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authorJörg Frings-Fürst <debian@jff-webhosting.net>2016-12-28 16:52:56 +0100
committerJörg Frings-Fürst <debian@jff-webhosting.net>2016-12-28 16:52:56 +0100
commit7b358424ebad9349421acd533c2fa1cbf6cf3e3e (patch)
tree686678532eefed525c242fd214d0cfb2914726c5 /app/tools/halibut/charset/big5enc.c
Initial import of xtrkcad version 1:4.0.2-2
Diffstat (limited to 'app/tools/halibut/charset/big5enc.c')
-rw-r--r--app/tools/halibut/charset/big5enc.c93
1 files changed, 93 insertions, 0 deletions
diff --git a/app/tools/halibut/charset/big5enc.c b/app/tools/halibut/charset/big5enc.c
new file mode 100644
index 0000000..d3e48ff
--- /dev/null
+++ b/app/tools/halibut/charset/big5enc.c
@@ -0,0 +1,93 @@
+/*
+ * big5enc.c - multibyte encoding of Big5
+ */
+
+#ifndef ENUM_CHARSETS
+
+#include "charset.h"
+#include "internal.h"
+
+/*
+ * Big5 has no associated data, so `charset' may be ignored.
+ */
+
+static void read_big5(charset_spec const *charset, long int input_chr,
+ charset_state *state,
+ void (*emit)(void *ctx, long int output), void *emitctx)
+{
+ UNUSEDARG(charset);
+
+ /*
+ * For reading Big5, state->s0 simply contains the single
+ * stored lead byte when we are half way through a double-byte
+ * character, or 0 if we aren't.
+ */
+
+ if (state->s0 == 0) {
+ if (input_chr >= 0xA1 && input_chr <= 0xFE) {
+ /*
+ * Lead byte. Just store it.
+ */
+ state->s0 = input_chr;
+ } else {
+ /*
+ * Anything else we pass straight through unchanged.
+ */
+ emit(emitctx, input_chr);
+ }
+ } else {
+ /*
+ * We have a stored lead byte. We expect a valid followup
+ * byte.
+ */
+ if ((input_chr >= 0x40 && input_chr <= 0x7E) ||
+ (input_chr >= 0xA1 && input_chr <= 0xFE)) {
+ emit(emitctx, big5_to_unicode(state->s0 - 0xA1, input_chr - 0x40));
+ } else {
+ emit(emitctx, ERROR);
+ }
+ state->s0 = 0;
+ }
+}
+
+/*
+ * Big5 is a stateless multi-byte encoding (in the sense that just
+ * after any character has been completed, the state is always the
+ * same); hence when writing it, there is no need to use the
+ * charset_state.
+ */
+
+static int write_big5(charset_spec const *charset, long int input_chr,
+ charset_state *state,
+ void (*emit)(void *ctx, long int output), void *emitctx)
+{
+ UNUSEDARG(charset);
+ UNUSEDARG(state);
+
+ if (input_chr == -1)
+ return TRUE; /* stateless; no cleanup required */
+
+ if (input_chr < 0x80) {
+ emit(emitctx, input_chr);
+ return TRUE;
+ } else {
+ int r, c;
+ if (unicode_to_big5(input_chr, &r, &c)) {
+ emit(emitctx, r + 0xA1);
+ emit(emitctx, c + 0x40);
+ return TRUE;
+ } else {
+ return FALSE;
+ }
+ }
+}
+
+const charset_spec charset_CS_BIG5 = {
+ CS_BIG5, read_big5, write_big5, NULL
+};
+
+#else /* ENUM_CHARSETS */
+
+ENUM_CHARSET(CS_BIG5)
+
+#endif /* ENUM_CHARSETS */