Add wchar -> mb conversion routines.

This is infrastructure for Alexander Korotkov's work on indexing regular
expression searches.

Alexander Korotkov, with a bit of further hackery on the MULE conversion
by me

3 files changed, 248 insertions, 45 deletions

diff --git a/src/backend/utils/mb/mbutils.c b/src/backend/utils/mb/mbutils.c
index 848c26f41fb..287ff808fc1 100644
--- a/src/backend/utils/mb/mbutils.c
+++ b/src/backend/utils/mb/mbutils.c
@@ -710,6 +710,28 @@ pg_encoding_mb2wchar_with_len(int encoding,
 	return (*pg_wchar_table[encoding].mb2wchar_with_len) ((const unsigned char *) from, to, len);
 }
 
+/* convert a wchar string to a multibyte */
+int
+pg_wchar2mb(const pg_wchar *from, char *to)
+{
+	return (*pg_wchar_table[DatabaseEncoding->encoding].wchar2mb_with_len) (from, (unsigned char *)to, pg_wchar_strlen(from));
+}
+
+/* convert a wchar string to a multibyte with a limited length */
+int
+pg_wchar2mb_with_len(const pg_wchar *from, char *to, int len)
+{
+	return (*pg_wchar_table[DatabaseEncoding->encoding].wchar2mb_with_len) (from, (unsigned char *)to, len);
+}
+
+/* same, with any encoding */
+int
+pg_encoding_wchar2mb_with_len(int encoding,
+							  const pg_wchar *from, char *to, int len)
+{
+	return (*pg_wchar_table[encoding].wchar2mb_with_len) (from, (unsigned char *)to, len);
+}
+
 /* returns the byte length of a multibyte character */
 int
 pg_mblen(const char *mbstr)
diff --git a/src/backend/utils/mb/wchar.c b/src/backend/utils/mb/wchar.c
index 2e1db5ebf4b..1755be5ebfa 100644
--- a/src/backend/utils/mb/wchar.c
+++ b/src/backend/utils/mb/wchar.c
@@ -340,6 +340,54 @@ pg_euctw_dsplen(const unsigned char *s)
 }
 
 /*
+ * 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++;
+		}		
+		len--;
+	}
+	*to = 0;
+	return cnt;
+}
+
+
+/*
  * JOHAB
  */
 static int
@@ -453,6 +501,30 @@ unicode_to_utf8(pg_wchar c, unsigned char *utf8string)
 	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);
+		len--;
+		cnt += char_len;
+		to += char_len;
+	}
+	*to = 0;
+	return cnt;
+}
 
 /*
  * Return the byte length of a UTF8 character pointed to by s
@@ -719,6 +791,75 @@ pg_mule2wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
 	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;
+	unsigned char lb;
+
+	while (len > 0 && *from)
+	{
+		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++ = lb;
+			cnt += 1;
+		}
+		len--;
+	}
+	*to = 0;
+	return cnt;
+}
+
 int
 pg_mule_mblen(const unsigned char *s)
 {
@@ -780,6 +921,28 @@ pg_latin12wchar_with_len(const unsigned char *from, pg_wchar *to, int len)
 	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)
 {
@@ -1556,48 +1719,48 @@ pg_eucjp_increment(unsigned char *charptr, int length)
  *-------------------------------------------------------------------
  */
 pg_wchar_tbl pg_wchar_table[] = {
-	{pg_ascii2wchar_with_len, pg_ascii_mblen, pg_ascii_dsplen, pg_ascii_verifier, 1},	/* PG_SQL_ASCII */
-	{pg_eucjp2wchar_with_len, pg_eucjp_mblen, pg_eucjp_dsplen, pg_eucjp_verifier, 3},	/* PG_EUC_JP */
-	{pg_euccn2wchar_with_len, pg_euccn_mblen, pg_euccn_dsplen, pg_euccn_verifier, 2},	/* PG_EUC_CN */
-	{pg_euckr2wchar_with_len, pg_euckr_mblen, pg_euckr_dsplen, pg_euckr_verifier, 3},	/* PG_EUC_KR */
-	{pg_euctw2wchar_with_len, pg_euctw_mblen, pg_euctw_dsplen, pg_euctw_verifier, 4},	/* PG_EUC_TW */
-	{pg_eucjp2wchar_with_len, pg_eucjp_mblen, pg_eucjp_dsplen, pg_eucjp_verifier, 3},	/* PG_EUC_JIS_2004 */
-	{pg_utf2wchar_with_len, pg_utf_mblen, pg_utf_dsplen, pg_utf8_verifier, 4},	/* PG_UTF8 */
-	{pg_mule2wchar_with_len, pg_mule_mblen, pg_mule_dsplen, pg_mule_verifier, 4},		/* PG_MULE_INTERNAL */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN1 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN2 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN3 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN4 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN5 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN6 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN7 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN8 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN9 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_LATIN10 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN1256 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN1258 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN866 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN874 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_KOI8R */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN1251 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN1252 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* ISO-8859-5 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* ISO-8859-6 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* ISO-8859-7 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* ISO-8859-8 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN1250 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN1253 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN1254 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN1255 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_WIN1257 */
-	{pg_latin12wchar_with_len, pg_latin1_mblen, pg_latin1_dsplen, pg_latin1_verifier, 1},		/* PG_KOI8U */
-	{0, pg_sjis_mblen, pg_sjis_dsplen, pg_sjis_verifier, 2},	/* PG_SJIS */
-	{0, pg_big5_mblen, pg_big5_dsplen, pg_big5_verifier, 2},	/* PG_BIG5 */
-	{0, pg_gbk_mblen, pg_gbk_dsplen, pg_gbk_verifier, 2},		/* PG_GBK */
-	{0, pg_uhc_mblen, pg_uhc_dsplen, pg_uhc_verifier, 2},		/* PG_UHC */
-	{0, pg_gb18030_mblen, pg_gb18030_dsplen, pg_gb18030_verifier, 4},	/* PG_GB18030 */
-	{0, pg_johab_mblen, pg_johab_dsplen, pg_johab_verifier, 3}, /* PG_JOHAB */
-	{0, pg_sjis_mblen, pg_sjis_dsplen, pg_sjis_verifier, 2}		/* PG_SHIFT_JIS_2004 */
+	{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 */
diff --git a/src/include/mb/pg_wchar.h b/src/include/mb/pg_wchar.h
index 1d6d9554bd4..1bcdfbceb93 100644
--- a/src/include/mb/pg_wchar.h
+++ b/src/include/mb/pg_wchar.h
@@ -140,6 +140,10 @@ typedef unsigned int pg_wchar;
 #define LCPRV1_A		0x9a
 #define LCPRV1_B		0x9b
 #define IS_LCPRV1(c)	((unsigned char)(c) == LCPRV1_A || (unsigned char)(c) == LCPRV1_B)
+#define IS_LCPRV1_A_RANGE(c)	\
+	((unsigned char)(c) >= 0xa0 && (unsigned char)(c) <= 0xdf)
+#define IS_LCPRV1_B_RANGE(c)	\
+	((unsigned char)(c) >= 0xe0 && (unsigned char)(c) <= 0xef)
 
 /*
  * Postgres-specific prefix bytes for "private" multibyte encodings
@@ -148,6 +152,10 @@ typedef unsigned int pg_wchar;
 #define LCPRV2_A		0x9c
 #define LCPRV2_B		0x9d
 #define IS_LCPRV2(c)	((unsigned char)(c) == LCPRV2_A || (unsigned char)(c) == LCPRV2_B)
+#define IS_LCPRV2_A_RANGE(c)	\
+	((unsigned char)(c) >= 0xf0 && (unsigned char)(c) <= 0xf4)
+#define IS_LCPRV2_B_RANGE(c)	\
+	((unsigned char)(c) >= 0xf5 && (unsigned char)(c) <= 0xfe)
 
 /*
  * Charset IDs for private single byte encodings (0xa0-0xef)
@@ -324,7 +332,11 @@ extern pg_enc2gettext pg_enc2gettext_tbl[];
  * pg_wchar stuff
  */
 typedef int (*mb2wchar_with_len_converter) (const unsigned char *from,
-														pg_wchar *to,
+													pg_wchar *to,
+													int len);
+
+typedef int (*wchar2mb_with_len_converter) (const pg_wchar *from,
+														unsigned char *to,
 														int len);
 
 typedef int (*mblen_converter) (const unsigned char *mbstr);
@@ -337,8 +349,10 @@ typedef int (*mbverifier) (const unsigned char *mbstr, int len);
 
 typedef struct
 {
-	mb2wchar_with_len_converter mb2wchar_with_len;		/* convert a multibyte
-														 * string to a wchar */
+	mb2wchar_with_len_converter mb2wchar_with_len;	/* convert a multibyte
+													 * string to a wchar */
+	wchar2mb_with_len_converter wchar2mb_with_len;	/* convert a wchar
+													 * string to a multibyte */
 	mblen_converter mblen;		/* get byte length of a char */
 	mbdisplaylen_converter dsplen;		/* get display width of a char */
 	mbverifier	mbverify;		/* verify multibyte sequence */
@@ -419,6 +433,10 @@ extern int	pg_mb2wchar(const char *from, pg_wchar *to);
 extern int	pg_mb2wchar_with_len(const char *from, pg_wchar *to, int len);
 extern int pg_encoding_mb2wchar_with_len(int encoding,
 							  const char *from, pg_wchar *to, int len);
+extern int	pg_wchar2mb(const pg_wchar *from, char *to);
+extern int	pg_wchar2mb_with_len(const pg_wchar *from, char *to, int len);
+extern int pg_encoding_wchar2mb_with_len(int encoding,
+							  const pg_wchar *from, char *to, int len);
 extern int	pg_char_and_wchar_strcmp(const char *s1, const pg_wchar *s2);
 extern int	pg_wchar_strncmp(const pg_wchar *s1, const pg_wchar *s2, size_t n);
 extern int	pg_char_and_wchar_strncmp(const char *s1, const pg_wchar *s2, size_t n);