF8(const uint8_t* source, int length)

{

  uint8_t a = 0;

  const uint8_t* srcptr = source + length;

  switch (length)

  {

    default:

      return false;

      /* Everything else falls through when "true"... */

    case 4:

      if ((a = (*--srcptr)) < 0x80 || a > 0xBF)

        return false;

      /* fallthrough */

      WINPR_FALLTHROUGH

    case 3:

      if ((a = (*--srcptr)) < 0x80 || a > 0xBF)

        return false;

      /* fallthrough */

      WINPR_FALLTHROUGH

    case 2:

      if ((a = (*--srcptr)) > 0xBF)

        return false;

      switch (*source)

      {

          /* no fall-through in this inner switch */

        case 0xE0:

          if (a < 0xA0)

            return false;

          break;

        case 0xED:

          if (a > 0x9F)

            return false;

          break;

        case 0xF0:

          if (a < 0x90)

            return false;

          break;

        case 0xF4:

          if (a > 0x8F)

            return false;

          break;

        default:

          if (a < 0x80)

            return false;

          break;

      }

      /* fallthrough */

      WINPR_FALLTHROUGH

    case 1:

      if (*source >= 0x80 && *source < 0xC2)

        return false;

  }

  if (*source > 0xF4)

    return false;

  return true;

}

/* --------------------------------------------------------------------- */

static ConversionResult winpr_ConvertUTF8toUTF16_Internal(const uint8_t** sourceStart,

                                                          const uint8_t* sourceEnd,

                                                          uint16_t** targetStart,

                                                          uint16_t* targetEnd,

                                                          ConversionFlags flags)

{

  bool computeLength = (!targetEnd) ? true : false;

  ConversionResult result = conversionOK;

  const uint8_t* source = *sourceStart;

  uint16_t* target = *targetStart;

  while (source < sourceEnd)

  {

    uint32_t ch = 0;

    unsigned short extraBytesToRead = trailingBytesForUTF8[*source];

    if ((source + extraBytesToRead) >= sourceEnd)

    {

      result = sourceExhausted;

      break;

    }

    /* Do this check whether lenient or strict */

    if (!isLegalUTF8(source, extraBytesToRead + 1))

    {

      result = sourceIllegal;

      break;

    }

    /*

     * The cases all fall through. See "Note A" below.

     */

    switch (extraBytesToRead)

    {

      case 5:

        ch += *source++;

        ch <<= 6; /* remember, illegal UTF-8 */

                  /* fallthrough */

        WINPR_FALLTHROUGH

      case 4:

        ch += *source++;

        ch <<= 6; /* remember, illegal UTF-8 */

                  /* fallthrough */

        WINPR_FALLTHROUGH

      case 3:

        ch += *source++;

        ch <<= 6;

        /* fallthrough */

        WINPR_FALLTHROUGH

      case 2:

        ch += *source++;

        ch <<= 6;

        /* fallthrough */

        WINPR_FALLTHROUGH

      case 1:

        ch += *source++;

        ch <<= 6;

        /* fallthrough */

        WINPR_FALLTHROUGH

      case 0:

        ch += *source++;

    }

    ch -= offsetsFromUTF8[extraBytesToRead];

    if ((target >= targetEnd) && (!computeLength))

    {

      source -= (extraBytesToRead + 1); /* Back up source pointer! */

      result = targetExhausted;

      break;

    }

    if (ch <= UNI_MAX_BMP)

    {

      /* Target is a character <= 0xFFFF */

      /* UTF-16 surrogate values are illegal in UTF-32 */

      if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END)

      {

        if (flags == strictConversion)

        {

          source -= (extraBytesToRead + 1); /* return to the illegal value itself */

          result = sourceIllegal;

          break;

        }

        else

        {

          if (!computeLength)

            *target++ = UNI_REPLACEMENT_CHAR;

          else

            target++;

        }

      }

      else

      {

        if (!computeLength)

          *target++ = (uint16_t)ch; /* normal case */

        else

          target++;

      }

    }

    else if (ch > UNI_MAX_UTF16)

    {

      if (flags == strictConversion)

      {

        result = sourceIllegal;

        source -= (extraBytesToRead + 1); /* return to the start */

        break;                            /* Bail out; shouldn't continue */

      }

      else

      {

        if (!computeLength)

          *target++ = UNI_REPLACEMENT_CHAR;

        else

          target++;

      }

    }

    else

    {

      /* target is a character in range 0xFFFF - 0x10FFFF. */

      if ((target + 1 >= targetEnd) && (!computeLength))

      {

        source -= (extraBytesToRead + 1); /* Back up source pointer! */

        result = targetExhausted;

        break;

      }

      ch -= halfBase;

      if (!computeLength)

      {

        *target++ = (uint16_t)((ch >> halfShift) + UNI_SUR_HIGH_START);

        *target++ = (uint16_t)((ch & halfMask) + UNI_SUR_LOW_START);

      }

      else

      {

        target++;

        target++;

      }

    }

  }

  *sourceStart = source;

  *targetStart = target;

  return result;

}

/**

 * WinPR built-in Unicode API

 */

static int winpr_ConvertUTF8toUTF16(const uint8_t* src, int cchSrc, uint16_t* dst, int cchDst)

{

  size_t length = 0;

  uint16_t* dstBeg = NULL;

  uint16_t* dstEnd = NULL;

  const uint8_t* srcBeg = NULL;

  const uint8_t* srcEnd = NULL;

  ConversionResult result = sourceIllegal;

  if (cchSrc == -1)

    cchSrc = strlen((char*)src) + 1;

  srcBeg = src;

  srcEnd = &src[cchSrc];

  if (cchDst == 0)

  {

    result =

        winpr_ConvertUTF8toUTF16_Internal(&srcBeg, srcEnd, &dstBeg, dstEnd, strictConversion);

    length = dstBeg - (uint16_t*)NULL;

  }

  else

  {

    dstBeg = dst;

    dstEnd = &dst[cchDst];

    result =

        winpr_ConvertUTF8toUTF16_Internal(&srcBeg, srcEnd, &dstBeg, dstEnd, strictConversion);

    length = dstBeg - dst;

  }

  if (result == targetExhausted)

  {

    SetLastError(ERROR_INSUFFICIENT_BUFFER);

    return 0;

  }

  return (result == conversionOK) ? length : 0;

}

static int winpr_ConvertUTF16toUTF8(const uint16_t* src, int cchSrc, uint8_t* dst, int cchDst)

{

  size_t length = 0;

  uint8_t* dstBeg = NULL;

  uint8_t* dstEnd = NULL;

  const uint16_t* srcBeg = NULL;

  const uint16_t* srcEnd = NULL;

  ConversionResult result = sourceIllegal;

  if (cchSrc == -1)

    cchSrc = _wcslen((uint16_t*)src) + 1;

  srcBeg = src;

  srcEnd = &src[cchSrc];

  if (cchDst == 0)

  {

    result =

        winpr_ConvertUTF16toUTF8_Internal(&srcBeg, srcEnd, &dstBeg, dstEnd, strictConversion);

    length = dstBeg - ((uint8_t*)NULL);

  }

  else

  {

    dstBeg = dst;

    dstEnd = &dst[cchDst];

    result =

        winpr_ConvertUTF16toUTF8_Internal(&srcBeg, srcEnd, &dstBeg, dstEnd, strictConversion);

    length = dstBeg - dst;

  }

  if (result == targetExhausted)

  {

    SetLastError(ERROR_INSUFFICIENT_BUFFER);

    return 0;

  }

  return (result == conversionOK) ? length : 0;

}

/* --------------------------------------------------------------------- */

int int_MultiByteToWideChar(UINT CodePage, DWORD dwFlags, LPCSTR lpMultiByteStr, int cbMultiByte,

                            LPWSTR lpWideCharStr, int cchWideChar)

{

  size_t cbCharLen = (size_t)cbMultiByte;

  WINPR_UNUSED(dwFlags);

  /* If cbMultiByte is 0, the function fails */

  if ((cbMultiByte == 0) || (cbMultiByte < -1))

    return 0;

  if (cchWideChar < 0)

    return -1;

  if (cbMultiByte < 0)

  {

    const size_t len = strlen(lpMultiByteStr);

    if (len >= INT32_MAX)

      return 0;

    cbCharLen = (int)len + 1;

  }

  else

    cbCharLen = cbMultiByte;

  WINPR_ASSERT(lpMultiByteStr);

  switch (CodePage)

  {

    case CP_ACP:

    case CP_UTF8:

      break;

    default:

      WLog_ERR(TAG, "Unsupported encoding %u", CodePage);

      return 0;

  }

  return winpr_ConvertUTF8toUTF16((const uint8_t*)lpMultiByteStr, cbCharLen,

                                  (uint16_t*)lpWideCharStr, cchWideChar);

}

int int_WideCharToMultiByte(UINT CodePage, DWORD dwFlags, LPCWSTR lpWideCharStr, int cchWideChar,

                            LPSTR lpMultiByteStr, int cbMultiByte, LPCSTR lpDefaultChar,

                            LPBOOL lpUsedDefaultChar)

{

  size_t cbCharLen = (size_t)cchWideChar;

  WINPR_UNUSED(dwFlags);

  /* If cchWideChar is 0, the function fails */

  if ((cchWideChar == 0) || (cchWideChar < -1))

    return 0;

  if (cbMultiByte < 0)

    return -1;

  WINPR_ASSERT(lpWideCharStr);

  /* If cchWideChar is -1, the string is null-terminated */

  if (cchWideChar == -1)

  {

    const size_t len = _wcslen(lpWideCharStr);

    if (len >= INT32_MAX)

      return 0;

    cbCharLen = (int)len + 1;

  }

  else

    cbCharLen = cchWideChar;

  /*

   * if cbMultiByte is 0, the function returns the required buffer size

   * in bytes for lpMultiByteStr and makes no use of the output parameter itself.

   */

  return winpr_ConvertUTF16toUTF8((const uint16_t*)lpWideCharStr, cbCharLen,

                                  (uint8_t*)lpMultiByteStr, cbMultiByte);

}