text: /*-------------------------------------------------------------------------
   *
   *	  EUC_TW, BIG5 and MULE_INTERNAL
   *
   * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   * IDENTIFICATION
   *	  src/backend/utils/mb/conversion_procs/euc_tw_and_big5/euc_tw_and_big5.c
   *
   *-------------------------------------------------------------------------
   */
  
  #include "postgres.h"
  #include "fmgr.h"
  #include "mb/pg_wchar.h"
  
  #define ENCODING_GROWTH_RATE 4
  
  PG_MODULE_MAGIC;
  
  PG_FUNCTION_INFO_V1(euc_tw_to_big5);
  PG_FUNCTION_INFO_V1(big5_to_euc_tw);
  PG_FUNCTION_INFO_V1(euc_tw_to_mic);
  PG_FUNCTION_INFO_V1(mic_to_euc_tw);
  PG_FUNCTION_INFO_V1(big5_to_mic);
  PG_FUNCTION_INFO_V1(mic_to_big5);
  
  /* ----------
   * conv_proc(
   *		INTEGER,	-- source encoding id
   *		INTEGER,	-- destination encoding id
   *		CSTRING,	-- source string (null terminated C string)
   *		CSTRING,	-- destination string (null terminated C string)
   *		INTEGER		-- source string length
   * ) returns VOID;
   * ----------
   */
  
  static void euc_tw2big5(const unsigned char *euc, unsigned char *p, int len);
  static void big52euc_tw(const unsigned char *euc, unsigned char *p, int len);
  static void big52mic(const unsigned char *big5, unsigned char *p, int len);
  static void mic2big5(const unsigned char *mic, unsigned char *p, int len);
  static void euc_tw2mic(const unsigned char *euc, unsigned char *p, int len);
  static void mic2euc_tw(const unsigned char *mic, unsigned char *p, int len);
  
  Datum
  euc_tw_to_big5(PG_FUNCTION_ARGS)
  {
  	unsigned char *src = (unsigned char *) PG_GETARG_CSTRING(2);
  	unsigned char *dest = (unsigned char *) PG_GETARG_CSTRING(3);
  	int			len = PG_GETARG_INT32(4);
  
  	CHECK_ENCODING_CONVERSION_ARGS(PG_EUC_TW, PG_BIG5);
  
  	euc_tw2big5(src, dest, len);
  
  	PG_RETURN_VOID();
  }
  
  Datum
  big5_to_euc_tw(PG_FUNCTION_ARGS)
  {
  	unsigned char *src = (unsigned char *) PG_GETARG_CSTRING(2);
  	unsigned char *dest = (unsigned char *) PG_GETARG_CSTRING(3);
  	int			len = PG_GETARG_INT32(4);
  
  	CHECK_ENCODING_CONVERSION_ARGS(PG_BIG5, PG_EUC_TW);
  
  	big52euc_tw(src, dest, len);
  
  	PG_RETURN_VOID();
  }
  
  Datum
  euc_tw_to_mic(PG_FUNCTION_ARGS)
  {
  	unsigned char *src = (unsigned char *) PG_GETARG_CSTRING(2);
  	unsigned char *dest = (unsigned char *) PG_GETARG_CSTRING(3);
  	int			len = PG_GETARG_INT32(4);
  
  	CHECK_ENCODING_CONVERSION_ARGS(PG_EUC_TW, PG_MULE_INTERNAL);
  
  	euc_tw2mic(src, dest, len);
  
  	PG_RETURN_VOID();
  }
  
  Datum
  mic_to_euc_tw(PG_FUNCTION_ARGS)
  {
  	unsigned char *src = (unsigned char *) PG_GETARG_CSTRING(2);
  	unsigned char *dest = (unsigned char *) PG_GETARG_CSTRING(3);
  	int			len = PG_GETARG_INT32(4);
  
  	CHECK_ENCODING_CONVERSION_ARGS(PG_MULE_INTERNAL, PG_EUC_TW);
  
  	mic2euc_tw(src, dest, len);
  
  	PG_RETURN_VOID();
  }
  
  Datum
  big5_to_mic(PG_FUNCTION_ARGS)
  {
  	unsigned char *src = (unsigned char *) PG_GETARG_CSTRING(2);
  	unsigned char *dest = (unsigned char *) PG_GETARG_CSTRING(3);
  	int			len = PG_GETARG_INT32(4);
  
  	CHECK_ENCODING_CONVERSION_ARGS(PG_BIG5, PG_MULE_INTERNAL);
  
  	big52mic(src, dest, len);
  
  	PG_RETURN_VOID();
  }
  
  Datum
  mic_to_big5(PG_FUNCTION_ARGS)
  {
  	unsigned char *src = (unsigned char *) PG_GETARG_CSTRING(2);
  	unsigned char *dest = (unsigned char *) PG_GETARG_CSTRING(3);
  	int			len = PG_GETARG_INT32(4);
  
  	CHECK_ENCODING_CONVERSION_ARGS(PG_MULE_INTERNAL, PG_BIG5);
  
  	mic2big5(src, dest, len);
  
  	PG_RETURN_VOID();
  }
  
  
  /*
   * EUC_TW ---> Big5
   */
  static void
  euc_tw2big5(const unsigned char *euc, unsigned char *p, int len)
  {
  	unsigned char c1;
  	unsigned short big5buf,
  				cnsBuf;
  	unsigned char lc;
  	int			l;
  
  	while (len > 0)
  	{
  		c1 = *euc;
  		if (IS_HIGHBIT_SET(c1))
  		{
  			/* Verify and decode the next EUC_TW input character */
  			l = pg_encoding_verifymbchar(PG_EUC_TW, (const char *) euc, len);
  			if (l < 0)
  				report_invalid_encoding(PG_EUC_TW,
  										(const char *) euc, len);
  			if (c1 == SS2)
  			{
  				c1 = euc[1];	/* plane No. */
  				if (c1 == 0xa1)
  					lc = LC_CNS11643_1;
  				else if (c1 == 0xa2)
  					lc = LC_CNS11643_2;
  				else
  					lc = c1 - 0xa3 + LC_CNS11643_3;
  				cnsBuf = (euc[2] << 8) | euc[3];
  			}
  			else
  			{					/* CNS11643-1 */
  				lc = LC_CNS11643_1;
  				cnsBuf = (c1 << 8) | euc[1];
  			}
  
  			/* Write it out in Big5 */
  			big5buf = CNStoBIG5(cnsBuf, lc);
  			if (big5buf == 0)
  				report_untranslatable_char(PG_EUC_TW, PG_BIG5,
  										   (const char *) euc, len);
  			*p++ = (big5buf >> 8) & 0x00ff;
  			*p++ = big5buf & 0x00ff;
  
  			euc += l;
  			len -= l;
  		}
  		else
  		{						/* should be ASCII */
  			if (c1 == 0)
  				report_invalid_encoding(PG_EUC_TW,
  										(const char *) euc, len);
  			*p++ = c1;
  			euc++;
  			len--;
  		}
  	}
  	*p = '\0';
  }
  
  /*
   * Big5 ---> EUC_TW
   */
  static void
  big52euc_tw(const unsigned char *big5, unsigned char *p, int len)
  {
  	unsigned short c1;
  	unsigned short big5buf,
  				cnsBuf;
  	unsigned char lc;
  	int			l;
  
  	while (len > 0)
  	{
  		/* Verify and decode the next Big5 input character */
  		c1 = *big5;
  		if (IS_HIGHBIT_SET(c1))
  		{
  			l = pg_encoding_verifymbchar(PG_BIG5, (const char *) big5, len);
  			if (l < 0)
  				report_invalid_encoding(PG_BIG5,
  										(const char *) big5, len);
  			big5buf = (c1 << 8) | big5[1];
  			cnsBuf = BIG5toCNS(big5buf, &lc);
  
  			if (lc == LC_CNS11643_1)
  			{
  				*p++ = (cnsBuf >> 8) & 0x00ff;
  				*p++ = cnsBuf & 0x00ff;
  			}
  			else if (lc == LC_CNS11643_2)
  			{
  				*p++ = SS2;
  				*p++ = 0xa2;
  				*p++ = (cnsBuf >> 8) & 0x00ff;
  				*p++ = cnsBuf & 0x00ff;
  			}
  			else if (lc >= LC_CNS11643_3 && lc <= LC_CNS11643_7)
  			{
  				*p++ = SS2;
  				*p++ = lc - LC_CNS11643_3 + 0xa3;
  				*p++ = (cnsBuf >> 8) & 0x00ff;
  				*p++ = cnsBuf & 0x00ff;
  			}
  			else
  				report_untranslatable_char(PG_BIG5, PG_EUC_TW,
  										   (const char *) big5, len);
  
  			big5 += l;
  			len -= l;
  		}
  		else
  		{
  			/* ASCII */
  			if (c1 == 0)
  				report_invalid_encoding(PG_BIG5,
  										(const char *) big5, len);
  			*p++ = c1;
  			big5++;
  			len--;
  			continue;
  		}
  	}
  	*p = '\0';
  }
  
  /*
   * EUC_TW ---> MIC
   */
  static void
  euc_tw2mic(const unsigned char *euc, unsigned char *p, int len)
  {
  	int			c1;
  	int			l;
  
  	while (len > 0)
  	{
  		c1 = *euc;
  		if (IS_HIGHBIT_SET(c1))
  		{
  			l = pg_encoding_verifymbchar(PG_EUC_TW, (const char *) euc, len);
  			if (l < 0)
  				report_invalid_encoding(PG_EUC_TW,
  										(const char *) euc, len);
  			if (c1 == SS2)
  			{
  				c1 = euc[1];	/* plane No. */
  				if (c1 == 0xa1)
  					*p++ = LC_CNS11643_1;
  				else if (c1 == 0xa2)
  					*p++ = LC_CNS11643_2;
  				else
  				{
  					/* other planes are MULE private charsets */
  					*p++ = LCPRV2_B;
  					*p++ = c1 - 0xa3 + LC_CNS11643_3;
  				}
  				*p++ = euc[2];
  				*p++ = euc[3];
  			}
  			else
  			{					/* CNS11643-1 */
  				*p++ = LC_CNS11643_1;
  				*p++ = c1;
  				*p++ = euc[1];
  			}
  			euc += l;
  			len -= l;
  		}
  		else
  		{						/* should be ASCII */
  			if (c1 == 0)
  				report_invalid_encoding(PG_EUC_TW,
  										(const char *) euc, len);
  			*p++ = c1;
  			euc++;
  			len--;
  		}
  	}
  	*p = '\0';
  }
  
  /*
   * MIC ---> EUC_TW
   */
  static void
  mic2euc_tw(const unsigned char *mic, unsigned char *p, int len)
  {
  	int			c1;
  	int			l;
  
  	while (len > 0)
  	{
  		c1 = *mic;
  		if (!IS_HIGHBIT_SET(c1))
  		{
  			/* ASCII */
  			if (c1 == 0)
  				report_invalid_encoding(PG_MULE_INTERNAL,
  										(const char *) mic, len);
  			*p++ = c1;
  			mic++;
  			len--;
  			continue;
  		}
  		l = pg_encoding_verifymbchar(PG_MULE_INTERNAL, (const char *) mic, len);
  		if (l < 0)
  			report_invalid_encoding(PG_MULE_INTERNAL,
  									(const char *) mic, len);
  		if (c1 == LC_CNS11643_1)
  		{
  			*p++ = mic[1];
  			*p++ = mic[2];
  		}
  		else if (c1 == LC_CNS11643_2)
  		{
  			*p++ = SS2;
  			*p++ = 0xa2;
  			*p++ = mic[1];
  			*p++ = mic[2];
  		}
  		else if (c1 == LCPRV2_B &&
  				 mic[1] >= LC_CNS11643_3 && mic[1] <= LC_CNS11643_7)
  		{
  			*p++ = SS2;
  			*p++ = mic[1] - LC_CNS11643_3 + 0xa3;
  			*p++ = mic[2];
  			*p++ = mic[3];
  		}
  		else
  			report_untranslatable_char(PG_MULE_INTERNAL, PG_EUC_TW,
  									   (const char *) mic, len);
  		mic += l;
  		len -= l;
  	}
  	*p = '\0';
  }
  
  /*
   * Big5 ---> MIC
   */
  static void
  big52mic(const unsigned char *big5, unsigned char *p, int len)
  {
  	unsigned short c1;
  	unsigned short big5buf,
  				cnsBuf;
  	unsigned char lc;
  	int			l;
  
  	while (len > 0)
  	{
  		c1 = *big5;
  		if (!IS_HIGHBIT_SET(c1))
  		{
  			/* ASCII */
  			if (c1 == 0)
  				report_invalid_encoding(PG_BIG5,
  										(const char *) big5, len);
  			*p++ = c1;
  			big5++;
  			len--;
  			continue;
  		}
  		l = pg_encoding_verifymbchar(PG_BIG5, (const char *) big5, len);
  		if (l < 0)
  			report_invalid_encoding(PG_BIG5,
  									(const char *) big5, len);
  		big5buf = (c1 << 8) | big5[1];
  		cnsBuf = BIG5toCNS(big5buf, &lc);
  		if (lc != 0)
  		{
  			/* Planes 3 and 4 are MULE private charsets */
  			if (lc == LC_CNS11643_3 || lc == LC_CNS11643_4)
  				*p++ = LCPRV2_B;
  			*p++ = lc;			/* Plane No. */
  			*p++ = (cnsBuf >> 8) & 0x00ff;
  			*p++ = cnsBuf & 0x00ff;
  		}
  		else
  			report_untranslatable_char(PG_BIG5, PG_MULE_INTERNAL,
  									   (const char *) big5, len);
  		big5 += l;
  		len -= l;
  	}
  	*p = '\0';
  }
  
  /*
   * MIC ---> Big5
   */
  static void
  mic2big5(const unsigned char *mic, unsigned char *p, int len)
  {
  	unsigned short c1;
  	unsigned short big5buf,
  				cnsBuf;
  	int			l;
  
  	while (len > 0)
  	{
  		c1 = *mic;
  		if (!IS_HIGHBIT_SET(c1))
  		{
  			/* ASCII */
  			if (c1 == 0)
  				report_invalid_encoding(PG_MULE_INTERNAL,
  										(const char *) mic, len);
  			*p++ = c1;
  			mic++;
  			len--;
  			continue;
  		}
  		l = pg_encoding_verifymbchar(PG_MULE_INTERNAL, (const char *) mic, len);
  		if (l < 0)
  			report_invalid_encoding(PG_MULE_INTERNAL,
  									(const char *) mic, len);
  		if (c1 == LC_CNS11643_1 || c1 == LC_CNS11643_2 || c1 == LCPRV2_B)
  		{
  			if (c1 == LCPRV2_B)
  			{
  				c1 = mic[1];	/* get plane no. */
  				cnsBuf = (mic[2] << 8) | mic[3];
  			}
  			else
  			{
  				cnsBuf = (mic[1] << 8) | mic[2];
  			}
  			big5buf = CNStoBIG5(cnsBuf, c1);
  			if (big5buf == 0)
  				report_untranslatable_char(PG_MULE_INTERNAL, PG_BIG5,
  										   (const char *) mic, len);
  			*p++ = (big5buf >> 8) & 0x00ff;
  			*p++ = big5buf & 0x00ff;
  		}
  		else
  			report_untranslatable_char(PG_MULE_INTERNAL, PG_BIG5,
  									   (const char *) mic, len);
  		mic += l;
  		len -= l;
  	}
  	*p = '\0';
  }
  