/*-------------------------------------------------------------------------
 *
 *	  Utility functions for conversion procs.
 *
 * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *	  src/backend/utils/mb/conv.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
#include "mb/pg_wchar.h"


/*
 * LATINn ---> MIC when the charset's local codes map directly to MIC
 *
 * l points to the source string of length len
 * p is the output area (must be large enough!)
 * lc is the mule character set id for the local encoding
 * encoding is the PG identifier for the local encoding
 */
void
latin2mic(const unsigned char *l, unsigned char *p, int len,
		  int lc, int encoding)
{
	int			c1;

	while (len > 0)
	{
		c1 = *l;
		if (c1 == 0)
			report_invalid_encoding(encoding, (const char *) l, len);
		if (IS_HIGHBIT_SET(c1))
			*p++ = lc;
		*p++ = c1;
		l++;
		len--;
	}
	*p = '\0';
}

/*
 * MIC ---> LATINn when the charset's local codes map directly to MIC
 *
 * mic points to the source string of length len
 * p is the output area (must be large enough!)
 * lc is the mule character set id for the local encoding
 * encoding is the PG identifier for the local encoding
 */
void
mic2latin(const unsigned char *mic, unsigned char *p, int len,
		  int lc, int encoding)
{
	int			c1;

	while (len > 0)
	{
		c1 = *mic;
		if (c1 == 0)
			report_invalid_encoding(PG_MULE_INTERNAL, (const char *) mic, len);
		if (!IS_HIGHBIT_SET(c1))
		{
			/* easy for ASCII */
			*p++ = c1;
			mic++;
			len--;
		}
		else
		{
			int			l = pg_mic_mblen(mic);

			if (len < l)
				report_invalid_encoding(PG_MULE_INTERNAL, (const char *) mic,
										len);
			if (l != 2 || c1 != lc || !IS_HIGHBIT_SET(mic[1]))
				report_untranslatable_char(PG_MULE_INTERNAL, encoding,
										   (const char *) mic, len);
			*p++ = mic[1];
			mic += 2;
			len -= 2;
		}
	}
	*p = '\0';
}


/*
 * ASCII ---> MIC
 *
 * While ordinarily SQL_ASCII encoding is forgiving of high-bit-set
 * characters, here we must take a hard line because we don't know
 * the appropriate MIC equivalent.
 */
void
pg_ascii2mic(const unsigned char *l, unsigned char *p, int len)
{
	int			c1;

	while (len > 0)
	{
		c1 = *l;
		if (c1 == 0 || IS_HIGHBIT_SET(c1))
			report_invalid_encoding(PG_SQL_ASCII, (const char *) l, len);
		*p++ = c1;
		l++;
		len--;
	}
	*p = '\0';
}

/*
 * MIC ---> ASCII
 */
void
pg_mic2ascii(const unsigned char *mic, unsigned char *p, int len)
{
	int			c1;

	while (len > 0)
	{
		c1 = *mic;
		if (c1 == 0 || IS_HIGHBIT_SET(c1))
			report_untranslatable_char(PG_MULE_INTERNAL, PG_SQL_ASCII,
									   (const char *) mic, len);
		*p++ = c1;
		mic++;
		len--;
	}
	*p = '\0';
}

/*
 * latin2mic_with_table: a generic single byte charset encoding
 * conversion from a local charset to the mule internal code.
 *
 * l points to the source string of length len
 * p is the output area (must be large enough!)
 * lc is the mule character set id for the local encoding
 * encoding is the PG identifier for the local encoding
 * tab holds conversion entries for the local charset
 * starting from 128 (0x80). each entry in the table
 * holds the corresponding code point for the mule internal code.
 */
void
latin2mic_with_table(const unsigned char *l,
					 unsigned char *p,
					 int len,
					 int lc,
					 int encoding,
					 const unsigned char *tab)
{
	unsigned char c1,
				c2;

	while (len > 0)
	{
		c1 = *l;
		if (c1 == 0)
			report_invalid_encoding(encoding, (const char *) l, len);
		if (!IS_HIGHBIT_SET(c1))
			*p++ = c1;
		else
		{
			c2 = tab[c1 - HIGHBIT];
			if (c2)
			{
				*p++ = lc;
				*p++ = c2;
			}
			else
				report_untranslatable_char(encoding, PG_MULE_INTERNAL,
										   (const char *) l, len);
		}
		l++;
		len--;
	}
	*p = '\0';
}

/*
 * mic2latin_with_table: a generic single byte charset encoding
 * conversion from the mule internal code to a local charset.
 *
 * mic points to the source string of length len
 * p is the output area (must be large enough!)
 * lc is the mule character set id for the local encoding
 * encoding is the PG identifier for the local encoding
 * tab holds conversion entries for the mule internal code's
 * second byte, starting from 128 (0x80). each entry in the table
 * holds the corresponding code point for the local charset.
 */
void
mic2latin_with_table(const unsigned char *mic,
					 unsigned char *p,
					 int len,
					 int lc,
					 int encoding,
					 const unsigned char *tab)
{
	unsigned char c1,
				c2;

	while (len > 0)
	{
		c1 = *mic;
		if (c1 == 0)
			report_invalid_encoding(PG_MULE_INTERNAL, (const char *) mic, len);
		if (!IS_HIGHBIT_SET(c1))
		{
			/* easy for ASCII */
			*p++ = c1;
			mic++;
			len--;
		}
		else
		{
			int			l = pg_mic_mblen(mic);

			if (len < l)
				report_invalid_encoding(PG_MULE_INTERNAL, (const char *) mic,
										len);
			if (l != 2 || c1 != lc || !IS_HIGHBIT_SET(mic[1]) ||
				(c2 = tab[mic[1] - HIGHBIT]) == 0)
			{
				report_untranslatable_char(PG_MULE_INTERNAL, encoding,
										   (const char *) mic, len);
				break;			/* keep compiler quiet */
			}
			*p++ = c2;
			mic += 2;
			len -= 2;
		}
	}
	*p = '\0';
}

/*
 * comparison routine for bsearch()
 * this routine is intended for UTF8 -> local code
 */
static int
compare1(const void *p1, const void *p2)
{
	uint32		v1,
				v2;

	v1 = *(const uint32 *) p1;
	v2 = ((const pg_utf_to_local *) p2)->utf;
	return (v1 > v2) ? 1 : ((v1 == v2) ? 0 : -1);
}

/*
 * comparison routine for bsearch()
 * this routine is intended for local code -> UTF8
 */
static int
compare2(const void *p1, const void *p2)
{
	uint32		v1,
				v2;

	v1 = *(const uint32 *) p1;
	v2 = ((const pg_local_to_utf *) p2)->code;
	return (v1 > v2) ? 1 : ((v1 == v2) ? 0 : -1);
}

/*
 * comparison routine for bsearch()
 * this routine is intended for combined UTF8 -> local code
 */
static int
compare3(const void *p1, const void *p2)
{
	uint32		s1,
				s2,
				d1,
				d2;

	s1 = *(const uint32 *) p1;
	s2 = *((const uint32 *) p1 + 1);
	d1 = ((const pg_utf_to_local_combined *) p2)->utf1;
	d2 = ((const pg_utf_to_local_combined *) p2)->utf2;
	return (s1 > d1 || (s1 == d1 && s2 > d2)) ? 1 : ((s1 == d1 && s2 == d2) ? 0 : -1);
}

/*
 * comparison routine for bsearch()
 * this routine is intended for local code -> combined UTF8
 */
static int
compare4(const void *p1, const void *p2)
{
	uint32		v1,
				v2;

	v1 = *(const uint32 *) p1;
	v2 = ((const pg_local_to_utf_combined *) p2)->code;
	return (v1 > v2) ? 1 : ((v1 == v2) ? 0 : -1);
}

/*
 * convert 32bit wide character to mutibye stream pointed to by iso
 */
static unsigned char *
set_iso_code(unsigned char *iso, uint32 code)
{
	if (code & 0xff000000)
		*iso++ = code >> 24;
	if (code & 0x00ff0000)
		*iso++ = (code & 0x00ff0000) >> 16;
	if (code & 0x0000ff00)
		*iso++ = (code & 0x0000ff00) >> 8;
	if (code & 0x000000ff)
		*iso++ = code & 0x000000ff;
	return iso;
}

/*
 * UTF8 ---> local code
 *
 * utf: input UTF8 string (need not be null-terminated).
 * iso: pointer to the output area (must be large enough!)
 * map: the conversion map.
 * cmap: the conversion map for combined characters.
 *		  (optional)
 * size1: the size of the conversion map.
 * size2: the size of the conversion map for combined characters
 *		  (optional)
 * encoding: the PG identifier for the local encoding.
 * len: length of input string.
 */
void
UtfToLocal(const unsigned char *utf, unsigned char *iso,
		   const pg_utf_to_local *map, const pg_utf_to_local_combined *cmap,
		   int size1, int size2, int encoding, int len)
{
	uint32		iutf;
	uint32		cutf[2];
	uint32		code;
	pg_utf_to_local *p;
	pg_utf_to_local_combined *cp;
	int			l;

	for (; len > 0; len -= l)
	{
		/* "break" cases all represent errors */
		if (*utf == '\0')
			break;

		l = pg_utf_mblen(utf);

		if (len < l)
			break;

		if (!pg_utf8_islegal(utf, l))
			break;

		if (l == 1)
		{
			/* ASCII case is easy */
			*iso++ = *utf++;
			continue;
		}
		else if (l == 2)
		{
			iutf = *utf++ << 8;
			iutf |= *utf++;
		}
		else if (l == 3)
		{
			iutf = *utf++ << 16;
			iutf |= *utf++ << 8;
			iutf |= *utf++;
		}
		else if (l == 4)
		{
			iutf = *utf++ << 24;
			iutf |= *utf++ << 16;
			iutf |= *utf++ << 8;
			iutf |= *utf++;
		}
		else
		{
			elog(ERROR, "unsupported character length %d", l);
			iutf = 0;			/* keep compiler quiet */
		}

		/*
		 * first, try with combined map if possible
		 */
		if (cmap && len > l)
		{
			const unsigned char *utf_save = utf;
			int			len_save = len;
			int			l_save = l;

			len -= l;

			l = pg_utf_mblen(utf);
			if (len < l)
				break;

			if (!pg_utf8_islegal(utf, l))
				break;

			cutf[0] = iutf;

			if (l == 1)
			{
				if (len_save > 1)
				{
					p = bsearch(&cutf[0], map, size1,
								sizeof(pg_utf_to_local), compare1);
					if (p == NULL)
						report_untranslatable_char(PG_UTF8, encoding,
							   (const char *) (utf_save - l_save), len_save);
					iso = set_iso_code(iso, p->code);
				}

				/* ASCII case is easy */
				*iso++ = *utf++;
				continue;
			}
			else if (l == 2)
			{
				iutf = *utf++ << 8;
				iutf |= *utf++;
			}
			else if (l == 3)
			{
				iutf = *utf++ << 16;
				iutf |= *utf++ << 8;
				iutf |= *utf++;
			}
			else if (l == 4)
			{
				iutf = *utf++ << 24;
				iutf |= *utf++ << 16;
				iutf |= *utf++ << 8;
				iutf |= *utf++;
			}
			else
			{
				elog(ERROR, "unsupported character length %d", l);
				iutf = 0;		/* keep compiler quiet */
			}

			cutf[1] = iutf;
			cp = bsearch(cutf, cmap, size2,
						 sizeof(pg_utf_to_local_combined), compare3);
			if (cp)
				code = cp->code;
			else
			{
				/* not found in combined map. try with ordinary map */
				p = bsearch(&cutf[0], map, size1,
							sizeof(pg_utf_to_local), compare1);
				if (p == NULL)
					report_untranslatable_char(PG_UTF8, encoding,
							   (const char *) (utf_save - l_save), len_save);
				iso = set_iso_code(iso, p->code);

				p = bsearch(&cutf[1], map, size1,
							sizeof(pg_utf_to_local), compare1);
				if (p == NULL)
					report_untranslatable_char(PG_UTF8, encoding,
											   (const char *) (utf - l), len);
				code = p->code;
			}
		}
		else	/* no cmap or no remaining data */
		{
			p = bsearch(&iutf, map, size1,
						sizeof(pg_utf_to_local), compare1);
			if (p == NULL)
				report_untranslatable_char(PG_UTF8, encoding,
										   (const char *) (utf - l), len);
			code = p->code;
		}
		iso = set_iso_code(iso, code);
	}

	if (len > 0)
		report_invalid_encoding(PG_UTF8, (const char *) utf, len);

	*iso = '\0';
}

/*
 * local code ---> UTF8
 *
 * iso: input local string (need not be null-terminated).
 * utf: pointer to the output area (must be large enough!)
 * map: the conversion map.
 * cmap: the conversion map for combined characters.
 *		  (optional)
 * size1: the size of the conversion map.
 * size2: the size of the conversion map for combined characters
 *		  (optional)
 * encoding: the PG identifier for the local encoding.
 * len: length of input string.
 */
void
LocalToUtf(const unsigned char *iso, unsigned char *utf,
		   const pg_local_to_utf *map, const pg_local_to_utf_combined *cmap,
		   int size1, int size2, int encoding, int len)
{
	unsigned int iiso;
	int			l;
	pg_local_to_utf *p;
	pg_local_to_utf_combined *cp;

	if (!PG_VALID_ENCODING(encoding))
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				 errmsg("invalid encoding number: %d", encoding)));

	for (; len > 0; len -= l)
	{
		/* "break" cases all represent errors */
		if (*iso == '\0')
			break;

		if (!IS_HIGHBIT_SET(*iso))
		{
			/* ASCII case is easy */
			*utf++ = *iso++;
			l = 1;
			continue;
		}

		l = pg_encoding_verifymb(encoding, (const char *) iso, len);
		if (l < 0)
			break;

		if (l == 1)
			iiso = *iso++;
		else if (l == 2)
		{
			iiso = *iso++ << 8;
			iiso |= *iso++;
		}
		else if (l == 3)
		{
			iiso = *iso++ << 16;
			iiso |= *iso++ << 8;
			iiso |= *iso++;
		}
		else if (l == 4)
		{
			iiso = *iso++ << 24;
			iiso |= *iso++ << 16;
			iiso |= *iso++ << 8;
			iiso |= *iso++;
		}
		else
		{
			elog(ERROR, "unsupported character length %d", l);
			iiso = 0;			/* keep compiler quiet */
		}

		p = bsearch(&iiso, map, size1,
					sizeof(pg_local_to_utf), compare2);

		if (p == NULL)
		{
			/*
			 * not found in the ordinary map. if there's a combined character
			 * map, try with it
			 */
			if (cmap)
			{
				cp = bsearch(&iiso, cmap, size2,
							 sizeof(pg_local_to_utf_combined), compare4);

				if (cp)
				{
					if (cp->utf1 & 0xff000000)
						*utf++ = cp->utf1 >> 24;
					if (cp->utf1 & 0x00ff0000)
						*utf++ = (cp->utf1 & 0x00ff0000) >> 16;
					if (cp->utf1 & 0x0000ff00)
						*utf++ = (cp->utf1 & 0x0000ff00) >> 8;
					if (cp->utf1 & 0x000000ff)
						*utf++ = cp->utf1 & 0x000000ff;

					if (cp->utf2 & 0xff000000)
						*utf++ = cp->utf2 >> 24;
					if (cp->utf2 & 0x00ff0000)
						*utf++ = (cp->utf2 & 0x00ff0000) >> 16;
					if (cp->utf2 & 0x0000ff00)
						*utf++ = (cp->utf2 & 0x0000ff00) >> 8;
					if (cp->utf2 & 0x000000ff)
						*utf++ = cp->utf2 & 0x000000ff;

					continue;
				}
			}

			report_untranslatable_char(encoding, PG_UTF8,
									   (const char *) (iso - l), len);

		}
		else
		{
			if (p->utf & 0xff000000)
				*utf++ = p->utf >> 24;
			if (p->utf & 0x00ff0000)
				*utf++ = (p->utf & 0x00ff0000) >> 16;
			if (p->utf & 0x0000ff00)
				*utf++ = (p->utf & 0x0000ff00) >> 8;
			if (p->utf & 0x000000ff)
				*utf++ = p->utf & 0x000000ff;
		}
	}

	if (len > 0)
		report_invalid_encoding(encoding, (const char *) iso, len);

	*utf = '\0';
}
