1 files changed, 82 insertions, 0 deletions
diff --git a/generic/regerror.c b/generic/regerror.c
new file mode 100644
index 0000000..6779e51
--- /dev/null
+++ b/generic/regerror.c
@@ -0,0 +1,82 @@
+/*
+ * regerror - error-code expansion
+ */
+
+#include "regguts.h"
+
+/* unknown-error explanation */
+static char unk[] = "*** unknown regex error code 0x%x ***";
+
+/* struct to map among codes, code names, and explanations */
+static struct rerr {
+	int code;
+	char *name;
+	char *explain;
+} rerrs[] = {
+	/* the actual table is built from regex.h */
+#	include "regerrs.h"
+	{ -1,	"",	"oops" },	/* explanation special-cased in code */
+};
+
+/*
+ - regerror - the interface to error numbers
+ */
+/* ARGSUSED */
+size_t				/* actual space needed (including NUL) */
+regerror(errcode, preg, errbuf, errbuf_size)
+int errcode;			/* error code, or REG_ATOI or REG_ITOA */
+CONST regex_t *preg;		/* associated regex_t (unused at present) */
+char *errbuf;			/* result buffer (unless errbuf_size==0) */
+size_t errbuf_size;		/* available space in errbuf, can be 0 */
+{
+	struct rerr *r;
+	char *msg;
+	char convbuf[sizeof(unk)+50];	/* 50 = plenty for int */
+	size_t len;
+	int icode;
+
+	switch (errcode) {
+	case REG_ATOI:		/* convert name to number */
+		for (r = rerrs; r->code >= 0; r++)
+			if (strcmp(r->name, errbuf) == 0)
+				break;
+		sprintf(convbuf, "%d", r->code);	/* -1 for unknown */
+		msg = convbuf;
+		break;
+	case REG_ITOA:		/* convert number to name */
+		icode = atoi(errbuf);	/* not our problem if this fails */
+		for (r = rerrs; r->code >= 0; r++)
+			if (r->code == icode)
+				break;
+		if (r->code >= 0)
+			msg = r->name;
+		else {			/* unknown; tell him the number */
+			sprintf(convbuf, "REG_%u", (unsigned)icode);
+			msg = convbuf;
+		}
+		break;
+	default:		/* a real, normal error code */
+		for (r = rerrs; r->code >= 0; r++)
+			if (r->code == errcode)
+				break;
+		if (r->code >= 0)
+			msg = r->explain;
+		else {			/* unknown; say so */
+			sprintf(convbuf, unk, errcode);
+			msg = convbuf;
+		}
+		break;
+	}
+
+	len = strlen(msg) + 1;		/* space needed, including NUL */
+	if (errbuf_size > 0) {
+		if (errbuf_size > len)
+			strcpy(errbuf, msg);
+		else {			/* truncate to fit */
+			strncpy(errbuf, msg, errbuf_size-1);
+			errbuf[errbuf_size-1] = '\0';
+		}
+	}
+
+	return len;
+}