unicode_builtin.c

/*
 * 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 <winpr/cast.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 sequence
 * for *legal* UTF-8 will be 4 or fewer bytes total.
 */
static const uint8_t firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
 
/* We always need UTF-16LE, even on big endian systems! */
static WCHAR setWcharFrom(WCHAR w)
{
#if defined(__BIG_ENDIAN__)
  union
  {
    WCHAR w;
    char c[2];
  } cnv;
 
  cnv.w = w;
  const char c = cnv.c[0];
  cnv.c[0] = cnv.c[1];
  cnv.c[1] = c;
  return cnv.w;
#else
  return w;
#endif
}
 
/* --------------------------------------------------------------------- */
 
/* 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,
                                                          const 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 = setWcharFrom(*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 = setWcharFrom(*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]);
          break;
        default:
          return sourceIllegal;
      }
    }
    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;
          break;
        default:
          return sourceIllegal;
      }
    }
 
    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,
                                                          const 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 =
        WINPR_ASSERTING_INT_CAST(unsigned short, 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++;
        break;
      default:
        return sourceIllegal;
    }
 
    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++ = setWcharFrom(UNI_REPLACEMENT_CHAR);
          else
            target++;
        }
      }
      else
      {
        if (!computeLength)
          *target++ = setWcharFrom((WCHAR)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++ = setWcharFrom(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++ = setWcharFrom((WCHAR)((ch >> halfShift) + UNI_SUR_HIGH_START));
        *target++ = setWcharFrom((WCHAR)((ch & halfMask) + UNI_SUR_LOW_START));
      }
      else
      {
        target++;
        target++;
      }
    }
  }
 
  *sourceStart = source;
  *targetStart = target;
  return result;
}
 
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 = (int)strnlen((const char*)src, INT32_MAX - 1) + 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) ? WINPR_ASSERTING_INT_CAST(int, 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 = (int)_wcsnlen((const WCHAR*)src, INT32_MAX - 1) + 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) ? WINPR_ASSERTING_INT_CAST(int, 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,
                                  WINPR_ASSERTING_INT_CAST(int, 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,
                                  WINPR_ASSERTING_INT_CAST(int, cbCharLen),
                                  (uint8_t*)lpMultiByteStr, cbMultiByte);
}