i think i fixed it

mm/mm.c

@@ -20,7 +20,7 @@
 #include <signal.h> /* signal(2), SIG_ERR, SIG_IGN, SIGINT */
 #include <stdio.h> /* fclose(3), fopen(3), fprintf(3), getc(3), putc(3),
                     * setvbuf(3), size_t, _IONBF, NULL */
-#include <stdlib.h> /* free(3), realloc(3) */
+#include <stdlib.h> /* free(3), malloc(3), realloc(3) */
 #include <string.h> /* strerror(3) */
 #include <unistd.h> /* getopt(3) */
 #if !defined EX_OSERR || !defined EX_USAGE
@@ -55,152 +55,35 @@ static char *stderr_name = "<stderr>";
 static char *(fmode[]) = { (char []){"rb"}, (char []){"rb+"} };
 static char *wharsh = "wb";
 
-/* Grows the files allocations by ALLOC_INCREMENT. */
-#define Files_grow(files) (\
-	(files->files = realloc(files->files, \
-				(files->a += ALLOC_INCREMENT) \
-				* sizeof *(files->files))) == NULL \
-			|| (files->names = realloc(files->names, \
-				files->a * sizeof *(files->names))) == NULL \
-		? NULL \
-		: files \
-	)
-
 /* Opens the file at the path p and puts it in the files struct, returning NULL
  * if either the opening or the placement of the open FILE pointer fail. */
-#define Files_fopen(files, p) \
+#define Files_open(files, p) \
-	Files_fappend((files), fopen((p), (files)->mode), (p))
+	Files_append((files), fopen((p), (files)->mode), (p))
-
-/* Destructs the files[2] used by main. */
-#define terminate(files) do{ \
-	Files_destruct(&(files)[0]); \
-	Files_destruct(&(files)[1]); }while(0)
-
-static struct Files *Files_initialize(struct Files *files);
-/* Destructs a files struct by closing its files and freeing its files and
- * names arrays. Returns the destructed files. */
-static struct Files *
-Files_destruct(struct Files *files){
-	int i;
-
-	for(i = 0; i < files->s; fclose(files->files[i++]));
-	free(files->files);
-	free(files->names);
-
-	return Files_initialize(files);
-}
 
 /* Adds the open FILE pointer for the file at the path s to the files struct,
- * returning the FILE if successful and NULL if not. */
+ * returning the FILE if successful and NULL if not, allocating more memory in
+ * the files buffers as needed. */
 static FILE *
-Files_fappend(struct Files *files, FILE *file, char *name){
+Files_append(struct Files *files, FILE *file, char *name){
 
 	if(files->s == -1)
 		files->s = 0;
 
-	if(file == NULL || Files_grow(files) == NULL)
+	if(file == NULL || (files->s == files->a
+			&& ((files->files = realloc(files->files,
+					(files->a += (files->a == 0)
+						? ALLOC_INITIAL
+						: ALLOC_INCREMENT)
+					* sizeof *(files->files))) == NULL
+				|| (files->names = realloc(files->names,
+					files->a * sizeof *(files->names)))
+					== NULL)))
 		return NULL;
 
 	files->names[files->s] = name;
 	return files->files[files->s++] = file;
 }
 
-/* Returns the first index within files->files of the given FILE pointer f. If
- * f isn't within files->files, returns -1. */
-static int
-Files_fileindex(struct Files *files, FILE *f){
-	size_t i;
-
-	for(i = 0; i < files->s; ++i)
-		if(files->files[i] == f)
-			return i;
-
-	return -1;
-}
-
-/* Returns the corresponding file name in the files struct to the FILE pointer
- * f, or NULL if f is NULL or isn't in files->files. */
-static char *
-Files_filename(struct Files *files, FILE *f){
-	int i;
-
-	return (f == NULL || (i = Files_fileindex(files, f)) == -1)
-		? NULL
-		: files->names[i];
-}
-
-static struct Files *Files_fremove(struct Files *files, FILE *f);
-static FILE *Files_nextfile(struct Files *files, FILE *f);
-/* Prints c to all files, returning c. If a stream can't be written, a
- * message is printed to standard error and the stream is closed and removed
- * from files. If no stream can be written, returns EOF. */
-static int
-Io_fputc(struct Files *files, int c){
-	FILE *f;
-	FILE *lf;
-	char *ln;
-
-	f = NULL;
-	lf = NULL;
-	for(f = NULL; (f = Files_nextfile(files, f)) != NULL;){
-		if(lf != NULL){
-			if(fclose(lf) == EOF)
-				fprintf(stderr, "%s: %s: %s\n",
-					program_name, ln, strerror(errno));
-			if(Files_fremove(files, lf)->s == 0)
-				return EOF;
-			lf = NULL;
-		}
-		if(putc(c, f) == EOF)
-			ln = Files_filename(files, lf = f);
-	}
-
-	return c;
-}
-
-/* Removes a given file pointer f from the given files struct, returning NULL
- * if the file was already absent from files and otherwise files. */
-static struct Files *
-Files_fremove(struct Files *files, FILE *f){
-	size_t i;
-
-	if((i = Files_fileindex(files, f)) == -1)
-		return NULL;
-
-	for(; i < files->s - 1; ++i){
-		files->files[i] = files->files[i + 1];
-		files->names[i] = files->names[i + 1];
-	}
-	--files->s;
-
-	return files;
-}
-
-/* Initializes the members of the given files struct and returns files. */
-static struct Files *
-Files_initialize(struct Files *files){
-
-	files->a = 0;
-	files->s = 0;
-	files->files = NULL;
-	files->names = NULL;
-
-	return files;
-}
-
-/* Returns the first file in files if f is NULL, NULL if the file is the last
- * in or absent from files, or the file after f in files. */
-static FILE *
-Files_nextfile(struct Files *files, FILE *f){
-	int i;
-
-	return (f == NULL)
-		? files->files[0]
-		: ((i = Files_fileindex(files, f)) == -1 || i == files->s - 1)
-			? NULL
-			: files->files[i + 1];
-}
-
 /* Prints a diagnostic message based on errno and returns an exit status
  * appropriate for an OS error. */
 static int