1 files changed, 78 insertions, 0 deletions
diff --git a/tok_util.c b/tok_util.c
new file mode 100644
index 0000000..c17ca6d
--- /dev/null
+++ b/tok_util.c
@@ -0,0 +1,78 @@
+#include <string.h>
+#include <ctype.h>
+
+#include "lex.h"
+
+const char *tok_to_desc[] = {
+	[TOKEN_REGISTER] = "register",
+	[TOKEN_NUMERIC] = "numeric literal",
+	[TOKEN_KEYWORD] = "keyword",
+	[TOKEN_STRING] = "string literal",
+	[TOKEN_COMMA] = "comma",
+	[TOKEN_LABEL] = "label",
+	[TOKEN_IDENT] = "identifier",
+	[TOKEN_DOT] = "assembler directive",
+	[TOKEN_EOL] = "end of line",
+};
+
+const char * get_token_description(enum TOKEN_TYPE t)
+{
+	if (t < 0 || t >= sizeof(tok_to_desc)/sizeof(*tok_to_desc)) {
+		return "[internal error]";
+	} else {
+		return tok_to_desc[t];
+	}
+}
+
+void indicate_file_area(FILE* fd, size_t line, size_t column, size_t span)
+{
+	size_t i = 0;
+	const char margin[] = "  ";
+
+	char buf[1024] = { '\0' };
+	char *s = buf;
+	char c = '\0';
+
+	rewind(fd);
+	while (line && !feof(fd) && fgets(buf, sizeof(buf), fd)) {
+		s = buf;
+		while (*s) {
+			if (*(s++) == '\n') {
+				line--;
+			}
+		}
+	}
+
+	/* trim leading whitespace */
+	s = buf;
+	while (*s == '\t' || *s == ' ') {
+		s++;
+	}
+
+	/* filter non-printables to spaces to keep alignment correct */
+	for (i = 0; i < strlen(s); i++) {
+		if (!isprint(s[i]) && s[i] != '\n') {
+			s[i] = ' ';
+		}
+	}
+
+	fputs(margin, stderr);
+	fputs(s, stderr);
+
+	/* corner case (still needed?) - buf was just return */
+	if (strlen(buf) == 1 && buf[0] == '\n') {
+		fputc('\n', stderr);
+	}
+
+	fputs(margin, stderr);
+	column -= (s - buf);
+	for (column--; column; column--) {
+		fputc(' ', stderr);
+	}
+
+	c = span == 1 ? '^' : '"';
+	for (; span; span--) {
+		fputc(c, stderr);
+	}
+	fputc('\n', stderr);
+}