rewrite stripping

Previous version ignored some errors, and didn't free memory and close files.
Now no memory will be dynamically allocated to simplify error handling.

This commit also fixes a wrong check:

  files[i] = fopen(argv[i], "wb");
  if (!ireps[i]) {

Improve error messages a bit and add missing newline to one.

mrbgems/mruby-bin-strip/tools/mruby-strip/mruby-strip.c

@@ -6,6 +6,9 @@
 #include "mruby/dump.h"
 
 struct strip_args {
+  int argc_start;
+  int argc;
+  char **argv;
   mrb_bool lvar;
 };
 
@@ -64,14 +67,65 @@ parse_args(int argc, char **argv, struct strip_args *args)
   return i;
 }
 
+static int
+strip(mrb_state *mrb, struct strip_args *args)
+{
+  int i;
+
+  for (i = args->argc_start; i < args->argc; ++i) {
+    char *filename;
+    FILE *rfile;
+    mrb_irep *irep;
+    FILE *wfile;
+    int dump_result;
+
+    filename = args->argv[i];
+    rfile = fopen(filename, "rb");
+    if (rfile == NULL) {
+      fprintf(stderr, "can't open file for reading %s\n", filename);
+      return EXIT_FAILURE;
+    }
+
+    irep = mrb_read_irep_file(mrb, rfile);
+    fclose(rfile);
+    if (irep == NULL) {
+      fprintf(stderr, "can't read irep file %s\n", filename);
+      return EXIT_FAILURE;
+    }
+
+    /* clear lv if --lvar is enabled */
+    if (args->lvar) {
+      irep_remove_lv(mrb, irep);
+    }
+
+    wfile = fopen(filename, "wb");
+    if (wfile == NULL) {
+      fprintf(stderr, "can't open file for writing %s\n", filename);
+      mrb_irep_decref(mrb, irep);
+      return EXIT_FAILURE;
+    }
+
+    /* debug flag must always be false */
+    dump_result = mrb_dump_irep_binary(mrb, irep, FALSE, wfile);
+
+    fclose(wfile);
+    mrb_irep_decref(mrb, irep);
+
+    if (dump_result != MRB_DUMP_OK) {
+      fprintf(stderr, "error occurred during dumping %s\n", filename);
+      return EXIT_FAILURE;
+    }
+  }
+  return EXIT_SUCCESS;
+}
+
 int
 main(int argc, char **argv)
 {
   struct strip_args args;
-  int args_result, i, dump_result;
-  FILE **files;
-  mrb_irep **ireps;
+  int args_result;
   mrb_state *mrb;
+  int ret;
 
   if (argc <= 1) {
     printf("no files to strip\n");
@@ -85,15 +139,9 @@ main(int argc, char **argv)
     return EXIT_FAILURE;
   }
 
-  files = (FILE**)malloc(sizeof(FILE*) * argc);
-  for (i = args_result; i < argc; ++i) {
-    files[i] = fopen(argv[i], "rb");
-
-    if (!files[i]) {
-      fprintf(stderr, "can't open file %s\n", argv[i]);
-      return EXIT_FAILURE;
-    }
-  }
+  args.argc_start = args_result;
+  args.argc = argc;
+  args.argv = argv;
 
   mrb = mrb_open();
   if (mrb == NULL) {
@@ -101,35 +149,8 @@ main(int argc, char **argv)
     return EXIT_FAILURE;
   }
 
-  ireps = (mrb_irep**)malloc(sizeof(mrb_irep*) * argc);
-  for (i = args_result; i < argc; ++i) {
-    ireps[i] = mrb_read_irep_file(mrb, files[i]);
-    if (!ireps[i]) {
-      fprintf(stderr, "can't read irep file %s\n", argv[i]);
-      return EXIT_FAILURE;
-    }
-    fclose(files[i]);
-    files[i] = fopen(argv[i], "wb");
-    if (!ireps[i]) {
-      fprintf(stderr, "can't reopen irep file %s\n", argv[i]);
-      return EXIT_FAILURE;
-    }
-  }
-
-  for (i = args_result; i < argc; ++i) {
-    /* clear lv if --lvar is enabled */
-    if (args.lvar) {
-      irep_remove_lv(mrb, ireps[i]);
-    }
-
-    /* debug flag must be alway false */
-    dump_result = mrb_dump_irep_binary(mrb, ireps[i], FALSE, files[i]);
-    if (dump_result != MRB_DUMP_OK) {
-      fprintf(stderr, "error occur when dumping %s", argv[i]);
-      return EXIT_FAILURE;
-    }
-  }
+  ret = strip(mrb, &args);
 
   mrb_close(mrb);
-  return EXIT_SUCCESS;
+  return ret;
 }