/Users/deen/code/yugabyte-db/build/debugcov-clang-dynamic-arm64-ninja/postgres_build/src/interfaces/libpq/wchar.c

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/*
 * conversion functions between pg_wchar and multibyte streams.
 * Tatsuo Ishii
 * src/backend/utils/mb/wchar.c
 *
 */
/* can be used in either frontend or backend */
#ifdef FRONTEND
#include "postgres_fe.h"
#else
#include "postgres.h"
#endif

#include "mb/pg_wchar.h"


/*
 * conversion to pg_wchar is done by "table driven."
 * to add an encoding support, define mb2wchar_with_len(), mblen(), dsplen()
 * for the particular encoding. Note that if the encoding is only
 * supported in the client, you don't need to define
 * mb2wchar_with_len() function (SJIS is the case).
 *
 * These functions generally assume that their input is validly formed.
 * The "verifier" functions, further down in the file, have to be more
 * paranoid.  We expect that mblen() does not need to examine more than
 * the first byte of the character to discover the correct length.
 *
 * Note: for the display output of psql to work properly, the return values
 * of the dsplen functions must conform to the Unicode standard. In particular
 * the NUL character is zero width and control characters are generally
 * width -1. It is recommended that non-ASCII encodings refer their ASCII
 * subset to the ASCII routines to ensure consistency.
 */

/*
 * SQL/ASCII
 */
static int
pg_ascii2wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    *to++ = *from++;
    len--;
    cnt++;
  }
  *to = 0;
  return cnt;
}

static int
pg_ascii_mblen(const unsigned char *s)
{
  return 1;
}

static int
pg_ascii_dsplen(const unsigned char *s)
{
  if (*s == '\0')
    return 0;
  if (*s < 0x20 || *s == 0x7f)
    return -1;

  return 1;
}

/*
 * EUC
 */
static int
pg_euc2wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    if (*from == SS2 && len >= 2) /* JIS X 0201 (so called "1 byte
                     * KANA") */
    {
      from++;
      *to = (SS2 << 8) | *from++;
      len -= 2;
    }
    else if (*from == SS3 && len >= 3) /* JIS X 0212 KANJI */
    {
      from++;
      *to = (SS3 << 16) | (*from++ << 8);
      *to |= *from++;
      len -= 3;
    }
    else if (IS_HIGHBIT_SET(*from) && len >= 2) /* JIS X 0208 KANJI */
    {
      *to = *from++ << 8;
      *to |= *from++;
      len -= 2;
    }
    else          /* must be ASCII */
    {
      *to = *from++;
      len--;
    }
    to++;
    cnt++;
  }
  *to = 0;
  return cnt;
}

static inline int
pg_euc_mblen(const unsigned char *s)
{
  int     len;

  if (*s == SS2)
    len = 2;
  else if (*s == SS3)
    len = 3;
  else if (IS_HIGHBIT_SET(*s))
    len = 2;
  else
    len = 1;
  return len;
}

static inline int
pg_euc_dsplen(const unsigned char *s)
{
  int     len;

  if (*s == SS2)
    len = 2;
  else if (*s == SS3)
    len = 2;
  else if (IS_HIGHBIT_SET(*s))
    len = 2;
  else
    len = pg_ascii_dsplen(s);
  return len;
}

/*
 * EUC_JP
 */
static int
pg_eucjp2wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
{
  return pg_euc2wchar_with_len(from, to, len);
}

static int
pg_eucjp_mblen(const unsigned char *s)
{
  return pg_euc_mblen(s);
}

static int
pg_eucjp_dsplen(const unsigned char *s)
{
  int     len;

  if (*s == SS2)
    len = 1;
  else if (*s == SS3)
    len = 2;
  else if (IS_HIGHBIT_SET(*s))
    len = 2;
  else
    len = pg_ascii_dsplen(s);
  return len;
}

/*
 * EUC_KR
 */
static int
pg_euckr2wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
{
  return pg_euc2wchar_with_len(from, to, len);
}

static int
pg_euckr_mblen(const unsigned char *s)
{
  return pg_euc_mblen(s);
}

static int
pg_euckr_dsplen(const unsigned char *s)
{
  return pg_euc_dsplen(s);
}

/*
 * EUC_CN
 *
 */
static int
pg_euccn2wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    if (*from == SS2 && len >= 3) /* code set 2 (unused?) */
    {
      from++;
      *to = (SS2 << 16) | (*from++ << 8);
      *to |= *from++;
      len -= 3;
    }
    else if (*from == SS3 && len >= 3) /* code set 3 (unused ?) */
    {
      from++;
      *to = (SS3 << 16) | (*from++ << 8);
      *to |= *from++;
      len -= 3;
    }
    else if (IS_HIGHBIT_SET(*from) && len >= 2) /* code set 1 */
    {
      *to = *from++ << 8;
      *to |= *from++;
      len -= 2;
    }
    else
    {
      *to = *from++;
      len--;
    }
    to++;
    cnt++;
  }
  *to = 0;
  return cnt;
}

static int
pg_euccn_mblen(const unsigned char *s)
{
  int     len;

  if (IS_HIGHBIT_SET(*s))
    len = 2;
  else
    len = 1;
  return len;
}

static int
pg_euccn_dsplen(const unsigned char *s)
{
  int     len;

  if (IS_HIGHBIT_SET(*s))
    len = 2;
  else
    len = pg_ascii_dsplen(s);
  return len;
}

/*
 * EUC_TW
 *
 */
static int
pg_euctw2wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    if (*from == SS2 && len >= 4) /* code set 2 */
    {
      from++;
      *to = (((uint32) SS2) << 24) | (*from++ << 16);
      *to |= *from++ << 8;
      *to |= *from++;
      len -= 4;
    }
    else if (*from == SS3 && len >= 3) /* code set 3 (unused?) */
    {
      from++;
      *to = (SS3 << 16) | (*from++ << 8);
      *to |= *from++;
      len -= 3;
    }
    else if (IS_HIGHBIT_SET(*from) && len >= 2) /* code set 2 */
    {
      *to = *from++ << 8;
      *to |= *from++;
      len -= 2;
    }
    else
    {
      *to = *from++;
      len--;
    }
    to++;
    cnt++;
  }
  *to = 0;
  return cnt;
}

static int
pg_euctw_mblen(const unsigned char *s)
{
  int     len;

  if (*s == SS2)
    len = 4;
  else if (*s == SS3)
    len = 3;
  else if (IS_HIGHBIT_SET(*s))
    len = 2;
  else
    len = 1;
  return len;
}

static int
pg_euctw_dsplen(const unsigned char *s)
{
  int     len;

  if (*s == SS2)
    len = 2;
  else if (*s == SS3)
    len = 2;
  else if (IS_HIGHBIT_SET(*s))
    len = 2;
  else
    len = pg_ascii_dsplen(s);
  return len;
}

/*
 * Convert pg_wchar to EUC_* encoding.
 * caller must allocate enough space for "to", including a trailing zero!
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int
pg_wchar2euc_with_len(const pg_wchar *from, unsigned char *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    unsigned char c;

    if ((c = (*from >> 24)))
    {
      *to++ = c;
      *to++ = (*from >> 16) & 0xff;
      *to++ = (*from >> 8) & 0xff;
      *to++ = *from & 0xff;
      cnt += 4;
    }
    else if ((c = (*from >> 16)))
    {
      *to++ = c;
      *to++ = (*from >> 8) & 0xff;
      *to++ = *from & 0xff;
      cnt += 3;
    }
    else if ((c = (*from >> 8)))
    {
      *to++ = c;
      *to++ = *from & 0xff;
      cnt += 2;
    }
    else
    {
      *to++ = *from;
      cnt++;
    }
    from++;
    len--;
  }
  *to = 0;
  return cnt;
}


/*
 * JOHAB
 */
static int
pg_johab_mblen(const unsigned char *s)
{
  return pg_euc_mblen(s);
}

static int
pg_johab_dsplen(const unsigned char *s)
{
  return pg_euc_dsplen(s);
}

/*
 * convert UTF8 string to pg_wchar (UCS-4)
 * caller must allocate enough space for "to", including a trailing zero!
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int
pg_utf2wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
{
  int     cnt = 0;
  uint32    c1,
        c2,
        c3,
        c4;

  while (len > 0 && *from)
  {
    if ((*from & 0x80) == 0)
    {
      *to = *from++;
      len--;
    }
    else if ((*from & 0xe0) == 0xc0)
    {
      if (len < 2)
        break;     /* drop trailing incomplete char */
      c1 = *from++ & 0x1f;
      c2 = *from++ & 0x3f;
      *to = (c1 << 6) | c2;
      len -= 2;
    }
    else if ((*from & 0xf0) == 0xe0)
    {
      if (len < 3)
        break;     /* drop trailing incomplete char */
      c1 = *from++ & 0x0f;
      c2 = *from++ & 0x3f;
      c3 = *from++ & 0x3f;
      *to = (c1 << 12) | (c2 << 6) | c3;
      len -= 3;
    }
    else if ((*from & 0xf8) == 0xf0)
    {
      if (len < 4)
        break;     /* drop trailing incomplete char */
      c1 = *from++ & 0x07;
      c2 = *from++ & 0x3f;
      c3 = *from++ & 0x3f;
      c4 = *from++ & 0x3f;
      *to = (c1 << 18) | (c2 << 12) | (c3 << 6) | c4;
      len -= 4;
    }
    else
    {
      /* treat a bogus char as length 1; not ours to raise error */
      *to = *from++;
      len--;
    }
    to++;
    cnt++;
  }
  *to = 0;
  return cnt;
}


/*
 * Map a Unicode code point to UTF-8.  utf8string must have 4 bytes of
 * space allocated.
 */
unsigned char *
unicode_to_utf8(pg_wchar c, unsigned char *utf8string)
{
  if (c <= 0x7F)
  {
    utf8string[0] = c;
  }
  else if (c <= 0x7FF)
  {
    utf8string[0] = 0xC0 | ((c >> 6) & 0x1F);
    utf8string[1] = 0x80 | (c & 0x3F);
  }
  else if (c <= 0xFFFF)
  {
    utf8string[0] = 0xE0 | ((c >> 12) & 0x0F);
    utf8string[1] = 0x80 | ((c >> 6) & 0x3F);
    utf8string[2] = 0x80 | (c & 0x3F);
  }
  else
  {
    utf8string[0] = 0xF0 | ((c >> 18) & 0x07);
    utf8string[1] = 0x80 | ((c >> 12) & 0x3F);
    utf8string[2] = 0x80 | ((c >> 6) & 0x3F);
    utf8string[3] = 0x80 | (c & 0x3F);
  }

  return utf8string;
}

/*
 * Trivial conversion from pg_wchar to UTF-8.
 * caller should allocate enough space for "to"
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int
pg_wchar2utf_with_len(const pg_wchar *from, unsigned char *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    int     char_len;

    unicode_to_utf8(*from, to);
    char_len = pg_utf_mblen(to);
    cnt += char_len;
    to += char_len;
    from++;
    len--;
  }
  *to = 0;
  return cnt;
}

/*
 * Return the byte length of a UTF8 character pointed to by s
 *
 * Note: in the current implementation we do not support UTF8 sequences
 * of more than 4 bytes; hence do NOT return a value larger than 4.
 * We return "1" for any leading byte that is either flat-out illegal or
 * indicates a length larger than we support.
 *
 * pg_utf2wchar_with_len(), utf8_to_unicode(), pg_utf8_islegal(), and perhaps
 * other places would need to be fixed to change this.
 */
int
pg_utf_mblen(const unsigned char *s)
{
  int     len;

  if ((*s & 0x80) == 0)
    len = 1;
  else if ((*s & 0xe0) == 0xc0)
    len = 2;
  else if ((*s & 0xf0) == 0xe0)
    len = 3;
  else if ((*s & 0xf8) == 0xf0)
    len = 4;
#ifdef NOT_USED
  else if ((*s & 0xfc) == 0xf8)
    len = 5;
  else if ((*s & 0xfe) == 0xfc)
    len = 6;
#endif
  else
    len = 1;
  return len;
}

/*
 * This is an implementation of wcwidth() and wcswidth() as defined in
 * "The Single UNIX Specification, Version 2, The Open Group, 1997"
 * <http://www.UNIX-systems.org/online.html>
 *
 * Markus Kuhn -- 2001-09-08 -- public domain
 *
 * customised for PostgreSQL
 *
 * original available at : http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
 */

struct mbinterval
{
  unsigned short first;
  unsigned short last;
};

/* auxiliary function for binary search in interval table */
static int
mbbisearch(pg_wchar ucs, const struct mbinterval *table, int max)
{
  int     min = 0;
  int     mid;

  if (ucs < table[0].first || ucs > table[max].last)
    return 0;
  while (max >= min)
  {
    mid = (min + max) / 2;
    if (ucs > table[mid].last)
      min = mid + 1;
    else if (ucs < table[mid].first)
      max = mid - 1;
    else
      return 1;
  }

  return 0;
}


/* The following functions define the column width of an ISO 10646
 * character as follows:
 *
 *    - The null character (U+0000) has a column width of 0.
 *
 *    - Other C0/C1 control characters and DEL will lead to a return
 *    value of -1.
 *
 *    - Non-spacing and enclosing combining characters (general
 *    category code Mn or Me in the Unicode database) have a
 *    column width of 0.
 *
 *    - Other format characters (general category code Cf in the Unicode
 *    database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
 *
 *    - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
 *    have a column width of 0.
 *
 *    - Spacing characters in the East Asian Wide (W) or East Asian
 *    FullWidth (F) category as defined in Unicode Technical
 *    Report #11 have a column width of 2.
 *
 *    - All remaining characters (including all printable
 *    ISO 8859-1 and WGL4 characters, Unicode control characters,
 *    etc.) have a column width of 1.
 *
 * This implementation assumes that wchar_t characters are encoded
 * in ISO 10646.
 */

static int
ucs_wcwidth(pg_wchar ucs)
{
  /* sorted list of non-overlapping intervals of non-spacing characters */
  static const struct mbinterval combining[] = {
    {0x0300, 0x034E}, {0x0360, 0x0362}, {0x0483, 0x0486},
    {0x0488, 0x0489}, {0x0591, 0x05A1}, {0x05A3, 0x05B9},
    {0x05BB, 0x05BD}, {0x05BF, 0x05BF}, {0x05C1, 0x05C2},
    {0x05C4, 0x05C4}, {0x064B, 0x0655}, {0x0670, 0x0670},
    {0x06D6, 0x06E4}, {0x06E7, 0x06E8}, {0x06EA, 0x06ED},
    {0x070F, 0x070F}, {0x0711, 0x0711}, {0x0730, 0x074A},
    {0x07A6, 0x07B0}, {0x0901, 0x0902}, {0x093C, 0x093C},
    {0x0941, 0x0948}, {0x094D, 0x094D}, {0x0951, 0x0954},
    {0x0962, 0x0963}, {0x0981, 0x0981}, {0x09BC, 0x09BC},
    {0x09C1, 0x09C4}, {0x09CD, 0x09CD}, {0x09E2, 0x09E3},
    {0x0A02, 0x0A02}, {0x0A3C, 0x0A3C}, {0x0A41, 0x0A42},
    {0x0A47, 0x0A48}, {0x0A4B, 0x0A4D}, {0x0A70, 0x0A71},
    {0x0A81, 0x0A82}, {0x0ABC, 0x0ABC}, {0x0AC1, 0x0AC5},
    {0x0AC7, 0x0AC8}, {0x0ACD, 0x0ACD}, {0x0B01, 0x0B01},
    {0x0B3C, 0x0B3C}, {0x0B3F, 0x0B3F}, {0x0B41, 0x0B43},
    {0x0B4D, 0x0B4D}, {0x0B56, 0x0B56}, {0x0B82, 0x0B82},
    {0x0BC0, 0x0BC0}, {0x0BCD, 0x0BCD}, {0x0C3E, 0x0C40},
    {0x0C46, 0x0C48}, {0x0C4A, 0x0C4D}, {0x0C55, 0x0C56},
    {0x0CBF, 0x0CBF}, {0x0CC6, 0x0CC6}, {0x0CCC, 0x0CCD},
    {0x0D41, 0x0D43}, {0x0D4D, 0x0D4D}, {0x0DCA, 0x0DCA},
    {0x0DD2, 0x0DD4}, {0x0DD6, 0x0DD6}, {0x0E31, 0x0E31},
    {0x0E34, 0x0E3A}, {0x0E47, 0x0E4E}, {0x0EB1, 0x0EB1},
    {0x0EB4, 0x0EB9}, {0x0EBB, 0x0EBC}, {0x0EC8, 0x0ECD},
    {0x0F18, 0x0F19}, {0x0F35, 0x0F35}, {0x0F37, 0x0F37},
    {0x0F39, 0x0F39}, {0x0F71, 0x0F7E}, {0x0F80, 0x0F84},
    {0x0F86, 0x0F87}, {0x0F90, 0x0F97}, {0x0F99, 0x0FBC},
    {0x0FC6, 0x0FC6}, {0x102D, 0x1030}, {0x1032, 0x1032},
    {0x1036, 0x1037}, {0x1039, 0x1039}, {0x1058, 0x1059},
    {0x1160, 0x11FF}, {0x17B7, 0x17BD}, {0x17C6, 0x17C6},
    {0x17C9, 0x17D3}, {0x180B, 0x180E}, {0x18A9, 0x18A9},
    {0x200B, 0x200F}, {0x202A, 0x202E}, {0x206A, 0x206F},
    {0x20D0, 0x20E3}, {0x302A, 0x302F}, {0x3099, 0x309A},
    {0xFB1E, 0xFB1E}, {0xFE20, 0xFE23}, {0xFEFF, 0xFEFF},
    {0xFFF9, 0xFFFB}
  };

  /* test for 8-bit control characters */
  if (ucs == 0)
    return 0;

  if (ucs < 0x20 || (ucs >= 0x7f && ucs < 0xa0) || ucs > 0x0010ffff)
    return -1;

  /* binary search in table of non-spacing characters */
  if (mbbisearch(ucs, combining,
           sizeof(combining) / sizeof(struct mbinterval) - 1))
    return 0;

  /*
   * if we arrive here, ucs is not a combining or C0/C1 control character
   */

  return 1 +
    (ucs >= 0x1100 &&
     (ucs <= 0x115f ||   /* Hangul Jamo init. consonants */
      (ucs >= 0x2e80 && ucs <= 0xa4cf && (ucs & ~0x0011) != 0x300a &&
       ucs != 0x303f) ||  /* CJK ... Yi */
      (ucs >= 0xac00 && ucs <= 0xd7a3) ||  /* Hangul Syllables */
      (ucs >= 0xf900 && ucs <= 0xfaff) ||  /* CJK Compatibility
                         * Ideographs */
      (ucs >= 0xfe30 && ucs <= 0xfe6f) ||  /* CJK Compatibility Forms */
      (ucs >= 0xff00 && ucs <= 0xff5f) ||  /* Fullwidth Forms */
      (ucs >= 0xffe0 && ucs <= 0xffe6) ||
      (ucs >= 0x20000 && ucs <= 0x2ffff)));
}

/*
 * Convert a UTF-8 character to a Unicode code point.
 * This is a one-character version of pg_utf2wchar_with_len.
 *
 * No error checks here, c must point to a long-enough string.
 */
pg_wchar
utf8_to_unicode(const unsigned char *c)
{
  if ((*c & 0x80) == 0)
    return (pg_wchar) c[0];
  else if ((*c & 0xe0) == 0xc0)
    return (pg_wchar) (((c[0] & 0x1f) << 6) |
               (c[1] & 0x3f));
  else if ((*c & 0xf0) == 0xe0)
    return (pg_wchar) (((c[0] & 0x0f) << 12) |
               ((c[1] & 0x3f) << 6) |
               (c[2] & 0x3f));
  else if ((*c & 0xf8) == 0xf0)
    return (pg_wchar) (((c[0] & 0x07) << 18) |
               ((c[1] & 0x3f) << 12) |
               ((c[2] & 0x3f) << 6) |
               (c[3] & 0x3f));
  else
    /* that is an invalid code on purpose */
    return 0xffffffff;
}

static int
pg_utf_dsplen(const unsigned char *s)
{
  return ucs_wcwidth(utf8_to_unicode(s));
}

/*
 * convert mule internal code to pg_wchar
 * caller should allocate enough space for "to"
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int
pg_mule2wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    if (IS_LC1(*from) && len >= 2)
    {
      *to = *from++ << 16;
      *to |= *from++;
      len -= 2;
    }
    else if (IS_LCPRV1(*from) && len >= 3)
    {
      from++;
      *to = *from++ << 16;
      *to |= *from++;
      len -= 3;
    }
    else if (IS_LC2(*from) && len >= 3)
    {
      *to = *from++ << 16;
      *to |= *from++ << 8;
      *to |= *from++;
      len -= 3;
    }
    else if (IS_LCPRV2(*from) && len >= 4)
    {
      from++;
      *to = *from++ << 16;
      *to |= *from++ << 8;
      *to |= *from++;
      len -= 4;
    }
    else
    {           /* assume ASCII */
      *to = (unsigned char) *from++;
      len--;
    }
    to++;
    cnt++;
  }
  *to = 0;
  return cnt;
}

/*
 * convert pg_wchar to mule internal code
 * caller should allocate enough space for "to"
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int
pg_wchar2mule_with_len(const pg_wchar *from, unsigned char *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    unsigned char lb;

    lb = (*from >> 16) & 0xff;
    if (IS_LC1(lb))
    {
      *to++ = lb;
      *to++ = *from & 0xff;
      cnt += 2;
    }
    else if (IS_LC2(lb))
    {
      *to++ = lb;
      *to++ = (*from >> 8) & 0xff;
      *to++ = *from & 0xff;
      cnt += 3;
    }
    else if (IS_LCPRV1_A_RANGE(lb))
    {
      *to++ = LCPRV1_A;
      *to++ = lb;
      *to++ = *from & 0xff;
      cnt += 3;
    }
    else if (IS_LCPRV1_B_RANGE(lb))
    {
      *to++ = LCPRV1_B;
      *to++ = lb;
      *to++ = *from & 0xff;
      cnt += 3;
    }
    else if (IS_LCPRV2_A_RANGE(lb))
    {
      *to++ = LCPRV2_A;
      *to++ = lb;
      *to++ = (*from >> 8) & 0xff;
      *to++ = *from & 0xff;
      cnt += 4;
    }
    else if (IS_LCPRV2_B_RANGE(lb))
    {
      *to++ = LCPRV2_B;
      *to++ = lb;
      *to++ = (*from >> 8) & 0xff;
      *to++ = *from & 0xff;
      cnt += 4;
    }
    else
    {
      *to++ = *from & 0xff;
      cnt += 1;
    }
    from++;
    len--;
  }
  *to = 0;
  return cnt;
}

int
pg_mule_mblen(const unsigned char *s)
{
  int     len;

  if (IS_LC1(*s))
    len = 2;
  else if (IS_LCPRV1(*s))
    len = 3;
  else if (IS_LC2(*s))
    len = 3;
  else if (IS_LCPRV2(*s))
    len = 4;
  else
    len = 1;       /* assume ASCII */
  return len;
}

static int
pg_mule_dsplen(const unsigned char *s)
{
  int     len;

  /*
   * Note: it's not really appropriate to assume that all multibyte charsets
   * are double-wide on screen.  But this seems an okay approximation for
   * the MULE charsets we currently support.
   */

  if (IS_LC1(*s))
    len = 1;
  else if (IS_LCPRV1(*s))
    len = 1;
  else if (IS_LC2(*s))
    len = 2;
  else if (IS_LCPRV2(*s))
    len = 2;
  else
    len = 1;       /* assume ASCII */

  return len;
}

/*
 * ISO8859-1
 */
static int
pg_latin12wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    *to++ = *from++;
    len--;
    cnt++;
  }
  *to = 0;
  return cnt;
}

/*
 * Trivial conversion from pg_wchar to single byte encoding. Just ignores
 * high bits.
 * caller should allocate enough space for "to"
 * len: length of from.
 * "from" not necessarily null terminated.
 */
static int
pg_wchar2single_with_len(const pg_wchar *from, unsigned char *to, int len)
{
  int     cnt = 0;

  while (len > 0 && *from)
  {
    *to++ = *from++;
    len--;
    cnt++;
  }
  *to = 0;
  return cnt;
}

static int
pg_latin1_mblen(const unsigned char *s)
{
  return 1;
}

static int
pg_latin1_dsplen(const unsigned char *s)
{
  return pg_ascii_dsplen(s);
}

/*
 * SJIS
 */
static int
pg_sjis_mblen(const unsigned char *s)
{
  int     len;

  if (*s >= 0xa1 && *s <= 0xdf)
    len = 1;       /* 1 byte kana? */
  else if (IS_HIGHBIT_SET(*s))
    len = 2;       /* kanji? */
  else
    len = 1;       /* should be ASCII */
  return len;
}

static int
pg_sjis_dsplen(const unsigned char *s)
{
  int     len;

  if (*s >= 0xa1 && *s <= 0xdf)
    len = 1;       /* 1 byte kana? */
  else if (IS_HIGHBIT_SET(*s))
    len = 2;       /* kanji? */
  else
    len = pg_ascii_dsplen(s); /* should be ASCII */
  return len;
}

/*
 * Big5
 */
static int
pg_big5_mblen(const unsigned char *s)
{
  int     len;

  if (IS_HIGHBIT_SET(*s))
    len = 2;       /* kanji? */
  else
    len = 1;       /* should be ASCII */
  return len;
}

static int
pg_big5_dsplen(const unsigned char *s)
{
  int     len;

  if (IS_HIGHBIT_SET(*s))
    len = 2;       /* kanji? */
  else
    len = pg_ascii_dsplen(s); /* should be ASCII */
  return len;
}

/*
 * GBK
 */
static int
pg_gbk_mblen(const unsigned char *s)
{
  int     len;

  if (IS_HIGHBIT_SET(*s))
    len = 2;       /* kanji? */
  else
    len = 1;       /* should be ASCII */
  return len;
}

static int
pg_gbk_dsplen(const unsigned char *s)
{
  int     len;

  if (IS_HIGHBIT_SET(*s))
    len = 2;       /* kanji? */
  else
    len = pg_ascii_dsplen(s); /* should be ASCII */
  return len;
}

/*
 * UHC
 */
static int
pg_uhc_mblen(const unsigned char *s)
{
  int     len;

  if (IS_HIGHBIT_SET(*s))
    len = 2;       /* 2byte? */
  else
    len = 1;       /* should be ASCII */
  return len;
}

static int
pg_uhc_dsplen(const unsigned char *s)
{
  int     len;

  if (IS_HIGHBIT_SET(*s))
    len = 2;       /* 2byte? */
  else
    len = pg_ascii_dsplen(s); /* should be ASCII */
  return len;
}

/*
 * GB18030
 *  Added by Bill Huang <bhuang@redhat.com>,<bill_huanghb@ybb.ne.jp>
 */
static int
pg_gb18030_mblen(const unsigned char *s)
{
  int     len;

  if (!IS_HIGHBIT_SET(*s))
    len = 1;       /* ASCII */
  else if (*(s + 1) >= 0x30 && *(s + 1) <= 0x39)
    len = 4;
  else
    len = 2;
  return len;
}

static int
pg_gb18030_dsplen(const unsigned char *s)
{
  int     len;

  if (IS_HIGHBIT_SET(*s))
    len = 2;
  else
    len = pg_ascii_dsplen(s); /* ASCII */
  return len;
}

/*
 *-------------------------------------------------------------------
 * multibyte sequence validators
 *
 * These functions accept "s", a pointer to the first byte of a string,
 * and "len", the remaining length of the string.  If there is a validly
 * encoded character beginning at *s, return its length in bytes; else
 * return -1.
 *
 * The functions can assume that len > 0 and that *s != '\0', but they must
 * test for and reject zeroes in any additional bytes of a multibyte character.
 *
 * Note that this definition allows the function for a single-byte
 * encoding to be just "return 1".
 *-------------------------------------------------------------------
 */

static int
pg_ascii_verifier(const unsigned char *s, int len)
{
  return 1;
}

#define IS_EUC_RANGE_VALID(c) ((c) >= 0xa1 && (c) <= 0xfe)

static int
pg_eucjp_verifier(const unsigned char *s, int len)
{
  int     l;
  unsigned char c1,
        c2;

  c1 = *s++;

  switch (c1)
  {
    case SS2:       /* JIS X 0201 */
      l = 2;
      if (l > len)
        return -1;
      c2 = *s++;
      if (c2 < 0xa1 || c2 > 0xdf)
        return -1;
      break;

    case SS3:       /* JIS X 0212 */
      l = 3;
      if (l > len)
        return -1;
      c2 = *s++;
      if (!IS_EUC_RANGE_VALID(c2))
        return -1;
      c2 = *s++;
      if (!IS_EUC_RANGE_VALID(c2))
        return -1;
      break;

    default:
      if (IS_HIGHBIT_SET(c1)) /* JIS X 0208? */
      {
        l = 2;
        if (l > len)
          return -1;
        if (!IS_EUC_RANGE_VALID(c1))
          return -1;
        c2 = *s++;
        if (!IS_EUC_RANGE_VALID(c2))
          return -1;
      }
      else
        /* must be ASCII */
      {
        l = 1;
      }
      break;
  }

  return l;
}

static int
pg_euckr_verifier(const unsigned char *s, int len)
{
  int     l;
  unsigned char c1,
        c2;

  c1 = *s++;

  if (IS_HIGHBIT_SET(c1))
  {
    l = 2;
    if (l > len)
      return -1;
    if (!IS_EUC_RANGE_VALID(c1))
      return -1;
    c2 = *s++;
    if (!IS_EUC_RANGE_VALID(c2))
      return -1;
  }
  else
    /* must be ASCII */
  {
    l = 1;
  }

  return l;
}

/* EUC-CN byte sequences are exactly same as EUC-KR */
#define pg_euccn_verifier pg_euckr_verifier

static int
pg_euctw_verifier(const unsigned char *s, int len)
{
  int     l;
  unsigned char c1,
        c2;

  c1 = *s++;

  switch (c1)
  {
    case SS2:       /* CNS 11643 Plane 1-7 */
      l = 4;
      if (l > len)
        return -1;
      c2 = *s++;
      if (c2 < 0xa1 || c2 > 0xa7)
        return -1;
      c2 = *s++;
      if (!IS_EUC_RANGE_VALID(c2))
        return -1;
      c2 = *s++;
      if (!IS_EUC_RANGE_VALID(c2))
        return -1;
      break;

    case SS3:       /* unused */
      return -1;

    default:
      if (IS_HIGHBIT_SET(c1)) /* CNS 11643 Plane 1 */
      {
        l = 2;
        if (l > len)
          return -1;
        /* no further range check on c1? */
        c2 = *s++;
        if (!IS_EUC_RANGE_VALID(c2))
          return -1;
      }
      else
        /* must be ASCII */
      {
        l = 1;
      }
      break;
  }
  return l;
}

static int
pg_johab_verifier(const unsigned char *s, int len)
{
  int     l,
        mbl;
  unsigned char c;

  l = mbl = pg_johab_mblen(s);

  if (len < l)
    return -1;

  if (!IS_HIGHBIT_SET(*s))
    return mbl;

  while (--l > 0)
  {
    c = *++s;
    if (!IS_EUC_RANGE_VALID(c))
      return -1;
  }
  return mbl;
}

static int
pg_mule_verifier(const unsigned char *s, int len)
{
  int     l,
        mbl;
  unsigned char c;

  l = mbl = pg_mule_mblen(s);

  if (len < l)
    return -1;

  while (--l > 0)
  {
    c = *++s;
    if (!IS_HIGHBIT_SET(c))
      return -1;
  }
  return mbl;
}

static int
pg_latin1_verifier(const unsigned char *s, int len)
{
  return 1;
}

static int
pg_sjis_verifier(const unsigned char *s, int len)
{
  int     l,
        mbl;
  unsigned char c1,
        c2;

  l = mbl = pg_sjis_mblen(s);

  if (len < l)
    return -1;

  if (l == 1)         /* pg_sjis_mblen already verified it */
    return mbl;

  c1 = *s++;
  c2 = *s;
  if (!ISSJISHEAD(c1) || !ISSJISTAIL(c2))
    return -1;
  return mbl;
}

static int
pg_big5_verifier(const unsigned char *s, int len)
{
  int     l,
        mbl;

  l = mbl = pg_big5_mblen(s);

  if (len < l)
    return -1;

  while (--l > 0)
  {
    if (*++s == '\0')
      return -1;
  }

  return mbl;
}

static int
pg_gbk_verifier(const unsigned char *s, int len)
{
  int     l,
        mbl;

  l = mbl = pg_gbk_mblen(s);

  if (len < l)
    return -1;

  while (--l > 0)
  {
    if (*++s == '\0')
      return -1;
  }

  return mbl;
}

static int
pg_uhc_verifier(const unsigned char *s, int len)
{
  int     l,
        mbl;

  l = mbl = pg_uhc_mblen(s);

  if (len < l)
    return -1;

  while (--l > 0)
  {
    if (*++s == '\0')
      return -1;
  }

  return mbl;
}

static int
pg_gb18030_verifier(const unsigned char *s, int len)
{
  int     l;

  if (!IS_HIGHBIT_SET(*s))
    l = 1;         /* ASCII */
  else if (len >= 4 && *(s + 1) >= 0x30 && *(s + 1) <= 0x39)
  {
    /* Should be 4-byte, validate remaining bytes */
    if (*s >= 0x81 && *s <= 0xfe &&
      *(s + 2) >= 0x81 && *(s + 2) <= 0xfe &&
      *(s + 3) >= 0x30 && *(s + 3) <= 0x39)
      l = 4;
    else
      l = -1;
  }
  else if (len >= 2 && *s >= 0x81 && *s <= 0xfe)
  {
    /* Should be 2-byte, validate */
    if ((*(s + 1) >= 0x40 && *(s + 1) <= 0x7e) ||
      (*(s + 1) >= 0x80 && *(s + 1) <= 0xfe))
      l = 2;
    else
      l = -1;
  }
  else
    l = -1;
  return l;
}

static int
pg_utf8_verifier(const unsigned char *s, int len)
{
  int     l = pg_utf_mblen(s);

  if (len < l)
    return -1;

  if (!pg_utf8_islegal(s, l))
    return -1;

  return l;
}

/*
 * Check for validity of a single UTF-8 encoded character
 *
 * This directly implements the rules in RFC3629.  The bizarre-looking
 * restrictions on the second byte are meant to ensure that there isn't
 * more than one encoding of a given Unicode character point; that is,
 * you may not use a longer-than-necessary byte sequence with high order
 * zero bits to represent a character that would fit in fewer bytes.
 * To do otherwise is to create security hazards (eg, create an apparent
 * non-ASCII character that decodes to plain ASCII).
 *
 * length is assumed to have been obtained by pg_utf_mblen(), and the
 * caller must have checked that that many bytes are present in the buffer.
 */
bool
pg_utf8_islegal(const unsigned char *source, int length)
{
  unsigned char a;

  switch (length)
  {
    default:
      /* reject lengths 5 and 6 for now */
      return false;
    case 4:
      a = source[3];
      if (a < 0x80 || a > 0xBF)
        return false;
      switch_fallthrough();
    case 3:
      a = source[2];
      if (a < 0x80 || a > 0xBF)
        return false;
      switch_fallthrough();
    case 2:
      a = source[1];
      switch (*source)
      {
        case 0xE0:
          if (a < 0xA0 || a > 0xBF)
            return false;
          break;
        case 0xED:
          if (a < 0x80 || a > 0x9F)
            return false;
          break;
        case 0xF0:
          if (a < 0x90 || a > 0xBF)
            return false;
          break;
        case 0xF4:
          if (a < 0x80 || a > 0x8F)
            return false;
          break;
        default:
          if (a < 0x80 || a > 0xBF)
            return false;
          break;
      }
      switch_fallthrough();
    case 1:
      a = *source;
      if (a >= 0x80 && a < 0xC2)
        return false;
      if (a > 0xF4)
        return false;
      break;
  }
  return true;
}

#ifndef FRONTEND

/*
 * Generic character incrementer function.
 *
 * Not knowing anything about the properties of the encoding in use, we just
 * keep incrementing the last byte until we get a validly-encoded result,
 * or we run out of values to try.  We don't bother to try incrementing
 * higher-order bytes, so there's no growth in runtime for wider characters.
 * (If we did try to do that, we'd need to consider the likelihood that 255
 * is not a valid final byte in the encoding.)
 */
static bool
pg_generic_charinc(unsigned char *charptr, int len)
{
  unsigned char *lastbyte = charptr + len - 1;
  mbverifier  mbverify;

  /* We can just invoke the character verifier directly. */
  mbverify = pg_wchar_table[GetDatabaseEncoding()].mbverify;

  while (*lastbyte < (unsigned char) 255)
  {
    (*lastbyte)++;
    if ((*mbverify) (charptr, len) == len)
      return true;
  }

  return false;
}

/*
 * UTF-8 character incrementer function.
 *
 * For a one-byte character less than 0x7F, we just increment the byte.
 *
 * For a multibyte character, every byte but the first must fall between 0x80
 * and 0xBF; and the first byte must be between 0xC0 and 0xF4.  We increment
 * the last byte that's not already at its maximum value.  If we can't find a
 * byte that's less than the maximum allowable value, we simply fail.  We also
 * need some special-case logic to skip regions used for surrogate pair
 * handling, as those should not occur in valid UTF-8.
 *
 * Note that we don't reset lower-order bytes back to their minimums, since
 * we can't afford to make an exhaustive search (see make_greater_string).
 */
static bool
pg_utf8_increment(unsigned char *charptr, int length)
{
  unsigned char a;
  unsigned char limit;

  switch (length)
  {
    default:
      /* reject lengths 5 and 6 for now */
      return false;
    case 4:
      a = charptr[3];
      if (a < 0xBF)
      {
        charptr[3]++;
        break;
      }
      switch_fallthrough();
    case 3:
      a = charptr[2];
      if (a < 0xBF)
      {
        charptr[2]++;
        break;
      }
      switch_fallthrough();
    case 2:
      a = charptr[1];
      switch (*charptr)
      {
        case 0xED:
          limit = 0x9F;
          break;
        case 0xF4:
          limit = 0x8F;
          break;
        default:
          limit = 0xBF;
          break;
      }
      if (a < limit)
      {
        charptr[1]++;
        break;
      }
      switch_fallthrough();
    case 1:
      a = *charptr;
      if (a == 0x7F || a == 0xDF || a == 0xEF || a == 0xF4)
        return false;
      charptr[0]++;
      break;
  }

  return true;
}

/*
 * EUC-JP character incrementer function.
 *
 * If the sequence starts with SS2 (0x8e), it must be a two-byte sequence
 * representing JIS X 0201 characters with the second byte ranging between
 * 0xa1 and 0xdf.  We just increment the last byte if it's less than 0xdf,
 * and otherwise rewrite the whole sequence to 0xa1 0xa1.
 *
 * If the sequence starts with SS3 (0x8f), it must be a three-byte sequence
 * in which the last two bytes range between 0xa1 and 0xfe.  The last byte
 * is incremented if possible, otherwise the second-to-last byte.
 *
 * If the sequence starts with a value other than the above and its MSB
 * is set, it must be a two-byte sequence representing JIS X 0208 characters
 * with both bytes ranging between 0xa1 and 0xfe.  The last byte is
 * incremented if possible, otherwise the second-to-last byte.
 *
 * Otherwise, the sequence is a single-byte ASCII character. It is
 * incremented up to 0x7f.
 */
static bool
pg_eucjp_increment(unsigned char *charptr, int length)
{
  unsigned char c1,
        c2;
  int     i;

  c1 = *charptr;

  switch (c1)
  {
    case SS2:       /* JIS X 0201 */
      if (length != 2)
        return false;

      c2 = charptr[1];

      if (c2 >= 0xdf)
        charptr[0] = charptr[1] = 0xa1;
      else if (c2 < 0xa1)
        charptr[1] = 0xa1;
      else
        charptr[1]++;
      break;

    case SS3:       /* JIS X 0212 */
      if (length != 3)
        return false;

      for (i = 2; i > 0; i--)
      {
        c2 = charptr[i];
        if (c2 < 0xa1)
        {
          charptr[i] = 0xa1;
          return true;
        }
        else if (c2 < 0xfe)
        {
          charptr[i]++;
          return true;
        }
      }

      /* Out of 3-byte code region */
      return false;

    default:
      if (IS_HIGHBIT_SET(c1)) /* JIS X 0208? */
      {
        if (length != 2)
          return false;

        for (i = 1; i >= 0; i--)
        {
          c2 = charptr[i];
          if (c2 < 0xa1)
          {
            charptr[i] = 0xa1;
            return true;
          }
          else if (c2 < 0xfe)
          {
            charptr[i]++;
            return true;
          }
        }

        /* Out of 2 byte code region */
        return false;
      }
      else
      {         /* ASCII, single byte */
        if (c1 > 0x7e)
          return false;
        (*charptr)++;
      }
      break;
  }

  return true;
}
#endif              /* !FRONTEND */


/*
 *-------------------------------------------------------------------
 * encoding info table
 * XXX must be sorted by the same order as enum pg_enc (in mb/pg_wchar.h)
 *-------------------------------------------------------------------
 */
const pg_wchar_tbl pg_wchar_table[] = {
  {pg_ascii2wchar_with_len, pg_wchar2single_with_len, pg_ascii_mblen, pg_ascii_dsplen, pg_ascii_verifier, 1}, /* PG_SQL_ASCII */
  {pg_eucjp2wchar_with_len, pg_wchar2euc_with_len, pg_eucjp_mblen, pg_eucjp_dsplen, pg_eucjp_verifier, 3},  /* PG_EUC_JP */
  {pg_euccn2wchar_with_len, pg_wchar2euc_with_len, pg_euccn_mblen, pg_euccn_dsplen, pg_euccn_verifier, 2},  /* PG_EUC_CN */
  {pg_euckr2wchar_with_len, pg_wchar2euc_with_len, pg_euckr_mblen, pg_euckr_dsplen, pg_euckr_verifier, 3},  /* PG_EUC_KR */
  {pg_euctw2wchar_with_len, pg_wchar2euc_with_len, pg_euctw_mblen, pg_euctw_dsplen, pg_euctw_verifier, 4},  /* PG_EUC_TW */
  {pg_eucjp2wchar_with_len, pg_wchar2euc_with_len, pg_eucjp_mblen, pg_eucjp_dsplen, pg_eucjp_verifier, 3},  /* PG_EUC_JIS_2004 */
  {pg_utf2wchar_with_len, pg_wchar2utf_with_len, pg_utf_mblen, pg_utf_dsplen, pg_utf8_verifier, 4}, /* PG_UTF8 */
  {pg_mule2wchar_with_len, pg_wchar2mule_with_len, pg_mule_mblen, pg_mule_dsplen, pg_mule_verifier, 4}, /* PG_MULE_INTERNAL */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN1 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN2 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN3 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN4 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN5 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN6 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN7 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN8 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN9 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_LATIN10 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN1256 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN1258 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN866 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN874 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_KOI8R */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN1251 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN1252 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* ISO-8859-5 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* ISO-8859-6 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* ISO-8859-7 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* ISO-8859-8 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN1250 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN1253 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN1254 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN1255 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_WIN1257 */
  {pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1}, /* PG_KOI8U */
  {0, 0, pg_sjis_mblen, pg_sjis_dsplen, pg_sjis_verifier, 2}, /* PG_SJIS */
  {0, 0, pg_big5_mblen, pg_big5_dsplen, pg_big5_verifier, 2}, /* PG_BIG5 */
  {0, 0, pg_gbk_mblen, pg_gbk_dsplen, pg_gbk_verifier, 2},  /* PG_GBK */
  {0, 0, pg_uhc_mblen, pg_uhc_dsplen, pg_uhc_verifier, 2},  /* PG_UHC */
  {0, 0, pg_gb18030_mblen, pg_gb18030_dsplen, pg_gb18030_verifier, 4},  /* PG_GB18030 */
  {0, 0, pg_johab_mblen, pg_johab_dsplen, pg_johab_verifier, 3},  /* PG_JOHAB */
  {0, 0, pg_sjis_mblen, pg_sjis_dsplen, pg_sjis_verifier, 2}  /* PG_SHIFT_JIS_2004 */
};

/* returns the byte length of a word for mule internal code */
int
pg_mic_mblen(const unsigned char *mbstr)
{
  return pg_mule_mblen(mbstr);
}

/*
 * Returns the byte length of a multibyte character.
 */
int
pg_encoding_mblen(int encoding, const char *mbstr)
{
  return (PG_VALID_ENCODING(encoding) ?
      pg_wchar_table[encoding].mblen((const unsigned char *) mbstr) :
      pg_wchar_table[PG_SQL_ASCII].mblen((const unsigned char *) mbstr));
}

/*
 * Returns the display length of a multibyte character.
 */
int
pg_encoding_dsplen(int encoding, const char *mbstr)
{
  return (PG_VALID_ENCODING(encoding) ?
      pg_wchar_table[encoding].dsplen((const unsigned char *) mbstr) :
      pg_wchar_table[PG_SQL_ASCII].dsplen((const unsigned char *) mbstr));
}

/*
 * Verify the first multibyte character of the given string.
 * Return its byte length if good, -1 if bad.  (See comments above for
 * full details of the mbverify API.)
 */
int
pg_encoding_verifymb(int encoding, const char *mbstr, int len)
{
  return (PG_VALID_ENCODING(encoding) ?
      pg_wchar_table[encoding].mbverify((const unsigned char *) mbstr, len) :
      pg_wchar_table[PG_SQL_ASCII].mbverify((const unsigned char *) mbstr, len));
}

/*
 * fetch maximum length of a given encoding
 */
int
pg_encoding_max_length(int encoding)
{
  Assert(PG_VALID_ENCODING(encoding));

  return pg_wchar_table[encoding].maxmblen;
}

#ifndef FRONTEND

/*
 * fetch maximum length of the encoding for the current database
 */
int
pg_database_encoding_max_length(void)
{
  return pg_wchar_table[GetDatabaseEncoding()].maxmblen;
}

/*
 * get the character incrementer for the encoding for the current database
 */
mbcharacter_incrementer
pg_database_encoding_character_incrementer(void)
{
  /*
   * Eventually it might be best to add a field to pg_wchar_table[], but for
   * now we just use a switch.
   */
  switch (GetDatabaseEncoding())
  {
    case PG_UTF8:
      return pg_utf8_increment;

    case PG_EUC_JP:
      return pg_eucjp_increment;

    default:
      return pg_generic_charinc;
  }
}

/*
 * Verify mbstr to make sure that it is validly encoded in the current
 * database encoding.  Otherwise same as pg_verify_mbstr().
 */
bool
pg_verifymbstr(const char *mbstr, int len, bool noError)
{
  return
    pg_verify_mbstr_len(GetDatabaseEncoding(), mbstr, len, noError) >= 0;
}

/*
 * Verify mbstr to make sure that it is validly encoded in the specified
 * encoding.
 */
bool
pg_verify_mbstr(int encoding, const char *mbstr, int len, bool noError)
{
  return pg_verify_mbstr_len(encoding, mbstr, len, noError) >= 0;
}

/*
 * Verify mbstr to make sure that it is validly encoded in the specified
 * encoding.
 *
 * mbstr is not necessarily zero terminated; length of mbstr is
 * specified by len.
 *
 * If OK, return length of string in the encoding.
 * If a problem is found, return -1 when noError is
 * true; when noError is false, ereport() a descriptive message.
 */
int
pg_verify_mbstr_len(int encoding, const char *mbstr, int len, bool noError)
{
  mbverifier  mbverify;
  int     mb_len;

  Assert(PG_VALID_ENCODING(encoding));

  /*
   * In single-byte encodings, we need only reject nulls (\0).
   */
  if (pg_encoding_max_length(encoding) <= 1)
  {
    const char *nullpos = memchr(mbstr, 0, len);

    if (nullpos == NULL)
      return len;
    if (noError)
      return -1;
    report_invalid_encoding(encoding, nullpos, 1);
  }

  /* fetch function pointer just once */
  mbverify = pg_wchar_table[encoding].mbverify;

  mb_len = 0;

  while (len > 0)
  {
    int     l;

    /* fast path for ASCII-subset characters */
    if (!IS_HIGHBIT_SET(*mbstr))
    {
      if (*mbstr != '\0')
      {
        mb_len++;
        mbstr++;
        len--;
        continue;
      }
      if (noError)
        return -1;
      report_invalid_encoding(encoding, mbstr, len);
    }

    l = (*mbverify) ((const unsigned char *) mbstr, len);

    if (l < 0)
    {
      if (noError)
        return -1;
      report_invalid_encoding(encoding, mbstr, len);
    }

    mbstr += l;
    len -= l;
    mb_len++;
  }
  return mb_len;
}

/*
 * check_encoding_conversion_args: check arguments of a conversion function
 *
 * "expected" arguments can be either an encoding ID or -1 to indicate that
 * the caller will check whether it accepts the ID.
 *
 * Note: the errors here are not really user-facing, so elog instead of
 * ereport seems sufficient.  Also, we trust that the "expected" encoding
 * arguments are valid encoding IDs, but we don't trust the actuals.
 */
void
check_encoding_conversion_args(int src_encoding,
                 int dest_encoding,
                 int len,
                 int expected_src_encoding,
                 int expected_dest_encoding)
{
  if (!PG_VALID_ENCODING(src_encoding))
    elog(ERROR, "invalid source encoding ID: %d", src_encoding);
  if (src_encoding != expected_src_encoding && expected_src_encoding >= 0)
    elog(ERROR, "expected source encoding \"%s\", but got \"%s\"",
       pg_enc2name_tbl[expected_src_encoding].name,
       pg_enc2name_tbl[src_encoding].name);
  if (!PG_VALID_ENCODING(dest_encoding))
    elog(ERROR, "invalid destination encoding ID: %d", dest_encoding);
  if (dest_encoding != expected_dest_encoding && expected_dest_encoding >= 0)
    elog(ERROR, "expected destination encoding \"%s\", but got \"%s\"",
       pg_enc2name_tbl[expected_dest_encoding].name,
       pg_enc2name_tbl[dest_encoding].name);
  if (len < 0)
    elog(ERROR, "encoding conversion length must not be negative");
}

/*
 * report_invalid_encoding: complain about invalid multibyte character
 *
 * note: len is remaining length of string, not length of character;
 * len must be greater than zero, as we always examine the first byte.
 */
void
report_invalid_encoding(int encoding, const char *mbstr, int len)
{
  int     l = pg_encoding_mblen(encoding, mbstr);
  char    buf[8 * 5 + 1];
  char     *p = buf;
  int     j,
        jlimit;

  jlimit = Min(l, len);
  jlimit = Min(jlimit, 8);  /* prevent buffer overrun */

  for (j = 0; j < jlimit; j++)
  {
    p += sprintf(p, "0x%02x", (unsigned char) mbstr[j]);
    if (j < jlimit - 1)
      p += sprintf(p, " ");
  }

  ereport(ERROR,
      (errcode(ERRCODE_CHARACTER_NOT_IN_REPERTOIRE),
       errmsg("invalid byte sequence for encoding \"%s\": %s",
          pg_enc2name_tbl[encoding].name,
          buf)));
}

/*
 * report_untranslatable_char: complain about untranslatable character
 *
 * note: len is remaining length of string, not length of character;
 * len must be greater than zero, as we always examine the first byte.
 */
void
report_untranslatable_char(int src_encoding, int dest_encoding,
               const char *mbstr, int len)
{
  int     l = pg_encoding_mblen(src_encoding, mbstr);
  char    buf[8 * 5 + 1];
  char     *p = buf;
  int     j,
        jlimit;

  jlimit = Min(l, len);
  jlimit = Min(jlimit, 8);  /* prevent buffer overrun */

  for (j = 0; j < jlimit; j++)
  {
    p += sprintf(p, "0x%02x", (unsigned char) mbstr[j]);
    if (j < jlimit - 1)
      p += sprintf(p, " ");
  }

  ereport(ERROR,
      (errcode(ERRCODE_UNTRANSLATABLE_CHARACTER),
       errmsg("character with byte sequence %s in encoding \"%s\" has no equivalent in encoding \"%s\"",
          buf,
          pg_enc2name_tbl[src_encoding].name,
          pg_enc2name_tbl[dest_encoding].name)));
}

#endif              /* !FRONTEND */

YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

Coverage Report

Created: 2022-03-09 17:30