Add loopfiles() function, make catv use it.
diff --git a/lib/lib.c b/lib/lib.c
index 5d01efc..6aaf7b0 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -545,3 +545,26 @@
xwrite(fd, spid, sprintf(spid, "%ld\n", (long)getpid()));
close(fd);
}
+
+// Iterate through an array of files, opening each one (read only) and
+// calling a function on that filehandle and name. The special filename
+// "-" means stdin. An empty argument list calls function() on stdin.
+void loopfiles(char **argv, void (*function)(int fd, char *name))
+{
+ int fd;
+
+ // If no arguments, read from stdin.
+ if (!*argv) function(0, *argv);
+ else do {
+ // Filename "-" means read from stdin.
+ // Inability to open a file prints a warning, but doesn't exit.
+
+ if (!strcmp(*argv,"-")) fd=0;
+ else if (0>(fd = open(*argv, O_RDONLY))) {
+ perror_msg("%s",*argv);
+ toys.exitval = 1;
+ }
+ function(fd, *argv);
+ close(fd);
+ } while (*++argv);
+}