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Diffstat (limited to 'app/tools/halibut/charset/euc.c')
-rw-r--r--app/tools/halibut/charset/euc.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/app/tools/halibut/charset/euc.c b/app/tools/halibut/charset/euc.c
new file mode 100644
index 0000000..b3d43ff
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+++ b/app/tools/halibut/charset/euc.c
@@ -0,0 +1,272 @@
+/*
+ * euc.c - routines to handle the various EUC multibyte encodings.
+ */
+
+#ifndef ENUM_CHARSETS
+
+#include "charset.h"
+#include "internal.h"
+
+struct euc {
+ int nchars[3]; /* GR, SS2+GR, SS3+GR */
+ long int (*to_ucs)(unsigned long state);
+ unsigned long (*from_ucs)(long int ucs);
+};
+
+static void read_euc(charset_spec const *charset, long int input_chr,
+ charset_state *state,
+ void (*emit)(void *ctx, long int output), void *emitctx)
+{
+ struct euc const *euc = (struct euc *)charset->data;
+
+ /*
+ * For EUC input, our state variable divides into three parts:
+ *
+ * - Topmost nibble (bits 31:28) is nonzero if we're
+ * accumulating a multibyte character, and it indicates
+ * which section we're in: 1 for GR chars, 2 for things
+ * beginning with SS2, 3 for things beginning with SS3.
+ *
+ * - Next nibble (bits 27:24) indicates how many bytes of the
+ * character we've accumulated so far.
+ *
+ * - The rest (bits 23:0) are those bytes in full, accumulated
+ * as a large integer (so that seeing A1 A2 A3, in a
+ * hypothetical EUC whose GR encoding is three-byte, runs
+ * our state variable from 0 -> 0x110000A1 -> 0x1200A1A2 ->
+ * 0x13A1A2A3, at which point it gets translated and output
+ * and resets to zero).
+ */
+
+ if (state->s0 != 0) {
+
+ /*
+ * At this point, no matter whether we had an SS2 or SS3
+ * introducer or not, we _always_ expect a GR character.
+ * Anything else causes us to emit ERROR for an incomplete
+ * character, and then reset to state 0 to process the
+ * character in its own way.
+ */
+ if (input_chr < 0xA1 || input_chr == 0xFF) {
+ emit(emitctx, ERROR);
+ state->s0 = 0;
+ } else
+ state->s0 = (((state->s0 & 0xFF000000) + 0x01000000) |
+ ((state->s0 & 0x0000FFFF) << 8) | input_chr);
+
+ }
+
+ if (state->s0 == 0) {
+ /*
+ * The input character determines which of the four
+ * possible charsets we're going to be in.
+ */
+ if (input_chr < 0x80) { /* this is always ASCII */
+ emit(emitctx, input_chr);
+ } else if (input_chr == 0x8E) {/* SS2 means charset 2 */
+ state->s0 = 0x20000000;
+ } else if (input_chr == 0x8F) {/* SS3 means charset 3 */
+ state->s0 = 0x30000000;
+ } else if (input_chr < 0xA1 || input_chr == 0xFF) { /* errors */
+ emit(emitctx, ERROR);
+ } else { /* A1-FE means charset 1 */
+ state->s0 = 0x11000000 | input_chr;
+ }
+ }
+
+ /*
+ * Finally, if we have accumulated a complete character, output
+ * it.
+ */
+ if (state->s0 != 0 &&
+ ((state->s0 & 0x0F000000) >> 24) >=
+ (unsigned)euc->nchars[(state->s0 >> 28)-1]) {
+ emit(emitctx, euc->to_ucs(state->s0));
+ state->s0 = 0;
+ }
+}
+
+/*
+ * All EUCs are stateless multi-byte encodings (in the sense that
+ * just after any character has been completed, the state is always
+ * the same); hence when writing them, there is no need to use the
+ * charset_state.
+ */
+
+static int write_euc(charset_spec const *charset, long int input_chr,
+ charset_state *state,
+ void (*emit)(void *ctx, long int output), void *emitctx)
+{
+ struct euc const *euc = (struct euc *)charset->data;
+ unsigned long c;
+ int cset, len;
+
+ UNUSEDARG(state);
+
+ if (input_chr == -1)
+ return TRUE; /* stateless; no cleanup required */
+
+ /* ASCII is the easy bit, and is always the same. */
+ if (input_chr < 0x80) {
+ emit(emitctx, input_chr);
+ return TRUE;
+ }
+
+ c = euc->from_ucs(input_chr);
+ if (!c) {
+ return FALSE;
+ }
+
+ cset = c >> 28;
+ len = euc->nchars[cset-1];
+ c &= 0xFFFFFF;
+
+ if (cset > 1)
+ emit(emitctx, 0x8C + cset); /* SS2/SS3 */
+
+ while (len--)
+ emit(emitctx, (c >> (8*len)) & 0xFF);
+ return TRUE;
+}
+
+/*
+ * EUC-CN encodes GB2312 only.
+ */
+static long int euc_cn_to_ucs(unsigned long state)
+{
+ switch (state >> 28) {
+ case 1: return gb2312_to_unicode(((state >> 8) & 0xFF) - 0xA1,
+ ((state ) & 0xFF) - 0xA1);
+ default: return ERROR;
+ }
+}
+static unsigned long euc_cn_from_ucs(long int ucs)
+{
+ int r, c;
+ if (unicode_to_gb2312(ucs, &r, &c))
+ return 0x10000000 | ((r+0xA1) << 8) | (c+0xA1);
+ else
+ return 0;
+}
+static const struct euc euc_cn = {
+ {2,0,0}, euc_cn_to_ucs, euc_cn_from_ucs
+};
+const charset_spec charset_CS_EUC_CN = {
+ CS_EUC_CN, read_euc, write_euc, &euc_cn
+};
+
+/*
+ * EUC-KR encodes KS X 1001 only.
+ */
+static long int euc_kr_to_ucs(unsigned long state)
+{
+ switch (state >> 28) {
+ case 1: return ksx1001_to_unicode(((state >> 8) & 0xFF) - 0xA1,
+ ((state ) & 0xFF) - 0xA1);
+ default: return ERROR;
+ }
+}
+static unsigned long euc_kr_from_ucs(long int ucs)
+{
+ int r, c;
+ if (unicode_to_ksx1001(ucs, &r, &c))
+ return 0x10000000 | ((r+0xA1) << 8) | (c+0xA1);
+ else
+ return 0;
+}
+static const struct euc euc_kr = {
+ {2,0,0}, euc_kr_to_ucs, euc_kr_from_ucs
+};
+const charset_spec charset_CS_EUC_KR = {
+ CS_EUC_KR, read_euc, write_euc, &euc_kr
+};
+
+/*
+ * EUC-JP encodes several character sets.
+ */
+static long int euc_jp_to_ucs(unsigned long state)
+{
+ switch (state >> 28) {
+ case 1: return jisx0208_to_unicode(((state >> 8) & 0xFF) - 0xA1,
+ ((state ) & 0xFF) - 0xA1);
+ case 2:
+ /*
+ * This is the top half of JIS X 0201. That means A1-DF map
+ * to FF61-FF9F, and nothing else is valid.
+ */
+ {
+ int c = state & 0xFF;
+ if (c >= 0xA1 && c <= 0xDF)
+ return c + (0xFF61 - 0xA1);
+ else
+ return ERROR;
+ }
+ /* (no break needed since all control paths have returned) */
+ case 3: return jisx0212_to_unicode(((state >> 8) & 0xFF) - 0xA1,
+ ((state ) & 0xFF) - 0xA1);
+ default: return ERROR; /* placate optimisers */
+ }
+}
+static unsigned long euc_jp_from_ucs(long int ucs)
+{
+ int r, c;
+ if (ucs >= 0xFF61 && ucs <= 0xFF9F)
+ return 0x20000000 | (ucs - (0xFF61 - 0xA1));
+ else if (unicode_to_jisx0208(ucs, &r, &c))
+ return 0x10000000 | ((r+0xA1) << 8) | (c+0xA1);
+ else if (unicode_to_jisx0212(ucs, &r, &c))
+ return 0x30000000 | ((r+0xA1) << 8) | (c+0xA1);
+ else
+ return 0;
+}
+static const struct euc euc_jp = {
+ {2,1,2}, euc_jp_to_ucs, euc_jp_from_ucs
+};
+const charset_spec charset_CS_EUC_JP = {
+ CS_EUC_JP, read_euc, write_euc, &euc_jp
+};
+
+/*
+ * EUC-TW encodes CNS 11643 (all planes).
+ */
+static long int euc_tw_to_ucs(unsigned long state)
+{
+ int plane;
+ switch (state >> 28) {
+ case 1: return cns11643_to_unicode(0, ((state >> 8) & 0xFF) - 0xA1,
+ ((state ) & 0xFF) - 0xA1);
+ case 2:
+ plane = ((state >> 8) & 0xFF) - 0xA1;
+ if (plane >= 7) return ERROR;
+ return cns11643_to_unicode(plane, ((state >> 8) & 0xFF) - 0xA1,
+ ((state ) & 0xFF) - 0xA1);
+ default: return ERROR;
+ }
+}
+static unsigned long euc_tw_from_ucs(long int ucs)
+{
+ int p, r, c;
+ if (unicode_to_cns11643(ucs, &p, &r, &c)) {
+ if (p == 0)
+ return 0x10000000 | ((r+0xA1) << 8) | (c+0xA1);
+ else
+ return 0x20000000 |
+ ((p + 0xA1) << 16) | ((r+0xA1) << 8) | (c+0xA1);
+ } else
+ return 0;
+}
+static const struct euc euc_tw = {
+ {2,3,0}, euc_tw_to_ucs, euc_tw_from_ucs
+};
+const charset_spec charset_CS_EUC_TW = {
+ CS_EUC_TW, read_euc, write_euc, &euc_tw
+};
+
+#else /* ENUM_CHARSETS */
+
+ENUM_CHARSET(CS_EUC_CN)
+ENUM_CHARSET(CS_EUC_KR)
+ENUM_CHARSET(CS_EUC_JP)
+ENUM_CHARSET(CS_EUC_TW)
+
+#endif /* ENUM_CHARSETS */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-01 00:01:40 +0000