/* utfebcdic.h
*
- * Copyright (C) 2001, 2002, 2003, 2005, 2006, 2007, by Larry Wall, Nick
- * Ing-Simmons, and others
+ * Copyright (C) 2001, 2002, 2003, 2005, 2006, 2007, 2009 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
* Taken from version 7.1 of Unicode Techical 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 this file that does this is for
+ * EBCDIC bytes is PL_e2a (with inverse PLa2e). The 'a' stands for
+ * ASCIIish, meaning latin1.
+ * 2) convert that to a utf8-like string called I8 with variant characters
+ * occupying multiple bytes. This step is similar to the utf8-creating
+ * step from Unicode, but the details are different. 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 table published in tr16 to convert each byte from step 2 into
+ * final UTF-EBCDIC. The table in this file is PL_utf2e, and its inverse
+ * is PL_e2utf. They are constructed so that all EBCDIC invariants remain
+ * invariant, but no others do. 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 typicially 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. The
+ * table is constructed so that the first bytes of a variant will always
+ * have its upper bit set (at least in the encodings that Perl recognizes,
+ * and probably all).
+ *
+ * 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. (My guess is that this is because
+ * the C1 control NEL (and maybe others) is important in IBM.)
+ *
+ * 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,
+ * a "shadow", or parallel table, PL_utf8skip, has been constructed so that for
+ * each byte, it says how long the sequence is if that byte were to begin it
+ *
+ * There are actually 3 slightly different UTF-EBCDIC encodings in this file,
+ * 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 other EBCDIC code pages, it may not
+ * compile, or silently mistake it for one of the three.)
+ *
+ * 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 PLe2f, and the same 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
};
#endif
-/* Transform tables from tr16 applied after encoding to render encoding EBCDIC like */
+/* Transform tables from tr16 applied after encoding to render encoding EBCDIC
+ * like, meaning that all the invariants are actually invariant, eg, that 'A'
+ * remains 'A' */
#if '^' == 95 /* if defined(__MVS__) || defined(??) (VM/ESA?) 1047 */
EXTCONST unsigned char PL_utf2e[] = { /* UTF-8-mod to EBCDIC (IBM-1047) */
0x74, 0x75, 0x76, 0x77, 0x78, 0x80, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x9A, 0x9B, 0x9C,
0x9D, 0x9E, 0x9F, 0xA0, 0xAA, 0xAB, 0xAC, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6,
0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBE, 0xBF, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xDA, 0xDB,
- 0xDC, 0xDD, 0xDE, 0xDF, 0xE1, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE,
+ 0xDC, 0xDD, 0xDE, 0xDF, 0xE1, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE
};
EXTCONST unsigned char PL_e2utf[] = { /* EBCDIC (IBM-1047) to UTF-8-mod */
0x7B, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED,
0x7D, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3,
0x5C, 0xF4, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA,
- 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF, 0x9F,
+ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF, 0x9F
};
#endif /* 1047 */
0x74, 0x75, 0x76, 0x77, 0x78, 0x80, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x9A, 0x9B, 0x9C,
0x9D, 0x9E, 0x9F, 0xA0, 0xAA, 0xAB, 0xAC, 0xAE, 0xAF, 0xBA, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6,
0xB7, 0xB8, 0xB9, 0xAD, 0x79, 0xA1, 0xBE, 0xBF, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xDA, 0xDB,
- 0xDC, 0xC0, 0xDE, 0xDF, 0xE1, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xFA, 0xDD, 0xFC, 0xE0, 0xFE,
+ 0xDC, 0xC0, 0xDE, 0xDF, 0xE1, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xFA, 0xDD, 0xFC, 0xE0, 0xFE
};
unsigned char PL_e2utf[] = { /* EBCDIC (POSIX-BC) to UTF-8-mod */
0xF1, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED,
0xBB, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0xEE, 0xEF, 0xF0, 0xFC, 0xF2, 0xF3,
0xFE, 0xF4, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA,
- 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0xFB, 0x7B, 0xFD, 0x7D, 0xFF, 0x7E,
+ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0xFB, 0x7B, 0xFD, 0x7D, 0xFF, 0x7E
};
#endif /* POSIX-BC */
0x74, 0x75, 0x76, 0x77, 0x78, 0x80, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x9A, 0x9B, 0x9C,
0x9D, 0x9E, 0x9F, 0xA0, 0xAA, 0xAB, 0xAC, 0xAE, 0xAF, 0x5F, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6,
0xB7, 0xB8, 0xB9, 0xAD, 0xBD, 0xBC, 0xBE, 0xBF, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xDA, 0xDB,
- 0xDC, 0xDD, 0xDE, 0xDF, 0xE1, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE,
+ 0xDC, 0xDD, 0xDE, 0xDF, 0xE1, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE
};
unsigned char PL_e2utf[] = { /* EBCDIC (IBM-037) to UTF-8-mod */
0x7B, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED,
0x7D, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3,
0x5C, 0xF4, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA,
- 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF, 0x9F,
+ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF, 0x9F
};
#endif /* 037 */
/* Native to iso-8859-1 */
#define NATIVE_TO_ASCII(ch) PL_e2a[(U8)(ch)]
+#define NATIVE8_TO_UNI(ch) NATIVE_TO_ASCII(ch) /* synonym */
#define ASCII_TO_NATIVE(ch) PL_a2e[(U8)(ch)]
/* Transform after encoding */
#define NATIVE_TO_UTF(ch) PL_e2utf[(U8)(ch)]
#define UNI_IS_INVARIANT(c) ((c) < 0xA0)
/* UTF-EBCDIC sematic macros - transform back into UTF-8-Mod and then compare */
-#define NATIVE_IS_INVARIANT(c) UNI_IS_INVARIANT(NATIVE_TO_ASCII(c))
+#define NATIVE_IS_INVARIANT(c) UNI_IS_INVARIANT(NATIVE8_TO_UNI(c))
#define UTF8_IS_INVARIANT(c) UNI_IS_INVARIANT(NATIVE_TO_UTF(c))
#define UTF8_IS_START(c) (NATIVE_TO_UTF(c) >= 0xA0 && (NATIVE_TO_UTF(c) & 0xE0) != 0xA0)
#define UTF8_IS_CONTINUATION(c) ((NATIVE_TO_UTF(c) & 0xE0) == 0xA0)
#define UTF8_IS_CONTINUED(c) (NATIVE_TO_UTF(c) >= 0xA0)
#define UTF8_IS_DOWNGRADEABLE_START(c) (NATIVE_TO_UTF(c) >= 0xA0 && (NATIVE_TO_UTF(c) & 0xF8) == 0xC0)
-#define UTF_START_MARK(len) ((len > 7) ? 0xFF : (0xFE << (7-len)))
-#define UTF_START_MASK(len) ((len >= 6) ? 0x01 : (0x1F >> (len-2)))
+#define UTF_START_MARK(len) (((len) > 7) ? 0xFF : ((U8)(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