dj(1): refactor source

src/dj.c

@@ -46,31 +46,11 @@ struct Io{
 /* 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) */
+static char *fmt_asv   = "%d\037%d\036%d\037%d\035%d\036%d\034";
 
-/* (-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 */
-
-/* (-n)  */ static char noerror;     /* 0 - exits on partial reads or writes
-                                      *     (default)
-                                      * 1 - retries on partial reads/writes
-                                      *     (-n) */
+/* (-H) Human-readable statistics */
+static char *fmt_human = "%d+%d > %d+%d; %d > %d\n";
 
 /* Non-configurable defaults. */
 #define bs_default 1024 /* GNU dd(1) default; twice POSIX but a neat 2^10 */
@@ -80,19 +60,8 @@ static char *stdout_name = "<stdout>";
 static int read_flags = O_RDONLY; /* These flags are consistent with Busybox */
 static int write_flags = O_WRONLY | O_CREAT; /* dd(1). */
 
-/* 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)
-
 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
+#define MAX(a, b) (((a) > (b)) ? (a) : (b))
 
 /* Macro to check if fd is a std* file, e.g. stdin. */
 #define fdisstd(fd) \
@@ -104,43 +73,16 @@ static int write_flags = O_WRONLY | O_CREAT; /* dd(1). */
  * 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). */
 #define terminate(io) do{ \
-	Io_buffree(&(io)[0]); \
-	Io_buffree(&(io)[1]); \
+	free((io)[0].buf); \
+	free((io)[1].buf); \
 	Io_fdclose(&(io)[0]); \
 	Io_fdclose(&(io)[1]); }while(0)
 
-/* Allocates *io's buffer. Returns NULL if unsuccessful. */
-static void *
-Io_bufalloc(struct Io *io){
-
-	return (io->buf = malloc(io->bs * (sizeof *io->buf)));
-}
-
-/* Frees *io's buffer. Returns io. */
-static struct Io *
-Io_buffree(struct Io *io){
-
-	free(io->buf);
-
-	return io;
-}
-
-/* Fills the unused portion of io's buffer with padding, updating io->bufuse.
- * Returns io. */
-static struct Io *
-Io_bufrpad(struct Io *io, int padding){
-	
-	memset(io->buf + io->bufuse, padding, io->bs - io->bufuse);
-	io->bufuse = io->bs;
-
-	return io;
-}
-
 /* Copies from the buffer in src as much as possible to the free space in the
  * dest buffer, removing the copied units from src and permuting the remaining
  * units in the src buffer to the start of the buffer, modifying both the src
  * and dest bufuse and returning dest. */
-static struct Io*
+static struct Io *
 Io_bufxapp(struct Io *dest, struct Io *src){
 	int n;
 
@@ -157,7 +99,7 @@ Io_bufxapp(struct Io *dest, struct Io *src){
  * removing the copied units from src and permuting the remaining units in the
  * src buffer to the start of the buffer, modifying both the src and dest
  * bufuse and returning dest. */
-static struct Io*
+static struct Io *
 Io_bufxfer(struct Io *dest, struct Io *src, int n){
 
 	memcpy(dest->buf, src->buf, (dest->bufuse = n));
@@ -167,13 +109,10 @@ Io_bufxfer(struct Io *dest, struct Io *src, int n){
 }
 
 /* Closes io->fn and returns -1 on error, otherwise io->fd. */
-static int
-Io_fdclose(struct Io *io){
-
-	return fdisstd(io->fd)
-		? 0
-		: close(io->fd);
-}
+#define Io_fdclose(io) \
+	(fdisstd((io)->fd) \
+		? 0 \
+		: close((io)->fd))
 
 /* Opens io->fn and saves the file descriptor into io->fd. Returns io->fd,
  * which will be -1 if an error occured. */
@@ -199,8 +138,7 @@ Io_fdopen(struct Io *io, char *fn){
  * be set to zero to indicate the seek occurred. */
 static int
 Io_fdseek(struct Io *io){
-	int (*op)(int, void *, size_t);
-	
+
 	if(!fdisstd(io->fd) && lseek(io->fd, io->seek, SEEK_SET) != -1)
 		return -1;
 
@@ -283,19 +221,6 @@ oserr(char *s){
 	return EX_OSERR;
 }
 
-/* Prints statistics regarding the use of dj, particularly partially and
- * completely read and written records, accessing debug, ep, and fmt_output. */
-static void
-output(void){
-
-	if(debug >= 1)
-		fprintf(stderr, fmt_output,
-			ep[0].rec, ep[0].prec, ep[1].rec, ep[1].prec,
-			ep[0].bytes, ep[1].bytes);
-
-	return;
-}
-
 /* Parses the string s to an integer, returning either the integer or in the
  * case of an error a negative integer. This is used for argument parsing
  * (e.g. -B [int]) in dj and no negative integer would be valid anyway. */
@@ -321,11 +246,30 @@ usage(void){
 	return EX_USAGE;
 }
 
-int main(int argc, char *argv[]){
-	int c;
-	int i;
+/* For use in main only.
+ * Prints statistics regarding the use of dj, particularly partially and
+ * completely read and written records, accessing ep, and fmt_output. */
+#define output fprintf(stderr, fmt_output, \
+	ep[0].rec, ep[0].prec, ep[1].rec, ep[1].prec, ep[0].bytes, ep[1].bytes \
+)
 
-	setdefaults;
+int main(int argc, char *argv[]){
+	int align; /* Only the lower 8b are used, negative if no alignment. */
+	int count;
+	int c, i;
+	enum { QUIETER = 0, TYPICAL = 1, VERBOSE = 2 } debug;
+	enum { GIVEUP = 0, RETRY = 1 } error;
+	char *fmt_output = fmt_asv;
+
+	ep[0].fl = read_flags;
+	Io_setdefaults(&ep[0]);
+	ep[1].fl = write_flags;
+	Io_setdefaults(&ep[1]);
+
+	align = -1;
+	count = 0;
+	debug = TYPICAL;
+	error = GIVEUP;
 
 	if(argc > 0){
 		program_name = argv[0];
@@ -342,10 +286,10 @@ int main(int argc, char *argv[]){
 				terminate(ep);
 				return oserr(optarg);
 			case 'A': align = '\0'; break;
-			case 'd': ++debug; break;
-			case 'n': noerror = 1; break;
+			case 'd': debug = VERBOSE; break;
+			case 'n': error = RETRY; break;
 			case 'H': fmt_output = fmt_human; break;
-			case 'q': --debug; break;
+			case 'q': debug = QUIETER; break;
 			case 'a':
 				if(optarg[0] != '\0' && optarg[1] == '\0'){
 					align = optarg[0];
@@ -367,14 +311,15 @@ int main(int argc, char *argv[]){
 			}
 	}
 
-	if(debug >= 3)
+	if(debug >= VERBOSE)
 		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",
+			"out=%s\tobs=%d\tseek=%ld\tdebug=%2d\terror=%s\n",
 			program_name,
 			ep[0].fn, ep[0].bs, ep[0].seek, align, count,
-			ep[1].fn, ep[1].bs, ep[1].seek, debug, noerror);
+			ep[1].fn, ep[1].bs, ep[1].seek, debug,
+		    error == GIVEUP ? "GIVEUP" : "RETRY");
 
 	if(argc > optind){
 		terminate(ep);
@@ -382,36 +327,37 @@ int main(int argc, char *argv[]){
 	}
 
 	for(i = 0; i <= 1; ++i){
-		if(Io_bufalloc(&ep[i]) == NULL){
+		if((ep[i].buf = malloc(ep[i].bs * (sizeof ep[i].buf))) == NULL){
 			fprintf(stderr, "%s: Failed to allocate %d bytes\n",
-				program_name, ep[i].bs);
+				program_name, ep[i].bs * (sizeof ep[i].buf));
 			terminate(ep);
 			return EX_OSERR;
-		}else if(ep[i].seek > 0)
-			switch(Io_fdseek(&ep[i])){
-			case EX_OK:
-				output();
-				terminate(ep);
-				return EX_OK;
-			}
+		}else if(ep[i].seek > 0 && (c = Io_fdseek(&ep[i])) != -1){
+			output;
+			terminate(ep);
+			return c;
+		}
 	}
 
 	do{	/* read */
 		Io_read(&ep[0]);
-		if(!noerror && ep[0].bufuse == 0)
+		if(error == RETRY && ep[0].bufuse == 0)
 			Io_read(&ep[0]); /* second chance */
 		if(ep[0].bufuse == 0) /* that's all she wrote */
 			break;
 		else if(ep[0].bufuse < ep[0].bs){
 			++ep[0].prec;
-			if(debug >= 2){
+			if(debug >= TYPICAL){
 				fprintf(stderr, "%s: Partial read:\n\t", program_name);
-				output();
+				output;
 			}
-			if(!noerror)
+			if(error == GIVEUP)
 				count = 1;
-			if(align >= 0)
-				Io_bufrpad(&ep[0], align);
+			if(align >= 0){
+				memset(ep[0].buf + ep[0].bufuse, align,
+					ep[0].bs - ep[0].bufuse);
+				ep[0].bufuse = ep[0].bs;
+			}
 		}else
 			++ep[0].rec;
 
@@ -425,18 +371,18 @@ int main(int argc, char *argv[]){
 
 			c = ep[1].bufuse;
 			Io_write(&ep[1]);
-			if(!noerror && ep[1].bufuse == c)
+			if(error == GIVEUP && ep[1].bufuse == c)
 				Io_write(&ep[1]); /* second chance */
 			if(c == ep[1].bufuse){ /* no more love */
 				count = 1;
 				break;
 			}else if(c > ep[1].bufuse && ep[1].bufuse > 0){
 				ep[1].prec += 1;
-				if(debug >= 2){
+				if(debug >= TYPICAL){
 					fprintf(stderr, "%s: Partial write:\n\t", program_name);
-					output();
+					output;
 				}
-				if(!noerror)
+				if(error == GIVEUP)
 					count = 1;
 			}else if(ep[1].bufuse == 0 && c < ep[1].bs)
 				++ep[1].prec;
@@ -445,7 +391,7 @@ int main(int argc, char *argv[]){
 		}while(ep[0].bufuse > 0);
 	}while(count == 0 || --count > 0);
 
-	output();
+	output;
 	terminate(ep);
 
 	return EX_OK;