2024-01-02 work

Wip/dj/dj.c

@@ -8,6 +8,42 @@
                        STDIN_FILENO, STDOUT_FILENO */
 
 #define ARGV0 (argv[0] == NULL ? "<no argv[0]>" : argv[0])
+#define fdisnotstd(fd) \
+		((fd) != STDIN_FILENO \
+		&& (fd) != STDOUT_FILENO \
+		&& (fd) != STDERR_FILENO)
+
+/* information that needs to be kept about each file in the "pipe" */
+struct Io{
+	size_t index;	/* index in io[] array */
+	char *fn;		/* file name (may be stdin_name or stdout_name) */
+	int rec;		/* records processed */
+	int prec;		/* partial records processed */
+	int fd;			/* file descriptor */
+	int seek;		/* bytes to seek/skip (will be 0 after skippage) */
+	int bs;			/* buffer size */
+	size_t bufuse;	/* buffer usage */
+	char *buf;		/* buffer */
+};
+
+static char stdin_name = "<stdin>";
+static char stdout_name = "<stdout>";
+
+static void
+Io_setdefaults(struct Io io[2]){
+
+	io[0].bs = io[1].bs = 1024;
+	io[0].buf = io[1].buf = NULL;
+	io[0].fd = STDIN_FILENO;
+	io[0].fn = stdin_name;
+	io[1].fd = STDOUT_FILENO;
+	io[1].fn = stdout_name;
+	io[0].index = 0;
+	io[1].index = 1;
+	io[0].seek = io[1].seek = 0;
+
+	return;
+}
 
 /* read(2) but with a second chance if it returns zero */
 static int
@@ -32,12 +68,15 @@ parse(char *s){
 		: r;
 }
 
+/* s is the component (e.g. filename) that failed */
 static int
 oserr(char *argv0, char *s){
 	fprintf(stderr, "%s: %s: %s\n", argv0, s, strerror(errno));
 	return EX_OSERR;
 }
 
+/* diagnostic output
+ * dd(1p) does %d+%d\n%d+%d\n */
 struct Io *
 output(struct Io io[2]){
 
@@ -50,7 +89,7 @@ static int
 terminate(struct Io io[2]){
 
 	for(;; ++io){
-		if(io->fd != STDIN_FILENO && io->fd != STDOUT_FILENO)
+		if(fdisnotstd(io->fd))
 			close(io->fd);
 		free(io->buf);
 		if(io->index == 1)
@@ -62,6 +101,7 @@ terminate(struct Io io[2]){
 
 static int
 usage(char *argv0){
+
 	fprintf(stderr, "Usage: %s (-af) (-c [count]\n"
 		"\t(-i [input file]) (-b [input block size])"
 			" (-s [input offset])\n"
@@ -70,41 +110,20 @@ usage(char *argv0){
 	return EX_USAGE;
 }
 
-static char stdin_name = "<stdin>";
-static char stdout_name = "<stdout>";
 
 int main(int argc, char *argv[]){
-	struct Io{
-		size_t index;
-		char *fn;
-		int rec;
-		int prec;
-		int fd;
-		int seek;
-		int bs;
-		size_t bufuse;
-		char *buf;
-	} io[2]; /* { read, write } same as pipe(2) */
 	char align;
+	char noerror;
 	int c;
 	int count;
-	size_t i;
+	int p; /* pipe side */
-	size_t p;
+	struct Io io[2]; /* { read, write } same as pipe(2) */
-	char noerror;
 
 	/* defaults */
 	align = 0;
 	count = 0;
 	noerror = 0;
-	io[0].bs = io[1].bs = 1024;
+	Io_setdefaults(io);
-	io[0].buf = io[1].buf = NULL;
-	io[0].fd = STDIN_FILENO;
-	io[0].fn = stdin_name;
-	io[1].fd = STDOUT_FILENO;
-	io[1].fn = stdout_name;
-	io[0].index = 0;
-	io[1].index = 1;
-	io[0].seek = io[1].seek = 0;
 
 	if(argc > 0)
 		while((c = getopt(argc, argv, "ac:i:b:fs:o:B:S:")) != -1)
@@ -112,14 +131,13 @@ int main(int argc, char *argv[]){
 				int t;
 
 				p = (c == 'o');
-				if(		(t = open(optarg,
+				if(		((t = open(optarg,
 								c == 'i'
 								? O_RDONLY
 								: O_WRONLY | O_CREAT))
 							== -1)
-						|| (io[p].fd != STDIN_FILENO
+						|| (fdisnotstd(io[p].fd)
-							&& io[p].fd != STDOUT_FILENO
+							&& close(io[p].fd) != 0)){
-							&& fclose(io[p].f) == EOF){
 					terminate(io);
 					return oserr(argv[0], optarg);
 				}else{
@@ -152,8 +170,7 @@ int main(int argc, char *argv[]){
 			terminate(io);
 			return EX_OSERR;
 		}else if(io[p].seek > 0){ /* seek */
-			if(io[p].fd == STDIN_FILENO
+			if(!fdisnotstd(io[p].fd)
-					|| io[p].fd == STDOUT_FILENO
 					|| lseek(io[p].fd, io[p].seek, SEEK_SET) == -1){					
 				if(p == 0){
 					do	if((io[p].bufuse = _read(io[p].fd, io[p].buf,
@@ -185,16 +202,29 @@ int main(int argc, char *argv[]){
 
 	io[0].prec = io[0].rec = io[1].prec = io[1].rec = 0;
 
-	do{	if(		(io[0].bufuse
+	do{	/* read */ if((io[0].bufuse
-					= fread(io[0].buf, sizeof io[0].buf, io[0].bs, io[0].f))
+				= read(io[0].fd, io[0].buf, io[0].bs))
-				< ibs){
+				< io[0].bs){
-			if(feof(io[0].f) != 0)
+			if(io[0].bufuse == 0 && (!noerror
+					|| ((io[0].bufuse = read(io[0].fd, io[0].buf, io[0].bs))
+						== 0)))
+				break; /* that's all she wrote */
+			else{
+				io[0].prec += 1;
+				if(noerror){
+					
+				}else
 					count = 1;
+				if(align){
+					memset(io[0].buf + io[0].bufuse, '\0',
+						io[0].bs - io[0].bufuse);
+					io[0].bufuse = io[0].bs;
+				}
+			}
 		}
 
-		while(io[0].bufuse > 0){
+		/* write */ while(io[0].bufuse > 0){
 		}
-
 	}while(count == 0 || --count > 0);
 
 	return terminate(output(io));