[perl5.git] / utfebcdic.h

/*    utfebcdic.h
 *
 *    Copyright (C) 2001, 2002, 2003, 2005, 2006, 2007, 2009,
 *    2010, 2011 by Larry Wall, Nick Ing-Simmons, and others
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 *
 * Macros to implement UTF-EBCDIC as perl's internal encoding
 * Adapted from version 7.1 of Unicode Technical Report #16:
 *  http://www.unicode.org/unicode/reports/tr16
 *
 * To summarize, the way it works is:
 * To convert an EBCDIC character to UTF-EBCDIC:
 *  1)	convert to Unicode.  The table in the generated file 'ebcdic_tables.h'
 *      that does this for EBCDIC bytes is PL_e2a (with inverse PL_a2e).  The
 *      'a' stands for ASCII platform, meaning latin1.
 *  2)	convert that to a utf8-like string called I8 ('I' stands for
 *	intermediate) with variant characters occupying multiple bytes.  This
 *	step is similar to the utf8-creating step from Unicode, but the details
 *	are different.  This transformation is called UTF8-Mod.  There is a
 *	chart about the bit patterns in a comment later in this file.  But
 *	essentially here are the differences:
 *			    UTF8		I8
 *	invariant byte	    starts with 0	starts with 0 or 100
 *	continuation byte   starts with 10	starts with 101
 *	start byte	    same in both: if the code point requires N bytes,
 *			    then the leading N bits are 1, followed by a 0.  (No
 *			    trailing 0 for the very largest possible allocation
 *			    in I8, far beyond the current Unicode standard's
 *			    max, as shown in the comment later in this file.)
 *  3)	Use the algorithm in tr16 to convert each byte from step 2 into
 *	final UTF-EBCDIC.  This is done by table lookup from a table
 *	constructed from the algorithm, reproduced in ebcdic_tables.h as
 *	PL_utf2e, with its inverse being PL_e2utf.  They are constructed so that
 *	all EBCDIC invariants remain invariant, but no others do, and the first
 *	byte of a variant will always have its upper bit set.  But note that
 *	the upper bit of some invariants is also 1.
 *
 *  For example, the ordinal value of 'A' is 193 in EBCDIC, and also is 193 in
 *  UTF-EBCDIC.  Step 1) converts it to 65, Step 2 leaves it at 65, and Step 3
 *  converts it back to 193.  As an example of how a variant character works,
 *  take LATIN SMALL LETTER Y WITH DIAERESIS, which is typically 0xDF in
 *  EBCDIC.  Step 1 converts it to the Unicode value, 0xFF.  Step 2 converts
 *  that to two bytes = 11000111 10111111 = C7 BF, and Step 3 converts those to
 *  0x8B 0x73.
 *
 * If you're starting from Unicode, skip step 1.  For UTF-EBCDIC to straight
 * EBCDIC, reverse the steps.
 *
 * The EBCDIC invariants have been chosen to be those characters whose Unicode
 * equivalents have ordinal numbers less than 160, that is the same characters
 * that are expressible in ASCII, plus the C1 controls.  So there are 160
 * invariants instead of the 128 in UTF-8.
 *
 * The purpose of Step 3 is to make the encoding be invariant for the chosen
 * characters.  This messes up the convenient patterns found in step 2, so
 * generally, one has to undo step 3 into a temporary to use them.  However,
 * one "shadow", or parallel table, PL_utf8skip, has been constructed that
 * doesn't require undoing things.  It is such that for each byte, it says
 * how long the sequence is if that (UTF-EBCDIC) byte were to begin it
 *
 * There are actually 3 slightly different UTF-EBCDIC encodings in
 * ebcdic_tables.h, one for each of the code pages recognized by Perl.  That
 * means that there are actually three different sets of tables, one for each
 * code page.  (If Perl is compiled on platforms using another EBCDIC code
 * page, it may not compile, or Perl may silently mistake it for one of the
 * three.)
 *
 * Note that tr16 actually only specifies one version of UTF-EBCDIC, based on
 * the 1047 encoding, and which is supposed to be used for all code pages.
 * But this doesn't work.  To illustrate the problem, consider the '^' character.
 * On a 037 code page it is the single byte 176, whereas under 1047 UTF-EBCDIC
 * it is the single byte 95.  If Perl implemented tr16 exactly, it would mean
 * that changing a string containing '^' to UTF-EBCDIC would change that '^'
 * from 176 to 95 (and vice-versa), violating the rule that ASCII-range
 * characters are the same in UTF-8 or not.  Much code in Perl assumes this
 * rule.  See for example
 * http://grokbase.com/t/perl/mvs/025xf0yhmn/utf-ebcdic-for-posix-bc-malformed-utf-8-character
 * What Perl does is create a version of UTF-EBCDIC suited to each code page;
 * the one for the 1047 code page is identical to what's specified in tr16.
 * This complicates interchanging files between computers using different code
 * pages.  Best is to convert to I8 before sending them, as the I8
 * representation is the same no matter what the underlying code page is.
 *
 * Because of the way UTF-EBCDIC is constructed, the lowest 32 code points that
 * aren't equivalent to ASCII characters nor C1 controls form the set of
 * continuation bytes; the remaining 64 non-ASCII, non-control code points form
 * the potential start bytes, in order.  (However, the first 5 of these lead to
 * malformed overlongs, so there really are only 59 start bytes.) Hence the
 * UTF-EBCDIC for the smallest variant code point, 0x160, will have likely 0x41
 * as its continuation byte, provided 0x41 isn't an ASCII or C1 equivalent.
 * And its start byte will be the code point that is 37 (32+5) non-ASCII,
 * non-control code points past it.  (0 - 3F are controls, and 40 is SPACE,
 * leaving 41 as the first potentially available one.)  In contrast, on ASCII
 * platforms, the first 64 (not 32) non-ASCII code points are the continuation
 * bytes.  And the first 2 (not 5) potential start bytes form overlong
 * malformed sequences.
 *
 * EBCDIC characters above 0xFF are the same as Unicode in Perl's
 * implementation of all 3 encodings, so for those Step 1 is trivial.
 *
 * (Note that the entries for invariant characters are necessarily the same in
 * PL_e2a and PL_e2utf; likewise for their inverses.)
 *
 * UTF-EBCDIC strings are the same length or longer than UTF-8 representations
 * of the same string.  The maximum code point representable as 2 bytes in
 * UTF-EBCDIC is 0x3FFF, instead of 0x7FFF in UTF-8.
 */

START_EXTERN_C

#ifdef DOINIT

#include "ebcdic_tables.h"

#else
EXTCONST U8 PL_utf8skip[];
EXTCONST U8 PL_e2utf[];
EXTCONST U8 PL_utf2e[];
EXTCONST U8 PL_e2a[];
EXTCONST U8 PL_a2e[];
EXTCONST U8 PL_fold[];
EXTCONST U8 PL_fold_latin1[];
EXTCONST U8 PL_latin1_lc[];
EXTCONST U8 PL_mod_latin1_uc[];
#endif

END_EXTERN_C

/* EBCDIC-happy ways of converting native code to UTF-8 */

#define NATIVE_TO_LATIN1(ch)            PL_e2a[(U8)(ch)]
#define LATIN1_TO_NATIVE(ch)            PL_a2e[(U8)(ch)]

#define NATIVE_UTF8_TO_I8(ch)           PL_e2utf[(U8)(ch)]
#define I8_TO_NATIVE_UTF8(ch)           PL_utf2e[(U8)(ch)]

/* Transforms in wide UV chars */
#define NATIVE_TO_UNI(ch)        (((ch) > 255) ? (ch) : NATIVE_TO_LATIN1(ch))
#define UNI_TO_NATIVE(ch)        (((ch) > 255) ? (ch) : LATIN1_TO_NATIVE(ch))

/*
  The following table is adapted from tr16, it shows I8 encoding of Unicode code points.

        Unicode                             Bit pattern 1st Byte 2nd Byte 3rd Byte 4th Byte 5th Byte 6th Byte 7th byte
    U+0000..U+007F                     000000000xxxxxxx 0xxxxxxx
    U+0080..U+009F                     00000000100xxxxx 100xxxxx
    U+00A0..U+03FF                     000000yyyyyxxxxx 110yyyyy 101xxxxx
    U+0400..U+3FFF                     00zzzzyyyyyxxxxx 1110zzzz 101yyyyy 101xxxxx
    U+4000..U+3FFFF                 0wwwzzzzzyyyyyxxxxx 11110www 101zzzzz 101yyyyy 101xxxxx
   U+40000..U+3FFFFF            0vvwwwwwzzzzzyyyyyxxxxx 111110vv 101wwwww 101zzzzz 101yyyyy 101xxxxx
  U+400000..U+3FFFFFF       0uvvvvvwwwwwzzzzzyyyyyxxxxx 1111110u 101vvvvv 101wwwww 101zzzzz 101yyyyy 101xxxxx
 U+4000000..U+7FFFFFFF 0tuuuuuvvvvvwwwwwzzzzzyyyyyxxxxx 1111111t 101uuuuu 101vvvvv 101wwwww 101zzzzz 101yyyyy 101xxxxx

  Note: The I8 transformation is valid for UCS-4 values X'0' to
  X'7FFFFFFF' (the full extent of ISO/IEC 10646 coding space).

 */

/* Input is a true Unicode (not-native) code point */
#define OFFUNISKIP(uv) ( (uv) < 0xA0        ? 1 : \
		      (uv) < 0x400          ? 2 : \
		      (uv) < 0x4000         ? 3 : \
		      (uv) < 0x40000        ? 4 : \
		      (uv) < 0x400000       ? 5 : \
		      (uv) < 0x4000000      ? 6 : 7 )

#define UNI_IS_INVARIANT(c)		(((UV)(c)) <  0xA0)

/* UTF-EBCDIC semantic macros - transform back into I8 and then compare
 * Comments as to the meaning of each are given at their corresponding utf8.h
 * definitions */

#define UTF8_IS_START(c)		(NATIVE_UTF8_TO_I8(c) >= 0xC5     \
                                         && NATIVE_UTF8_TO_I8(c) != 0xE0)
#define UTF8_IS_CONTINUATION(c)		((NATIVE_UTF8_TO_I8(c) & 0xE0) == 0xA0)
#define UTF8_IS_CONTINUED(c) 		(NATIVE_UTF8_TO_I8(c) >= 0xA0)

#define UTF8_IS_DOWNGRADEABLE_START(c)	(NATIVE_UTF8_TO_I8(c) >= 0xC5     \
                                         && NATIVE_UTF8_TO_I8(c) <= 0xC7)
/* Saying it this way adds a runtime test, but removes 2 run-time lookups */
/*#define UTF8_IS_DOWNGRADEABLE_START(c)  ((c) == I8_TO_NATIVE_UTF8(0xC5)     \
                                         || (c) == I8_TO_NATIVE_UTF8(0xC6)  \
                                         || (c) == I8_TO_NATIVE_UTF8(0xC7))
*/
#define UTF8_IS_ABOVE_LATIN1(c)	(NATIVE_UTF8_TO_I8(c) >= 0xC8)

/* Can't exceed 7 on EBCDIC platforms */
#define UTF_START_MARK(len) (0xFF & (0xFE << (7-(len))))

#define UTF_START_MASK(len) (((len) >= 6) ? 0x01 : (0x1F >> ((len)-2)))
#define UTF_CONTINUATION_MARK		0xA0
#define UTF_CONTINUATION_MASK		((U8)0x1f)
#define UTF_ACCUMULATION_SHIFT		5

/* How wide can a single UTF-8 encoded character become in bytes. */
/* NOTE: Strictly speaking Perl's UTF-8 should not be called UTF-8 since UTF-8
 * is an encoding of Unicode, and Unicode's upper limit, 0x10FFFF, can be
 * expressed with 5 bytes.  However, Perl thinks of UTF-8 as a way to encode
 * non-negative integers in a binary format, even those above Unicode */
#define UTF8_MAXBYTES 7

/* The maximum number of UTF-8 bytes a single Unicode character can
 * uppercase/lowercase/fold into.  Unicode guarantees that the maximum
 * expansion is 3 characters.  On EBCDIC platforms, the highest Unicode
 * character occupies 5 bytes, therefore this number is 15 */
#define UTF8_MAXBYTES_CASE	15

/* ^? is defined to be APC on EBCDIC systems.  See the definition of toCTRL()
 * for more */
#define QUESTION_MARK_CTRL   LATIN1_TO_NATIVE(0x9F)

#define MAX_UTF8_TWO_BYTE 0x3FF

/*
 * ex: set ts=8 sts=4 sw=4 et:
 */
Commit	Line	Data
1d72bdf6 NIS	1	/* utfebcdic.h
1d72bdf6 NIS	2	*
2eee27d7 SS	3	* Copyright (C) 2001, 2002, 2003, 2005, 2006, 2007, 2009,
2eee27d7 SS	4	* 2010, 2011 by Larry Wall, Nick Ing-Simmons, and others
1d72bdf6 NIS	5	*
	6	* You may distribute under the terms of either the GNU General Public
	7	* License or the Artistic License, as specified in the README file.
	8	*
	9	* Macros to implement UTF-EBCDIC as perl's internal encoding
97237291	10	* Adapted from version 7.1 of Unicode Technical Report #16:
1d72bdf6	11	* http://www.unicode.org/unicode/reports/tr16
fe749c9a KW	12	*
	13	* To summarize, the way it works is:
	14	* To convert an EBCDIC character to UTF-EBCDIC:
4bc3dcfa KW	15	* 1) convert to Unicode. The table in the generated file 'ebcdic_tables.h'
	16	* that does this for EBCDIC bytes is PL_e2a (with inverse PL_a2e). The
	17	* 'a' stands for ASCII platform, meaning latin1.
97237291	18	* 2) convert that to a utf8-like string called I8 ('I' stands for
d06134e5 KW	19	* intermediate) with variant characters occupying multiple bytes. This
	20	* step is similar to the utf8-creating step from Unicode, but the details
	21	* are different. This transformation is called UTF8-Mod. There is a
	22	* chart about the bit patterns in a comment later in this file. But
fe749c9a KW	23	* essentially here are the differences:
	24	* UTF8 I8
	25	* invariant byte starts with 0 starts with 0 or 100
	26	* continuation byte starts with 10 starts with 101
	27	* start byte same in both: if the code point requires N bytes,
	28	* then the leading N bits are 1, followed by a 0. (No
	29	* trailing 0 for the very largest possible allocation
	30	* in I8, far beyond the current Unicode standard's
	31	* max, as shown in the comment later in this file.)
97237291 KW	32	* 3) Use the algorithm in tr16 to convert each byte from step 2 into
97237291 KW	33	* final UTF-EBCDIC. This is done by table lookup from a table
4bc3dcfa	34	* constructed from the algorithm, reproduced in ebcdic_tables.h as
97237291 KW	35	* PL_utf2e, with its inverse being PL_e2utf. They are constructed so that
	36	* all EBCDIC invariants remain invariant, but no others do, and the first
	37	* byte of a variant will always have its upper bit set. But note that
	38	* the upper bit of some invariants is also 1.
	39	*
	40	* For example, the ordinal value of 'A' is 193 in EBCDIC, and also is 193 in
	41	* UTF-EBCDIC. Step 1) converts it to 65, Step 2 leaves it at 65, and Step 3
	42	* converts it back to 193. As an example of how a variant character works,
	43	* take LATIN SMALL LETTER Y WITH DIAERESIS, which is typically 0xDF in
	44	* EBCDIC. Step 1 converts it to the Unicode value, 0xFF. Step 2 converts
	45	* that to two bytes = 11000111 10111111 = C7 BF, and Step 3 converts those to
	46	* 0x8B 0x73.
45f80db9	47	*
fe749c9a KW	48	* If you're starting from Unicode, skip step 1. For UTF-EBCDIC to straight
	49	* EBCDIC, reverse the steps.
	50	*
	51	* The EBCDIC invariants have been chosen to be those characters whose Unicode
	52	* equivalents have ordinal numbers less than 160, that is the same characters
	53	* that are expressible in ASCII, plus the C1 controls. So there are 160
bc2161fd	54	* invariants instead of the 128 in UTF-8.
fe749c9a KW	55	*
	56	* The purpose of Step 3 is to make the encoding be invariant for the chosen
	57	* characters. This messes up the convenient patterns found in step 2, so
	58	* generally, one has to undo step 3 into a temporary to use them. However,
97237291 KW	59	* one "shadow", or parallel table, PL_utf8skip, has been constructed that
	60	* doesn't require undoing things. It is such that for each byte, it says
	61	* how long the sequence is if that (UTF-EBCDIC) byte were to begin it
	62	*
	63	* There are actually 3 slightly different UTF-EBCDIC encodings in
4bc3dcfa	64	* ebcdic_tables.h, one for each of the code pages recognized by Perl. That
97237291 KW	65	* means that there are actually three different sets of tables, one for each
	66	* code page. (If Perl is compiled on platforms using another EBCDIC code
	67	* page, it may not compile, or Perl may silently mistake it for one of the
	68	* three.)
fe749c9a	69	*
97237291 KW	70	* Note that tr16 actually only specifies one version of UTF-EBCDIC, based on
	71	* the 1047 encoding, and which is supposed to be used for all code pages.
	72	* But this doesn't work. To illustrate the problem, consider the '^' character.
	73	* On a 037 code page it is the single byte 176, whereas under 1047 UTF-EBCDIC
	74	* it is the single byte 95. If Perl implemented tr16 exactly, it would mean
	75	* that changing a string containing '^' to UTF-EBCDIC would change that '^'
	76	* from 176 to 95 (and vice-versa), violating the rule that ASCII-range
	77	* characters are the same in UTF-8 or not. Much code in Perl assumes this
	78	* rule. See for example
	79	* http://grokbase.com/t/perl/mvs/025xf0yhmn/utf-ebcdic-for-posix-bc-malformed-utf-8-character
	80	* What Perl does is create a version of UTF-EBCDIC suited to each code page;
	81	* the one for the 1047 code page is identical to what's specified in tr16.
	82	* This complicates interchanging files between computers using different code
	83	* pages. Best is to convert to I8 before sending them, as the I8
	84	* representation is the same no matter what the underlying code page is.
fe749c9a	85	*
ff982d00 KW	86	* Because of the way UTF-EBCDIC is constructed, the lowest 32 code points that
	87	* aren't equivalent to ASCII characters nor C1 controls form the set of
	88	* continuation bytes; the remaining 64 non-ASCII, non-control code points form
	89	* the potential start bytes, in order. (However, the first 5 of these lead to
	90	* malformed overlongs, so there really are only 59 start bytes.) Hence the
	91	* UTF-EBCDIC for the smallest variant code point, 0x160, will have likely 0x41
	92	* as its continuation byte, provided 0x41 isn't an ASCII or C1 equivalent.
	93	* And its start byte will be the code point that is 37 (32+5) non-ASCII,
	94	* non-control code points past it. (0 - 3F are controls, and 40 is SPACE,
	95	* leaving 41 as the first potentially available one.) In contrast, on ASCII
	96	* platforms, the first 64 (not 32) non-ASCII code points are the continuation
	97	* bytes. And the first 2 (not 5) potential start bytes form overlong
	98	* malformed sequences.
	99	*
fe749c9a KW	100	* EBCDIC characters above 0xFF are the same as Unicode in Perl's
	101	* implementation of all 3 encodings, so for those Step 1 is trivial.
	102	*
	103	* (Note that the entries for invariant characters are necessarily the same in
97237291	104	* PL_e2a and PL_e2utf; likewise for their inverses.)
fe749c9a KW	105	*
	106	* UTF-EBCDIC strings are the same length or longer than UTF-8 representations
	107	* of the same string. The maximum code point representable as 2 bytes in
	108	* UTF-EBCDIC is 0x3FFF, instead of 0x7FFF in UTF-8.
1d72bdf6 NIS	109	*/
	110
	111	START_EXTERN_C
	112
	113	#ifdef DOINIT
f5e1abaf	114
4bc3dcfa	115	#include "ebcdic_tables.h"
44f2fc15	116
1d72bdf6	117	#else
f466f02a KW	118	EXTCONST U8 PL_utf8skip[];
	119	EXTCONST U8 PL_e2utf[];
	120	EXTCONST U8 PL_utf2e[];
	121	EXTCONST U8 PL_e2a[];
	122	EXTCONST U8 PL_a2e[];
	123	EXTCONST U8 PL_fold[];
	124	EXTCONST U8 PL_fold_latin1[];
	125	EXTCONST U8 PL_latin1_lc[];
	126	EXTCONST U8 PL_mod_latin1_uc[];
1d72bdf6 NIS	127	#endif
	128
	129	END_EXTERN_C
	130
1e54db1a	131	/* EBCDIC-happy ways of converting native code to UTF-8 */
1d72bdf6	132
59a449d5 KW	133	#define NATIVE_TO_LATIN1(ch) PL_e2a[(U8)(ch)]
	134	#define LATIN1_TO_NATIVE(ch) PL_a2e[(U8)(ch)]
	135
d53cee75 JG	136	#define NATIVE_UTF8_TO_I8(ch) PL_e2utf[(U8)(ch)]
d53cee75 JG	137	#define I8_TO_NATIVE_UTF8(ch) PL_utf2e[(U8)(ch)]
59a449d5	138
bc3632a8 KW	139	/* Transforms in wide UV chars */
	140	#define NATIVE_TO_UNI(ch) (((ch) > 255) ? (ch) : NATIVE_TO_LATIN1(ch))
	141	#define UNI_TO_NATIVE(ch) (((ch) > 255) ? (ch) : LATIN1_TO_NATIVE(ch))
	142
1d72bdf6	143	/*
d06134e5	144	The following table is adapted from tr16, it shows I8 encoding of Unicode code points.
1d72bdf6 NIS	145
	146	Unicode Bit pattern 1st Byte 2nd Byte 3rd Byte 4th Byte 5th Byte 6th Byte 7th byte
	147	U+0000..U+007F 000000000xxxxxxx 0xxxxxxx
	148	U+0080..U+009F 00000000100xxxxx 100xxxxx
1d72bdf6 NIS	149	U+00A0..U+03FF 000000yyyyyxxxxx 110yyyyy 101xxxxx
	150	U+0400..U+3FFF 00zzzzyyyyyxxxxx 1110zzzz 101yyyyy 101xxxxx
	151	U+4000..U+3FFFF 0wwwzzzzzyyyyyxxxxx 11110www 101zzzzz 101yyyyy 101xxxxx
	152	U+40000..U+3FFFFF 0vvwwwwwzzzzzyyyyyxxxxx 111110vv 101wwwww 101zzzzz 101yyyyy 101xxxxx
	153	U+400000..U+3FFFFFF 0uvvvvvwwwwwzzzzzyyyyyxxxxx 1111110u 101vvvvv 101wwwww 101zzzzz 101yyyyy 101xxxxx
	154	U+4000000..U+7FFFFFFF 0tuuuuuvvvvvwwwwwzzzzzyyyyyxxxxx 1111111t 101uuuuu 101vvvvv 101wwwww 101zzzzz 101yyyyy 101xxxxx
	155
d06134e5	156	Note: The I8 transformation is valid for UCS-4 values X'0' to
1d72bdf6 NIS	157	X'7FFFFFFF' (the full extent of ISO/IEC 10646 coding space).
	158
	159	*/
	160
5aaebcb3 KW	161	/* Input is a true Unicode (not-native) code point */
5aaebcb3 KW	162	#define OFFUNISKIP(uv) ( (uv) < 0xA0 ? 1 : \
1d72bdf6 NIS	163	(uv) < 0x400 ? 2 : \
	164	(uv) < 0x4000 ? 3 : \
	165	(uv) < 0x40000 ? 4 : \
	166	(uv) < 0x400000 ? 5 : \
	167	(uv) < 0x4000000 ? 6 : 7 )
	168
4ed7d5f0	169	#define UNI_IS_INVARIANT(c) (((UV)(c)) < 0xA0)
530495eb	170
15824458 KW	171	/* UTF-EBCDIC semantic macros - transform back into I8 and then compare
	172	* Comments as to the meaning of each are given at their corresponding utf8.h
	173	* definitions */
0447e8df	174
bc3632a8 KW	175	#define UTF8_IS_START(c) (NATIVE_UTF8_TO_I8(c) >= 0xC5 \
	176	&& NATIVE_UTF8_TO_I8(c) != 0xE0)
	177	#define UTF8_IS_CONTINUATION(c) ((NATIVE_UTF8_TO_I8(c) & 0xE0) == 0xA0)
	178	#define UTF8_IS_CONTINUED(c) (NATIVE_UTF8_TO_I8(c) >= 0xA0)
e5119cf4	179
bc3632a8 KW	180	#define UTF8_IS_DOWNGRADEABLE_START(c) (NATIVE_UTF8_TO_I8(c) >= 0xC5 \
bc3632a8 KW	181	&& NATIVE_UTF8_TO_I8(c) <= 0xC7)
e5119cf4	182	/* Saying it this way adds a runtime test, but removes 2 run-time lookups */
f466f02a	183	/*#define UTF8_IS_DOWNGRADEABLE_START(c) ((c) == I8_TO_NATIVE_UTF8(0xC5) \
e5119cf4 KW	184	\|\| (c) == I8_TO_NATIVE_UTF8(0xC6) \
	185	\|\| (c) == I8_TO_NATIVE_UTF8(0xC7))
	186	*/
bc3632a8	187	#define UTF8_IS_ABOVE_LATIN1(c) (NATIVE_UTF8_TO_I8(c) >= 0xC8)
1d72bdf6	188
ee372ee9 KW	189	/* Can't exceed 7 on EBCDIC platforms */
	190	#define UTF_START_MARK(len) (0xFF & (0xFE << (7-(len))))
	191
22901f30	192	#define UTF_START_MASK(len) (((len) >= 6) ? 0x01 : (0x1F >> ((len)-2)))
1d72bdf6 NIS	193	#define UTF_CONTINUATION_MARK 0xA0
	194	#define UTF_CONTINUATION_MASK ((U8)0x1f)
	195	#define UTF_ACCUMULATION_SHIFT 5
	196
03c76984 KW	197	/* How wide can a single UTF-8 encoded character become in bytes. */
	198	/* NOTE: Strictly speaking Perl's UTF-8 should not be called UTF-8 since UTF-8
	199	* is an encoding of Unicode, and Unicode's upper limit, 0x10FFFF, can be
	200	* expressed with 5 bytes. However, Perl thinks of UTF-8 as a way to encode
	201	* non-negative integers in a binary format, even those above Unicode */
	202	#define UTF8_MAXBYTES 7
	203
	204	/* The maximum number of UTF-8 bytes a single Unicode character can
	205	* uppercase/lowercase/fold into. Unicode guarantees that the maximum
	206	* expansion is 3 characters. On EBCDIC platforms, the highest Unicode
	207	* character occupies 5 bytes, therefore this number is 15 */
	208	#define UTF8_MAXBYTES_CASE 15
	209
0ed2b00b KW	210	/* ^? is defined to be APC on EBCDIC systems. See the definition of toCTRL()
	211	* for more */
	212	#define QUESTION_MARK_CTRL LATIN1_TO_NATIVE(0x9F)
	213
843a4590 KW	214	#define MAX_UTF8_TWO_BYTE 0x3FF
843a4590 KW	215
e9a8c099	216	/*
14d04a33	217	* ex: set ts=8 sts=4 sw=4 et:
e9a8c099	218	*/