* iso2022.c - support for ISO/IEC 2022 (alias ECMA-35).
*
* This isn't a complete implementation of ISO/IEC 2022, but it's
- * close. It only handles decoding, because a fully general encoder
- * isn't really useful. It can decode 8-bit and 7-bit versions, with
- * support for single-byte and multi-byte character sets, all four
- * containers (G0, G1, G2, and G3), using both single-shift and
- * locking-shift sequences.
+ * close. It can decode 8-bit and 7-bit versions, with support for
+ * single-byte and multi-byte character sets, all four containers
+ * (G0, G1, G2, and G3), using both single-shift and locking-shift
+ * sequences.
*
* The general principle is that any valid ISO/IEC 2022 sequence
* should either be correctly decoded or should emit an ERROR. The
#ifndef ENUM_CHARSETS
#include <assert.h>
+#include <string.h>
#include "charset.h"
#include "internal.h"
static long int emacs_big5_1_to_unicode(int, int);
static long int emacs_big5_2_to_unicode(int, int);
+static int unicode_to_emacs_big5(long int, int *, int *, int *);
static long int cns11643_1_to_unicode(int, int);
static long int cns11643_2_to_unicode(int, int);
static long int cns11643_3_to_unicode(int, int);
static long int cns11643_6_to_unicode(int, int);
static long int cns11643_7_to_unicode(int, int);
static long int null_dbcs_to_unicode(int, int);
+static int unicode_to_null_dbcs(long int, int *, int *);
+
+typedef int (*to_dbcs_t)(long int, int *, int *);
+typedef int (*to_dbcs_planar_t)(long int, int *, int *, int *);
+
+/*
+ * These macros cast between to_dbcs_planar_t and to_dbcs_t, in
+ * such a way as to cause a compile-time error if the input is not
+ * of the appropriate type.
+ *
+ * Defining these portably is quite fiddly. My first effort was as
+ * follows:
+ * #define DEPLANARISE(x) ( (x) == (to_dbcs_planar_t)NULL, (to_dbcs_t)(x) )
+ *
+ * so that the comparison on the left of the comma provokes the
+ * type check error, and the cast on the right is the actual
+ * desired result.
+ *
+ * gcc was entirely happy with this. However, when used in a static
+ * initialiser, MSVC objected - justifiably - that the first half
+ * of the comma expression wasn't constant and thus the expression
+ * as a whole was not a constant expression. We can get round this
+ * by enclosing the comparison in `sizeof', so that it isn't
+ * actually evaluated.
+ *
+ * But then we run into a second problem, which is that C actually
+ * disallows the use of the comma operator within a constant
+ * expression for any purpose at all! Presumably this is on the
+ * basis that its purpose is to have side effects and constant
+ * expressions can't; unfortunately, this specific case is one in
+ * which the desired side effect is a compile-time rather than a
+ * run-time one.
+ *
+ * We are permitted to use ?:, however, and that works quite well
+ * since the actual result of the sizeof expression _is_ evaluable
+ * at compile time. So here's my final answer:
+ */
+#define TYPECHECK(x,y) ( sizeof((x)) == sizeof((x)) ? (y) : (y) )
+#define DEPLANARISE(x) TYPECHECK((x) == (to_dbcs_planar_t)NULL, (to_dbcs_t)(x))
+#define REPLANARISE(x) TYPECHECK((x) == (to_dbcs_t)NULL, (to_dbcs_planar_t)(x))
+
+/*
+ * Values used in the `enable' field. Each of these identifies a
+ * class of character sets; we then have a bitmask indicating which
+ * classes are allowable in a given mode.
+ *
+ * These values are currently only checked on output: for input,
+ * any ISO 2022 we can comprehend at all is considered acceptable.
+ */
+#define CCS 1 /* CTEXT standard */
+#define COS 2 /* other standard */
+#define CPU 3 /* private use */
+#define CDC 4 /* DOCS for CTEXT */
+#define CDU 5 /* DOCS for UTF-8 */
+#define CNU 31 /* never used */
+
+struct iso2022_mode {
+ int enable_mask;
+ char ltype, li, lf, rtype, ri, rf;
+};
const struct iso2022_subcharset {
- char type, i, f;
+ char type, i, f, enable;
int offset;
const sbcs_data *sbcs_base;
- long int (*dbcs_fn)(int, int);
+ long int (*from_dbcs)(int, int);
+
+ /*
+ * If to_dbcs_plane < 0, then to_dbcs is used as expected.
+ * However, if to_dbcs_plane >= 0, then to_dbcs is expected to
+ * be cast to a to_dbcs_planar_t before use, and the returned
+ * plane value (the first int *) must equal to_dbcs_plane.
+ *
+ * I'd have preferred to do this by means of a union, but you
+ * can't initialise a selected field of a union at compile
+ * time. Function pointer casts are guaranteed to work sensibly
+ * in ISO C (that is, it's undefined what happens if you call a
+ * function via the wrong type of pointer, but if you cast it
+ * back to the right type before calling it then it must work),
+ * so this is safe if ugly.
+ */
+ to_dbcs_t to_dbcs;
+ int to_dbcs_plane; /* use to_dbcs_planar iff >= 0 */
} iso2022_subcharsets[] = {
- { S4, 0, '0', 0x00, &sbcsdata_CS_DEC_GRAPHICS },
- { S4, 0, '<', 0x80, &sbcsdata_CS_DEC_MCS },
- { S4, 0, 'A', 0x00, &sbcsdata_CS_BS4730 },
- { S4, 0, 'B', 0x00, &sbcsdata_CS_ASCII },
- { S4, 0, 'I', 0x80, &sbcsdata_CS_JISX0201 },
- { S4, 0, 'J', 0x00, &sbcsdata_CS_JISX0201 },
- { S4, 0, '~' },
- { S6, 0, 'A', 0x80, &sbcsdata_CS_ISO8859_1 },
- { S6, 0, 'B', 0x80, &sbcsdata_CS_ISO8859_2 },
- { S6, 0, 'C', 0x80, &sbcsdata_CS_ISO8859_3 },
- { S6, 0, 'D', 0x80, &sbcsdata_CS_ISO8859_4 },
- { S6, 0, 'F', 0x80, &sbcsdata_CS_ISO8859_7 },
- { S6, 0, 'G', 0x80, &sbcsdata_CS_ISO8859_6 },
- { S6, 0, 'H', 0x80, &sbcsdata_CS_ISO8859_8 },
- { S6, 0, 'L', 0x80, &sbcsdata_CS_ISO8859_5 },
- { S6, 0, 'M', 0x80, &sbcsdata_CS_ISO8859_9 },
- { S6, 0, 'T', 0x80, &sbcsdata_CS_ISO8859_11 },
- { S6, 0, 'V', 0x80, &sbcsdata_CS_ISO8859_10 },
- { S6, 0, 'Y', 0x80, &sbcsdata_CS_ISO8859_13 },
- { S6, 0, '_', 0x80, &sbcsdata_CS_ISO8859_14 },
- { S6, 0, 'b', 0x80, &sbcsdata_CS_ISO8859_15 },
- { S6, 0, 'f', 0x80, &sbcsdata_CS_ISO8859_16 },
- { S6, 0, '~' }, /* empty 96-set */
+ /*
+ * We list these subcharsets in preference order for output.
+ * Since the best-defined use of ISO 2022 output is compound
+ * text, we'll use a preference order which matches that. So we
+ * begin with the charsets defined in the compound text spec.
+ */
+ { S4, 0, 'B', CCS, 0x00, &sbcsdata_CS_ASCII, NULL, NULL, 0 },
+ { S6, 0, 'A', CCS, 0x80, &sbcsdata_CS_ISO8859_1, NULL, NULL, 0 },
+ { S6, 0, 'B', CCS, 0x80, &sbcsdata_CS_ISO8859_2, NULL, NULL, 0 },
+ { S6, 0, 'C', CCS, 0x80, &sbcsdata_CS_ISO8859_3, NULL, NULL, 0 },
+ { S6, 0, 'D', CCS, 0x80, &sbcsdata_CS_ISO8859_4, NULL, NULL, 0 },
+ { S6, 0, 'F', CCS, 0x80, &sbcsdata_CS_ISO8859_7, NULL, NULL, 0 },
+ { S6, 0, 'G', CCS, 0x80, &sbcsdata_CS_ISO8859_6, NULL, NULL, 0 },
+ { S6, 0, 'H', CCS, 0x80, &sbcsdata_CS_ISO8859_8, NULL, NULL, 0 },
+ { S6, 0, 'L', CCS, 0x80, &sbcsdata_CS_ISO8859_5, NULL, NULL, 0 },
+ { S6, 0, 'M', CCS, 0x80, &sbcsdata_CS_ISO8859_9, NULL, NULL, 0 },
+ { S4, 0, 'I', CCS, 0x80, &sbcsdata_CS_JISX0201, NULL, NULL, 0 },
+ { S4, 0, 'J', CCS, 0x00, &sbcsdata_CS_JISX0201, NULL, NULL, 0 },
+ { M4, 0, 'A', CCS, -0x21, 0, &gb2312_to_unicode, &unicode_to_gb2312, -1 },
+ { M4, 0, 'B', CCS, -0x21, 0, &jisx0208_to_unicode, &unicode_to_jisx0208, -1 },
+ { M4, 0, 'C', CCS, -0x21, 0, &ksx1001_to_unicode, &unicode_to_ksx1001, -1 },
+ { M4, 0, 'D', CCS, -0x21, 0, &jisx0212_to_unicode, &unicode_to_jisx0212, -1 },
+
+ /*
+ * Next, other reasonably standard things: the rest of the ISO
+ * 8859 sets, UK-ASCII, and CNS 11643.
+ */
+ { S6, 0, 'T', COS, 0x80, &sbcsdata_CS_ISO8859_11, NULL, NULL, 0 },
+ { S6, 0, 'V', COS, 0x80, &sbcsdata_CS_ISO8859_10, NULL, NULL, 0 },
+ { S6, 0, 'Y', COS, 0x80, &sbcsdata_CS_ISO8859_13, NULL, NULL, 0 },
+ { S6, 0, '_', COS, 0x80, &sbcsdata_CS_ISO8859_14, NULL, NULL, 0 },
+ { S6, 0, 'b', COS, 0x80, &sbcsdata_CS_ISO8859_15, NULL, NULL, 0 },
+ { S6, 0, 'f', COS, 0x80, &sbcsdata_CS_ISO8859_16, NULL, NULL, 0 },
+ { S4, 0, 'A', COS, 0x00, &sbcsdata_CS_BS4730, NULL, NULL, 0 },
+ { M4, 0, 'G', COS, -0x21, 0, &cns11643_1_to_unicode, DEPLANARISE(&unicode_to_cns11643), 0 },
+ { M4, 0, 'H', COS, -0x21, 0, &cns11643_2_to_unicode, DEPLANARISE(&unicode_to_cns11643), 1 },
+ { M4, 0, 'I', COS, -0x21, 0, &cns11643_3_to_unicode, DEPLANARISE(&unicode_to_cns11643), 2 },
+ { M4, 0, 'J', COS, -0x21, 0, &cns11643_4_to_unicode, DEPLANARISE(&unicode_to_cns11643), 3 },
+ { M4, 0, 'K', COS, -0x21, 0, &cns11643_5_to_unicode, DEPLANARISE(&unicode_to_cns11643), 4 },
+ { M4, 0, 'L', COS, -0x21, 0, &cns11643_6_to_unicode, DEPLANARISE(&unicode_to_cns11643), 5 },
+ { M4, 0, 'M', COS, -0x21, 0, &cns11643_7_to_unicode, DEPLANARISE(&unicode_to_cns11643), 6 },
+
+ /*
+ * Private-use designations: DEC private sets and Emacs's Big5
+ * abomination.
+ */
+ { S4, 0, '0', CPU, 0x00, &sbcsdata_CS_DEC_GRAPHICS, NULL, NULL, 0 },
+ { S4, 0, '<', CPU, 0x80, &sbcsdata_CS_DEC_MCS, NULL, NULL, 0 },
+ { M4, 0, '0', CPU, -0x21, 0, &emacs_big5_1_to_unicode, DEPLANARISE(&unicode_to_emacs_big5), 1 },
+ { M4, 0, '1', CPU, -0x21, 0, &emacs_big5_2_to_unicode, DEPLANARISE(&unicode_to_emacs_big5), 2 },
+
+ /*
+ * Ben left this conditioned out without explanation,
+ * presumably on the grounds that we don't have a translation
+ * table for it.
+ */
#if 0
- { M4, 0, '@' }, /* JIS C 6226-1978 */
+ { M4, 0, '@', CNU }, /* JIS C 6226-1978 */
#endif
- { M4, 0, '0', -0x21, 0, &emacs_big5_1_to_unicode },
- { M4, 0, '1', -0x21, 0, &emacs_big5_2_to_unicode },
- { M4, 0, 'A', -0x21, 0, &gb2312_to_unicode },
- { M4, 0, 'B', -0x21, 0, &jisx0208_to_unicode },
- { M4, 0, 'C', -0x21, 0, &ksx1001_to_unicode },
- { M4, 0, 'D', -0x21, 0, &jisx0212_to_unicode },
- { M4, 0, 'G', -0x21, 0, &cns11643_1_to_unicode },
- { M4, 0, 'H', -0x21, 0, &cns11643_2_to_unicode },
- { M4, 0, 'I', -0x21, 0, &cns11643_3_to_unicode },
- { M4, 0, 'J', -0x21, 0, &cns11643_4_to_unicode },
- { M4, 0, 'K', -0x21, 0, &cns11643_5_to_unicode },
- { M4, 0, 'L', -0x21, 0, &cns11643_6_to_unicode },
- { M4, 0, 'M', -0x21, 0, &cns11643_7_to_unicode },
- { M4, 0, '~', 0, 0, &null_dbcs_to_unicode }, /* empty 94^n-set */
- { M6, 0, '~', 0, 0, &null_dbcs_to_unicode }, /* empty 96^n-set */
+
+ /*
+ * Finally, fallback entries for null character sets.
+ */
+ { S4, 0, '~', CNU, 0, NULL, NULL, NULL, 0 },
+ { S6, 0, '~', CNU, 0, NULL, NULL, NULL, 0 }, /* empty 96-set */
+ { M4, 0, '~', CNU, 0, 0, &null_dbcs_to_unicode, &unicode_to_null_dbcs, -1 }, /* empty 94^n-set */
+ { M6, 0, '~', CNU, 0, 0, &null_dbcs_to_unicode, &unicode_to_null_dbcs, -1 }, /* empty 96^n-set */
};
static long int null_dbcs_to_unicode(int r, int c)
{
+ UNUSEDARG(r);
+ UNUSEDARG(c);
return ERROR;
}
+static int unicode_to_null_dbcs(long int unicode, int *r, int *c)
+{
+ UNUSEDARG(unicode);
+ UNUSEDARG(r);
+ UNUSEDARG(c);
+ return 0; /* failed to convert anything */
+}
/*
* Emacs encodes Big5 in COMPOUND_TEXT as two 94x94 character sets.
return big5_to_unicode(r, c);
}
+static int unicode_to_emacs_big5(long int unicode, int *p, int *r, int *c)
+{
+ int rr, cc, s;
+ if (!unicode_to_big5(unicode, &rr, &cc))
+ return 0;
+ if (cc >= 64) {
+ cc -= 34;
+ assert(cc >= 64);
+ }
+ s = rr * 157 + cc;
+ if (s >= 40*157) {
+ *p = 2;
+ s -= 40*157;
+ } else {
+ *p = 1;
+ }
+ *r = s / 94;
+ *c = s % 94;
+ return 1;
+}
+
/* Wrappers for cns11643_to_unicode() */
static long int cns11643_1_to_unicode(int r, int c)
{
struct ctext_encoding {
char const *name;
+ char octets_per_char, enable;
charset_spec const *subcs;
};
/*
- * In theory, this list is in <http://ftp.x.org/pub/docs/registry>,
+ * In theory, this list is in <ftp://ftp.x.org/pub/DOCS/registry>,
* but XLib appears to have its own ideas, and encodes these three
* (as of X11R6.8.2)
*/
extern charset_spec const charset_CS_BIG5;
static struct ctext_encoding const ctext_encodings[] = {
- { "big5-0\2", &charset_CS_BIG5 },
- { "iso8859-14\2", &charset_CS_ISO8859_14 },
- { "iso8859-15\2", &charset_CS_ISO8859_15 }
+ { "big5-0\2", 0 /* variable */, CDC, &charset_CS_BIG5 },
+ { "iso8859-14\2", 1, CDC, &charset_CS_ISO8859_14 },
+ { "iso8859-15\2", 1, CDC, &charset_CS_ISO8859_15 }
};
static void docs_ctext(long int input_chr,
int n = (state->s0 >> 22) & 0xf, i = (state->s0 >> 26) & 3, oi = i, j;
int length = (state->s0 >> 8) & 0x3fff;
+ /*
+ * Note that we do not bother checking the octets-per-character
+ * byte against the selected charset when reading. It's
+ * extremely unlikely that this code will ever have to deal
+ * with two charset identifiers with the same name and
+ * different octets-per-character values! If it ever happens,
+ * we'll have to edit this file anyway so we can modify the
+ * code then...
+ */
+
if (!length) {
/* Haven't read length yet */
if ((state->s0 & 0xff) == 0)
if (input_chr == 2)
state->s0 = (state->s0 & 0xf0000000) | (i << 26) | (0xf << 22);
} else if (n != 0xf) {
- while (j < lenof(ctext_encodings) &&
+ while ((unsigned)j < lenof(ctext_encodings) &&
!memcmp(ctext_encodings[j].name,
ctext_encodings[oi].name, n)) {
if (ctext_encodings[j].name[n] < input_chr)
else
break;
}
- if (i >= lenof(ctext_encodings) ||
+ if ((unsigned)i >= lenof(ctext_encodings) ||
memcmp(ctext_encodings[i].name,
ctext_encodings[oi].name, n) ||
ctext_encodings[i].name[n] != input_chr) {
assert(i < 4 && n < 16);
state->s0 = (state->s0 & 0xf0000000) | (i << 26) | (n << 22);
} else {
- if (i >= lenof(ctext_encodings))
+ if ((unsigned)i >= lenof(ctext_encodings))
emit(emitctx, ERROR);
else {
charset_state substate;
}
static void read_iso2022(charset_spec const *charset, long int input_chr,
- charset_state *state,
- void (*emit)(void *ctx, long int output),
- void *emitctx)
+ charset_state *state,
+ void (*emit)(void *ctx, long int output),
+ void *emitctx)
{
+ struct iso2022_mode const *mode = (struct iso2022_mode *)charset->data;
/* dump_state(state); */
/*
#define LEFT 30
#define RIGHT 28
#define LOCKING_SHIFT(n,side) \
- (state->s1 = (state->s1 & ~(3L<<(side))) | ((n ## L)<<(side)))
-#define MODE ((state->s0 & 0xe0000000L) >> 29)
-#define ENTER_MODE(m) (state->s0 = (state->s0 & ~0xe0000000L) | ((m)<<29))
+ (state->s1 = (state->s1 & ~(3UL<<(side))) | ((n ## UL)<<(side)))
+#define MODE ((state->s0 & 0xe0000000UL) >> 29)
+#define ENTER_MODE(m) (state->s0 = (state->s0 & ~0xe0000000UL) | ((unsigned long)(m)<<29))
#define SINGLE_SHIFT(n) ENTER_MODE(SS2CHAR - 2 + (n))
#define ASSERT_IDLE do { \
if (state->s0 != 0) emit(emitctx, ERROR); \
*/
LOCKING_SHIFT(0, LEFT);
LOCKING_SHIFT(1, RIGHT);
- designate(state, 0, S4, 0, 'B');
- designate(state, 1, S4, 0, 'B');
+ designate(state, 0, mode->ltype, mode->li, mode->lf);
+ designate(state, 1, mode->rtype, mode->ri, mode->rf);
designate(state, 2, S4, 0, 'B');
designate(state, 3, S4, 0, 'B');
}
return;
} else {
emit(emitctx,
- subcs->dbcs_fn(((state->s0 >> 16) & 0x7f) + subcs->offset,
- input_7bit + subcs->offset));
+ subcs->from_dbcs(((state->s0 >> 16) & 0x7f) +
+ subcs->offset,
+ input_7bit + subcs->offset));
}
} else {
if ((state->s0 & 0x00ff0000L) != 0)
}
}
+static void oselect(charset_state *state, int i, int right,
+ void (*emit)(void *ctx, long int output),
+ void *emitctx)
+{
+ int shift = (right ? 31-7 : 31-7-7);
+ struct iso2022_subcharset const *subcs = &iso2022_subcharsets[i];
+
+ if (((state->s1 >> shift) & 0x7F) != (unsigned)i) {
+ state->s1 &= ~(0x7FL << shift);
+ state->s1 |= (i << shift);
+
+ if (emit) {
+ emit(emitctx, ESC);
+ if (subcs->type == M4 || subcs->type == M6)
+ emit(emitctx, '$');
+ if (subcs->type == S6 || subcs->type == M6) {
+ assert(right);
+ emit(emitctx, '-');
+ } else if (right) {
+ emit(emitctx, ')');
+ } else {
+ emit(emitctx, '(');
+ }
+ if (subcs->i)
+ emit(emitctx, subcs->i);
+ emit(emitctx, subcs->f);
+ }
+ }
+}
+
+static void docs_char(charset_state *state,
+ void (*emit)(void *ctx, long int output),
+ void *emitctx, int cset, char *data, int datalen)
+{
+ int curr_cset, currlen, i;
+
+ /*
+ * cset is the index into ctext_encodings[]. It can also be -1
+ * to mean DOCS UTF-8, or -2 to mean no DOCS (ordinary 2022).
+ * In the latter case, `chr' is ignored.
+ */
+
+ /*
+ * First, terminate a DOCS segment if necessary. We always have
+ * to terminate a DOCS segment if one is active and we're about
+ * to switch to a different one; we might also have to
+ * terminate a length-encoded DOCS segment if we've run out of
+ * storage space to accumulate characters in it.
+ */
+ curr_cset = ((state->s1 >> 14) & 7) - 2;
+ currlen = ((state->s1 >> 11) & 7);
+ if ((curr_cset != -2 && curr_cset != cset) ||
+ (curr_cset >= 0 && currlen + datalen > 5)) {
+ if (curr_cset == -1) {
+ /*
+ * Terminating DOCS UTF-8 is easy.
+ */
+ emit(emitctx, ESC);
+ emit(emitctx, '%');
+ emit(emitctx, '@');
+ } else {
+ int len;
+
+ /*
+ * To terminate a length-encoded DOCS segment we must
+ * actually output the whole thing.
+ */
+ emit(emitctx, ESC);
+ emit(emitctx, '%');
+ emit(emitctx, '/');
+ emit(emitctx, '0' + ctext_encodings[curr_cset].octets_per_char);
+ len = currlen + datalen +
+ strlen(ctext_encodings[curr_cset].name);
+ assert(len < (1 << 14));
+ emit(emitctx, 0x80 | ((len >> 7) & 0x7F));
+ emit(emitctx, 0x80 | ((len ) & 0x7F));
+ /* The name stored in ctext_encodings[] includes the trailing \2 */
+ for (i = 0; ctext_encodings[curr_cset].name[i]; i++)
+ emit(emitctx, ctext_encodings[curr_cset].name[i]);
+ for (i = 0; i < currlen; i++)
+ emit(emitctx,
+ (i == 0 ? state->s1 : state->s0 >> (8*(4-i))) & 0xFF);
+ for (i = 0; i < datalen; i++)
+ emit(emitctx, data[i]);
+
+ /*
+ * We've now dealt with the input data, so clear it so
+ * we don't try to do so again below.
+ */
+ datalen = 0;
+ }
+ curr_cset = -2;
+ }
+
+ /*
+ * Now, start a DOCS segment if necessary.
+ */
+ if (curr_cset != cset) {
+ assert(cset != -2);
+ if (cset == -1) {
+ /*
+ * Start DOCS UTF-8.
+ */
+ emit(emitctx, ESC);
+ emit(emitctx, '%');
+ emit(emitctx, 'G');
+ } else {
+ /*
+ * Starting a length-encoded DOCS segment is simply a
+ * matter of setting our stored length counter to zero.
+ */
+ currlen = 0;
+ state->s1 &= ~(7 << 11);
+ state->s1 &= ~0xFF;
+ state->s0 = 0;
+ }
+ }
+ state->s1 &= ~(7 << 14);
+ assert((cset+2) >= 0 && (cset+2) < 8);
+ state->s1 |= ((cset+2) << 14);
+
+ /*
+ * Now we're in the right DOCS state. Actually deal with the
+ * input data, if we haven't already done so above.
+ */
+ if (datalen > 0) {
+ assert(cset != 2);
+ if (cset == -1) {
+ /*
+ * In DOCS UTF-8, we output data as soon as we get it.
+ */
+ for (i = 0; i < datalen; i++)
+ emit(emitctx, data[i]);
+ } else {
+ /*
+ * In length-encoded DOCS, we just store our data and
+ * bide our time. It'll all be output when we fill up
+ * or switch to another character set.
+ */
+ assert(currlen + datalen <= 5); /* overflow handled already */
+ for (i = 0; i < datalen; i++) {
+ if (currlen + i == 0)
+ state->s1 |= data[i] & 0xFF;
+ else
+ state->s0 |= (data[i] & 0xFF) << (8*(4-(currlen+i)));
+ }
+ currlen += datalen;
+ assert(currlen >= 0 && currlen < 8);
+ state->s1 &= ~(7 << 11);
+ state->s1 |= (currlen << 11);
+ }
+ }
+}
+
+static void write_to_pointer(void *ctx, long int output)
+{
+ char **ptr = (char **)ctx;
+ *(*ptr)++ = output;
+}
+
+/*
+ * Writing full ISO-2022 is not useful in very many circumstances.
+ * One of the few situations in which it _is_ useful is generating
+ * X11 COMPOUND_TEXT; therefore, this writing function will obey
+ * the compound text restrictions and hence output the subset of
+ * ISO-2022 that's usable in that context.
+ *
+ * The subset in question is roughly that we use GL/GR for G0/G1
+ * always, and that the _only_ escape sequences we output (other
+ * than the occasional DOCS) are those which designate different
+ * subcharsets into G0 and G1. There are additional constraints
+ * about which things go in which container; see below.
+ *
+ * FIXME: this wants some decent tests to be written, and also the
+ * exact output policy for compound text wants thinking about more
+ * carefully.
+ */
static int write_iso2022(charset_spec const *charset, long int input_chr,
charset_state *state,
void (*emit)(void *ctx, long int output),
void *emitctx)
{
+ int i;
+ struct iso2022_subcharset const *subcs;
+ struct iso2022_mode const *mode = (struct iso2022_mode *)charset->data;
+ to_dbcs_planar_t last_planar_dbcs = NULL;
+ int last_p, last_r, last_c;
+ long int c1, c2;
+
+ /*
+ * For output, I allocate the state variables as follows:
+ *
+ * s1[31] == 1 if output state has been initialised
+ * s1[30:24] == G1 charset (always in GR)
+ * s1[23:17] == G0 charset (always in GL)
+ * s1[16:14] == DOCS index plus 2 (because -1 and -2 are special)
+ * s1[13:11] == number of DOCS accumulated characters (up to five)
+ * s1[7:0] + s0[31:0] == DOCS collected characters
+ */
+
+ if (!state->s1) {
+ state->s0 = 0x00000000UL;
+ state->s1 = 0x80000000UL;
+ /*
+ * Start with US-ASCII in GL and also in GR.
+ */
+ for (i = 0; (unsigned)i < lenof(iso2022_subcharsets); i++) {
+ subcs = &iso2022_subcharsets[i];
+ if (subcs->type == mode->ltype &&
+ subcs->i == mode->li &&
+ subcs->f == mode->lf)
+ oselect(state, i, FALSE, NULL, NULL);
+ if (subcs->type == mode->rtype &&
+ subcs->i == mode->ri &&
+ subcs->f == mode->rf)
+ oselect(state, i, TRUE, NULL, NULL);
+ }
+ }
+
+ if (input_chr == -1) {
+ /*
+ * Special case: reset encoding state.
+ */
+ docs_char(state, emit, emitctx, -2, NULL, 0); /* leave DOCS */
+
+ for (i = 0; (unsigned)i < lenof(iso2022_subcharsets); i++) {
+ subcs = &iso2022_subcharsets[i];
+ if (subcs->type == mode->ltype &&
+ subcs->i == mode->li &&
+ subcs->f == mode->lf)
+ oselect(state, i, FALSE, emit, emitctx);
+ if (subcs->type == mode->rtype &&
+ subcs->i == mode->ri &&
+ subcs->f == mode->rf)
+ oselect(state, i, TRUE, emit, emitctx);
+ }
+ return TRUE;
+ }
+
+ /*
+ * Special-case characters: Space, Delete, and anything in C0
+ * or C1 are output unchanged.
+ */
+ if (input_chr <= 0x20 || (input_chr >= 0x7F && input_chr < 0xA0)) {
+ emit(emitctx, input_chr);
+ return TRUE;
+ }
+
+ /*
+ * Analyse the input character and work out which subcharset it
+ * belongs to.
+ */
+ for (i = 0; (unsigned)i < lenof(iso2022_subcharsets); i++) {
+ subcs = &iso2022_subcharsets[i];
+ if (!(mode->enable_mask & (1 << subcs->enable)))
+ continue; /* this charset is disabled */
+ if (subcs->sbcs_base) {
+ c1 = sbcs_from_unicode(subcs->sbcs_base, input_chr);
+ c1 -= subcs->offset;
+ if (c1 >= 0x20 && c1 <= 0x7f) {
+ c2 = 0;
+ break;
+ }
+ } else if (subcs->to_dbcs) {
+ if (subcs->to_dbcs_plane >= 0) {
+ /*
+ * Since multiplanar DBCSes almost by definition
+ * involve several entries in iso2022_subcharsets
+ * with the same to_dbcs function and different
+ * plane values, we remember the last such function
+ * we called and what its result was, so that we
+ * don't (for example) have to call
+ * unicode_to_cns11643 seven times.
+ */
+ if (last_planar_dbcs != REPLANARISE(subcs->to_dbcs)) {
+ last_planar_dbcs = REPLANARISE(subcs->to_dbcs);
+ if (!last_planar_dbcs(input_chr,
+ &last_p, &last_r, &last_c))
+ last_p = -1;
+ }
+ } else {
+ last_p = subcs->to_dbcs_plane;
+ if (!subcs->to_dbcs(input_chr, &last_r, &last_c))
+ last_p = 0; /* cannot match since to_dbcs_plane<0 */
+ }
+
+ if (last_p == subcs->to_dbcs_plane) {
+ c1 = last_r - subcs->offset;
+ c2 = last_c - subcs->offset;
+ assert(c1 >= 0x20 && c1 <= 0x7f);
+ assert(c2 >= 0x20 && c2 <= 0x7f);
+ break;
+ }
+ }
+ }
+
+ if ((unsigned)i < lenof(iso2022_subcharsets)) {
+ int right;
+
+ /*
+ * Our character is represented by c1 (and possibly also
+ * c2) in subcharset `subcs'. So now we must decide whether
+ * to designate that character set into G0/GL or G1/GR.
+ *
+ * Any S6 or M6 subcharset has to go in GR because it won't
+ * fit in GL. In addition, the compound text rules state
+ * that any single-byte subcharset defined as the
+ * right-hand half of some SBCS must go in GR.
+ *
+ * M4 subcharsets can go in either half according to the
+ * rules. I choose to put them in GR always because it's a
+ * simple policy with reasonable behaviour (facilitates
+ * switching between them and ASCII).
+ */
+ right = (subcs->type == S6 || subcs->type == M6 || subcs->type == M4 ||
+ (subcs->sbcs_base && subcs->offset == 0x80));
+
+ /*
+ * If we're in a DOCS mode, leave it.
+ */
+ docs_char(state, emit, emitctx, -2, NULL, 0);
+
+ /*
+ * If this subcharset is not already selected in that
+ * container, select it.
+ */
+ oselect(state, i, right, emit, emitctx);
+
+ /*
+ * Now emit the actual characters.
+ */
+ if (right) {
+ assert(c1 >= 0x20 && c1 <= 0x7f);
+ emit(emitctx, c1 | 0x80);
+ if (c2) {
+ assert(c2 >= 0x20 && c2 <= 0x7f);
+ emit(emitctx, c2 | 0x80);
+ }
+ } else {
+ assert(c1 > 0x20 && c1 < 0x7f);
+ emit(emitctx, c1);
+ if (c2) {
+ assert(c2 > 0x20 && c2 < 0x7f);
+ emit(emitctx, c2);
+ }
+ }
+
+ return TRUE;
+ }
+
+ /*
+ * Fall back to DOCS.
+ */
+ {
+ char data[10];
+ char *p = data;
+ int i, cs;
+
+ cs = -2; /* means failure */
+
+ for (i = 0; (unsigned)i <= lenof(ctext_encodings); i++) {
+ charset_state substate;
+ charset_spec const *subcs = ctext_encodings[i].subcs;
+
+ /*
+ * We assume that all character sets dealt with by DOCS
+ * are stateless for output purposes.
+ */
+ substate.s1 = substate.s0 = 0;
+ p = data;
+
+ if ((unsigned)i < lenof(ctext_encodings)) {
+ if ((mode->enable_mask & (1 << ctext_encodings[i].enable)) &&
+ subcs->write(subcs, input_chr, &substate,
+ write_to_pointer, &p)) {
+ cs = i;
+ break;
+ }
+ } else {
+ if ((mode->enable_mask & (1 << CDU)) &&
+ write_utf8(NULL, input_chr, NULL, write_to_pointer, &p)) {
+ cs = -1;
+ break;
+ }
+ }
+ }
+
+ if (cs != -2) {
+ docs_char(state, emit, emitctx, cs, data, p - data);
+ return TRUE;
+ }
+ }
+
return FALSE;
}
+/*
+ * Full ISO 2022 output with all options on. Not entirely sure what
+ * if anything this is useful for, but here it is anyway. All
+ * output character sets and DOCS variants are permitted; all
+ * containers start out with ASCII in them.
+ */
+static const struct iso2022_mode iso2022_all = {
+ (1<<CCS) | (1<<COS) | (1<<CPU) | (1<<CDC) | (1<<CDU),
+ S4, 0, 'B', S4, 0, 'B',
+};
+
const charset_spec charset_CS_ISO2022 = {
- CS_ISO2022, read_iso2022, write_iso2022, NULL
+ CS_ISO2022, read_iso2022, write_iso2022, &iso2022_all
+};
+
+/*
+ * X11 compound text. A subset of output charsets is permitted, and
+ * G1/GR starts off in ISO8859-1.
+ */
+static const struct iso2022_mode iso2022_ctext = {
+ (1<<CCS) | (1<<CDC),
+ S4, 0, 'B', S6, 0, 'A',
+};
+
+const charset_spec charset_CS_CTEXT = {
+ CS_CTEXT, read_iso2022, write_iso2022, &iso2022_ctext
};
#ifdef TESTMODE
~mdw / sgt / charset / blobdiff