listamsb: stop using ungetc().

1 files changed, 16 insertions, 12 deletions

diff --git a/listamsb.c b/listamsb.c
index 17ca3fc..6092dfa 100644
--- a/listamsb.c
+++ b/listamsb.c
@@ -178,17 +178,13 @@ unsigned char unlock_byte(unsigned char b) {
 /* the "encryption" is the same (process is reversible) */
 #define lock_byte(x) unlock_byte(x)
 
+/* read and (if needed) decrypt a byte from the program. */
 unsigned char read_prog_byte(void) {
 	unsigned char b = read_byte();
 	return locked ? unlock_byte(b) : b;
 }
 
-void unread_prog_byte(unsigned char b) {
-	if(locked) b = lock_byte(b);
-	ungetc(b, infile);
-	bytes_read--;
-}
-
+/* read a word from the program, does not decrypt */
 int read_word(void) {
 	int w;
 
@@ -198,6 +194,7 @@ int read_word(void) {
 	return w;
 }
 
+/* read and (if needed) decrypt a word from the program. */
 int read_prog_word(void) {
 	int w;
 
@@ -250,7 +247,7 @@ void unknown_token(unsigned char byte, int ext) {
 int next_line(void) {
 	static int last_lineno = -1;
 	static int last_ptr = -1;
-	int ptr, lineno, was_ff, in_string, in_comment, offset, len;
+	int ptr, lineno, was_ff, was_colon, in_string, in_comment, offset, len;
 	int printing;
 	unsigned char byte;
 
@@ -308,6 +305,7 @@ int next_line(void) {
 	if(printing) fprintf(outfile, "%d ", lineno);
 
 	was_ff = 0;
+	was_colon = 0;
 	in_string = 0;
 	in_comment = 0;
 
@@ -333,16 +331,22 @@ int next_line(void) {
 					if(byte == '"') putc(byte, outfile);
 				}
 			}
+			continue;
 		} else if(in_comment) {
 			/* null byte ends both the comment and the line of code. */
 			if(byte == 0x00) break;
 			if(printing) putc(byte, outfile);
-		} else if(byte == ':') {
+			continue;
+		}
+
+		if(was_colon && byte != TOK_SQUOTE && byte != TOK_BANG) {
+			if(printing) putc(':', outfile);
+			was_colon = 0;
+		}
+
+		if(byte == ':') {
 			/* don't print the colon if the next token is a ! or ' for a comment */
-			unsigned char next = read_prog_byte();
-			if( !(next == TOK_SQUOTE || next == TOK_BANG) )
-				if(printing) putc(byte, outfile);
-			unread_prog_byte(next);
+			was_colon = 1;
 		} else if(byte == '"') {
 			/* strings start but *don't end* with a double-quote */
 			in_string = 1;