zilasm/main: Construct output filename from input filename adding .dat

diff --git a/zilasm/main.c b/zilasm/main.c
index 811a6dff447195fdce942b554b07f64cf821acf3..bbc5a9327bc0654d3a4a065cfd1e173a85821ff4 100644 (file)
--- a/zilasm/main.c
+++ b/zilasm/main.c
@@ -142,6 +142,23 @@ void parse_zserial(void)
     wrong_arg("Wrong zserial value %s, must be 6 ascii characters\n", optarg);
 }
 
+void new_file_suffix(char *result, size_t maxlen, const char *src, const char *newsuffix)
+{
+    strncpy(result, src, maxlen);
+    char *p = strrchr(result, '.');
+    if (p && strchr(p, '/'))
+        p = NULL;
+    if (p)
+    {
+        strncpy(p, newsuffix, maxlen - (p - result));
+    }
+    else
+    {
+        strncat(result, newsuffix, maxlen);
+    }
+    result[maxlen] = 0;
+}
+
 int main(int argc, char *argv[], char *envp[])
 {
     const char *output_file = NULL;
@@ -176,13 +193,27 @@ int main(int argc, char *argv[], char *envp[])
         }
     }
 
+    int first_input_file = optind;
+    if (first_input_file >= argc)
+        wrong_arg("Missing input file\n");
+
+    if (!output_file)
+    {
+        const char suffix[] = ".dat";
+        const char *input_file = argv[first_input_file];
+        int n = strlen(input_file) + strlen(suffix);
+        char *ofile = malloc(n);  /* todo!!! check for NULL. free. */
+        new_file_suffix(ofile, n, input_file, suffix);
+        output_file = ofile;
+    }
+
     // TODO: Everything :)
 
     printf("Input files:\n");
     for (i = optind; i < argc; i++)
         printf("\t%s\n", argv[i]);
 
-    printf("Output file: %s\n\n", output_file ? output_file : "MISSING");
+    printf("Output file: %s\n\n", output_file);
 
     printf("Config:\n"
            "- ZVersion: %d\n"