Adding upstream version 15.5.upstream/15.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2192 insertions, 0 deletions

diff --git a/src/common/wchar.c b/src/common/wchar.c
new file mode 100644
index 0000000..1e6e198
--- /dev/null
+++ b/src/common/wchar.c
@@ -0,0 +1,2192 @@
+/*-------------------------------------------------------------------------
+ *
+ * wchar.c
+ *	  Functions for working with multibyte characters in various encodings.
+ *
+ * Portions Copyright (c) 1998-2022, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  src/common/wchar.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "c.h"
+
+#include "mb/pg_wchar.h"
+
+
+/*
+ * Operations on multi-byte encodings are driven by a table of helper
+ * functions.
+ *
+ * To add an encoding support, define mblen(), dsplen(), verifychar() and
+ * verifystr() for the encoding.  For server-encodings, also define mb2wchar()
+ * and wchar2mb() conversion functions.
+ *
+ * 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.  GB18030 is an exception
+ * to that rule, though, as it also looks at second byte.  But even that
+ * behaves in a predictable way, if you only pass the first byte: it will
+ * treat 4-byte encoded characters as two 2-byte encoded characters, which is
+ * good enough for all current uses.
+ *
+ * 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.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 int first;
+	unsigned int 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.
+ *
+ *	  - 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)
+{
+#include "common/unicode_combining_table.h"
+#include "common/unicode_east_asian_fw_table.h"
+
+	/* 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
+	 *
+	 * XXX: In the official Unicode sources, it is possible for a character to
+	 * be described as both non-spacing and wide at the same time. As of
+	 * Unicode 13.0, treating the non-spacing property as the determining
+	 * factor for display width leads to the correct behavior, so do that
+	 * search first.
+	 */
+	if (mbbisearch(ucs, combining,
+				   sizeof(combining) / sizeof(struct mbinterval) - 1))
+		return 0;
+
+	/* binary search in table of wide characters */
+	if (mbbisearch(ucs, east_asian_fw,
+				   sizeof(east_asian_fw) / sizeof(struct mbinterval) - 1))
+		return 2;
+
+	return 1;
+}
+
+/*
+ * 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;
+}
+
+/* exported for direct use by conv.c */
+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>
+ */
+
+/*
+ * Unlike all other mblen() functions, this also looks at the second byte of
+ * the input.  However, if you only pass the first byte of a multi-byte
+ * string, and \0 as the second byte, this still works in a predictable way:
+ * a 4-byte character will be reported as two 2-byte characters.  That's
+ * enough for all current uses, as a client-only encoding.  It works that
+ * way, because in any valid 4-byte GB18030-encoded character, the third and
+ * fourth byte look like a 2-byte encoded character, when looked at
+ * separately.
+ */
+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
+ *
+ * The verifychar 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 verifystr functions also accept "s", a pointer to a string and "len",
+ * the length of the string.  They verify the whole string, and return the
+ * number of input bytes (<= len) that are valid.  In other words, if the
+ * whole string is valid, verifystr returns "len", otherwise it returns the
+ * byte offset of the first invalid character.  The verifystr functions must
+ * test for and reject zeroes in the input.
+ *
+ * The verifychar 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_verifychar(const unsigned char *s, int len)
+{
+	return 1;
+}
+
+static int
+pg_ascii_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *nullpos = memchr(s, 0, len);
+
+	if (nullpos == NULL)
+		return len;
+	else
+		return nullpos - s;
+}
+
+#define IS_EUC_RANGE_VALID(c)	((c) >= 0xa1 && (c) <= 0xfe)
+
+static int
+pg_eucjp_verifychar(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_eucjp_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_eucjp_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+static int
+pg_euckr_verifychar(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;
+}
+
+static int
+pg_euckr_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_euckr_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+/* EUC-CN byte sequences are exactly same as EUC-KR */
+#define pg_euccn_verifychar	pg_euckr_verifychar
+#define pg_euccn_verifystr	pg_euckr_verifystr
+
+static int
+pg_euctw_verifychar(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_euctw_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_euctw_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+static int
+pg_johab_verifychar(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_johab_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_johab_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+static int
+pg_mule_verifychar(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_mule_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_mule_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+static int
+pg_latin1_verifychar(const unsigned char *s, int len)
+{
+	return 1;
+}
+
+static int
+pg_latin1_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *nullpos = memchr(s, 0, len);
+
+	if (nullpos == NULL)
+		return len;
+	else
+		return nullpos - s;
+}
+
+static int
+pg_sjis_verifychar(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_sjis_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_sjis_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+static int
+pg_big5_verifychar(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_big5_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_big5_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+static int
+pg_gbk_verifychar(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_gbk_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_gbk_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+static int
+pg_uhc_verifychar(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_uhc_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_uhc_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+static int
+pg_gb18030_verifychar(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_gb18030_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_gb18030_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+static int
+pg_utf8_verifychar(const unsigned char *s, int len)
+{
+	int			l;
+
+	if ((*s & 0x80) == 0)
+	{
+		if (*s == '\0')
+			return -1;
+		return 1;
+	}
+	else if ((*s & 0xe0) == 0xc0)
+		l = 2;
+	else if ((*s & 0xf0) == 0xe0)
+		l = 3;
+	else if ((*s & 0xf8) == 0xf0)
+		l = 4;
+	else
+		l = 1;
+
+	if (l > len)
+		return -1;
+
+	if (!pg_utf8_islegal(s, l))
+		return -1;
+
+	return l;
+}
+
+/*
+ * The fast path of the UTF-8 verifier uses a deterministic finite automaton
+ * (DFA) for multibyte characters. In a traditional table-driven DFA, the
+ * input byte and current state are used to compute an index into an array of
+ * state transitions. Since the address of the next transition is dependent
+ * on this computation, there is latency in executing the load instruction,
+ * and the CPU is not kept busy.
+ *
+ * Instead, we use a "shift-based" DFA as described by Per Vognsen:
+ *
+ * https://gist.github.com/pervognsen/218ea17743e1442e59bb60d29b1aa725
+ *
+ * In a shift-based DFA, the input byte is an index into array of integers
+ * whose bit pattern encodes the state transitions. To compute the next
+ * state, we simply right-shift the integer by the current state and apply a
+ * mask. In this scheme, the address of the transition only depends on the
+ * input byte, so there is better pipelining.
+ *
+ * The naming convention for states and transitions was adopted from a UTF-8
+ * to UTF-16/32 transcoder, whose table is reproduced below:
+ *
+ * https://github.com/BobSteagall/utf_utils/blob/6b7a465265de2f5fa6133d653df0c9bdd73bbcf8/src/utf_utils.cpp
+ *
+ * ILL  ASC  CR1  CR2  CR3  L2A  L3A  L3B  L3C  L4A  L4B  L4C CLASS / STATE
+ * ==========================================================================
+ * err, END, err, err, err, CS1, P3A, CS2, P3B, P4A, CS3, P4B,      | BGN/END
+ * err, err, err, err, err, err, err, err, err, err, err, err,      | ERR
+ *                                                                  |
+ * err, err, END, END, END, err, err, err, err, err, err, err,      | CS1
+ * err, err, CS1, CS1, CS1, err, err, err, err, err, err, err,      | CS2
+ * err, err, CS2, CS2, CS2, err, err, err, err, err, err, err,      | CS3
+ *                                                                  |
+ * err, err, err, err, CS1, err, err, err, err, err, err, err,      | P3A
+ * err, err, CS1, CS1, err, err, err, err, err, err, err, err,      | P3B
+ *                                                                  |
+ * err, err, err, CS2, CS2, err, err, err, err, err, err, err,      | P4A
+ * err, err, CS2, err, err, err, err, err, err, err, err, err,      | P4B
+ *
+ * In the most straightforward implementation, a shift-based DFA for UTF-8
+ * requires 64-bit integers to encode the transitions, but with an SMT solver
+ * it's possible to find state numbers such that the transitions fit within
+ * 32-bit integers, as Dougall Johnson demonstrated:
+ *
+ * https://gist.github.com/dougallj/166e326de6ad4cf2c94be97a204c025f
+ *
+ * This packed representation is the reason for the seemingly odd choice of
+ * state values below.
+ */
+
+/* Error */
+#define	ERR  0
+/* Begin */
+#define	BGN 11
+/* Continuation states, expect 1/2/3 continuation bytes */
+#define	CS1 16
+#define	CS2  1
+#define	CS3  5
+/* Partial states, where the first continuation byte has a restricted range */
+#define	P3A  6					/* Lead was E0, check for 3-byte overlong */
+#define	P3B 20					/* Lead was ED, check for surrogate */
+#define	P4A 25					/* Lead was F0, check for 4-byte overlong */
+#define	P4B 30					/* Lead was F4, check for too-large */
+/* Begin and End are the same state */
+#define	END BGN
+
+/* the encoded state transitions for the lookup table */
+
+/* ASCII */
+#define ASC (END << BGN)
+/* 2-byte lead */
+#define L2A (CS1 << BGN)
+/* 3-byte lead */
+#define L3A (P3A << BGN)
+#define L3B (CS2 << BGN)
+#define L3C (P3B << BGN)
+/* 4-byte lead */
+#define L4A (P4A << BGN)
+#define L4B (CS3 << BGN)
+#define L4C (P4B << BGN)
+/* continuation byte */
+#define CR1 (END << CS1) | (CS1 << CS2) | (CS2 << CS3) | (CS1 << P3B) | (CS2 << P4B)
+#define CR2 (END << CS1) | (CS1 << CS2) | (CS2 << CS3) | (CS1 << P3B) | (CS2 << P4A)
+#define CR3 (END << CS1) | (CS1 << CS2) | (CS2 << CS3) | (CS1 << P3A) | (CS2 << P4A)
+/* invalid byte */
+#define ILL ERR
+
+static const uint32 Utf8Transition[256] =
+{
+	/* ASCII */
+
+	ILL, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+	ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,
+
+	/* continuation bytes */
+
+	/* 80..8F */
+	CR1, CR1, CR1, CR1, CR1, CR1, CR1, CR1,
+	CR1, CR1, CR1, CR1, CR1, CR1, CR1, CR1,
+
+	/* 90..9F */
+	CR2, CR2, CR2, CR2, CR2, CR2, CR2, CR2,
+	CR2, CR2, CR2, CR2, CR2, CR2, CR2, CR2,
+
+	/* A0..BF */
+	CR3, CR3, CR3, CR3, CR3, CR3, CR3, CR3,
+	CR3, CR3, CR3, CR3, CR3, CR3, CR3, CR3,
+	CR3, CR3, CR3, CR3, CR3, CR3, CR3, CR3,
+	CR3, CR3, CR3, CR3, CR3, CR3, CR3, CR3,
+
+	/* leading bytes */
+
+	/* C0..DF */
+	ILL, ILL, L2A, L2A, L2A, L2A, L2A, L2A,
+	L2A, L2A, L2A, L2A, L2A, L2A, L2A, L2A,
+	L2A, L2A, L2A, L2A, L2A, L2A, L2A, L2A,
+	L2A, L2A, L2A, L2A, L2A, L2A, L2A, L2A,
+
+	/* E0..EF */
+	L3A, L3B, L3B, L3B, L3B, L3B, L3B, L3B,
+	L3B, L3B, L3B, L3B, L3B, L3C, L3B, L3B,
+
+	/* F0..FF */
+	L4A, L4B, L4B, L4B, L4C, ILL, ILL, ILL,
+	ILL, ILL, ILL, ILL, ILL, ILL, ILL, ILL
+};
+
+static void
+utf8_advance(const unsigned char *s, uint32 *state, int len)
+{
+	/* Note: We deliberately don't check the state's value here. */
+	while (len > 0)
+	{
+		/*
+		 * It's important that the mask value is 31: In most instruction sets,
+		 * a shift by a 32-bit operand is understood to be a shift by its mod
+		 * 32, so the compiler should elide the mask operation.
+		 */
+		*state = Utf8Transition[*s++] >> (*state & 31);
+		len--;
+	}
+
+	*state &= 31;
+}
+
+static int
+pg_utf8_verifystr(const unsigned char *s, int len)
+{
+	const unsigned char *start = s;
+	const int	orig_len = len;
+	uint32		state = BGN;
+
+/*
+ * Sixteen seems to give the best balance of performance across different
+ * byte distributions.
+ */
+#define STRIDE_LENGTH 16
+
+	if (len >= STRIDE_LENGTH)
+	{
+		while (len >= STRIDE_LENGTH)
+		{
+			/*
+			 * If the chunk is all ASCII, we can skip the full UTF-8 check,
+			 * but we must first check for a non-END state, which means the
+			 * previous chunk ended in the middle of a multibyte sequence.
+			 */
+			if (state != END || !is_valid_ascii(s, STRIDE_LENGTH))
+				utf8_advance(s, &state, STRIDE_LENGTH);
+
+			s += STRIDE_LENGTH;
+			len -= STRIDE_LENGTH;
+		}
+
+		/* The error state persists, so we only need to check for it here. */
+		if (state == ERR)
+		{
+			/*
+			 * Start over from the beginning with the slow path so we can
+			 * count the valid bytes.
+			 */
+			len = orig_len;
+			s = start;
+		}
+		else if (state != END)
+		{
+			/*
+			 * The fast path exited in the middle of a multibyte sequence.
+			 * Walk backwards to find the leading byte so that the slow path
+			 * can resume checking from there. We must always backtrack at
+			 * least one byte, since the current byte could be e.g. an ASCII
+			 * byte after a 2-byte lead, which is invalid.
+			 */
+			do
+			{
+				Assert(s > start);
+				s--;
+				len++;
+				Assert(IS_HIGHBIT_SET(*s));
+			} while (pg_utf_mblen(s) <= 1);
+		}
+	}
+
+	/* check remaining bytes */
+	while (len > 0)
+	{
+		int			l;
+
+		/* fast path for ASCII-subset characters */
+		if (!IS_HIGHBIT_SET(*s))
+		{
+			if (*s == '\0')
+				break;
+			l = 1;
+		}
+		else
+		{
+			l = pg_utf8_verifychar(s, len);
+			if (l == -1)
+				break;
+		}
+		s += l;
+		len -= l;
+	}
+
+	return s - start;
+}
+
+/*
+ * 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;
+			/* FALL THRU */
+		case 3:
+			a = source[2];
+			if (a < 0x80 || a > 0xBF)
+				return false;
+			/* FALL THRU */
+		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;
+			}
+			/* FALL THRU */
+		case 1:
+			a = *source;
+			if (a >= 0x80 && a < 0xC2)
+				return false;
+			if (a > 0xF4)
+				return false;
+			break;
+	}
+	return true;
+}
+
+
+/*
+ *-------------------------------------------------------------------
+ * 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_verifychar, pg_ascii_verifystr, 1},	/* PG_SQL_ASCII */
+	{pg_eucjp2wchar_with_len, pg_wchar2euc_with_len, pg_eucjp_mblen, pg_eucjp_dsplen, pg_eucjp_verifychar, pg_eucjp_verifystr, 3},	/* PG_EUC_JP */
+	{pg_euccn2wchar_with_len, pg_wchar2euc_with_len, pg_euccn_mblen, pg_euccn_dsplen, pg_euccn_verifychar, pg_euccn_verifystr, 2},	/* PG_EUC_CN */
+	{pg_euckr2wchar_with_len, pg_wchar2euc_with_len, pg_euckr_mblen, pg_euckr_dsplen, pg_euckr_verifychar, pg_euckr_verifystr, 3},	/* PG_EUC_KR */
+	{pg_euctw2wchar_with_len, pg_wchar2euc_with_len, pg_euctw_mblen, pg_euctw_dsplen, pg_euctw_verifychar, pg_euctw_verifystr, 4},	/* PG_EUC_TW */
+	{pg_eucjp2wchar_with_len, pg_wchar2euc_with_len, pg_eucjp_mblen, pg_eucjp_dsplen, pg_eucjp_verifychar, pg_eucjp_verifystr, 3},	/* PG_EUC_JIS_2004 */
+	{pg_utf2wchar_with_len, pg_wchar2utf_with_len, pg_utf_mblen, pg_utf_dsplen, pg_utf8_verifychar, pg_utf8_verifystr, 4},	/* PG_UTF8 */
+	{pg_mule2wchar_with_len, pg_wchar2mule_with_len, pg_mule_mblen, pg_mule_dsplen, pg_mule_verifychar, pg_mule_verifystr, 4},	/* PG_MULE_INTERNAL */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN1 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN2 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN3 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN4 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN5 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN6 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN7 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN8 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN9 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_LATIN10 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN1256 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN1258 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN866 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN874 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_KOI8R */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN1251 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN1252 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* ISO-8859-5 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* ISO-8859-6 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* ISO-8859-7 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* ISO-8859-8 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN1250 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN1253 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN1254 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN1255 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_WIN1257 */
+	{pg_latin12wchar_with_len, pg_wchar2single_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifychar, pg_latin1_verifystr, 1},	/* PG_KOI8U */
+	{0, 0, pg_sjis_mblen, pg_sjis_dsplen, pg_sjis_verifychar, pg_sjis_verifystr, 2},	/* PG_SJIS */
+	{0, 0, pg_big5_mblen, pg_big5_dsplen, pg_big5_verifychar, pg_big5_verifystr, 2},	/* PG_BIG5 */
+	{0, 0, pg_gbk_mblen, pg_gbk_dsplen, pg_gbk_verifychar, pg_gbk_verifystr, 2},	/* PG_GBK */
+	{0, 0, pg_uhc_mblen, pg_uhc_dsplen, pg_uhc_verifychar, pg_uhc_verifystr, 2},	/* PG_UHC */
+	{0, 0, pg_gb18030_mblen, pg_gb18030_dsplen, pg_gb18030_verifychar, pg_gb18030_verifystr, 4},	/* PG_GB18030 */
+	{0, 0, pg_johab_mblen, pg_johab_dsplen, pg_johab_verifychar, pg_johab_verifystr, 3},	/* PG_JOHAB */
+	{0, 0, pg_sjis_mblen, pg_sjis_dsplen, pg_sjis_verifychar, pg_sjis_verifystr, 2} /* PG_SHIFT_JIS_2004 */
+};
+
+/*
+ * Returns the byte length of a multibyte character.
+ *
+ * Caution: when dealing with text that is not certainly valid in the
+ * specified encoding, the result may exceed the actual remaining
+ * string length.  Callers that are not prepared to deal with that
+ * should use pg_encoding_mblen_bounded() instead.
+ */
+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 byte length of a multibyte character; but not more than
+ * the distance to end of string.
+ */
+int
+pg_encoding_mblen_bounded(int encoding, const char *mbstr)
+{
+	return strnlen(mbstr, pg_encoding_mblen(encoding, 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 mbverifychar API.)
+ */
+int
+pg_encoding_verifymbchar(int encoding, const char *mbstr, int len)
+{
+	return (PG_VALID_ENCODING(encoding) ?
+			pg_wchar_table[encoding].mbverifychar((const unsigned char *) mbstr, len) :
+			pg_wchar_table[PG_SQL_ASCII].mbverifychar((const unsigned char *) mbstr, len));
+}
+
+/*
+ * Verify that a string is valid for the given encoding.
+ * Returns the number of input bytes (<= len) that form a valid string.
+ * (See comments above for full details of the mbverifystr API.)
+ */
+int
+pg_encoding_verifymbstr(int encoding, const char *mbstr, int len)
+{
+	return (PG_VALID_ENCODING(encoding) ?
+			pg_wchar_table[encoding].mbverifystr((const unsigned char *) mbstr, len) :
+			pg_wchar_table[PG_SQL_ASCII].mbverifystr((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;
+}