add directory study

study/linux-travel/MINIX-1.5/1.5/Source/commands/width.c

@@ -0,0 +1,117 @@
+/* width - force a file to a fixed width	Author: Andy Tanenbaum */
+
+/* This program reads an input file (by default, stdin), and forces each
+ * line to a certain length (by default 80 columns).  Lines that are
+ * shorter than this are padded with spaces.  Lines that are longer are
+ * truncated.  Tabs are expanded to spaces in the output.
+ *
+ * Examples:	width x y 	# copy x to y and make all lines 80 cols
+ *		width x		# copy x to stdout and force all lines to 80
+ *		width -40 x	# copy x to stdout and force to 40 cols
+ *		width -30 x y	# copy x to y and force to 30 cols
+ *		width -20	# copy stdin to stdout and force to 20 cols
+ */
+
+#include <stdio.h>
+
+#define MAX_WIDTH	1024	/* longest acceptable line */
+#define TAB_WIDTH          8	/* spacing between tab stops */
+
+main(argc, argv)
+int argc;
+char *argv[];
+{
+
+  int width, k;
+  char *p;
+  FILE *in, *out;
+
+  /* Process command line. */
+  p = argv[1];
+  k = 1;
+  width = 80;
+  if (argc > 1 && *p == '-') {
+	width = atoi(p + 1);
+	if (width < 1 || width > MAX_WIDTH) usage(argv[0]);
+	k = 2;
+  }
+  if (argc == k) {
+	/* No file arguments. */
+	process(stdin, stdout, width);
+  } else if (argc == k + 1) {
+	/* For example: width file   or   width -30 file */
+	if ((in = fopen(argv[k], "r")) == (FILE *) NULL)
+		cant_open(argv[0], argv[k]);
+	process(in, stdout, width);
+  } else if (argc == k + 2) {
+	/* For example, width inf outf  or   width -30 inf outf */
+	if ((in = fopen(argv[k], "r")) == (FILE *) NULL)
+		cant_open(argv[0], argv[k]);
+	if ((out = fopen(argv[k + 1], "w")) == (FILE *) NULL)
+		cant_open(argv[0], argv[k]);
+	process(in, out, width);
+  } else {
+	usage(argv[0]);
+  }
+  exit(0);
+}
+
+
+process(in, out, width)
+FILE *in, *out;
+int width;
+{
+/* Copy in to out and force all the lines to width. */
+
+  int col, spaces;
+  register char *p, *q;
+  char in_buf[MAX_WIDTH + 1], out_buf[MAX_WIDTH + 1];
+
+  while (fgets(in_buf, MAX_WIDTH, in) != (char *) NULL) {
+	/* This loop executed once for each line in the input file. */
+	p = in_buf;
+	q = out_buf;
+	col = 0;
+	while (*p != 0) {
+		/* This loop executed once for each character in the line. */
+		if (*p != '\t') {
+			/* Not a tab. */
+			*q++ = *p++;
+			col++;
+		} else {
+			/* Tab. */
+			spaces = TAB_WIDTH - (col % TAB_WIDTH);
+			col += spaces;
+			while (spaces--) *q++ = ' ';
+			p++;
+		}
+	}
+	if (*(q - 1) == '\n') *(q - 1) = ' ';
+	while (q < &out_buf[width]) *q++ = ' ';
+	out_buf[width] = '\n';
+	out_buf[width + 1] = 0;
+	fputs(out_buf, out);
+  }
+}
+
+
+cant_open(program, file)
+char *program;
+char *file;
+{
+  fputs(program, stderr);
+  fputs(": cannot open ", stderr);
+  fputs(file, stderr);
+  putc('\n', stderr);
+  exit(1);
+}
+
+
+usage(s)
+char *s;
+{
+  fputs("Usage: ", stderr);
+  fputs(s, stderr);
+  fputs(" [-<width>] [infile [outfile] ]\n", stderr);
+  exit(1);
+}