From 8ebefb29746e8ebbb891408f5e34e50962273991 Mon Sep 17 00:00:00 2001
From: Tibor Bizjak <tibor.bizjak@gmail.com>
Date: Sun, 23 Jul 2023 14:04:29 +0200
Subject: [PATCH] changed find loop

---
 .../04-find/find-no-overflow.c                | 20 ++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/k&r/04-funcs-and-prog-struct/04-find/find-no-overflow.c b/k&r/04-funcs-and-prog-struct/04-find/find-no-overflow.c
index 8ac1245..d3d3e89 100644
--- a/k&r/04-funcs-and-prog-struct/04-find/find-no-overflow.c
+++ b/k&r/04-funcs-and-prog-struct/04-find/find-no-overflow.c
@@ -9,25 +9,31 @@ void ignoreln_lnbuff(void);
 /* find: prints lines containing pattern, returns number of matching lines
  * gracefully handle line overflow 
  * compile with -O3 */
-int find(char *pattern, char lineno_flag, char except_flag)
+int find(const char *pattern, char lineno_flag, char except_flag)
 {
 
     extern long lineno;
-    int i, c, found;
-    const int plen = strlen(pattern);
-    i = found = 0;
+    int c, found = 0;
+    const char * const pstart = pattern;
 
     while ((c = getch_lnbuff()) != EOF) {
-        i = (c == pattern[i]) ? i+1 : 0;
+        if (c == *pattern) {
+            pattern++;
+            continue; 
+        }
 
-        if (except_flag && i == plen)
+        char match = !*pattern - (c == '\n');
+        match *= except_flag ? -1 : 1;
+
+        if (match < 0 && except_flag) // no match
             ignoreln_lnbuff();
-        else if (except_flag ? c == '\n' : i == plen) { // match
+        else if (match > 0) { // match
             found++;
             if (lineno_flag)
                 printf("%ld:", lineno);
             flush_lnbuff();
         }
+        pattern = pstart;
     }
 
     return found;