alf: Bounds checking on input and output sizes. Document unalf bug with files >=15MB. Use atarified filename in 'Crunching' message.

1 files changed, 14 insertions, 4 deletions

diff --git a/src/alf.c b/src/alf.c
index 12aafad..c3b210d 100644
--- a/src/alf.c
+++ b/src/alf.c
@@ -26,7 +26,7 @@
 u8 input_buf[MAX_INPUT_SIZE];
 u8 output_buf[MAX_INPUT_SIZE];
 u8 byte_tokens[256];
-int input_len, output_len, out_bitpos;
+unsigned int input_len, output_len, out_bitpos;
 
 int opt_append = 0;
 int opt_overwrite = 0;
@@ -145,6 +145,7 @@ void create_header(void) {
 	char hdr_filename[13];
 
 	atarify_filename(hdr_filename);
+	printf("Crunching %s\n", hdr_filename);
 
 	output_buf[0] = 0x1a;
 	output_buf[1] = 0x0f;
@@ -169,12 +170,19 @@ void open_input(const char *filename) {
 	}
 }
 
+void inc_output_len(void) {
+	if(++output_len == MAX_INPUT_SIZE) {
+		fprintf(stderr, "%s: fatal: compressed file would be >16MB.\n", self);
+		exit(1);
+	}
+}
+
 void append_bit(int bit) {
 	output_buf[output_len] |= (bit << (7 - out_bitpos));
 	out_bitpos++;
 	if(out_bitpos == 8) {
 		out_bitpos = 0;
-		output_len++;
+		inc_output_len();
 	}
 }
 
@@ -244,18 +252,20 @@ void crunch(void) {
 	}
 
 	store_token(TOK_END);
-	if(out_bitpos) output_len++;
+	if(out_bitpos) inc_output_len();
 	update_header();
 }
 
 void crunch_file(const char *filename) {
 	init_table();
 
-	printf("Crunching %s\n", filename);
 	open_input(filename);
 
 	/* read in entire input, couldn't do it this way on the Atari */
 	input_len = fread(input_buf, 1, MAX_INPUT_SIZE - 1, in_file);
+	if(!feof(in_file)) {
+		fprintf(stderr, "%s: warning: this file is too large; only compressing the first 16MB.\n", self);
+	}
 	output_len = 0;
 	fstat(fileno(in_file), &in_file_stat); /* for timestamp */
 	fclose(in_file);