add wc.c

user/wc.c

@@ -0,0 +1,54 @@
+#include "kernel/types.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+
+char buf[512];
+
+void
+wc(int fd, char *name)
+{
+  int i, n;
+  int l, w, c, inword;
+
+  l = w = c = 0;
+  inword = 0;
+  while((n = read(fd, buf, sizeof(buf))) > 0){
+    for(i=0; i<n; i++){
+      c++;
+      if(buf[i] == '\n')
+        l++;
+      if(strchr(" \r\t\n\v", buf[i]))
+        inword = 0;
+      else if(!inword){
+        w++;
+        inword = 1;
+      }
+    }
+  }
+  if(n < 0){
+    printf("wc: read error\n");
+    exit(1);
+  }
+  printf("%d %d %d %s\n", l, w, c, name);
+}
+
+int
+main(int argc, char *argv[])
+{
+  int fd, i;
+
+  if(argc <= 1){
+    wc(0, "");
+    exit(0);
+  }
+
+  for(i = 1; i < argc; i++){
+    if((fd = open(argv[i], 0)) < 0){
+      printf("wc: cannot open %s\n", argv[i]);
+      exit(1);
+    }
+    wc(fd, argv[i]);
+    close(fd);
+  }
+  exit(0);
+}