add directory study

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

@@ -0,0 +1,66 @@
+/*  fold - folds long lines		Author: Terrence W. Holm */
+
+/*  Usage:  fold  [ -width ]  [ file ... ]  */
+
+#include <stdio.h>
+
+#define  TAB		8
+#define  DEFAULT_WIDTH  80
+
+int column = 0;			/* Current column, retained between files  */
+
+main(argc, argv)
+int argc;
+char *argv[];
+{
+  int width = DEFAULT_WIDTH;
+  int i;
+  FILE *f;
+
+  if (argc > 1 && argv[1][0] == '-') {
+	if ((width = atoi(&argv[1][1])) <= 0) {
+		fprintf(stderr, "Bad number for fold\n");
+		exit(1);
+	}
+	--argc;
+	++argv;
+  }
+  if (argc == 1)
+	Fold(stdin, width);
+  else {
+	for (i = 1; i < argc; ++i) {
+		if ((f = fopen(argv[i], "r")) == NULL) {
+			perror(argv[i]);
+			exit(1);
+		}
+		Fold(f, width);
+		fclose(f);
+	}
+  }
+  exit(0);
+}
+
+
+Fold(f, width)
+FILE *f;
+int width;
+{
+  int c;
+
+  while ((c = getc(f)) != EOF) {
+	if (c == '\t')
+		column = (column / TAB + 1) * TAB;
+	else if (c == '\b')
+		column = column > 0 ? column - 1 : 0;
+	else if (c == '\n' || c == '\r')
+		column = 0;
+	else
+		++column;
+
+	if (column > width) {
+		putchar('\n');
+		column = c == '\t' ? TAB : 1;
+	}
+	putchar(c);
+  }
+}