dj(1): move open(2) flags, remove unnecessary comments

src/dj.c

@@ -56,6 +56,9 @@ static char *fmt_human = "%d+%d > %d+%d; %d > %d\n";
 static char *stdin_name = "<stdin>";
 static char *stdout_name = "<stdout>";
 
+
+static int creat_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH
+	| S_IWOTH; /* Consistent with touch(1p). */
 static int read_flags = O_RDONLY; /* Consistent with Busybox dd(1). */
 static int write_flags = O_WRONLY | O_CREAT;
 
@@ -64,27 +67,34 @@ static int write_flags = O_WRONLY | O_CREAT;
 /* Macro to check if fd is stdin or stdout */
 #define fdisstd(fd) ((fd) == STDIN_FILENO || (fd) == STDOUT_FILENO)
 
-/* Reads io->bs bytes from *io's file descriptor into io->buf, storing the
- * number of read bytes in io->bufuse and updating io->bytes. If io->bufuse is
- * 0, errno will probably be set. Returns io. */
 static struct Io *
 Io_read(struct Io *io){
 
+	assert(io->bs > 0);
+
 	io->bytes += (io->bufuse = read(io->fd, io->buf, io->bs));
 
+	assert(io->bufuse <= io->bs);
+
+	io->prec += (0 < io->bufuse && io->bufuse < io->bs);
+	io->rec  += (io->bufuse == io->bs);
+
 	return io;
 }
 
-/* Writes io->bufuse units from io->buf to io->fd, permuting any unwritten
- * bytes to the start of io->buf and updating io->bufuse. If io->bufuse doesn't
- * change, errno will probably be set. Returns io. */
 static struct Io *
 Io_write(struct Io *io){
 	int t;
 
+	assert(io->bufuse > 0);
+	assert(io->bufuse <= io->bs);
+
 	if((t = write(io->fd, io->buf, io->bufuse)) > 0)
 		memmove(io->buf, io->buf + t, (io->bufuse -= t));
+
 	io->bytes += t;
+	io->prec  += (t > 0 && io->bufuse > 0);
+	io->rec   += (t > 0 && io->bufuse == 0);
 
 	return io;
 }
@@ -102,9 +112,9 @@ oserr(char *s){
 /* Prints statistics regarding the use of dj, particularly partially and
  * completely read and written records. */
 static void
-printio(char *fmt, struct Io io[2]){
+fprintio(FILE *stream, char *fmt, struct Io io[2]){
 
-	fprintf(stderr, fmt,
+	fprintf(stream, fmt,
 		io[0].rec, io[0].prec, io[1].rec, io[1].prec,
 		io[0].bytes, io[1].bytes);
 
@@ -175,10 +185,7 @@ int main(int argc, char *argv[]){
 				}else{
 					int fd;
 
-					if((fd = open(optarg, io[i].fl, /* touch(1p) flags */
-									S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP
-										| S_IROTH | S_IWOTH))
-								!= -1
+					if((fd = open(optarg, io[i].fl, creat_mode)) != -1
 							&& (fdisstd(io[i].fd) || close(io[i].fd) == 0)){
 						io[i].fd = fd;
 						io[i].fn = optarg;
@@ -263,15 +270,14 @@ int main(int argc, char *argv[]){
 			return oserr(io[i].fn);
 
 	do{	/* read */
-		Io_read(&io[0]);
-		if(!noerror && io[0].bufuse == 0)
+		if(Io_read(&io[0])->bufuse == 0 && !noerror)
 			Io_read(&io[0]); /* second chance */
 		if(io[0].bufuse == 0) /* that's all she wrote */
 			break;
-		else if(io[0].bufuse < io[0].bs){
-			++io[0].prec;
+
+		if(io[0].bufuse < io[0].bs){
 			fprintf(stderr, "%s: Partial read:\n\t", program_name);
-			printio(fmt, io);
+			fprintio(stderr, fmt, io);
 			if(!noerror)
 				count = 1;
 			if(align >= 0){
@@ -280,8 +286,7 @@ int main(int argc, char *argv[]){
 					io[0].bs - io[0].bufuse);
 				io->bufuse = io->bs;
 			}
-		}else
-			++io[0].rec;
+		}
 
 		/* write */
 		do{
@@ -311,26 +316,23 @@ int main(int argc, char *argv[]){
 			}
 
 			t = io[1].bufuse;
-			Io_write(&io[1]);
-			if(!noerror && io[1].bufuse == t)
+			if(Io_write(&io[1])->bufuse == t && !noerror)
 				Io_write(&io[1]); /* second chance */
-			if(t == io[1].bufuse){ /* no more love */
+			if(io[1].bufuse == t){ /* no more love */
 				count = 1;
 				break;
-			}else if(t > io[1].bufuse && io[1].bufuse > 0){
-				io[1].prec += 1;
+			}
+
+			if(0 < io[1].bufuse && io[1].bufuse < t){
 				fprintf(stderr, "%s: Partial write:\n\t", program_name);
-				printio(fmt, io);
+				fprintio(stderr, fmt, io);
 				if(!noerror)
 					count = 1;
-			}else if(io[1].bufuse == 0 && t < io[1].bs)
-				++io[1].prec;
-			else
-				++io[1].rec;
+			}
 		}while(io[0].bufuse > 0);
 	}while(count == 0 || --count > 0);
 
-	printio(fmt, io);
+	fprintio(stderr, fmt, io);
 
 	return EX_OK;
 }