Adding upstream version 16.2.upstream/16.2

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

1 files changed, 703 insertions, 0 deletions

diff --git a/src/include/mb/pg_wchar.h b/src/include/mb/pg_wchar.h
new file mode 100644
index 0000000..06a56a4
--- /dev/null
+++ b/src/include/mb/pg_wchar.h
@@ -0,0 +1,703 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_wchar.h
+ *	  multibyte-character support
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/mb/pg_wchar.h
+ *
+ *	NOTES
+ *		This is used both by the backend and by frontends, but should not be
+ *		included by libpq client programs.  In particular, a libpq client
+ *		should not assume that the encoding IDs used by the version of libpq
+ *		it's linked to match up with the IDs declared here.
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_WCHAR_H
+#define PG_WCHAR_H
+
+/*
+ * The pg_wchar type
+ */
+typedef unsigned int pg_wchar;
+
+/*
+ * Maximum byte length of multibyte characters in any backend encoding
+ */
+#define MAX_MULTIBYTE_CHAR_LEN	4
+
+/*
+ * various definitions for EUC
+ */
+#define SS2 0x8e				/* single shift 2 (JIS0201) */
+#define SS3 0x8f				/* single shift 3 (JIS0212) */
+
+/*
+ * SJIS validation macros
+ */
+#define ISSJISHEAD(c) (((c) >= 0x81 && (c) <= 0x9f) || ((c) >= 0xe0 && (c) <= 0xfc))
+#define ISSJISTAIL(c) (((c) >= 0x40 && (c) <= 0x7e) || ((c) >= 0x80 && (c) <= 0xfc))
+
+/*----------------------------------------------------
+ * MULE Internal Encoding (MIC)
+ *
+ * This encoding follows the design used within XEmacs; it is meant to
+ * subsume many externally-defined character sets.  Each character includes
+ * identification of the character set it belongs to, so the encoding is
+ * general but somewhat bulky.
+ *
+ * Currently PostgreSQL supports 5 types of MULE character sets:
+ *
+ * 1) 1-byte ASCII characters.  Each byte is below 0x80.
+ *
+ * 2) "Official" single byte charsets such as ISO-8859-1 (Latin1).
+ *	  Each MULE character consists of 2 bytes: LC1 + C1, where LC1 is
+ *	  an identifier for the charset (in the range 0x81 to 0x8d) and C1
+ *	  is the character code (in the range 0xa0 to 0xff).
+ *
+ * 3) "Private" single byte charsets such as SISHENG.  Each MULE
+ *	  character consists of 3 bytes: LCPRV1 + LC12 + C1, where LCPRV1
+ *	  is a private-charset flag, LC12 is an identifier for the charset,
+ *	  and C1 is the character code (in the range 0xa0 to 0xff).
+ *	  LCPRV1 is either 0x9a (if LC12 is in the range 0xa0 to 0xdf)
+ *	  or 0x9b (if LC12 is in the range 0xe0 to 0xef).
+ *
+ * 4) "Official" multibyte charsets such as JIS X0208.  Each MULE
+ *	  character consists of 3 bytes: LC2 + C1 + C2, where LC2 is
+ *	  an identifier for the charset (in the range 0x90 to 0x99) and C1
+ *	  and C2 form the character code (each in the range 0xa0 to 0xff).
+ *
+ * 5) "Private" multibyte charsets such as CNS 11643-1992 Plane 3.
+ *	  Each MULE character consists of 4 bytes: LCPRV2 + LC22 + C1 + C2,
+ *	  where LCPRV2 is a private-charset flag, LC22 is an identifier for
+ *	  the charset, and C1 and C2 form the character code (each in the range
+ *	  0xa0 to 0xff).  LCPRV2 is either 0x9c (if LC22 is in the range 0xf0
+ *	  to 0xf4) or 0x9d (if LC22 is in the range 0xf5 to 0xfe).
+ *
+ * "Official" encodings are those that have been assigned code numbers by
+ * the XEmacs project; "private" encodings have Postgres-specific charset
+ * identifiers.
+ *
+ * See the "XEmacs Internals Manual", available at http://www.xemacs.org,
+ * for more details.  Note that for historical reasons, Postgres'
+ * private-charset flag values do not match what XEmacs says they should be,
+ * so this isn't really exactly MULE (not that private charsets would be
+ * interoperable anyway).
+ *
+ * Note that XEmacs's implementation is different from what emacs does.
+ * We follow emacs's implementation, rather than XEmacs's.
+ *----------------------------------------------------
+ */
+
+/*
+ * Charset identifiers (also called "leading bytes" in the MULE documentation)
+ */
+
+/*
+ * Charset IDs for official single byte encodings (0x81-0x8e)
+ */
+#define LC_ISO8859_1		0x81	/* ISO8859 Latin 1 */
+#define LC_ISO8859_2		0x82	/* ISO8859 Latin 2 */
+#define LC_ISO8859_3		0x83	/* ISO8859 Latin 3 */
+#define LC_ISO8859_4		0x84	/* ISO8859 Latin 4 */
+#define LC_TIS620			0x85	/* Thai (not supported yet) */
+#define LC_ISO8859_7		0x86	/* Greek (not supported yet) */
+#define LC_ISO8859_6		0x87	/* Arabic (not supported yet) */
+#define LC_ISO8859_8		0x88	/* Hebrew (not supported yet) */
+#define LC_JISX0201K		0x89	/* Japanese 1 byte kana */
+#define LC_JISX0201R		0x8a	/* Japanese 1 byte Roman */
+/* Note that 0x8b seems to be unused as of Emacs 20.7.
+ * However, there might be a chance that 0x8b could be used
+ * in later versions of Emacs.
+ */
+#define LC_KOI8_R			0x8b	/* Cyrillic KOI8-R */
+#define LC_ISO8859_5		0x8c	/* ISO8859 Cyrillic */
+#define LC_ISO8859_9		0x8d	/* ISO8859 Latin 5 (not supported yet) */
+#define LC_ISO8859_15		0x8e	/* ISO8859 Latin 15 (not supported yet) */
+/* #define CONTROL_1		0x8f	control characters (unused) */
+
+/* Is a leading byte for "official" single byte encodings? */
+#define IS_LC1(c)	((unsigned char)(c) >= 0x81 && (unsigned char)(c) <= 0x8d)
+
+/*
+ * Charset IDs for official multibyte encodings (0x90-0x99)
+ * 0x9a-0x9d are free. 0x9e and 0x9f are reserved.
+ */
+#define LC_JISX0208_1978	0x90	/* Japanese Kanji, old JIS (not supported) */
+#define LC_GB2312_80		0x91	/* Chinese */
+#define LC_JISX0208			0x92	/* Japanese Kanji (JIS X 0208) */
+#define LC_KS5601			0x93	/* Korean */
+#define LC_JISX0212			0x94	/* Japanese Kanji (JIS X 0212) */
+#define LC_CNS11643_1		0x95	/* CNS 11643-1992 Plane 1 */
+#define LC_CNS11643_2		0x96	/* CNS 11643-1992 Plane 2 */
+#define LC_JISX0213_1		0x97	/* Japanese Kanji (JIS X 0213 Plane 1)
+									 * (not supported) */
+#define LC_BIG5_1			0x98	/* Plane 1 Chinese traditional (not
+									 * supported) */
+#define LC_BIG5_2			0x99	/* Plane 1 Chinese traditional (not
+									 * supported) */
+
+/* Is a leading byte for "official" multibyte encodings? */
+#define IS_LC2(c)	((unsigned char)(c) >= 0x90 && (unsigned char)(c) <= 0x99)
+
+/*
+ * Postgres-specific prefix bytes for "private" single byte encodings
+ * (According to the MULE docs, we should be using 0x9e for this)
+ */
+#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
+ * (According to the MULE docs, we should be using 0x9f for this)
+ */
+#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)
+ */
+#define LC_SISHENG			0xa0	/* Chinese SiSheng characters for
+									 * PinYin/ZhuYin (not supported) */
+#define LC_IPA				0xa1	/* IPA (International Phonetic
+									 * Association) (not supported) */
+#define LC_VISCII_LOWER		0xa2	/* Vietnamese VISCII1.1 lower-case (not
+									 * supported) */
+#define LC_VISCII_UPPER		0xa3	/* Vietnamese VISCII1.1 upper-case (not
+									 * supported) */
+#define LC_ARABIC_DIGIT		0xa4	/* Arabic digit (not supported) */
+#define LC_ARABIC_1_COLUMN	0xa5	/* Arabic 1-column (not supported) */
+#define LC_ASCII_RIGHT_TO_LEFT	0xa6	/* ASCII (left half of ISO8859-1) with
+										 * right-to-left direction (not
+										 * supported) */
+#define LC_LAO				0xa7	/* Lao characters (ISO10646 0E80..0EDF)
+									 * (not supported) */
+#define LC_ARABIC_2_COLUMN	0xa8	/* Arabic 1-column (not supported) */
+
+/*
+ * Charset IDs for private multibyte encodings (0xf0-0xff)
+ */
+#define LC_INDIAN_1_COLUMN	0xf0	/* Indian charset for 1-column width
+									 * glyphs (not supported) */
+#define LC_TIBETAN_1_COLUMN 0xf1	/* Tibetan 1-column width glyphs (not
+									 * supported) */
+#define LC_UNICODE_SUBSET_2 0xf2	/* Unicode characters of the range
+									 * U+2500..U+33FF. (not supported) */
+#define LC_UNICODE_SUBSET_3 0xf3	/* Unicode characters of the range
+									 * U+E000..U+FFFF. (not supported) */
+#define LC_UNICODE_SUBSET	0xf4	/* Unicode characters of the range
+									 * U+0100..U+24FF. (not supported) */
+#define LC_ETHIOPIC			0xf5	/* Ethiopic characters (not supported) */
+#define LC_CNS11643_3		0xf6	/* CNS 11643-1992 Plane 3 */
+#define LC_CNS11643_4		0xf7	/* CNS 11643-1992 Plane 4 */
+#define LC_CNS11643_5		0xf8	/* CNS 11643-1992 Plane 5 */
+#define LC_CNS11643_6		0xf9	/* CNS 11643-1992 Plane 6 */
+#define LC_CNS11643_7		0xfa	/* CNS 11643-1992 Plane 7 */
+#define LC_INDIAN_2_COLUMN	0xfb	/* Indian charset for 2-column width
+									 * glyphs (not supported) */
+#define LC_TIBETAN			0xfc	/* Tibetan (not supported) */
+/* #define FREE				0xfd	free (unused) */
+/* #define FREE				0xfe	free (unused) */
+/* #define FREE				0xff	free (unused) */
+
+/*----------------------------------------------------
+ * end of MULE stuff
+ *----------------------------------------------------
+ */
+
+/*
+ * PostgreSQL encoding identifiers
+ *
+ * WARNING: the order of this enum must be same as order of entries
+ *			in the pg_enc2name_tbl[] array (in src/common/encnames.c), and
+ *			in the pg_wchar_table[] array (in src/common/wchar.c)!
+ *
+ *			If you add some encoding don't forget to check
+ *			PG_ENCODING_BE_LAST macro.
+ *
+ * PG_SQL_ASCII is default encoding and must be = 0.
+ *
+ * XXX	We must avoid renumbering any backend encoding until libpq's major
+ * version number is increased beyond 5; it turns out that the backend
+ * encoding IDs are effectively part of libpq's ABI as far as 8.2 initdb and
+ * psql are concerned.
+ */
+typedef enum pg_enc
+{
+	PG_SQL_ASCII = 0,			/* SQL/ASCII */
+	PG_EUC_JP,					/* EUC for Japanese */
+	PG_EUC_CN,					/* EUC for Chinese */
+	PG_EUC_KR,					/* EUC for Korean */
+	PG_EUC_TW,					/* EUC for Taiwan */
+	PG_EUC_JIS_2004,			/* EUC-JIS-2004 */
+	PG_UTF8,					/* Unicode UTF8 */
+	PG_MULE_INTERNAL,			/* Mule internal code */
+	PG_LATIN1,					/* ISO-8859-1 Latin 1 */
+	PG_LATIN2,					/* ISO-8859-2 Latin 2 */
+	PG_LATIN3,					/* ISO-8859-3 Latin 3 */
+	PG_LATIN4,					/* ISO-8859-4 Latin 4 */
+	PG_LATIN5,					/* ISO-8859-9 Latin 5 */
+	PG_LATIN6,					/* ISO-8859-10 Latin6 */
+	PG_LATIN7,					/* ISO-8859-13 Latin7 */
+	PG_LATIN8,					/* ISO-8859-14 Latin8 */
+	PG_LATIN9,					/* ISO-8859-15 Latin9 */
+	PG_LATIN10,					/* ISO-8859-16 Latin10 */
+	PG_WIN1256,					/* windows-1256 */
+	PG_WIN1258,					/* Windows-1258 */
+	PG_WIN866,					/* (MS-DOS CP866) */
+	PG_WIN874,					/* windows-874 */
+	PG_KOI8R,					/* KOI8-R */
+	PG_WIN1251,					/* windows-1251 */
+	PG_WIN1252,					/* windows-1252 */
+	PG_ISO_8859_5,				/* ISO-8859-5 */
+	PG_ISO_8859_6,				/* ISO-8859-6 */
+	PG_ISO_8859_7,				/* ISO-8859-7 */
+	PG_ISO_8859_8,				/* ISO-8859-8 */
+	PG_WIN1250,					/* windows-1250 */
+	PG_WIN1253,					/* windows-1253 */
+	PG_WIN1254,					/* windows-1254 */
+	PG_WIN1255,					/* windows-1255 */
+	PG_WIN1257,					/* windows-1257 */
+	PG_KOI8U,					/* KOI8-U */
+	/* PG_ENCODING_BE_LAST points to the above entry */
+
+	/* followings are for client encoding only */
+	PG_SJIS,					/* Shift JIS (Windows-932) */
+	PG_BIG5,					/* Big5 (Windows-950) */
+	PG_GBK,						/* GBK (Windows-936) */
+	PG_UHC,						/* UHC (Windows-949) */
+	PG_GB18030,					/* GB18030 */
+	PG_JOHAB,					/* EUC for Korean JOHAB */
+	PG_SHIFT_JIS_2004,			/* Shift-JIS-2004 */
+	_PG_LAST_ENCODING_			/* mark only */
+
+} pg_enc;
+
+#define PG_ENCODING_BE_LAST PG_KOI8U
+
+/*
+ * Please use these tests before access to pg_enc2name_tbl[]
+ * or to other places...
+ */
+#define PG_VALID_BE_ENCODING(_enc) \
+		((_enc) >= 0 && (_enc) <= PG_ENCODING_BE_LAST)
+
+#define PG_ENCODING_IS_CLIENT_ONLY(_enc) \
+		((_enc) > PG_ENCODING_BE_LAST && (_enc) < _PG_LAST_ENCODING_)
+
+#define PG_VALID_ENCODING(_enc) \
+		((_enc) >= 0 && (_enc) < _PG_LAST_ENCODING_)
+
+/* On FE are possible all encodings */
+#define PG_VALID_FE_ENCODING(_enc)	PG_VALID_ENCODING(_enc)
+
+/*
+ * When converting strings between different encodings, we assume that space
+ * for converted result is 4-to-1 growth in the worst case.  The rate for
+ * currently supported encoding pairs are within 3 (SJIS JIS X0201 half width
+ * kana -> UTF8 is the worst case).  So "4" should be enough for the moment.
+ *
+ * Note that this is not the same as the maximum character width in any
+ * particular encoding.
+ */
+#define MAX_CONVERSION_GROWTH  4
+
+/*
+ * Maximum byte length of a string that's required in any encoding to convert
+ * at least one character to any other encoding.  In other words, if you feed
+ * MAX_CONVERSION_INPUT_LENGTH bytes to any encoding conversion function, it
+ * is guaranteed to be able to convert something without needing more input
+ * (assuming the input is valid).
+ *
+ * Currently, the maximum case is the conversion UTF8 -> SJIS JIS X0201 half
+ * width kana, where a pair of UTF-8 characters is converted into a single
+ * SHIFT_JIS_2004 character (the reverse of the worst case for
+ * MAX_CONVERSION_GROWTH).  It needs 6 bytes of input.  In theory, a
+ * user-defined conversion function might have more complicated cases, although
+ * for the reverse mapping you would probably also need to bump up
+ * MAX_CONVERSION_GROWTH.  But there is no need to be stingy here, so make it
+ * generous.
+ */
+#define MAX_CONVERSION_INPUT_LENGTH	16
+
+/*
+ * Maximum byte length of the string equivalent to any one Unicode code point,
+ * in any backend encoding.  The current value assumes that a 4-byte UTF-8
+ * character might expand by MAX_CONVERSION_GROWTH, which is a huge
+ * overestimate.  But in current usage we don't allocate large multiples of
+ * this, so there's little point in being stingy.
+ */
+#define MAX_UNICODE_EQUIVALENT_STRING	16
+
+/*
+ * Table for mapping an encoding number to official encoding name and
+ * possibly other subsidiary data.  Be careful to check encoding number
+ * before accessing a table entry!
+ *
+ * if (PG_VALID_ENCODING(encoding))
+ *		pg_enc2name_tbl[ encoding ];
+ */
+typedef struct pg_enc2name
+{
+	const char *name;
+	pg_enc		encoding;
+#ifdef WIN32
+	unsigned	codepage;		/* codepage for WIN32 */
+#endif
+} pg_enc2name;
+
+extern PGDLLIMPORT const pg_enc2name pg_enc2name_tbl[];
+
+/*
+ * Encoding names for gettext
+ */
+typedef struct pg_enc2gettext
+{
+	pg_enc		encoding;
+	const char *name;
+} pg_enc2gettext;
+
+extern PGDLLIMPORT const pg_enc2gettext pg_enc2gettext_tbl[];
+
+/*
+ * pg_wchar stuff
+ */
+typedef int (*mb2wchar_with_len_converter) (const unsigned char *from,
+											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);
+
+typedef int (*mbdisplaylen_converter) (const unsigned char *mbstr);
+
+typedef bool (*mbcharacter_incrementer) (unsigned char *mbstr, int len);
+
+typedef int (*mbchar_verifier) (const unsigned char *mbstr, int len);
+
+typedef int (*mbstr_verifier) (const unsigned char *mbstr, int len);
+
+typedef struct
+{
+	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 */
+	mbchar_verifier mbverifychar;	/* verify multibyte character */
+	mbstr_verifier mbverifystr; /* verify multibyte string */
+	int			maxmblen;		/* max bytes for a char in this encoding */
+} pg_wchar_tbl;
+
+extern PGDLLIMPORT const pg_wchar_tbl pg_wchar_table[];
+
+/*
+ * Data structures for conversions between UTF-8 and other encodings
+ * (UtfToLocal() and LocalToUtf()).  In these data structures, characters of
+ * either encoding are represented by uint32 words; hence we can only support
+ * characters up to 4 bytes long.  For example, the byte sequence 0xC2 0x89
+ * would be represented by 0x0000C289, and 0xE8 0xA2 0xB4 by 0x00E8A2B4.
+ *
+ * There are three possible ways a character can be mapped:
+ *
+ * 1. Using a radix tree, from source to destination code.
+ * 2. Using a sorted array of source -> destination code pairs. This
+ *	  method is used for "combining" characters. There are so few of
+ *	  them that building a radix tree would be wasteful.
+ * 3. Using a conversion function.
+ */
+
+/*
+ * Radix tree for character conversion.
+ *
+ * Logically, this is actually four different radix trees, for 1-byte,
+ * 2-byte, 3-byte and 4-byte inputs. The 1-byte tree is a simple lookup
+ * table from source to target code. The 2-byte tree consists of two levels:
+ * one lookup table for the first byte, where the value in the lookup table
+ * points to a lookup table for the second byte. And so on.
+ *
+ * Physically, all the trees are stored in one big array, in 'chars16' or
+ * 'chars32', depending on the maximum value that needs to be represented. For
+ * each level in each tree, we also store lower and upper bound of allowed
+ * values - values outside those bounds are considered invalid, and are left
+ * out of the tables.
+ *
+ * In the intermediate levels of the trees, the values stored are offsets
+ * into the chars[16|32] array.
+ *
+ * In the beginning of the chars[16|32] array, there is always a number of
+ * zeros, so that you safely follow an index from an intermediate table
+ * without explicitly checking for a zero. Following a zero any number of
+ * times will always bring you to the dummy, all-zeros table in the
+ * beginning. This helps to shave some cycles when looking up values.
+ */
+typedef struct
+{
+	/*
+	 * Array containing all the values. Only one of chars16 or chars32 is
+	 * used, depending on how wide the values we need to represent are.
+	 */
+	const uint16 *chars16;
+	const uint32 *chars32;
+
+	/* Radix tree for 1-byte inputs */
+	uint32		b1root;			/* offset of table in the chars[16|32] array */
+	uint8		b1_lower;		/* min allowed value for a single byte input */
+	uint8		b1_upper;		/* max allowed value for a single byte input */
+
+	/* Radix tree for 2-byte inputs */
+	uint32		b2root;			/* offset of 1st byte's table */
+	uint8		b2_1_lower;		/* min/max allowed value for 1st input byte */
+	uint8		b2_1_upper;
+	uint8		b2_2_lower;		/* min/max allowed value for 2nd input byte */
+	uint8		b2_2_upper;
+
+	/* Radix tree for 3-byte inputs */
+	uint32		b3root;			/* offset of 1st byte's table */
+	uint8		b3_1_lower;		/* min/max allowed value for 1st input byte */
+	uint8		b3_1_upper;
+	uint8		b3_2_lower;		/* min/max allowed value for 2nd input byte */
+	uint8		b3_2_upper;
+	uint8		b3_3_lower;		/* min/max allowed value for 3rd input byte */
+	uint8		b3_3_upper;
+
+	/* Radix tree for 4-byte inputs */
+	uint32		b4root;			/* offset of 1st byte's table */
+	uint8		b4_1_lower;		/* min/max allowed value for 1st input byte */
+	uint8		b4_1_upper;
+	uint8		b4_2_lower;		/* min/max allowed value for 2nd input byte */
+	uint8		b4_2_upper;
+	uint8		b4_3_lower;		/* min/max allowed value for 3rd input byte */
+	uint8		b4_3_upper;
+	uint8		b4_4_lower;		/* min/max allowed value for 4th input byte */
+	uint8		b4_4_upper;
+
+} pg_mb_radix_tree;
+
+/*
+ * UTF-8 to local code conversion map (for combined characters)
+ */
+typedef struct
+{
+	uint32		utf1;			/* UTF-8 code 1 */
+	uint32		utf2;			/* UTF-8 code 2 */
+	uint32		code;			/* local code */
+} pg_utf_to_local_combined;
+
+/*
+ * local code to UTF-8 conversion map (for combined characters)
+ */
+typedef struct
+{
+	uint32		code;			/* local code */
+	uint32		utf1;			/* UTF-8 code 1 */
+	uint32		utf2;			/* UTF-8 code 2 */
+} pg_local_to_utf_combined;
+
+/*
+ * callback function for algorithmic encoding conversions (in either direction)
+ *
+ * if function returns zero, it does not know how to convert the code
+ */
+typedef uint32 (*utf_local_conversion_func) (uint32 code);
+
+/*
+ * Support macro for encoding conversion functions to validate their
+ * arguments.  (This could be made more compact if we included fmgr.h
+ * here, but we don't want to do that because this header file is also
+ * used by frontends.)
+ */
+#define CHECK_ENCODING_CONVERSION_ARGS(srcencoding,destencoding) \
+	check_encoding_conversion_args(PG_GETARG_INT32(0), \
+								   PG_GETARG_INT32(1), \
+								   PG_GETARG_INT32(4), \
+								   (srcencoding), \
+								   (destencoding))
+
+
+/*
+ * Some handy functions for Unicode-specific tests.
+ */
+static inline bool
+is_valid_unicode_codepoint(pg_wchar c)
+{
+	return (c > 0 && c <= 0x10FFFF);
+}
+
+static inline bool
+is_utf16_surrogate_first(pg_wchar c)
+{
+	return (c >= 0xD800 && c <= 0xDBFF);
+}
+
+static inline bool
+is_utf16_surrogate_second(pg_wchar c)
+{
+	return (c >= 0xDC00 && c <= 0xDFFF);
+}
+
+static inline pg_wchar
+surrogate_pair_to_codepoint(pg_wchar first, pg_wchar second)
+{
+	return ((first & 0x3FF) << 10) + 0x10000 + (second & 0x3FF);
+}
+
+
+/*
+ * These functions are considered part of libpq's exported API and
+ * are also declared in libpq-fe.h.
+ */
+extern int	pg_char_to_encoding(const char *name);
+extern const char *pg_encoding_to_char(int encoding);
+extern int	pg_valid_server_encoding_id(int encoding);
+
+/*
+ * These functions are available to frontend code that links with libpgcommon
+ * (in addition to the ones just above).  The constant tables declared
+ * earlier in this file are also available from libpgcommon.
+ */
+extern int	pg_encoding_mblen(int encoding, const char *mbstr);
+extern int	pg_encoding_mblen_bounded(int encoding, const char *mbstr);
+extern int	pg_encoding_dsplen(int encoding, const char *mbstr);
+extern int	pg_encoding_verifymbchar(int encoding, const char *mbstr, int len);
+extern int	pg_encoding_verifymbstr(int encoding, const char *mbstr, int len);
+extern int	pg_encoding_max_length(int encoding);
+extern int	pg_valid_client_encoding(const char *name);
+extern int	pg_valid_server_encoding(const char *name);
+extern bool is_encoding_supported_by_icu(int encoding);
+extern const char *get_encoding_name_for_icu(int encoding);
+
+extern unsigned char *unicode_to_utf8(pg_wchar c, unsigned char *utf8string);
+extern pg_wchar utf8_to_unicode(const unsigned char *c);
+extern bool pg_utf8_islegal(const unsigned char *source, int length);
+extern int	pg_utf_mblen(const unsigned char *s);
+extern int	pg_mule_mblen(const unsigned char *s);
+
+/*
+ * The remaining functions are backend-only.
+ */
+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);
+extern size_t pg_wchar_strlen(const pg_wchar *str);
+extern int	pg_mblen(const char *mbstr);
+extern int	pg_dsplen(const char *mbstr);
+extern int	pg_mbstrlen(const char *mbstr);
+extern int	pg_mbstrlen_with_len(const char *mbstr, int limit);
+extern int	pg_mbcliplen(const char *mbstr, int len, int limit);
+extern int	pg_encoding_mbcliplen(int encoding, const char *mbstr,
+								  int len, int limit);
+extern int	pg_mbcharcliplen(const char *mbstr, int len, int limit);
+extern int	pg_database_encoding_max_length(void);
+extern mbcharacter_incrementer pg_database_encoding_character_incrementer(void);
+
+extern int	PrepareClientEncoding(int encoding);
+extern int	SetClientEncoding(int encoding);
+extern void InitializeClientEncoding(void);
+extern int	pg_get_client_encoding(void);
+extern const char *pg_get_client_encoding_name(void);
+
+extern void SetDatabaseEncoding(int encoding);
+extern int	GetDatabaseEncoding(void);
+extern const char *GetDatabaseEncodingName(void);
+extern void SetMessageEncoding(int encoding);
+extern int	GetMessageEncoding(void);
+
+#ifdef ENABLE_NLS
+extern int	pg_bind_textdomain_codeset(const char *domainname);
+#endif
+
+extern unsigned char *pg_do_encoding_conversion(unsigned char *src, int len,
+												int src_encoding,
+												int dest_encoding);
+extern int	pg_do_encoding_conversion_buf(Oid proc,
+										  int src_encoding,
+										  int dest_encoding,
+										  unsigned char *src, int srclen,
+										  unsigned char *dest, int destlen,
+										  bool noError);
+
+extern char *pg_client_to_server(const char *s, int len);
+extern char *pg_server_to_client(const char *s, int len);
+extern char *pg_any_to_server(const char *s, int len, int encoding);
+extern char *pg_server_to_any(const char *s, int len, int encoding);
+
+extern void pg_unicode_to_server(pg_wchar c, unsigned char *s);
+extern bool pg_unicode_to_server_noerror(pg_wchar c, unsigned char *s);
+
+extern unsigned short BIG5toCNS(unsigned short big5, unsigned char *lc);
+extern unsigned short CNStoBIG5(unsigned short cns, unsigned char lc);
+
+extern int	UtfToLocal(const unsigned char *utf, int len,
+					   unsigned char *iso,
+					   const pg_mb_radix_tree *map,
+					   const pg_utf_to_local_combined *cmap, int cmapsize,
+					   utf_local_conversion_func conv_func,
+					   int encoding, bool noError);
+extern int	LocalToUtf(const unsigned char *iso, int len,
+					   unsigned char *utf,
+					   const pg_mb_radix_tree *map,
+					   const pg_local_to_utf_combined *cmap, int cmapsize,
+					   utf_local_conversion_func conv_func,
+					   int encoding, bool noError);
+
+extern bool pg_verifymbstr(const char *mbstr, int len, bool noError);
+extern bool pg_verify_mbstr(int encoding, const char *mbstr, int len,
+							bool noError);
+extern int	pg_verify_mbstr_len(int encoding, const char *mbstr, int len,
+								bool noError);
+
+extern void check_encoding_conversion_args(int src_encoding,
+										   int dest_encoding,
+										   int len,
+										   int expected_src_encoding,
+										   int expected_dest_encoding);
+
+extern void report_invalid_encoding(int encoding, const char *mbstr, int len) pg_attribute_noreturn();
+extern void report_untranslatable_char(int src_encoding, int dest_encoding,
+									   const char *mbstr, int len) pg_attribute_noreturn();
+
+extern int	local2local(const unsigned char *l, unsigned char *p, int len,
+						int src_encoding, int dest_encoding,
+						const unsigned char *tab, bool noError);
+extern int	latin2mic(const unsigned char *l, unsigned char *p, int len,
+					  int lc, int encoding, bool noError);
+extern int	mic2latin(const unsigned char *mic, unsigned char *p, int len,
+					  int lc, int encoding, bool noError);
+extern int	latin2mic_with_table(const unsigned char *l, unsigned char *p,
+								 int len, int lc, int encoding,
+								 const unsigned char *tab, bool noError);
+extern int	mic2latin_with_table(const unsigned char *mic, unsigned char *p,
+								 int len, int lc, int encoding,
+								 const unsigned char *tab, bool noError);
+
+#ifdef WIN32
+extern WCHAR *pgwin32_message_to_UTF16(const char *str, int len, int *utf16len);
+#endif
+
+#endif							/* PG_WCHAR_H */