still broken

dj/dj.c

@@ -7,10 +7,60 @@
 #include <sysexits.h> /* EX_OK, EX_USAGE */
 #include <unistd.h> /* close(2), getopt(3), lseek(2), read(2), write(2),
                        optarg, optind, STDIN_FILENO, STDOUT_FILENO */
+extern int errno;
 
-/* Macro to use the appropriate string for argv[0] in the case that
+/* dj uses two structures that respectively correspond to the reading and
- * argc == 0. */
+ * writing ends of its jockeyed "pipe". User-configurable members are noted
-#define ARGV0(argv0) ((argv0) == NULL ? program_name : (argv0))
+ * with their relevant options. */
+struct Io{
+	int bs;			/* buffer size (-bB) */
+	size_t bufuse;	/* buffer usage */
+	char *buf;		/* buffer */
+	int bytes;		/* bytes processed */
+	int fd;			/* file descriptor */
+	int fl;			/* file opening flags */
+	char *fn;		/* file name (may be stdin_name or stdout_name) (-io) */
+	int prec;		/* partial records processed */
+	int rec;		/* records processed */
+	long seek;		/* bytes to seek/skip (will be 0 after skippage) (-sS) */
+} ep[2]; /* "engineered pipe"; also "extended play", for the deejay */
+
+/* Additionally, the following global variables are used to store user options.
+ */
+
+/* (-a)  */ static int align; /* Only the lower 8b are used but align is
+                               * negative if no alignment is being done. */
+
+/* (-c)  */ static int count; /* 0 if dj(1) runs until no more reads are
+                               * possible. */
+
+/* ASCII field separator delimited statistics */
+            static char *fmt_asv   = "%d\037%d\036%d\037%d\035%d\036%d\034";
+/* human-readable statistics */
+            static char *fmt_human = "%d+%d > %d+%d; %d > %d\n";
+/* pointer to chosen formatting */
+/* (-H)  */ static char *fmt_output; /* fmt_asv (default) or fmt_human (-H) */
+
+/* (-dq) */ static char debug;       /*
+ *  -d  increments             dj -qq | 0 - no diagnostic output whatsoever
+ *   -q decrements             dj -q  | 1 - typical output without
+ *                                    |     notifications on partial reads or
+ *                                    |     writes
+ *                             dj     | 2 - typical output (default)
+ *                             dj -d  | 3 - verbose status messages */
+
+/* (-f)  */ static char noerror;     /* 0 - exits on partial reads or writes
+                                      *     (default)
+                                      * 1 - retries on partial reads/writes
+                                      *     (-f) */
+
+/* Non-configurable defaults. */
+#define bs_default 1024
+static char *program_name = "<no argv[0]>";
+static char *stdin_name = "<stdin>";
+static char *stdout_name = "<stdout>";
+static int read_flags = O_RDONLY;
+static int write_flags = O_WRONLY | O_CREAT;
 
 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
 
@@ -20,6 +70,18 @@
 		|| (fd) == STDOUT_FILENO \
 		|| (fd) == STDERR_FILENO)
 
+/* Macro to set defaults for user-configurable options. */
+#define setdefaults do{ \
+	align = -1; \
+	count = 0; \
+	debug = 2; \
+	fmt_output = fmt_asv; \
+	noerror = 0; \
+	ep[0].fl = read_flags; \
+	Io_setdefaults(&ep[0]); \
+	ep[1].fl = write_flags; \
+	Io_setdefaults(&ep[1]); }while(0)
+
 /* Macro to call the cleanup functions that operate on struct io on the
  * particular io[2] used in main. Error conditions are not checked because this
  * is only used when the program is about to terminate (hence its name). */
@@ -29,31 +91,7 @@
 	Io_fdclose(&(io)[0]); \
 	Io_fdclose(&(io)[1]); }while(0)
 
-extern int errno;
+/* Allocates *io's buffer. Returns NULL if unsuccessful. */
-static char *fmt_asv = "%d\037%d\036%d\037%d\035%d\036%d\034";
-static char *fmt_human = "%d+%d > %d+%d; %d > %d\n";
-static char *fmt_output;
-static char *program_name = "<no argv[0]>";
-static char *stdin_name = "<stdin>";
-static char *stdout_name = "<stdout>";
-static int read_flags = O_RDONLY;
-static int write_flags = O_WRONLY | O_CREAT;
-
-/* information that needs to be kept about each file in the "pipe" */
-struct Io{
-	int bs;			/* buffer size */
-	size_t bufuse;	/* buffer usage */
-	char *buf;		/* buffer */
-	int bytes;		/* bytes processed */
-	int fd;			/* file descriptor */
-	int fl;			/* file opening flags */
-	char *fn;		/* file name (may be stdin_name or stdout_name) */
-	int prec;		/* partial records processed */
-	int rec;		/* records processed */
-	long seek;		/* bytes to seek/skip (will be 0 after skippage) */
-};
-
-/* Allocates *io's buffer. Returns NULL if successful. */
 static void *
 Io_bufalloc(struct Io *io){
 
@@ -137,17 +175,6 @@ Io_fdopen(struct Io *io, char *fn){
 	return fd;
 }
 
-/* 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){
-
-	io->bytes += (io->bufuse = read(io->fd, io->buf, io->bs));
-
-	return io;
-}
-
 /* Seeks io->seek bytes through *io's file descriptor, (counter-intuitively)
  * returning -1 if successful and a sysexits.h exit code if an unrecoverable
  * error occurred. io->buf will be cleared of useful bytes and io->seek will
@@ -186,12 +213,23 @@ Io_fdseek(struct Io *io){
 	return -1;
 }
 
+/* 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){
+
+	io->bytes += (io->bufuse = read(io->fd, io->buf, io->bs));
+
+	return io;
+}
+
 /* Sets the variables in a struct *io to the defaults. Identifies the read/
  * write ends of the "pipe" by checking io->fl. Returns io. */
 static struct Io *
 Io_setdefaults(struct Io *io){
 
-	io->bs = 1024;
+	io->bs = bs_default;
 	io->buf = NULL;
 	io->bytes = 0;
 	io->fd = (io->fl == read_flags) ? STDIN_FILENO : STDOUT_FILENO;
@@ -220,23 +258,24 @@ Io_write(struct Io *io){
 /* Prints an error message suitable for the event of an operating system error,
  * with the error itself to be described in the string s. */
 static int
-oserr(char *argv0, char *s){
+oserr(char *s){
 
-	fprintf(stderr, "%s: %s: %s\n", argv0, s, strerror(errno));
+	fprintf(stderr, "%s: %s: %s\n", program_name, s, strerror(errno));
 
 	return EX_OSERR;
 }
 
 /* Prints statistics regarding the use of dj, particularly partially and
- * completely read and written records. */
+ * completely read and written records, accessing debug, ep, and fmt_output. */
-struct Io *
+static void
-output(struct Io io[2]){
+output(void){
 
-	fprintf(stderr, fmt_output,
+	if(debug >= 1)
-		io[0].rec, io[0].prec, io[1].rec, io[1].prec,
+		fprintf(stderr, fmt_output,
-		io[0].bytes, io[1].bytes);
+			ep[0].rec, ep[0].prec, ep[1].rec, ep[1].prec,
+			ep[0].bytes, ep[1].bytes);
 
-	return io;
+	return;
 }
 
 /* Parses the string s to an integer, returning either the integer or in the
@@ -247,58 +286,43 @@ parse(char *s){
 	long r;
 
 	errno = 0;
-	r = (long)strtol(s, &s, 0);
+	r = strtol(s, &s, 0);
-	if(*s == '\0' /* no chars left unparsed */ && errno == 0)
+	return (*s == '\0' /* no chars left unparsed */ && errno == 0)
-		return r;
+		? r
-	else
+		: -1;
-		return -1;
 }
 
 static int
-usage(char *argv0){
+usage(void){
 
 	fprintf(stderr, "Usage: %s (-AdfHqQ) (-a [byte]) (-c [count])\n"
 		"\t(-i [input file]) (-b [input block size]) (-s [input offset])\n"
 		"\t(-o [output file]) (-B [output block size]) (-S [output offset])\n",
-		ARGV0(argv0));
+		program_name);
 
 	return EX_USAGE;
 }
 
 int main(int argc, char *argv[]){
-	int align;
-	char debug;
-	char noerror;
 	int c;
-	int count;
+	int i;
-	int p; /* pipe side */
-	struct Io io[2]; /* { read, write } same as pipe(2) */
 
-	/* defaults */
+	setdefaults;
-	align = -1;
-	count = 0;
-	debug = 2;
-	fmt_output = fmt_asv;
-	noerror = 0;
-	io[0].fl = read_flags;
-	Io_setdefaults(&io[0]);
-	io[1].fl = write_flags;
-	Io_setdefaults(&io[1]);
 
-	if(argc > 0)
+	if(argc > 0){
-		while((c = getopt(argc, argv, "a:Ab:B:c:di:fhHqQs:S:o:")) != -1)
+		program_name = argv[0];
+		while((c = getopt(argc, argv, "a:Ab:B:c:di:fhHqs:S:o:")) != -1)
 			switch(c){
 			case 'i': case 'o':
-				if(Io_fdopen(&io[c == 'o'], optarg) != -1)
+				if(Io_fdopen(&ep[c == 'o'], optarg) != -1)
 					break;
-				terminate(io);
+				terminate(ep);
-				return oserr(argv[0], optarg);
+				return oserr(optarg);
 			case 'A': align = '\0'; break;
-			case 'd': debug = 3; break;
+			case 'd': ++debug; break;
 			case 'f': noerror = 1; break;
 			case 'H': fmt_output = fmt_human; break;
-			case 'q': /* be quiet / BE QUIET */
+			case 'q': --debug; break;
-			case 'Q': debug -= 1 + (c == 'Q'); break;
 			case 'a':
 				if(optarg[0] != '\0' && optarg[1] == '\0'){
 					align = optarg[0];
@@ -307,97 +331,97 @@ int main(int argc, char *argv[]){
 			case 'c': case 'b': case 's': case 'B': case 'S':
 				if(c == 'c' && (count = parse(optarg)) >= 0)
 					break;
-				p = isupper(c);
+				i = isupper(c);
 				c = tolower(c);
-				if((c == 'b' && (io[p].bs = parse(optarg)) > 0)
+				if((c == 'b' && (ep[i].bs = parse(optarg)) > 0)
-						|| (c == 's' && (io[p].seek = parse(optarg)) >= 0))
+						|| (c == 's' && (ep[i].seek = parse(optarg)) >= 0))
 					break;
 			default:
-				terminate(io);
+				terminate(ep);
-				return usage(argv[0]);
+				return usage();
 			}
+	}
 
 	if(debug >= 3)
 		fprintf(stderr,
 			"argv0=%s\n"
 			"in=%s\tibs=%d\tskip=%ld\talign=%hhx\tcount=%d\n"
 			"out=%s\tobs=%d\tseek=%ld\tdebug=%2d\tnoerror=%d\n",
-			ARGV0(argv[0]),
+			program_name,
-			io[0].fn, io[0].bs, io[0].seek, align, count,
+			ep[0].fn, ep[0].bs, ep[0].seek, align, count,
-			io[1].fn, io[1].bs, io[1].seek, debug, noerror);
+			ep[1].fn, ep[1].bs, ep[1].seek, debug, noerror);
 
 	if(argc > optind){
-		terminate(io);
+		terminate(ep);
-		return usage(argv[0]);
+		return usage();
 	}
 
-	for(p = 0; p <= 1; ++p){
+	for(i = 0; i <= 1; ++i){
-		if(Io_bufalloc(&io[p]) == NULL){
+		if(Io_bufalloc(&ep[i]) == NULL){
 			fprintf(stderr, "%s: Failed to allocate %d bytes\n",
-				ARGV0(argv[0]), io[p].bs);
+				program_name, ep[i].bs);
-			terminate(io);
+			terminate(ep);
 			return EX_OSERR;
-		}else if(io[p].seek > 0)
+		}else if(ep[i].seek > 0)
-			switch(Io_fdseek(&io[p])){
+			switch(Io_fdseek(&ep[i])){
 			case EX_OK:
-				if(debug >= 1)
+				output();
-					output(io);
+				terminate(ep);
-				terminate(io);
 				return EX_OK;
 			}
 	}
 
 	do{	/* read */
-		Io_read(&io[0]);
+		Io_read(&ep[0]);
-		if(!noerror && io[0].bufuse == 0)
+		if(!noerror && ep[0].bufuse == 0)
-			Io_read(&io[0]); /* second chance */
+			Io_read(&ep[0]); /* second chance */
-		if(io[0].bufuse == 0) /* that's all she wrote */
+		if(ep[0].bufuse == 0) /* that's all she wrote */
 			break;
-		else if(io[0].bufuse < io[0].bs){
+		else if(ep[0].bufuse < ep[0].bs){
-			++io[0].prec;
+			++ep[0].prec;
 			if(debug >= 2){
-				fprintf(stderr, "%s: Partial read:\n\t", ARGV0(argv[0]));
+				fprintf(stderr, "%s: Partial read:\n\t", program_name);
-				output(io);
+				output();
 			}
 			if(!noerror)
 				count = 1;
 			if(align >= 0)
-				Io_bufrpad(&io[0], align);
+				Io_bufrpad(&ep[0], align);
 		}else
-			++io[0].rec;
+			++ep[0].rec;
 
 		/* write */
-		do{	if(io[1].bs > io[0].bs){ /* io[1].bs > io[0].bs */
+		do{	if(ep[1].bs > ep[0].bs){ /* io[1].bs > io[0].bs */
-				Io_bufxapp(&io[1], &io[0]);
+				Io_bufxapp(&ep[1], &ep[0]);
-				if(io[0].bs + io[1].bufuse <= io[1].bs && count != 1)
+				if(ep[0].bs + ep[1].bufuse <= ep[1].bs && count != 1)
 					continue; /* we could write more */
 			}else
-				Io_bufxfer(&io[1], &io[0], MIN(io[0].bufuse, io[1].bs));
+				Io_bufxfer(&ep[1], &ep[0], MIN(ep[0].bufuse, ep[1].bs));
 
-			c = io[1].bufuse;
+			c = ep[1].bufuse;
-			Io_write(&io[1]);
+			Io_write(&ep[1]);
-			if(!noerror && io[1].bufuse == c)
+			if(!noerror && ep[1].bufuse == c)
-				Io_write(&io[1]); /* second chance */
+				Io_write(&ep[1]); /* second chance */
-			if(c == io[1].bufuse) /* no more love */
+			if(c == ep[1].bufuse){ /* no more love */
 				count = 1;
-			else if(c > io[1].bufuse && io[1].bufuse > 0){
+				break;
-				io[1].prec += 1;
+			}else if(c > ep[1].bufuse && ep[1].bufuse > 0){
+				ep[1].prec += 1;
 				if(debug >= 2){
-					fprintf(stderr, "%s: Partial write:\n\t", ARGV0(argv[0]));
+					fprintf(stderr, "%s: Partial write:\n\t", program_name);
-					output(io);
+					output();
 				}
 				if(!noerror)
 					count = 1;
-			}else if(io[1].bufuse == 0 && c < io[1].bs)
+			}else if(ep[1].bufuse == 0 && c < ep[1].bs)
-				++io[1].prec;
+				++ep[1].prec;
 			else
-				++io[1].rec;
+				++ep[1].rec;
-		}while(io[0].bufuse > 0);
+		}while(ep[0].bufuse > 0);
 	}while(count == 0 || --count > 0);
 
-	if(debug >= 1)
+	output();
-		output(io);
+	terminate(ep);
-	terminate(io);
 
 	return EX_OK;
 }