dj(1): statistics now track hard seeks

docs/dj.1

@@ -41,10 +41,6 @@ with a skip offset of 1 skips one byte into the input and reads from the second
 byte onwards. A programmer may think of a file as a zero-indexed array of
 bytes; in this analogy, the offset given is the index of the byte at which to
 start reading or writing.
-
-Seeks aren\(cqt counted in the output statistics because they\(cqre guaranteed
-to succeed (or the utility will exit unsuccessfully, before it has written any
-data).
 .\"
 .SH OPTIONS
 
@@ -195,9 +191,10 @@ and
 .BR -S .
 The lowercase option affects input and the capitalized option affects output.
 
-The discarded but read bytes skipped while processing irregular files, such as
+The skipped or sought bytes while processing irregular files, such as streams,
-streams, are reported in the diagnostic output. Bytes skipped while processing
+are reported in the diagnostic output, because they were actually read or
-regular files are not reported, as the bytes weren\(cqt read.
+written. This is as opposed to bytes skipped while processing regular files,
+which are not reported.
 .\"
 .SH RATIONALE
 

src/dj.c

@@ -56,7 +56,6 @@ 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). */
@@ -239,37 +238,29 @@ int main(int argc, char *argv[]){
 
 	/* hard seeking */
 	if(io[1].seek > 0){
-		memset(io[1].buf, '\0', io[1].bs);
+		size_t t;
-		/* We're going to cheat and use bufuse as the retval for write(2),
-		 * which is fine because it'll be zeroed as this function returns
-		 * anyway. */
 		do{
-			if((io[1].bufuse = write(
+			memset(io[1].buf, '\0',
-						io[1].fd, io[1].buf, MIN(io[1].bs, io[1].seek)))
+				(t = io[1].bufuse = MIN(io[1].bs, io[1].seek)));
-					== 0)
+			if(Io_write(&io[1])->bufuse == t && !noerror)
-				/* second chance */
+				Io_write(&io[1]); /* second chance */
-				io[1].bufuse = write(
+		}while((io[1].seek -= (t - io[1].bufuse)) > 0 && io[1].bufuse != t);
-					io[1].fd, io[1].buf, MIN(io[1].bs, io[1].seek));
-		}while((io[1].seek -= io[1].bufuse) > 0 && io[1].bufuse != 0);
 		io[1].bufuse = 0;
 	}
 
-	/* Sought bytes aren't counted in the statistics because successful seeking
+	if(io[1].seek > 0){
-	 * is guaranteed here. */
+		fprintio(stderr, fmt, io);
-	if(io[1].seek > 0)
 		return oserr(io[1].fn);
+	}
 
 	do{
 		assert(io[0].bufuse == 0);
 
 		{ /* read */
-			static char skipping = 0;
+			char skipping;
 			int t;
 
-			if(io[0].seek > 0)
+			if((skipping = (io[0].seek > 0)) && io[0].seek < io[0].bs)
-				skipping = 1;
-
-			if(skipping && io[0].seek < io[0].bs)
 				io[0].bufuse = io[0].bs - io[0].seek;
 
 			t = io[0].bufuse;
@@ -279,11 +270,13 @@ int main(int argc, char *argv[]){
 				break;
 
 			if(/* t < io[0].bufuse && */ io[0].bufuse < io[0].bs){
+				assert(!skipping);
+
 				fprintf(stderr, "%s: Partial read:\n\t", program_name);
 				fprintio(stderr, fmt, io);
 				if(!noerror)
 					count = 1;
-				if(!skipping && align >= 0){
+				if(align >= 0){
 					/* fill the rest of the ibuf with padding */
 					memset(&(io[0].buf)[io[0].bufuse], align,
 						io[0].bs - io[0].bufuse);
@@ -292,7 +285,6 @@ int main(int argc, char *argv[]){
 			}
 
 			if(skipping){
-				skipping = (io[0].seek -= io[0].bufuse - t) > 0;
 				io[0].bufuse = 0;
 				count += (count != 0);
 				continue;