1 files changed, 72 insertions, 0 deletions
diff --git a/app/tools/halibut/charset/sbcs.c b/app/tools/halibut/charset/sbcs.c
new file mode 100644
index 0000000..e8be5a8
--- /dev/null
+++ b/app/tools/halibut/charset/sbcs.c
@@ -0,0 +1,72 @@
+/*
+ * sbcs.c - routines to handle single-byte character sets.
+ */
+
+#include "charset.h"
+#include "internal.h"
+
+/*
+ * The charset_spec for any single-byte character set should
+ * provide read_sbcs() as its read function, and its `data' field
+ * should be a wchar_t string constant containing the 256 entries
+ * of the translation table.
+ */
+
+long int sbcs_to_unicode(const struct sbcs_data *sd, long int input_chr)
+{
+    return sd->sbcs2ucs[input_chr];
+}
+
+void read_sbcs(charset_spec const *charset, long int input_chr,
+	       charset_state *state,
+	       void (*emit)(void *ctx, long int output), void *emitctx)
+{
+    const struct sbcs_data *sd = charset->data;
+
+    UNUSEDARG(state);
+
+    emit(emitctx, sbcs_to_unicode(sd, input_chr));
+}
+
+long int sbcs_from_unicode(const struct sbcs_data *sd, long int input_chr)
+{
+    int i, j, k, c;
+
+    /*
+     * Binary-search in the ucs2sbcs table.
+     */
+    i = -1;
+    j = sd->nvalid;
+    while (i+1 < j) {
+	k = (i+j)/2;
+	c = sd->ucs2sbcs[k];
+	if (input_chr < (long int)sd->sbcs2ucs[c])
+	    j = k;
+	else if (input_chr > (long int)sd->sbcs2ucs[c])
+	    i = k;
+	else {
+	    return c;
+	}
+    }
+    return ERROR;
+}
+
+int write_sbcs(charset_spec const *charset, long int input_chr,
+	       charset_state *state,
+	       void (*emit)(void *ctx, long int output), void *emitctx)
+{
+    const struct sbcs_data *sd = charset->data;
+    long int ret;
+
+    UNUSEDARG(state);
+
+    if (input_chr == -1)
+	return TRUE;		       /* stateless; no cleanup required */
+
+    ret = sbcs_from_unicode(sd, input_chr);
+    if (ret == ERROR)
+	return FALSE;
+
+    emit(emitctx, ret);
+    return TRUE;
+}