xref: /openbsd/gnu/usr.bin/perl/utf8.h (revision 5dea098c)
1 /*    utf8.h
2  *
3  * This file contains definitions for use with the UTF-8 encoding.  It
4  * actually also works with the variant UTF-8 encoding called UTF-EBCDIC, and
5  * hides almost all of the differences between these from the caller.  In other
6  * words, someone should #include this file, and if the code is being compiled
7  * on an EBCDIC platform, things should mostly just work.
8  *
9  *    Copyright (C) 2000, 2001, 2002, 2005, 2006, 2007, 2009,
10  *    2010, 2011 by Larry Wall and others
11  *
12  *    You may distribute under the terms of either the GNU General Public
13  *    License or the Artistic License, as specified in the README file.
14  *
15  * A note on nomenclature:  The term UTF-8 is used loosely and inconsistently
16  * in Perl documentation.  For one, perl uses an extension of UTF-8 to
17  * represent code points that Unicode considers illegal.  For another, ASCII
18  * platform UTF-8 is usually conflated with EBCDIC platform UTF-EBCDIC, because
19  * outside some of the macros in this this file, the differences are hopefully
20  * invisible at the semantic level.
21  *
22  * UTF-EBCDIC has an isomorphic translation named I8 (for "Intermediate eight")
23  * which differs from UTF-8 only in a few details.  It is often useful to
24  * translate UTF-EBCDIC into this form for processing.  In general, macros and
25  * functions that are expecting their inputs to be either in I8 or UTF-8 are
26  * named UTF_foo (without an '8'), to indicate this.
27  *
28  * Unfortunately there are inconsistencies.
29  *
30  */
31 
32 #ifndef PERL_UTF8_H_      /* Guard against recursive inclusion */
33 #define PERL_UTF8_H_ 1
34 
35 /* Use UTF-8 as the default script encoding?
36  * Turning this on will break scripts having non-UTF-8 binary
37  * data (such as Latin-1) in string literals. */
38 #ifdef USE_UTF8_SCRIPTS
39 #    define USE_UTF8_IN_NAMES (!IN_BYTES)
40 #else
41 #    define USE_UTF8_IN_NAMES (PL_hints & HINT_UTF8)
42 #endif
43 
44 #include "regcharclass.h"
45 #include "unicode_constants.h"
46 
47 /* For to_utf8_fold_flags, q.v. */
48 #define FOLD_FLAGS_LOCALE       0x1
49 #define FOLD_FLAGS_FULL         0x2
50 #define FOLD_FLAGS_NOMIX_ASCII  0x4
51 
52 /*
53 =for apidoc is_ascii_string
54 
55 This is a misleadingly-named synonym for L</is_utf8_invariant_string>.
56 On ASCII-ish platforms, the name isn't misleading: the ASCII-range characters
57 are exactly the UTF-8 invariants.  But EBCDIC machines have more invariants
58 than just the ASCII characters, so C<is_utf8_invariant_string> is preferred.
59 
60 =for apidoc is_invariant_string
61 
62 This is a somewhat misleadingly-named synonym for L</is_utf8_invariant_string>.
63 C<is_utf8_invariant_string> is preferred, as it indicates under what conditions
64 the string is invariant.
65 
66 =cut
67 */
68 #define is_ascii_string(s, len)     is_utf8_invariant_string(s, len)
69 #define is_invariant_string(s, len) is_utf8_invariant_string(s, len)
70 
71 #define uvoffuni_to_utf8_flags(d,uv,flags)                                     \
72                                uvoffuni_to_utf8_flags_msgs(d, uv, flags, 0)
73 #define uvchr_to_utf8(a,b)          uvchr_to_utf8_flags(a,b,0)
74 #define uvchr_to_utf8_flags(d,uv,flags)                                        \
75                                     uvchr_to_utf8_flags_msgs(d,uv,flags, 0)
76 #define uvchr_to_utf8_flags_msgs(d,uv,flags,msgs)                              \
77                 uvoffuni_to_utf8_flags_msgs(d,NATIVE_TO_UNI(uv),flags, msgs)
78 #define utf8_to_uvchr_buf(s, e, lenp)                                          \
79             utf8_to_uvchr_buf_helper((const U8 *) (s), (const U8 *) e, lenp)
80 #define utf8n_to_uvchr(s, len, lenp, flags)                                    \
81                                 utf8n_to_uvchr_error(s, len, lenp, flags, 0)
82 #define utf8n_to_uvchr_error(s, len, lenp, flags, errors)                      \
83                         utf8n_to_uvchr_msgs(s, len, lenp, flags, errors, 0)
84 
85 #define utf16_to_utf8(p, d, bytelen, newlen)                                \
86                             utf16_to_utf8_base(p, d, bytelen, newlen, 0, 1)
87 #define utf16_to_utf8_reversed(p, d, bytelen, newlen)                       \
88                             utf16_to_utf8_base(p, d, bytelen, newlen, 1, 0)
89 #define utf8_to_utf16(p, d, bytelen, newlen)                                \
90                             utf8_to_utf16_base(p, d, bytelen, newlen, 0, 1)
91 #define utf8_to_utf16_reversed(p, d, bytelen, newlen)                       \
92                             utf8_to_utf16_base(p, d, bytelen, newlen, 1, 0)
93 
94 #define to_uni_fold(c, p, lenp) _to_uni_fold_flags(c, p, lenp, FOLD_FLAGS_FULL)
95 
96 #define foldEQ_utf8(s1, pe1, l1, u1, s2, pe2, l2, u2) \
97                     foldEQ_utf8_flags(s1, pe1, l1, u1, s2, pe2, l2, u2, 0)
98 #define FOLDEQ_UTF8_NOMIX_ASCII   (1 << 0)
99 #define FOLDEQ_LOCALE             (1 << 1)
100 #define FOLDEQ_S1_ALREADY_FOLDED  (1 << 2)
101 #define FOLDEQ_S2_ALREADY_FOLDED  (1 << 3)
102 #define FOLDEQ_S1_FOLDS_SANE      (1 << 4)
103 #define FOLDEQ_S2_FOLDS_SANE      (1 << 5)
104 
105 /* This will be described more fully below, but it turns out that the
106  * fundamental difference between UTF-8 and UTF-EBCDIC is that the former has
107  * the upper 2 bits of a continuation byte be '10', and the latter has the
108  * upper 3 bits be '101', leaving 6 and 5 significant bits respectively.
109  *
110  * It is helpful to know the EBCDIC value on ASCII platforms, mainly to avoid
111  * some #ifdef's */
112 #define UTF_EBCDIC_CONTINUATION_BYTE_INFO_BITS 5
113 
114 /* See explanation below at 'UTF8_MAXBYTES' */
115 #define ASCII_PLATFORM_UTF8_MAXBYTES 13
116 
117 #ifdef EBCDIC
118 
119 /* The equivalent of the next few macros but implementing UTF-EBCDIC are in the
120  * following header file: */
121 #  include "utfebcdic.h"
122 
123 #  else	/* ! EBCDIC */
124 
125 START_EXTERN_C
126 
127 #  ifndef DOINIT
128 EXTCONST unsigned char PL_utf8skip[];
129 #  else
130 EXTCONST unsigned char PL_utf8skip[] = {
131 /* 0x00 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* ascii */
132 /* 0x10 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* ascii */
133 /* 0x20 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* ascii */
134 /* 0x30 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* ascii */
135 /* 0x40 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* ascii */
136 /* 0x50 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* ascii */
137 /* 0x60 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* ascii */
138 /* 0x70 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* ascii */
139 /* 0x80 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* bogus: continuation byte */
140 /* 0x90 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* bogus: continuation byte */
141 /* 0xA0 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* bogus: continuation byte */
142 /* 0xB0 */ 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* bogus: continuation byte */
143 /* 0xC0 */ 2,2,				    /* overlong */
144 /* 0xC2 */     2,2,2,2,2,2,2,2,2,2,2,2,2,2, /* U+0080 to U+03FF */
145 /* 0xD0 */ 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, /* U+0400 to U+07FF */
146 /* 0xE0 */ 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, /* U+0800 to U+FFFF */
147 /* 0xF0 */ 4,4,4,4,4,4,4,4,5,5,5,5,6,6,	    /* above BMP to 2**31 - 1 */
148            /* Perl extended (never was official UTF-8).  Up to 36 bit */
149 /* 0xFE */                             7,
150            /* More extended, Up to 72 bits (64-bit + reserved) */
151 /* 0xFF */                               ASCII_PLATFORM_UTF8_MAXBYTES
152 };
153 #  endif
154 
155 END_EXTERN_C
156 
157 /*
158 
159 =for apidoc Am|U8|NATIVE_TO_LATIN1|U8 ch
160 
161 Returns the Latin-1 (including ASCII and control characters) equivalent of the
162 input native code point given by C<ch>.  Thus, C<NATIVE_TO_LATIN1(193)> on
163 EBCDIC platforms returns 65.  These each represent the character C<"A"> on
164 their respective platforms.  On ASCII platforms no conversion is needed, so
165 this macro expands to just its input, adding no time nor space requirements to
166 the implementation.
167 
168 For conversion of code points potentially larger than will fit in a character,
169 use L</NATIVE_TO_UNI>.
170 
171 =for apidoc Am|U8|LATIN1_TO_NATIVE|U8 ch
172 
173 Returns the native  equivalent of the input Latin-1 code point (including ASCII
174 and control characters) given by C<ch>.  Thus, C<LATIN1_TO_NATIVE(66)> on
175 EBCDIC platforms returns 194.  These each represent the character C<"B"> on
176 their respective platforms.  On ASCII platforms no conversion is needed, so
177 this macro expands to just its input, adding no time nor space requirements to
178 the implementation.
179 
180 For conversion of code points potentially larger than will fit in a character,
181 use L</UNI_TO_NATIVE>.
182 
183 =for apidoc Am|UV|NATIVE_TO_UNI|UV ch
184 
185 Returns the Unicode  equivalent of the input native code point given by C<ch>.
186 Thus, C<NATIVE_TO_UNI(195)> on EBCDIC platforms returns 67.  These each
187 represent the character C<"C"> on their respective platforms.  On ASCII
188 platforms no conversion is needed, so this macro expands to just its input,
189 adding no time nor space requirements to the implementation.
190 
191 =for apidoc Am|UV|UNI_TO_NATIVE|UV ch
192 
193 Returns the native  equivalent of the input Unicode code point  given by C<ch>.
194 Thus, C<UNI_TO_NATIVE(68)> on EBCDIC platforms returns 196.  These each
195 represent the character C<"D"> on their respective platforms.  On ASCII
196 platforms no conversion is needed, so this macro expands to just its input,
197 adding no time nor space requirements to the implementation.
198 
199 =cut
200 */
201 
202 #define NATIVE_TO_LATIN1(ch)  (__ASSERT_(FITS_IN_8_BITS(ch)) ((U8) (ch)))
203 #define LATIN1_TO_NATIVE(ch)  (__ASSERT_(FITS_IN_8_BITS(ch)) ((U8) (ch)))
204 
205 /* I8 is an intermediate version of UTF-8 used only in UTF-EBCDIC.  We thus
206  * consider it to be identical to UTF-8 on ASCII platforms.  Strictly speaking
207  * UTF-8 and UTF-EBCDIC are two different things, but we often conflate them
208  * because they are 8-bit encodings that serve the same purpose in Perl, and
209  * rarely do we need to distinguish them.  The term "NATIVE_UTF8" applies to
210  * whichever one is applicable on the current platform */
211 #define NATIVE_UTF8_TO_I8(ch)  (__ASSERT_(FITS_IN_8_BITS(ch)) ((U8) (ch)))
212 #define I8_TO_NATIVE_UTF8(ch)  (__ASSERT_(FITS_IN_8_BITS(ch)) ((U8) (ch)))
213 
214 #define UNI_TO_NATIVE(ch)        ((UV) ASSERT_NOT_PTR(ch))
215 #define NATIVE_TO_UNI(ch)        ((UV) ASSERT_NOT_PTR(ch))
216 
217 /*
218 
219  The following table is from Unicode 3.2, plus the Perl extensions for above
220  U+10FFFF
221 
222  Code Points		1st Byte  2nd Byte  3rd    4th     5th     6th       7th   8th-13th
223 
224    U+0000..U+007F	00..7F
225    U+0080..U+07FF     * C2..DF    80..BF
226    U+0800..U+0FFF	E0      * A0..BF  80..BF
227    U+1000..U+CFFF       E1..EC    80..BF  80..BF
228    U+D000..U+D7FF       ED        80..9F  80..BF
229    U+D800..U+DFFF       ED        A0..BF  80..BF  (surrogates)
230    U+E000..U+FFFF       EE..EF    80..BF  80..BF
231   U+10000..U+3FFFF	F0      * 90..BF  80..BF  80..BF
232   U+40000..U+FFFFF	F1..F3    80..BF  80..BF  80..BF
233  U+100000..U+10FFFF	F4        80..8F  80..BF  80..BF
234     Below are above-Unicode code points
235  U+110000..U+13FFFF	F4        90..BF  80..BF  80..BF
236  U+110000..U+1FFFFF	F5..F7    80..BF  80..BF  80..BF
237  U+200000..U+FFFFFF     F8      * 88..BF  80..BF  80..BF  80..BF
238 U+1000000..U+3FFFFFF    F9..FB    80..BF  80..BF  80..BF  80..BF
239 U+4000000..U+3FFFFFFF    FC     * 84..BF  80..BF  80..BF  80..BF  80..BF
240 U+40000000..U+7FFFFFFF   FD       80..BF  80..BF  80..BF  80..BF  80..BF
241 U+80000000..U+FFFFFFFFF  FE     * 82..BF  80..BF  80..BF  80..BF  80..BF    80..BF
242 U+1000000000..           FF       80..BF  80..BF  80..BF  80..BF  80..BF  * 81..BF  80..BF
243 
244 Note the gaps before several of the byte entries above marked by '*'.  These are
245 caused by legal UTF-8 avoiding non-shortest encodings: it is technically
246 possible to UTF-8-encode a single code point in different ways, but that is
247 explicitly forbidden, and the shortest possible encoding should always be used
248 (and that is what Perl does).  The non-shortest ones are called 'overlongs'.
249 
250 Another way to look at it, as bits:
251 
252                   Code Points      1st Byte   2nd Byte   3rd Byte   4th Byte
253 
254                         0aaa aaaa  0aaa aaaa
255               0000 0bbb bbaa aaaa  110b bbbb  10aa aaaa
256               cccc bbbb bbaa aaaa  1110 cccc  10bb bbbb  10aa aaaa
257  00 000d ddcc cccc bbbb bbaa aaaa  1111 0ddd  10cc cccc  10bb bbbb  10aa aaaa
258 
259 As you can see, the continuation bytes all begin with C<10>, and the
260 leading bits of the start byte tell how many bytes there are in the
261 encoded character.
262 
263 Perl's extended UTF-8 means we can have start bytes up through FF, though any
264 beginning with FF yields a code point that is too large for 32-bit ASCII
265 platforms.  FF signals to use 13 bytes for the encoded character.  This breaks
266 the paradigm that the number of leading bits gives how many total bytes there
267 are in the character. */
268 
269 /* This is the number of low-order bits a continuation byte in a UTF-8 encoded
270  * sequence contributes to the specification of the code point.  In the bit
271  * maps above, you see that the first 2 bits are a constant '10', leaving 6 of
272  * real information */
273 #  define UTF_CONTINUATION_BYTE_INFO_BITS 6
274 
275 /* ^? is defined to be DEL on ASCII systems.  See the definition of toCTRL()
276  * for more */
277 #  define QUESTION_MARK_CTRL  DEL_NATIVE
278 
279 #endif /* EBCDIC vs ASCII */
280 
281 /* It turns out that in a number of cases, that handling ASCII vs EBCDIC is a
282  * matter of being off-by-one.  So this is a convenience macro, used to avoid
283  * some #ifdefs. */
284 #define ONE_IF_EBCDIC_ZERO_IF_NOT                                           \
285  (UTF_CONTINUATION_BYTE_INFO_BITS == UTF_EBCDIC_CONTINUATION_BYTE_INFO_BITS)
286 
287 /* Since the significant bits in a continuation byte are stored in the
288  * least-significant positions, we often find ourselves shifting by that
289  * amount.  This is a clearer name in such situations */
290 #define UTF_ACCUMULATION_SHIFT  UTF_CONTINUATION_BYTE_INFO_BITS
291 
292 /* 2**info_bits - 1.  This masks out all but the bits that carry real
293  * information in a continuation byte.  This turns out to be 0x3F in UTF-8,
294  * 0x1F in UTF-EBCDIC. */
295 #define UTF_CONTINUATION_MASK                                               \
296                         ((U8) nBIT_MASK(UTF_CONTINUATION_BYTE_INFO_BITS))
297 
298 /* For use in UTF8_IS_CONTINUATION().  This turns out to be 0xC0 in UTF-8,
299  * E0 in UTF-EBCDIC */
300 #define UTF_IS_CONTINUATION_MASK    ((U8) (0xFF << UTF_ACCUMULATION_SHIFT))
301 
302 /* This defines the bits that are to be in the continuation bytes of a
303  * multi-byte UTF-8 encoded character that mark it is a continuation byte.
304  * This turns out to be 0x80 in UTF-8, 0xA0 in UTF-EBCDIC.  (khw doesn't know
305  * the underlying reason that B0 works here, except it just happens to work.
306  * One could solve for two linear equations and come up with it.) */
307 #define UTF_CONTINUATION_MARK       (UTF_IS_CONTINUATION_MASK & 0xB0)
308 
309 /* This value is clearer in some contexts */
310 #define UTF_MIN_CONTINUATION_BYTE  UTF_CONTINUATION_MARK
311 
312 /* Is the byte 'c' part of a multi-byte UTF8-8 encoded sequence, and not the
313  * first byte thereof? */
314 #define UTF8_IS_CONTINUATION(c)     (__ASSERT_(FITS_IN_8_BITS(c))           \
315             (((NATIVE_UTF8_TO_I8(c) & UTF_IS_CONTINUATION_MASK)             \
316                                                 == UTF_CONTINUATION_MARK)))
317 
318 /* Is the representation of the Unicode code point 'cp' the same regardless of
319  * being encoded in UTF-8 or not? This is a fundamental property of
320  * UTF-8,EBCDIC */
321 #define OFFUNI_IS_INVARIANT(c)                                              \
322                         (((WIDEST_UTYPE)(c)) < UTF_MIN_CONTINUATION_BYTE)
323 
324 /*
325 =for apidoc Am|bool|UVCHR_IS_INVARIANT|UV cp
326 
327 Evaluates to 1 if the representation of code point C<cp> is the same whether or
328 not it is encoded in UTF-8; otherwise evaluates to 0.  UTF-8 invariant
329 characters can be copied as-is when converting to/from UTF-8, saving time.
330 C<cp> is Unicode if above 255; otherwise is platform-native.
331 
332 =cut
333  */
334 #if defined(__m88k__)
335 /* XXX workaround: m88k gcc3 produces wrong code with NATIVE_TO_UNI() */
336 #define UVCHR_IS_INVARIANT(cp)  (OFFUNI_IS_INVARIANT(cp))
337 #else	/* the original one */
338 #define UVCHR_IS_INVARIANT(cp)  (OFFUNI_IS_INVARIANT(NATIVE_TO_UNI(cp)))
339 #endif
340 
341 /* This defines the 1-bits that are to be in the first byte of a multi-byte
342  * UTF-8 encoded character that mark it as a start byte and give the number of
343  * bytes that comprise the character. 'len' is that number.
344  *
345  * To illustrate: len = 2 => ((U8) ~ 0b0011_1111) or 1100_0000
346  *                      7 => ((U8) ~ 0b0000_0001) or 1111_1110
347  *                    > 7 =>  0xFF
348  *
349  * This is not to be used on a single-byte character.  As in many places in
350  * perl, U8 must be 8 bits
351  */
352 #define UTF_START_MARK(len) ((U8) ~(0xFF >> (len)))
353 
354 /* Masks out the initial one bits in a start byte, leaving the following 0 bit
355  * and the real data bits.  'len' is the number of bytes in the multi-byte
356  * sequence that comprises the character.
357  *
358  * To illustrate: len = 2 => 0b0011_1111 works on start byte 110xxxxx
359  *                      6 => 0b0000_0011 works on start byte 1111110x
360  *                   >= 7 => There are no data bits in the start byte
361  * Note that on ASCII platforms, this can be passed a len=1 byte; and all the
362  * real data bits will be returned:
363                   len = 1 => 0b0111_1111
364  * This isn't true on EBCDIC platforms, where some len=1 bytes are of the form
365  * 0b101x_xxxx, so this can't be used there on single-byte characters. */
366 #define UTF_START_MASK(len) (0xFF >> (len))
367 
368 /*
369 
370 =for apidoc AmnU|STRLEN|UTF8_MAXBYTES
371 
372 The maximum width of a single UTF-8 encoded character, in bytes.
373 
374 NOTE: Strictly speaking Perl's UTF-8 should not be called UTF-8 since UTF-8
375 is an encoding of Unicode, and Unicode's upper limit, 0x10FFFF, can be
376 expressed with 4 bytes.  However, Perl thinks of UTF-8 as a way to encode
377 non-negative integers in a binary format, even those above Unicode.
378 
379 =cut
380 
381 The start byte 0xFE, never used in any ASCII platform UTF-8 specification, has
382 an obvious meaning, namely it has its upper 7 bits set, so it should start a
383 sequence of 7 bytes.  And in fact, this is exactly what standard UTF-EBCDIC
384 does.
385 
386 The start byte FF, on the other hand could have several different plausible
387 meanings:
388   1) The meaning in standard UTF-EBCDIC, namely as an FE start byte, with the
389      bottom bit that should be a fixed '0' to form FE, instead acting as an
390      info bit, 0 or 1.
391   2) That the sequence should have exactly 8 bytes.
392   3) That the next byte is to be treated as a sort of extended start byte,
393      which in combination with this one gives the total length of the sequence.
394      There are published UTF-8 extensions that do this, some string together
395      multiple initial FF start bytes to achieve arbitrary precision.
396   4) That the sequence has exactly n bytes, where n is what the implementation
397      chooses.
398 
399 Perl has chosen 4).
400 The goal is to be able to represent 64-bit values in UTF-8 or UTF-EBCDIC.  That
401 rules out items 1) and 2).  Item 3) has the deal-breaking disadvantage of
402 requiring one to read more than one byte to determine the total length of the
403 sequence.  So in Perl, a start byte of FF indicates a UTF-8 string consisting
404 of the start byte, plus enough continuation bytes to encode a 64 bit value.
405 This turns out to be 13 total bytes in UTF-8 and 14 in UTF-EBCDIC.  This is
406 because we get zero info bits from the start byte, plus
407     12 * 6 bits of info per continuation byte (could encode 72-bit numbers) on
408                 UTF-8 (khw knows not why 11, which would encode 66 bits wasn't
409                 chosen instead); and
410     13 * 5 bits of info per byte (could encode 65-bit numbers) on UTF-EBCDIC
411 
412 The disadvantages of this method are:
413   1) There's potentially a lot of wasted bytes for all but the largest values.
414      For example, something that could be represented by 7 continuation bytes,
415      instead requires the full 12 or 13.
416   2) There would be problems should larger values, 128-bit say, ever need to be
417      represented.
418 
419 WARNING: This number must be in sync with the value in
420 regen/charset_translations.pl. */
421 #define UTF8_MAXBYTES                                                       \
422                 (ASCII_PLATFORM_UTF8_MAXBYTES + ONE_IF_EBCDIC_ZERO_IF_NOT)
423 
424 /* Calculate how many bytes are necessary to represent a value whose most
425  * significant 1 bit is in bit position 'pos' of the word.  For 0x1, 'pos would
426  * be 0; and for 0x400, 'pos' would be 10, and the result would be:
427  *  EBCDIC floor((-1 + (10 + 5 - 1 - 1)) / (5 - 1))
428  *       = floor((-1 + (13)) / 4)
429  *       = floor(12 / 4)
430  *       = 3
431  *  ASCII  floor(( 0 + (10 + 6 - 1 - 1)) / (6 - 1))
432  *       = floor(14 / 5)
433  *       = 2
434  * The reason this works is because the number of bits needed to represent a
435  * value is proportional to (UTF_CONTINUATION_BYTE_INFO_BITS - 1).  The -1 is
436  * because each new continuation byte removes one bit of information from the
437  * start byte.
438  *
439  * This is a step function (we need to allocate a full extra byte if we
440  * overflow by just a single bit)
441  *
442  * The caller is responsible for making sure 'pos' is at least 8 (occupies 9
443  * bits), as it breaks down at the lower edge.  At the high end, if it returns
444  * 8 or more, Perl instead anomalously uses MAX_BYTES, so this would be wrong.
445  * */
446 #define UNISKIP_BY_MSB_(pos)                                                \
447   ( ( -ONE_IF_EBCDIC_ZERO_IF_NOT  /* platform break pos's are off-by-one */ \
448      + (pos) + ((UTF_CONTINUATION_BYTE_INFO_BITS - 1) - 1))  /* Step fcn */ \
449    / (UTF_CONTINUATION_BYTE_INFO_BITS - 1))             /* take floor of */
450 
451 /* Compute the number of UTF-8 bytes required for representing the input uv,
452  * which must be a Unicode, not native value.
453  *
454  * This uses msbit_pos() which doesn't work on NUL, and UNISKIP_BY_MSB_ breaks
455  * down for small code points.  So first check if the input is invariant to get
456  * around that, and use a helper for high code points to accommodate the fact
457  * that above 7 btyes, the value is anomalous.  The helper is empty on
458  * platforms that don't go that high */
459 #define OFFUNISKIP(uv)                                                      \
460     ((OFFUNI_IS_INVARIANT(uv))                                              \
461      ? 1                                                                    \
462      : (OFFUNISKIP_helper_(uv) UNISKIP_BY_MSB_(msbit_pos(uv))))
463 
464 /* We need to go to MAX_BYTES when we can't represent 'uv' by the number of
465  * information bits in 6 continuation bytes (when we get to 6, the start byte
466  * has no information bits to add to the total).  But on 32-bit ASCII
467  * platforms, that doesn't happen until 6*6 bits, so on those platforms, this
468  * will always be false */
469 #if UVSIZE * CHARBITS > (6 * UTF_CONTINUATION_BYTE_INFO_BITS)
470 #  define HAS_EXTRA_LONG_UTF8
471 #  define OFFUNISKIP_helper_(uv)                                            \
472      UNLIKELY(uv > nBIT_UMAX(6 * UTF_CONTINUATION_BYTE_INFO_BITS))          \
473       ? UTF8_MAXBYTES :
474 #else
475 #  define OFFUNISKIP_helper_(uv)
476 #endif
477 
478 /*
479 
480 =for apidoc Am|STRLEN|UVCHR_SKIP|UV cp
481 returns the number of bytes required to represent the code point C<cp> when
482 encoded as UTF-8.  C<cp> is a native (ASCII or EBCDIC) code point if less than
483 255; a Unicode code point otherwise.
484 
485 =cut
486  */
487 #define UVCHR_SKIP(uv)  OFFUNISKIP(NATIVE_TO_UNI(uv))
488 
489 #define NATIVE_SKIP(uv) UVCHR_SKIP(uv)  /* Old terminology */
490 
491 /* Most code which says UNISKIP is really thinking in terms of native code
492  * points (0-255) plus all those beyond.  This is an imprecise term, but having
493  * it means existing code continues to work.  For precision, use UVCHR_SKIP,
494  * NATIVE_SKIP, or OFFUNISKIP */
495 #define UNISKIP(uv)   UVCHR_SKIP(uv)
496 
497 /* Compute the start byte for a given code point.  This requires the log2 of
498  * the code point, which is hard to compute at compile time, which this macro
499  * wants to be.  (Perhaps deBruijn sequences could be used.)  So a parameter
500  * for the number of bits the value occupies is passed in, which the programmer
501  * has had to figure out to get compile-time effect.  And asserts are used to
502  * make sure the value is correct.
503  *
504  * Since we are interested only in the start byte, we ignore the lower bits
505  * accounted for by the continuation bytes.  Each continuation byte eats up
506  * UTF_CONTINUATION_BYTE_INFO_BITS bits, so the number of continuation bytes
507  * needed is floor(bits / UTF_CONTINUATION_BYTE_INFO_BITS).  That number is fed
508  * to UTF_START_MARK() to get the upper part of the start byte.  The left over
509  * bits form the lower part which is OR'd with the mark
510  *
511  * Note that on EBCDIC platforms, this is actually the I8 */
512 #define UTF_START_BYTE(uv, bits)                                            \
513            (__ASSERT_((uv) >> ((bits) - 1)) /* At least 'bits' */           \
514             __ASSERT_(((uv) & ~nBIT_MASK(bits)) == 0) /* No extra bits */   \
515               UTF_START_MARK(UNISKIP_BY_MSB_((bits) - 1))                   \
516             | ((uv) >> (((bits) / UTF_CONTINUATION_BYTE_INFO_BITS)          \
517                                 * UTF_CONTINUATION_BYTE_INFO_BITS)))
518 
519 /* Compute the first continuation byte for a given code point.  This is mostly
520  * for compile-time, so how many bits it occupies is also passed in).
521  *
522  * We are interested in the first continuation byte, so we ignore the lower
523  * bits accounted for by the rest of the continuation bytes by right shifting
524  * out their info bit, and mask out the higher bits that will go into the start
525  * byte.
526  *
527  * Note that on EBCDIC platforms, this is actually the I8 */
528 #define UTF_FIRST_CONT_BYTE(uv, bits)                                       \
529    (__ASSERT_((uv) >> ((bits) - 1)) /* At least 'bits' */                   \
530     __ASSERT_(((uv) & ~nBIT_MASK(bits)) == 0) /* No extra bits */           \
531        UTF_CONTINUATION_MARK                                                \
532     | (   UTF_CONTINUATION_MASK                                             \
533        & ((uv) >> ((((bits) / UTF_CONTINUATION_BYTE_INFO_BITS) - 1)         \
534                             * UTF_CONTINUATION_BYTE_INFO_BITS))))
535 
536 #define UTF_MIN_START_BYTE  UTF_START_BYTE(UTF_MIN_CONTINUATION_BYTE, 8)
537 
538 /* Is the byte 'c' the first byte of a multi-byte UTF8-8 encoded sequence?
539  * This excludes invariants (they are single-byte).  It also excludes the
540  * illegal overlong sequences that begin with C0 and C1 on ASCII platforms, and
541  * C0-C4 I8 start bytes on EBCDIC ones.  On EBCDIC E0 can't start a
542  * non-overlong sequence, so we define a base macro and for those platforms,
543  * extend it to also exclude E0 */
544 #define UTF8_IS_START_base(c)    (__ASSERT_(FITS_IN_8_BITS(c))              \
545                              (NATIVE_UTF8_TO_I8(c) >= UTF_MIN_START_BYTE))
546 #ifdef EBCDIC
547 #  define UTF8_IS_START(c)                                                  \
548                 (UTF8_IS_START_base(c) && (c) != I8_TO_NATIVE_UTF8(0xE0))
549 #else
550 #  define UTF8_IS_START(c)  UTF8_IS_START_base(c)
551 #endif
552 
553 #define UTF_MIN_ABOVE_LATIN1_BYTE  UTF_START_BYTE(0x100, 9)
554 
555 /* Is the UTF8-encoded byte 'c' the first byte of a sequence of bytes that
556  * represent a code point > 255? */
557 #define UTF8_IS_ABOVE_LATIN1(c)     (__ASSERT_(FITS_IN_8_BITS(c))           \
558                         (NATIVE_UTF8_TO_I8(c) >= UTF_MIN_ABOVE_LATIN1_BYTE))
559 
560 /* Is the UTF8-encoded byte 'c' the first byte of a two byte sequence?  Use
561  * UTF8_IS_NEXT_CHAR_DOWNGRADEABLE() instead if the input isn't known to
562  * be well-formed. */
563 #define UTF8_IS_DOWNGRADEABLE_START(c)	(__ASSERT_(FITS_IN_8_BITS(c))       \
564                 inRANGE_helper_(U8, NATIVE_UTF8_TO_I8(c),                   \
565                         UTF_MIN_START_BYTE, UTF_MIN_ABOVE_LATIN1_BYTE - 1))
566 
567 /* The largest code point representable by two UTF-8 bytes on this platform.
568  * The binary for that code point is:
569  *      1101_1111 10xx_xxxx in UTF-8, and
570  *      1101_1111 101y_yyyy in UTF-EBCDIC I8.
571  * where both x and y are 1, and shown this way to indicate there is one more x
572  * than there is y.  The number of x and y bits are their platform's respective
573  * UTF_CONTINUATION_BYTE_INFO_BITS.  Squeezing out the bits that don't
574  * contribute to the value, these evaluate to:
575  *      1_1111 xx_xxxx in UTF-8, and
576  *      1_1111 y_yyyy in UTF-EBCDIC I8.
577  * or, the maximum value of an unsigned with (5 + info_bit_count) bits */
578 #define MAX_UTF8_TWO_BYTE  nBIT_UMAX(5 + UTF_CONTINUATION_BYTE_INFO_BITS)
579 
580 /* The largest code point representable by two UTF-8 bytes on any platform that
581  * Perl runs on. */
582 #define MAX_PORTABLE_UTF8_TWO_BYTE                                          \
583                 nBIT_UMAX(5 + MIN(       UTF_CONTINUATION_BYTE_INFO_BITS,   \
584                                   UTF_EBCDIC_CONTINUATION_BYTE_INFO_BITS))
585 
586 /*
587 
588 =for apidoc AmnU|STRLEN|UTF8_MAXBYTES_CASE
589 
590 The maximum number of UTF-8 bytes a single Unicode character can
591 uppercase/lowercase/titlecase/fold into.
592 
593 =cut
594 
595  * Unicode guarantees that the maximum expansion is UTF8_MAX_FOLD_CHAR_EXPAND
596  * characters, but any above-Unicode code point will fold to itself, so we only
597  * have to look at the expansion of the maximum Unicode code point.  But this
598  * number may be less than the space occupied by a very large code point under
599  * Perl's extended UTF-8.  We have to make it large enough to fit any single
600  * character.  (It turns out that ASCII and EBCDIC differ in which is larger)
601  *
602 =cut
603 */
604 #define UTF8_MAXBYTES_CASE	                                            \
605         MAX(UTF8_MAXBYTES, UTF8_MAX_FOLD_CHAR_EXPAND * UNISKIP_BY_MSB_(20))
606 
607 /* Rest of these are attributes of Unicode and perl's internals rather than the
608  * encoding, or happen to be the same in both ASCII and EBCDIC (at least at
609  * this level; the macros that some of these call may have different
610  * definitions in the two encodings */
611 
612 /* In domain restricted to ASCII, these may make more sense to the reader than
613  * the ones with Latin1 in the name */
614 #define NATIVE_TO_ASCII(ch)      NATIVE_TO_LATIN1(ch)
615 #define ASCII_TO_NATIVE(ch)      LATIN1_TO_NATIVE(ch)
616 
617 /* More or less misleadingly-named defines, retained for back compat */
618 #define NATIVE_TO_UTF(ch)        NATIVE_UTF8_TO_I8(ch)
619 #define NATIVE_TO_I8(ch)         NATIVE_UTF8_TO_I8(ch)
620 #define UTF_TO_NATIVE(ch)        I8_TO_NATIVE_UTF8(ch)
621 #define I8_TO_NATIVE(ch)         I8_TO_NATIVE_UTF8(ch)
622 #define NATIVE8_TO_UNI(ch)       NATIVE_TO_LATIN1(ch)
623 
624 /* Adds a UTF8 continuation byte 'new' of information to a running total code
625  * point 'old' of all the continuation bytes so far.  This is designed to be
626  * used in a loop to convert from UTF-8 to the code point represented.  Note
627  * that this is asymmetric on EBCDIC platforms, in that the 'new' parameter is
628  * the UTF-EBCDIC byte, whereas the 'old' parameter is a Unicode (not EBCDIC)
629  * code point in process of being generated */
630 #define UTF8_ACCUMULATE(old, new) (__ASSERT_(FITS_IN_8_BITS(new))              \
631                                    ((old) << UTF_ACCUMULATION_SHIFT)           \
632                                    | ((NATIVE_UTF8_TO_I8(new))                 \
633                                        & UTF_CONTINUATION_MASK))
634 
635 /* This works in the face of malformed UTF-8. */
636 #define UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(s, e)                                 \
637                                        (   ( (e) - (s) > 1)                   \
638                                         && UTF8_IS_DOWNGRADEABLE_START(*(s))  \
639                                         && UTF8_IS_CONTINUATION(*((s)+1)))
640 
641 /* Longer, but more accurate name */
642 #define UTF8_IS_ABOVE_LATIN1_START(c)     UTF8_IS_ABOVE_LATIN1(c)
643 
644 /* Convert a UTF-8 variant Latin1 character to a native code point value.
645  * Needs just one iteration of accumulate.  Should be used only if it is known
646  * that the code point is < 256, and is not UTF-8 invariant.  Use the slower
647  * but more general TWO_BYTE_UTF8_TO_NATIVE() which handles any code point
648  * representable by two bytes (which turns out to be up through
649  * MAX_PORTABLE_UTF8_TWO_BYTE).  The two parameters are:
650  *  HI: a downgradable start byte;
651  *  LO: continuation.
652  * */
653 #define EIGHT_BIT_UTF8_TO_NATIVE(HI, LO)                                        \
654     ( __ASSERT_(UTF8_IS_DOWNGRADEABLE_START(HI))                                \
655       __ASSERT_(UTF8_IS_CONTINUATION(LO))                                       \
656      LATIN1_TO_NATIVE(UTF8_ACCUMULATE((                                         \
657                             NATIVE_UTF8_TO_I8(HI) & UTF_START_MASK(2)), (LO))))
658 
659 /* Convert a two (not one) byte utf8 character to a native code point value.
660  * Needs just one iteration of accumulate.  Should not be used unless it is
661  * known that the two bytes are legal: 1) two-byte start, and 2) continuation.
662  * Note that the result can be larger than 255 if the input character is not
663  * downgradable */
664 #define TWO_BYTE_UTF8_TO_NATIVE(HI, LO) \
665     (__ASSERT_(FITS_IN_8_BITS(HI))                                              \
666      __ASSERT_(FITS_IN_8_BITS(LO))                                              \
667      __ASSERT_(PL_utf8skip[HI] == 2)                                            \
668      __ASSERT_(UTF8_IS_CONTINUATION(LO))                                        \
669      UNI_TO_NATIVE(UTF8_ACCUMULATE((NATIVE_UTF8_TO_I8(HI) & UTF_START_MASK(2)), \
670                                    (LO))))
671 
672 /* Should never be used, and be deprecated */
673 #define TWO_BYTE_UTF8_TO_UNI(HI, LO) NATIVE_TO_UNI(TWO_BYTE_UTF8_TO_NATIVE(HI, LO))
674 
675 /*
676 
677 =for apidoc Am|STRLEN|UTF8SKIP|char* s
678 returns the number of bytes a non-malformed UTF-8 encoded character whose first
679 (perhaps only) byte is pointed to by C<s>.
680 
681 If there is a possibility of malformed input, use instead:
682 
683 =over
684 
685 =item C<L</UTF8_SAFE_SKIP>> if you know the maximum ending pointer in the
686 buffer pointed to by C<s>; or
687 
688 =item C<L</UTF8_CHK_SKIP>> if you don't know it.
689 
690 =back
691 
692 It is better to restructure your code so the end pointer is passed down so that
693 you know what it actually is at the point of this call, but if that isn't
694 possible, C<L</UTF8_CHK_SKIP>> can minimize the chance of accessing beyond the end
695 of the input buffer.
696 
697 =cut
698  */
699 #define UTF8SKIP(s)  PL_utf8skip[*(const U8*)(ASSERT_IS_PTR(s))]
700 
701 /*
702 =for apidoc Am|STRLEN|UTF8_SKIP|char* s
703 This is a synonym for C<L</UTF8SKIP>>
704 
705 =cut
706 */
707 
708 #define UTF8_SKIP(s) UTF8SKIP(s)
709 
710 /*
711 =for apidoc Am|STRLEN|UTF8_CHK_SKIP|char* s
712 
713 This is a safer version of C<L</UTF8SKIP>>, but still not as safe as
714 C<L</UTF8_SAFE_SKIP>>.  This version doesn't blindly assume that the input
715 string pointed to by C<s> is well-formed, but verifies that there isn't a NUL
716 terminating character before the expected end of the next character in C<s>.
717 The length C<UTF8_CHK_SKIP> returns stops just before any such NUL.
718 
719 Perl tends to add NULs, as an insurance policy, after the end of strings in
720 SV's, so it is likely that using this macro will prevent inadvertent reading
721 beyond the end of the input buffer, even if it is malformed UTF-8.
722 
723 This macro is intended to be used by XS modules where the inputs could be
724 malformed, and it isn't feasible to restructure to use the safer
725 C<L</UTF8_SAFE_SKIP>>, for example when interfacing with a C library.
726 
727 =cut
728 */
729 
730 #define UTF8_CHK_SKIP(s)                                                       \
731             (UNLIKELY(s[0] == '\0') ? 1 : MIN(UTF8SKIP(s),                     \
732                                     my_strnlen((char *) (s), UTF8SKIP(s))))
733 /*
734 
735 =for apidoc Am|STRLEN|UTF8_SAFE_SKIP|char* s|char* e
736 returns 0 if S<C<s E<gt>= e>>; otherwise returns the number of bytes in the
737 UTF-8 encoded character whose first  byte is pointed to by C<s>.  But it never
738 returns beyond C<e>.  On DEBUGGING builds, it asserts that S<C<s E<lt>= e>>.
739 
740 =cut
741  */
742 #define UTF8_SAFE_SKIP(s, e)  (__ASSERT_((e) >= (s))                \
743                               UNLIKELY(((e) - (s)) <= 0)            \
744                                ? 0                                  \
745                                : MIN(((e) - (s)), UTF8_SKIP(s)))
746 
747 /* Most code that says 'UNI_' really means the native value for code points up
748  * through 255 */
749 #define UNI_IS_INVARIANT(cp)   UVCHR_IS_INVARIANT(cp)
750 
751 /*
752 =for apidoc Am|bool|UTF8_IS_INVARIANT|char c
753 
754 Evaluates to 1 if the byte C<c> represents the same character when encoded in
755 UTF-8 as when not; otherwise evaluates to 0.  UTF-8 invariant characters can be
756 copied as-is when converting to/from UTF-8, saving time.
757 
758 In spite of the name, this macro gives the correct result if the input string
759 from which C<c> comes is not encoded in UTF-8.
760 
761 See C<L</UVCHR_IS_INVARIANT>> for checking if a UV is invariant.
762 
763 =cut
764 
765 The reason it works on both UTF-8 encoded strings and non-UTF-8 encoded, is
766 that it returns TRUE in each for the exact same set of bit patterns.  It is
767 valid on a subset of what UVCHR_IS_INVARIANT is valid on, so can just use that;
768 and the compiler should optimize out anything extraneous given the
769 implementation of the latter. */
770 #define UTF8_IS_INVARIANT(c)	UVCHR_IS_INVARIANT(ASSERT_NOT_PTR(c))
771 
772 /* Like the above, but its name implies a non-UTF8 input, which as the comments
773  * above show, doesn't matter as to its implementation */
774 #define NATIVE_BYTE_IS_INVARIANT(c)	UVCHR_IS_INVARIANT(c)
775 
776 /* Misleadingly named: is the UTF8-encoded byte 'c' part of a variant sequence
777  * in UTF-8?  This is the inverse of UTF8_IS_INVARIANT. */
778 #define UTF8_IS_CONTINUED(c)  (__ASSERT_(FITS_IN_8_BITS(c))                 \
779                                (! UTF8_IS_INVARIANT(c)))
780 
781 /* The macros in the next 4 sets are used to generate the two utf8 or utfebcdic
782  * bytes from an ordinal that is known to fit into exactly two (not one) bytes;
783  * it must be less than 0x3FF to work across both encodings. */
784 
785 /* These two are helper macros for the other three sets, and should not be used
786  * directly anywhere else.  'translate_function' is either NATIVE_TO_LATIN1
787  * (which works for code points up through 0xFF) or NATIVE_TO_UNI which works
788  * for any code point */
789 #define __BASE_TWO_BYTE_HI(c, translate_function)                               \
790            (__ASSERT_(! UVCHR_IS_INVARIANT(c))                                  \
791             I8_TO_NATIVE_UTF8((translate_function(c) >> UTF_ACCUMULATION_SHIFT) \
792                               | UTF_START_MARK(2)))
793 #define __BASE_TWO_BYTE_LO(c, translate_function)                               \
794              (__ASSERT_(! UVCHR_IS_INVARIANT(c))                                \
795               I8_TO_NATIVE_UTF8((translate_function(c) & UTF_CONTINUATION_MASK) \
796                                  | UTF_CONTINUATION_MARK))
797 
798 /* The next two macros should not be used.  They were designed to be usable as
799  * the case label of a switch statement, but this doesn't work for EBCDIC.  Use
800  * regen/unicode_constants.pl instead */
801 #define UTF8_TWO_BYTE_HI_nocast(c)  __BASE_TWO_BYTE_HI(c, NATIVE_TO_UNI)
802 #define UTF8_TWO_BYTE_LO_nocast(c)  __BASE_TWO_BYTE_LO(c, NATIVE_TO_UNI)
803 
804 /* The next two macros are used when the source should be a single byte
805  * character; checked for under DEBUGGING */
806 #define UTF8_EIGHT_BIT_HI(c) (__ASSERT_(FITS_IN_8_BITS(c))                    \
807                              ( __BASE_TWO_BYTE_HI(c, NATIVE_TO_LATIN1)))
808 #define UTF8_EIGHT_BIT_LO(c) (__ASSERT_(FITS_IN_8_BITS(c))                    \
809                              (__BASE_TWO_BYTE_LO(c, NATIVE_TO_LATIN1)))
810 
811 /* These final two macros in the series are used when the source can be any
812  * code point whose UTF-8 is known to occupy 2 bytes; they are less efficient
813  * than the EIGHT_BIT versions on EBCDIC platforms.  We use the logical '~'
814  * operator instead of "<=" to avoid getting compiler warnings.
815  * MAX_UTF8_TWO_BYTE should be exactly all one bits in the lower few
816  * places, so the ~ works */
817 #define UTF8_TWO_BYTE_HI(c)                                                    \
818        (__ASSERT_((sizeof(c) ==  1)                                            \
819                   || !(((WIDEST_UTYPE)(c)) & ~MAX_UTF8_TWO_BYTE))              \
820         (__BASE_TWO_BYTE_HI(c, NATIVE_TO_UNI)))
821 #define UTF8_TWO_BYTE_LO(c)                                                    \
822        (__ASSERT_((sizeof(c) ==  1)                                            \
823                   || !(((WIDEST_UTYPE)(c)) & ~MAX_UTF8_TWO_BYTE))              \
824         (__BASE_TWO_BYTE_LO(c, NATIVE_TO_UNI)))
825 
826 /* This is illegal in any well-formed UTF-8 in both EBCDIC and ASCII
827  * as it is only in overlongs. */
828 #define ILLEGAL_UTF8_BYTE   I8_TO_NATIVE_UTF8(0xC1)
829 
830 /*
831  * 'UTF' is whether or not p is encoded in UTF8.  The names 'foo_lazy_if' stem
832  * from an earlier version of these macros in which they didn't call the
833  * foo_utf8() macros (i.e. were 'lazy') unless they decided that *p is the
834  * beginning of a utf8 character.  Now that foo_utf8() determines that itself,
835  * no need to do it again here
836  */
837 #define isIDFIRST_lazy_if_safe(p, e, UTF)                                   \
838                    ((IN_BYTES || !UTF)                                      \
839                      ? isIDFIRST(*(p))                                      \
840                      : isIDFIRST_utf8_safe(p, e))
841 #define isWORDCHAR_lazy_if_safe(p, e, UTF)                                  \
842                    ((IN_BYTES || !UTF)                                      \
843                      ? isWORDCHAR(*(p))                                     \
844                      : isWORDCHAR_utf8_safe((U8 *) p, (U8 *) e))
845 #define isALNUM_lazy_if_safe(p, e, UTF) isWORDCHAR_lazy_if_safe(p, e, UTF)
846 
847 #define UTF8_MAXLEN  UTF8_MAXBYTES
848 
849 /* A Unicode character can fold to up to 3 characters */
850 #define UTF8_MAX_FOLD_CHAR_EXPAND  3
851 
852 #define IN_BYTES  UNLIKELY(CopHINTS_get(PL_curcop) & HINT_BYTES)
853 
854 /*
855 
856 =for apidoc Am|bool|DO_UTF8|SV* sv
857 Returns a bool giving whether or not the PV in C<sv> is to be treated as being
858 encoded in UTF-8.
859 
860 You should use this I<after> a call to C<SvPV()> or one of its variants, in
861 case any call to string overloading updates the internal UTF-8 encoding flag.
862 
863 =cut
864 */
865 #define DO_UTF8(sv) (SvUTF8(sv) && !IN_BYTES)
866 
867 /* Should all strings be treated as Unicode, and not just UTF-8 encoded ones?
868  * Is so within 'feature unicode_strings' or 'locale :not_characters', and not
869  * within 'use bytes'.  UTF-8 locales are not tested for here, but perhaps
870  * could be */
871 #define IN_UNI_8_BIT                                                    \
872             ((    (      (CopHINTS_get(PL_curcop) & HINT_UNI_8_BIT))    \
873                    || (   CopHINTS_get(PL_curcop) & HINT_LOCALE_PARTIAL \
874                             /* -1 below is for :not_characters */       \
875                        && _is_in_locale_category(FALSE, -1)))           \
876               && (! IN_BYTES))
877 
878 #define UNICODE_SURROGATE_FIRST		0xD800
879 #define UNICODE_SURROGATE_LAST		0xDFFF
880 
881 /*
882 =for apidoc Am|bool|UNICODE_IS_SURROGATE|const UV uv
883 
884 Returns a boolean as to whether or not C<uv> is one of the Unicode surrogate
885 code points
886 
887 =for apidoc Am|bool|UTF8_IS_SURROGATE|const U8 *s|const U8 *e
888 
889 Evaluates to non-zero if the first few bytes of the string starting at C<s> and
890 looking no further than S<C<e - 1>> are well-formed UTF-8 that represents one
891 of the Unicode surrogate code points; otherwise it evaluates to 0.  If
892 non-zero, the value gives how many bytes starting at C<s> comprise the code
893 point's representation.
894 
895 =cut
896  */
897 
898 #define UNICODE_IS_SURROGATE(uv) UNLIKELY(inRANGE(uv, UNICODE_SURROGATE_FIRST,  \
899                                                       UNICODE_SURROGATE_LAST))
900 #define UTF8_IS_SURROGATE(s, e)      is_SURROGATE_utf8_safe(s, e)
901 
902 /*
903 
904 =for apidoc AmnU|UV|UNICODE_REPLACEMENT
905 
906 Evaluates to 0xFFFD, the code point of the Unicode REPLACEMENT CHARACTER
907 
908 =for apidoc Am|bool|UNICODE_IS_REPLACEMENT|const UV uv
909 
910 Returns a boolean as to whether or not C<uv> is the Unicode REPLACEMENT
911 CHARACTER
912 
913 =for apidoc Am|bool|UTF8_IS_REPLACEMENT|const U8 *s|const U8 *e
914 
915 Evaluates to non-zero if the first few bytes of the string starting at C<s> and
916 looking no further than S<C<e - 1>> are well-formed UTF-8 that represents the
917 Unicode REPLACEMENT CHARACTER; otherwise it evaluates to 0.  If non-zero, the
918 value gives how many bytes starting at C<s> comprise the code point's
919 representation.
920 
921 =cut
922  */
923 #define UNICODE_REPLACEMENT		0xFFFD
924 #define UNICODE_IS_REPLACEMENT(uv)  UNLIKELY((UV) (uv) == UNICODE_REPLACEMENT)
925 #define UTF8_IS_REPLACEMENT(s, send)                                         \
926     UNLIKELY(                                                                \
927         ((send) - (s)) >= ((SSize_t)(sizeof(REPLACEMENT_CHARACTER_UTF8) - 1))\
928              && memEQ((s), REPLACEMENT_CHARACTER_UTF8,                       \
929                       sizeof(REPLACEMENT_CHARACTER_UTF8) - 1))
930 
931 /* Max legal code point according to Unicode */
932 #define PERL_UNICODE_MAX	0x10FFFF
933 
934 /*
935 
936 =for apidoc Am|bool|UNICODE_IS_SUPER|const UV uv
937 
938 Returns a boolean as to whether or not C<uv> is above the maximum legal Unicode
939 code point of U+10FFFF.
940 
941 =cut
942 */
943 
944 #define UNICODE_IS_SUPER(uv)  UNLIKELY((UV) (uv) > PERL_UNICODE_MAX)
945 
946 /*
947 =for apidoc Am|bool|UTF8_IS_SUPER|const U8 *s|const U8 *e
948 
949 Recall that Perl recognizes an extension to UTF-8 that can encode code
950 points larger than the ones defined by Unicode, which are 0..0x10FFFF.
951 
952 This macro evaluates to non-zero if the first few bytes of the string starting
953 at C<s> and looking no further than S<C<e - 1>> are from this UTF-8 extension;
954 otherwise it evaluates to 0.  If non-zero, the return is how many bytes
955 starting at C<s> comprise the code point's representation.
956 
957 0 is returned if the bytes are not well-formed extended UTF-8, or if they
958 represent a code point that cannot fit in a UV on the current platform.  Hence
959 this macro can give different results when run on a 64-bit word machine than on
960 one with a 32-bit word size.
961 
962 Note that it is illegal in Perl to have code points that are larger than what can
963 fit in an IV on the current machine; and illegal in Unicode to have any that
964 this macro matches
965 
966 =cut
967 
968  *		  ASCII		     EBCDIC I8
969  * U+10FFFF: \xF4\x8F\xBF\xBF	\xF9\xA1\xBF\xBF\xBF	max legal Unicode
970  * U+110000: \xF4\x90\x80\x80	\xF9\xA2\xA0\xA0\xA0
971  * U+110001: \xF4\x90\x80\x81	\xF9\xA2\xA0\xA0\xA1
972  */
973 #define UTF_START_BYTE_110000_  UTF_START_BYTE(PERL_UNICODE_MAX + 1, 21)
974 #define UTF_FIRST_CONT_BYTE_110000_                                         \
975                           UTF_FIRST_CONT_BYTE(PERL_UNICODE_MAX + 1, 21)
976 #define UTF8_IS_SUPER(s, e)                                                 \
977     (   ((e) - (s)) >= UNISKIP_BY_MSB_(20)                                  \
978      && (       NATIVE_UTF8_TO_I8(s[0]) >= UTF_START_BYTE_110000_           \
979          && (   NATIVE_UTF8_TO_I8(s[0]) >  UTF_START_BYTE_110000_           \
980              || NATIVE_UTF8_TO_I8(s[1]) >= UTF_FIRST_CONT_BYTE_110000_)))   \
981      ? isUTF8_CHAR(s, e)                                                    \
982      : 0
983 
984 /*
985 =for apidoc Am|bool|UNICODE_IS_NONCHAR|const UV uv
986 
987 Returns a boolean as to whether or not C<uv> is one of the Unicode
988 non-character code points
989 
990 =cut
991 */
992 
993 /* Is 'uv' one of the 32 contiguous-range noncharacters? */
994 #define UNICODE_IS_32_CONTIGUOUS_NONCHARS(uv)                               \
995                                     UNLIKELY(inRANGE(uv, 0xFDD0, 0xFDEF))
996 
997 /* Is 'uv' one of the 34 plane-ending noncharacters 0xFFFE, 0xFFFF, 0x1FFFE,
998  * 0x1FFFF, ... 0x10FFFE, 0x10FFFF, given that we know that 'uv' is not above
999  * the Unicode legal max */
1000 #define UNICODE_IS_END_PLANE_NONCHAR_GIVEN_NOT_SUPER(uv)                    \
1001                                   UNLIKELY(((UV) (uv) & 0xFFFE) == 0xFFFE)
1002 
1003 #define UNICODE_IS_NONCHAR(uv)                                              \
1004     (       UNLIKELY(UNICODE_IS_32_CONTIGUOUS_NONCHARS(uv))                 \
1005      || (   UNLIKELY(UNICODE_IS_END_PLANE_NONCHAR_GIVEN_NOT_SUPER(uv))      \
1006          && LIKELY(! UNICODE_IS_SUPER(uv))))
1007 
1008 /*
1009 =for apidoc Am|bool|UTF8_IS_NONCHAR|const U8 *s|const U8 *e
1010 
1011 Evaluates to non-zero if the first few bytes of the string starting at C<s> and
1012 looking no further than S<C<e - 1>> are well-formed UTF-8 that represents one
1013 of the Unicode non-character code points; otherwise it evaluates to 0.  If
1014 non-zero, the value gives how many bytes starting at C<s> comprise the code
1015 point's representation.
1016 
1017 =cut
1018 */
1019 #define UTF8_IS_NONCHAR(s, e)  is_NONCHAR_utf8_safe(s,e)
1020 
1021 /* This is now machine generated, and the 'given' clause is no longer
1022  * applicable */
1023 #define UTF8_IS_NONCHAR_GIVEN_THAT_NON_SUPER_AND_GE_PROBLEMATIC(s, e)       \
1024                                                 UTF8_IS_NONCHAR(s, e)
1025 
1026 /* Surrogates, non-character code points and above-Unicode code points are
1027  * problematic in some contexts.  These macros allow code that needs to check
1028  * for those to quickly exclude the vast majority of code points it will
1029  * encounter.
1030  *
1031  * The lowest such code point is the smallest surrogate, U+D800.  We calculate
1032  * the start byte of that.  0xD800 occupies 16 bits. */
1033 #define isUNICODE_POSSIBLY_PROBLEMATIC(uv) ((uv) >= UNICODE_SURROGATE_FIRST)
1034 #define isUTF8_POSSIBLY_PROBLEMATIC(c)                                      \
1035     (NATIVE_UTF8_TO_I8(c) >= UTF_START_BYTE(UNICODE_SURROGATE_FIRST, 16))
1036 
1037 /* Perl extends Unicode so that it is possible to encode (as extended UTF-8 or
1038  * UTF-EBCDIC) any 64-bit value.  No standard known to khw ever encoded higher
1039  * than a 31 bit value.  On ASCII platforms this just meant arbitrarily saying
1040  * nothing could be higher than this.  On these the start byte FD gets you to
1041  * 31 bits, and FE and FF are forbidden as start bytes.  On EBCDIC platforms,
1042  * FD gets you only to 26 bits; adding FE to mean 7 total bytes gets you to 30
1043  * bits.  To get to 31 bits, they treated an initial FF byte idiosyncratically.
1044  * It was considered to be the start byte FE meaning it had 7 total bytes, and
1045  * the final 1 was treated as an information bit, getting you to 31 bits.
1046  *
1047  * Perl used to accept this idiosyncratic interpretation of FF, but now rejects
1048  * it in order to get to being able to encode 64 bits.  The bottom line is that
1049  * it is a Perl extension to use the start bytes FE and FF on ASCII platforms,
1050  * and the start byte FF on EBCDIC ones.  That translates into that it is a
1051  * Perl extension to represent anything occupying more than 31 bits on ASCII
1052  * platforms; 30 bits on EBCDIC. */
1053 #define UNICODE_IS_PERL_EXTENDED(uv)                                        \
1054           UNLIKELY((UV) (uv) > nBIT_UMAX(31 - ONE_IF_EBCDIC_ZERO_IF_NOT))
1055 #define UTF8_IS_PERL_EXTENDED(s)                                            \
1056                            (UTF8SKIP(s) > 6 + ONE_IF_EBCDIC_ZERO_IF_NOT)
1057 
1058 /* Largest code point we accept from external sources */
1059 #define MAX_LEGAL_CP  ((UV)IV_MAX)
1060 
1061 #define UTF8_ALLOW_EMPTY		0x0001	/* Allow a zero length string */
1062 #define UTF8_GOT_EMPTY                  UTF8_ALLOW_EMPTY
1063 
1064 /* Allow first byte to be a continuation byte */
1065 #define UTF8_ALLOW_CONTINUATION		0x0002
1066 #define UTF8_GOT_CONTINUATION		UTF8_ALLOW_CONTINUATION
1067 
1068 /* Unexpected non-continuation byte */
1069 #define UTF8_ALLOW_NON_CONTINUATION	0x0004
1070 #define UTF8_GOT_NON_CONTINUATION	UTF8_ALLOW_NON_CONTINUATION
1071 
1072 /* expecting more bytes than were available in the string */
1073 #define UTF8_ALLOW_SHORT		0x0008
1074 #define UTF8_GOT_SHORT		        UTF8_ALLOW_SHORT
1075 
1076 /* Overlong sequence; i.e., the code point can be specified in fewer bytes.
1077  * First one will convert the overlong to the REPLACEMENT CHARACTER; second
1078  * will return what the overlong evaluates to */
1079 #define UTF8_ALLOW_LONG                 0x0010
1080 #define UTF8_ALLOW_LONG_AND_ITS_VALUE   (UTF8_ALLOW_LONG|0x0020)
1081 #define UTF8_GOT_LONG                   UTF8_ALLOW_LONG
1082 
1083 #define UTF8_ALLOW_OVERFLOW             0x0080
1084 #define UTF8_GOT_OVERFLOW               UTF8_ALLOW_OVERFLOW
1085 
1086 #define UTF8_DISALLOW_SURROGATE		0x0100	/* Unicode surrogates */
1087 #define UTF8_GOT_SURROGATE		UTF8_DISALLOW_SURROGATE
1088 #define UTF8_WARN_SURROGATE		0x0200
1089 
1090 /* Unicode non-character  code points */
1091 #define UTF8_DISALLOW_NONCHAR           0x0400
1092 #define UTF8_GOT_NONCHAR                UTF8_DISALLOW_NONCHAR
1093 #define UTF8_WARN_NONCHAR               0x0800
1094 
1095 /* Super-set of Unicode: code points above the legal max */
1096 #define UTF8_DISALLOW_SUPER		0x1000
1097 #define UTF8_GOT_SUPER		        UTF8_DISALLOW_SUPER
1098 #define UTF8_WARN_SUPER		        0x2000
1099 
1100 /* The original UTF-8 standard did not define UTF-8 with start bytes of 0xFE or
1101  * 0xFF, though UTF-EBCDIC did.  This allowed both versions to represent code
1102  * points up to 2 ** 31 - 1.  Perl extends UTF-8 so that 0xFE and 0xFF are
1103  * usable on ASCII platforms, and 0xFF means something different than
1104  * UTF-EBCDIC defines.  These changes allow code points of 64 bits (actually
1105  * somewhat more) to be represented on both platforms.  But these are Perl
1106  * extensions, and not likely to be interchangeable with other languages.  Note
1107  * that on ASCII platforms, FE overflows a signed 32-bit word, and FF an
1108  * unsigned one. */
1109 #define UTF8_DISALLOW_PERL_EXTENDED     0x4000
1110 #define UTF8_GOT_PERL_EXTENDED          UTF8_DISALLOW_PERL_EXTENDED
1111 #define UTF8_WARN_PERL_EXTENDED         0x8000
1112 
1113 /* For back compat, these old names are misleading for overlongs and
1114  * UTF_EBCDIC. */
1115 #define UTF8_DISALLOW_ABOVE_31_BIT      UTF8_DISALLOW_PERL_EXTENDED
1116 #define UTF8_GOT_ABOVE_31_BIT           UTF8_GOT_PERL_EXTENDED
1117 #define UTF8_WARN_ABOVE_31_BIT          UTF8_WARN_PERL_EXTENDED
1118 #define UTF8_DISALLOW_FE_FF             UTF8_DISALLOW_PERL_EXTENDED
1119 #define UTF8_WARN_FE_FF                 UTF8_WARN_PERL_EXTENDED
1120 
1121 #define UTF8_CHECK_ONLY			0x10000
1122 #define _UTF8_NO_CONFIDENCE_IN_CURLEN   0x20000  /* Internal core use only */
1123 
1124 /* For backwards source compatibility.  They do nothing, as the default now
1125  * includes what they used to mean.  The first one's meaning was to allow the
1126  * just the single non-character 0xFFFF */
1127 #define UTF8_ALLOW_FFFF 0
1128 #define UTF8_ALLOW_FE_FF 0
1129 #define UTF8_ALLOW_SURROGATE 0
1130 
1131 /* C9 refers to Unicode Corrigendum #9: allows but discourages non-chars */
1132 #define UTF8_DISALLOW_ILLEGAL_C9_INTERCHANGE                                    \
1133                                  (UTF8_DISALLOW_SUPER|UTF8_DISALLOW_SURROGATE)
1134 #define UTF8_WARN_ILLEGAL_C9_INTERCHANGE (UTF8_WARN_SUPER|UTF8_WARN_SURROGATE)
1135 
1136 #define UTF8_DISALLOW_ILLEGAL_INTERCHANGE                                       \
1137                   (UTF8_DISALLOW_ILLEGAL_C9_INTERCHANGE|UTF8_DISALLOW_NONCHAR)
1138 #define UTF8_WARN_ILLEGAL_INTERCHANGE \
1139                           (UTF8_WARN_ILLEGAL_C9_INTERCHANGE|UTF8_WARN_NONCHAR)
1140 
1141 /* This is typically used for code that processes UTF-8 input and doesn't want
1142  * to have to deal with any malformations that might be present.  All such will
1143  * be safely replaced by the REPLACEMENT CHARACTER, unless other flags
1144  * overriding this are also present. */
1145 #define UTF8_ALLOW_ANY ( UTF8_ALLOW_CONTINUATION                                \
1146                         |UTF8_ALLOW_NON_CONTINUATION                            \
1147                         |UTF8_ALLOW_SHORT                                       \
1148                         |UTF8_ALLOW_LONG                                        \
1149                         |UTF8_ALLOW_OVERFLOW)
1150 
1151 /* Accept any Perl-extended UTF-8 that evaluates to any UV on the platform, but
1152  * not any malformed.  This is the default. */
1153 #define UTF8_ALLOW_ANYUV   0
1154 #define UTF8_ALLOW_DEFAULT UTF8_ALLOW_ANYUV
1155 
1156 #define UNICODE_WARN_SURROGATE         0x0001	/* UTF-16 surrogates */
1157 #define UNICODE_WARN_NONCHAR           0x0002	/* Non-char code points */
1158 #define UNICODE_WARN_SUPER             0x0004	/* Above 0x10FFFF */
1159 #define UNICODE_WARN_PERL_EXTENDED     0x0008	/* Above 0x7FFF_FFFF */
1160 #define UNICODE_WARN_ABOVE_31_BIT      UNICODE_WARN_PERL_EXTENDED
1161 #define UNICODE_DISALLOW_SURROGATE     0x0010
1162 #define UNICODE_DISALLOW_NONCHAR       0x0020
1163 #define UNICODE_DISALLOW_SUPER         0x0040
1164 #define UNICODE_DISALLOW_PERL_EXTENDED 0x0080
1165 
1166 #ifdef PERL_CORE
1167 #  define UNICODE_ALLOW_ABOVE_IV_MAX   0x0100
1168 #endif
1169 #define UNICODE_DISALLOW_ABOVE_31_BIT  UNICODE_DISALLOW_PERL_EXTENDED
1170 
1171 #define UNICODE_GOT_SURROGATE       UNICODE_DISALLOW_SURROGATE
1172 #define UNICODE_GOT_NONCHAR         UNICODE_DISALLOW_NONCHAR
1173 #define UNICODE_GOT_SUPER           UNICODE_DISALLOW_SUPER
1174 #define UNICODE_GOT_PERL_EXTENDED   UNICODE_DISALLOW_PERL_EXTENDED
1175 
1176 #define UNICODE_WARN_ILLEGAL_C9_INTERCHANGE                                   \
1177                                   (UNICODE_WARN_SURROGATE|UNICODE_WARN_SUPER)
1178 #define UNICODE_WARN_ILLEGAL_INTERCHANGE                                      \
1179                    (UNICODE_WARN_ILLEGAL_C9_INTERCHANGE|UNICODE_WARN_NONCHAR)
1180 #define UNICODE_DISALLOW_ILLEGAL_C9_INTERCHANGE                               \
1181                           (UNICODE_DISALLOW_SURROGATE|UNICODE_DISALLOW_SUPER)
1182 #define UNICODE_DISALLOW_ILLEGAL_INTERCHANGE                                  \
1183            (UNICODE_DISALLOW_ILLEGAL_C9_INTERCHANGE|UNICODE_DISALLOW_NONCHAR)
1184 
1185 /* For backward source compatibility, as are now the default */
1186 #define UNICODE_ALLOW_SURROGATE 0
1187 #define UNICODE_ALLOW_SUPER	0
1188 #define UNICODE_ALLOW_ANY	0
1189 
1190 #define UNICODE_BYTE_ORDER_MARK		0xFEFF
1191 #define UNICODE_IS_BYTE_ORDER_MARK(uv)	UNLIKELY((UV) (uv)                  \
1192                                                 == UNICODE_BYTE_ORDER_MARK)
1193 
1194 #define LATIN_SMALL_LETTER_SHARP_S      LATIN_SMALL_LETTER_SHARP_S_NATIVE
1195 #define LATIN_SMALL_LETTER_Y_WITH_DIAERESIS                                  \
1196                                 LATIN_SMALL_LETTER_Y_WITH_DIAERESIS_NATIVE
1197 #define MICRO_SIGN      MICRO_SIGN_NATIVE
1198 #define LATIN_CAPITAL_LETTER_A_WITH_RING_ABOVE                               \
1199                             LATIN_CAPITAL_LETTER_A_WITH_RING_ABOVE_NATIVE
1200 #define LATIN_SMALL_LETTER_A_WITH_RING_ABOVE                                 \
1201                                 LATIN_SMALL_LETTER_A_WITH_RING_ABOVE_NATIVE
1202 #define UNICODE_GREEK_CAPITAL_LETTER_SIGMA	0x03A3
1203 #define UNICODE_GREEK_SMALL_LETTER_FINAL_SIGMA	0x03C2
1204 #define UNICODE_GREEK_SMALL_LETTER_SIGMA	0x03C3
1205 #define GREEK_SMALL_LETTER_MU                   0x03BC
1206 #define GREEK_CAPITAL_LETTER_MU                 0x039C	/* Upper and title case
1207                                                            of MICRON */
1208 #define LATIN_CAPITAL_LETTER_Y_WITH_DIAERESIS   0x0178	/* Also is title case */
1209 #ifdef LATIN_CAPITAL_LETTER_SHARP_S_UTF8
1210 #   define LATIN_CAPITAL_LETTER_SHARP_S	        0x1E9E
1211 #endif
1212 #define LATIN_CAPITAL_LETTER_I_WITH_DOT_ABOVE   0x130
1213 #define LATIN_SMALL_LETTER_DOTLESS_I            0x131
1214 #define LATIN_SMALL_LETTER_LONG_S               0x017F
1215 #define LATIN_SMALL_LIGATURE_LONG_S_T           0xFB05
1216 #define LATIN_SMALL_LIGATURE_ST                 0xFB06
1217 #define KELVIN_SIGN                             0x212A
1218 #define ANGSTROM_SIGN                           0x212B
1219 
1220 #define UNI_DISPLAY_ISPRINT	0x0001
1221 #define UNI_DISPLAY_BACKSLASH	0x0002
1222 #define UNI_DISPLAY_BACKSPACE	0x0004  /* Allow \b when also
1223                                            UNI_DISPLAY_BACKSLASH */
1224 #define UNI_DISPLAY_QQ		(UNI_DISPLAY_ISPRINT                \
1225                                 |UNI_DISPLAY_BACKSLASH              \
1226                                 |UNI_DISPLAY_BACKSPACE)
1227 
1228 /* Character classes could also allow \b, but not patterns in general */
1229 #define UNI_DISPLAY_REGEX	(UNI_DISPLAY_ISPRINT|UNI_DISPLAY_BACKSLASH)
1230 
1231 /* Should be removed; maybe deprecated, but not used in CPAN */
1232 #define SHARP_S_SKIP 2
1233 
1234 #define is_utf8_char_buf(buf, buf_end) isUTF8_CHAR(buf, buf_end)
1235 #define bytes_from_utf8(s, lenp, is_utf8p)                                  \
1236                             bytes_from_utf8_loc(s, lenp, is_utf8p, 0)
1237 
1238 /* Do not use; should be deprecated.  Use isUTF8_CHAR() instead; this is
1239  * retained solely for backwards compatibility */
1240 #define IS_UTF8_CHAR(p, n)      (isUTF8_CHAR(p, (p) + (n)) == n)
1241 
1242 #endif /* PERL_UTF8_H_ */
1243 
1244 /*
1245  * ex: set ts=8 sts=4 sw=4 et:
1246  */
1247