dla2csv: complain if input looks incorrect, user-friendly enhancements for atari.

1 files changed, 71 insertions, 12 deletions

diff --git a/dla2csv.c b/dla2csv.c
index 4605761..734ec57 100644
--- a/dla2csv.c
+++ b/dla2csv.c
@@ -36,25 +36,33 @@ char *eoltypes[][2] = {
 	{ NULL, NULL }
 };
 
-/* read a string from stdin (E: on the Atari). there could
-	be error checking here, but there's not. */
+/* read a string from stdin (E: on the Atari).
+	exit on EOF (or Break key on the Atari). */
 void readstring(void) {
-	fgets(stringbuf, 256, stdin);
+	if(fgets(stringbuf, 256, stdin) == NULL)
+		exit(1);
 }
 
 /* prompt for a filename, try to open it. if there's an error,
 	show error message and retry. will not return until it
-	opens the file.
-	there could be code here to prepend D: if it's missing, but
-	there isn't.
- */
+	opens the file. */
 FILE *prompt_filename(const char *name, const char *mode) {
 	FILE *f = NULL;
+	putchar('\n');
 	while(f == NULL) {
-		printf("\n%s file: ", name);
+		printf("%s file: ", name);
 		fflush(stdout);
 		readstring();
-		stringbuf[strlen(stringbuf) - 1] = '\0';
+		stringbuf[strlen(stringbuf) - 1] = '\0'; /* kill trailing \n */
+		if(strlen(stringbuf) == 0) continue;
+#ifdef __ATARI__
+		/* if there's no device spec (D: or D1: etc), prepend D: */
+		if(!strchr(stringbuf, ':')) {
+			memmove(stringbuf+2, stringbuf, strlen(stringbuf));
+			stringbuf[0] = 'D';
+			stringbuf[1] = ':';
+		}
+#endif
 		f = fopen(stringbuf, mode);
 		if(!f) perror(stringbuf);
 	}
@@ -96,10 +104,31 @@ void backspace3(void) {
 
 int main(int argc, char **argv) {
 	char *inp, *eol;
-	int bytes = 0, x, y, xmask;
+	int i, bytes = 0, x, y, xmask, warn;
+
+#ifdef __ATARI__
+	/* cc65's startup code turns off caps lock. turn it back on,
+		since we're typing DOS filenames. in BASIC this would be:
+		POKE 702,64 */
+	*((char *)0x02be) = 0x40;
+
+	/* clear the screen */
+	putchar(0x7d);
+#endif
+
+	printf("DLA to CSV converter.\n\n");
+
+#ifdef __ATARI__
+	/* Atari users aren't used to typing an EOF to exit */
+	printf("Note: Press Ctrl-3 or Break at any\nprompt to exit this program.\n");
+#endif
 
-	printf("DLA to CSV converter.\n");
 	while(1) {
+		warn = 0;
+
+		/* in case of short read on 2nd or later conversion: */
+		memset(inbuf, 0, INBUF_SIZE);
+
 		/* read whole input file into memory */
 		inf = prompt_filename("Input DLA", "rb");
 		printf("Reading...");
@@ -109,9 +138,39 @@ int main(int argc, char **argv) {
 			perror(stringbuf);
 			continue;
 		}
-		fclose(inf);
 		printf("Read %d bytes.\n", bytes);
 
+		/* warn if the file size is wrong... */
+		if(bytes < INBUF_SIZE) {
+			printf("Warning: File too short!\n");
+			warn = 1;
+		} else if(fgetc(inf) != EOF) {
+			printf("Warning: File too long!\n");
+			warn = 1;
+		} else {
+			printf("File size is OK.\n");
+		}
+		fclose(inf);
+
+		/* a DLA file never has non-zero bytes at the beginning. */
+		for(i = 0; i < 32; i++) {
+			if(inbuf[i]) {
+				printf("Warning: File doesn't look like a DLA!\n");
+				warn = 1;
+				break;
+			}
+		}
+
+		/* if anything looks wrong, we shouldn't proceed... but the user
+			is boss, so give him the choice to shoot himself in the foot. */
+		if(warn) {
+			printf("Try to convert anyway[y/N]? ");
+			fflush(stdout);
+			readstring();
+			if(stringbuf[0] != 'y' && stringbuf[0] != 'Y')
+				continue;
+		}
+
 		eol = prompt_eol();
 
 		outf = prompt_filename("Output CSV", "wb");