add directory study

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

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+/* gres - grep and substitute		Author: Martin C. Atkins */
+
+/*
+ *	globally search, and replace
+ *
+ *<-xtx-*>cc -o gres gres.c -lregexp
+ */
+
+/*
+ *	This program was written by:
+ *		Martin C. Atkins,
+ *		University of York,
+ *		Heslington,
+ *		York. Y01 5DD
+ *		England
+ *	and is released into the public domain, on the condition
+ *	that this comment is always included without alteration.
+ */
+
+#include <regexp.h>
+#include <string.h>
+#include <stdio.h>
+
+#define MAXLINE (1024)
+
+int status = 1;
+char *usagemsg = "Usage: gres [-g] search replace [file ...]\n";
+char *progname;
+int gflag = 0;			/* != 0 => only do first substitution on line */
+
+main(argc, argv)
+int argc;
+char *argv[];
+{
+  regexp *exp;
+  char *repstr;
+  char **argp = &argv[1];
+
+  progname = argv[0];
+  if (*argp != 0 && argp[0][0] == '-' && argp[0][1] == 'g') {
+	gflag = 1;
+	argp++, argc--;
+  }
+  if (argc < 3) {
+	std_err(usagemsg);
+	exit(2);
+  }
+  if (argp[0][0] == '\0') {
+	std_err("gres: null match string is silly\n");
+	exit(2);
+  }
+  if ((exp = regcomp(*argp++)) == (regexp *) NULL) {
+	std_err("gres: regcomp failed\n");
+	exit(2);
+  }
+  repstr = *argp++;
+  if (*argp == 0)
+	process(stdin, exp, repstr);
+  else
+	while (*argp) {
+		FILE *inf;
+
+		if (strcmp(*argp, "-") == 0)
+			process(stdin, exp, repstr);
+		else {
+			if ((inf = fopen(*argp, "r")) == (FILE *) NULL) {
+				std_err("gres: Can't open ");
+				std_err(*argp);
+				std_err("\n");
+				status = 2;
+			} else {
+				process(inf, exp, repstr);
+				fclose(inf);
+			}
+		}
+		argp++;
+	}
+  exit(status);
+}
+
+/* This routine does the processing. */
+process(inf, exp, repstr)
+FILE *inf;
+regexp *exp;
+char *repstr;
+{
+  char ibuf[MAXLINE];
+
+  while (fgets(ibuf, MAXLINE, inf) != (char *) NULL) {
+	char *cr = strchr(ibuf, '\n');
+	if (cr == 0)
+		std_err("gres: Line broken\n");
+	else
+		*cr = '\0';
+	if (regexec(exp, ibuf, 1)) {
+		pline(exp, ibuf, repstr);
+		if (status != 2) status = 0;
+	} else
+		puts(ibuf);
+  }
+}
+
+void regerror(s)
+char *s;
+{
+  std_err("gres: ");
+  std_err(s);
+  std_err("\n");
+  exit(2);
+}
+
+char *getbuf(exp, repstr)
+regexp *exp;
+char *repstr;
+{
+  char *malloc();
+  void free();
+  static bufsize = 0;
+  static char *buf = 0;
+  int guess = 10;
+  int ch;
+
+  while (*repstr) {
+	switch (*repstr) {
+	    case '&':
+		guess += exp->endp[0] - exp->startp[0];
+		break;
+	    case '\\':
+		if ((ch = *++repstr) < '0' || ch > '9')
+			guess += 2;
+		else {
+			ch -= '0';
+			guess += exp->endp[ch] - exp->startp[ch];
+		}
+		break;
+	    default:	guess++;
+	}
+	repstr++;
+  }
+  if (bufsize < guess) {
+	if (buf != 0) free((char *) buf);
+	buf = malloc(guess);
+  }
+  return buf;
+}
+
+pline(exp, ibuf, repstr)
+regexp *exp;
+char ibuf[];
+char *repstr;
+{
+  do {
+	dosub(exp, ibuf, repstr);
+	ibuf = exp->endp[0];
+	if (*ibuf == '\0') break;
+	if (ibuf == exp->startp[0]) putchar(*ibuf++);
+  } while (!gflag && regexec(exp, ibuf, 0));
+  puts(ibuf);
+}
+
+/* Print one subsitution. */
+dosub(exp, ibuf, repstr)
+regexp *exp;
+char ibuf[];
+char *repstr;
+{
+  char *buf = getbuf(exp, repstr);
+  char *end = exp->startp[0];
+  int ch = *end;
+
+  *end = '\0';
+  fputs(ibuf, stdout);		/* output the initial part of line */
+  *end = ch;
+  regsub(exp, repstr, buf);
+  fputs(buf, stdout);
+}