2024-01-03 work

Wip/dj/dj.c

@@ -15,19 +15,86 @@
 
 /* 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 */
+	int fd;			/* file descriptor */
+	int fl;			/* file opening flags */
+	char *fn;		/* file name (may be stdin_name or stdout_name) */
+	size_t index;	/* index in io[] array */
+	int prec;		/* partial records processed */
+	int rec;		/* records processed */
+	int seek;		/* bytes to seek/skip (will be 0 after skippage) */
 };
 
-static char stdin_name = "<stdin>";
+static char *stdin_name = "<stdin>";
-static char stdout_name = "<stdout>";
+static char *stdout_name = "<stdout>";
+
+static void *
+Io_bufalloc(struct Io *io){
+
+	return (io->buf = malloc(io->bs * (sizeof io->buf)));
+}
+
+static void
+Io_buffree(struct Io *io){
+
+	free(io->buf);
+
+	return;
+}
+
+static int
+Io_fdclose(struct Io *io){
+
+	return fdisnotstd(io->fd)
+		? close(io->fd)
+		: 0;
+}
+
+static int
+Io_fdopen(struct Io *io, char *fn){
+	int fd;
+	
+	if((fd = open(fn, io->fl)) != -1
+			&& (fdisnotstd(io->fd) || close(io->fd) == 0)){
+		io->fd = fd;
+		io->fn = fn;
+	}
+
+	return fd;
+}
+
+static int _read(int fd, void *b, size_t bs);
+
+/* counter-intuitively, returns negative if successful and a sysexits.h exit
+ * code if an unrecoverable error occurred */
+static int
+Io_seek(struct Io *io){
+	
+	if(fdisnotstd(io->fd) && lseek(io->fd, io->seek, SEEK_SET) == -1)
+		return -1;
+	else if(io->fl == O_RDONLY){
+		do	if((io->bufuse = _read(io->fd, io->buf,
+					(io->bs < io->seek) ? io->bs : io->seek)) != 0)								
+				io->seek -= io->bufuse;
+			else /* not enough to skip */
+				return EX_OK;
+		while(io->seek > 0);
+	}else{
+		memset(io->buf, '\0', io->bs);
+		/* cheat and use bufuse as the retval for write
+		 * (the buffer is zeroed, it doesn't matter) */
+		do	if((io->bufuse = write(io->fd, io->buf,
+						(io->bs < io->seek) ? io->bs : io->seek)) != 0)
+				io->seek -= io->bufuse;
+			else
+				return EX_OK;
+		while(io->seek > 0);
+	}
+
+	return -1;
+}
 
 static void
 Io_setdefaults(struct Io io[2]){