From 11e44def75845365646f4453d7200b90f996e215 Mon Sep 17 00:00:00 2001
From: Tibor Bizjak <tibor.bizjak@gmail.com>
Date: Sat, 22 Jul 2023 16:09:12 +0200
Subject: [PATCH] implemented optional argument flags

---
 .../04-find/04-find-no-overflow.c             | 39 +++++++++++++++----
 .../04-find/04-find-opt.c                     |  9 +++--
 .../04-find/04-find.c                         |  9 +++--
 3 files changed, 43 insertions(+), 14 deletions(-)

diff --git a/k&r/04-funcs-and-prog-struct/04-find/04-find-no-overflow.c b/k&r/04-funcs-and-prog-struct/04-find/04-find-no-overflow.c
index 138d009..e3396cc 100644
--- a/k&r/04-funcs-and-prog-struct/04-find/04-find-no-overflow.c
+++ b/k&r/04-funcs-and-prog-struct/04-find/04-find-no-overflow.c
@@ -7,25 +7,44 @@ void println(void);
 int flush_lnbuff(void);
 int getch_lnbuff(void);
 
+
 /* find: prints lines containing pattern, returns number of matching lines
  * gracefully handle line overflow */
-int find(char *pattern)
+int find(char *pattern, char lineno_flag, char except_flag)
 {
     int found, i, c;
     const int plen = strlen(pattern);
-
+    long lineno = 1;
     i = found = 0;
+    char match = 0;
 
-    while ((c = getch_lnbuff()) != EOF)
+#define print_lineno() if (lineno_flag) printf("%ld:", lineno)
+    while ((c = getch_lnbuff()) != EOF) {
+        if (c == '\n') { /* newline */
+            if (except_flag && !match) {
+                print_lineno();
+                flush_lnbuff();
+                putchar('\n');
+            }
+            match = 0;
+            lineno++;
+        }
         if (c != pattern[i])
             i = 0;
         else if (++i == plen) { // found match
+            if (except_flag) {
+                match = 1;
+                continue;
+            }
             i = 0;
             found++;
+            print_lineno();
             flush_lnbuff();
-            println(); 
+            println(), lineno++; 
         }
+    }
     return found;
+#undef print_lineno
 }
 
 /* println: prints next line from stdin
@@ -49,7 +68,8 @@ static_assert(!(LNBUFF_LEN % 2), "Line buffer length is not a power of two!");
 struct {
     char self[LNBUFF_LEN];
     unsigned len;
-} lnbuff = {.len= 0};
+    char newline;
+} lnbuff = {.len=0, .newline=1};
 
 /* LNBUFF_I: current index in line buffer */
 #define LNBUFF_I (lnbuff.len & (LNBUFF_LEN - 1))
@@ -58,9 +78,13 @@ struct {
 int getch_lnbuff()
 {
     int c = getchar();
-    
-    if (c == EOF || c == '\n') // new line
+   
+    if (lnbuff.newline) {
         lnbuff.len = 0;
+        lnbuff.newline = 0; 
+    }
+    if (c == EOF || c == '\n') // new line
+        lnbuff.newline = 1;
     else {
         lnbuff.self[LNBUFF_I] = c;
         lnbuff.len++;
@@ -89,3 +113,4 @@ int flush_lnbuff()
     lnbuff.len = 0;
     return i;
 }
+
diff --git a/k&r/04-funcs-and-prog-struct/04-find/04-find-opt.c b/k&r/04-funcs-and-prog-struct/04-find/04-find-opt.c
index 8ebebd4..047dae4 100644
--- a/k&r/04-funcs-and-prog-struct/04-find/04-find-opt.c
+++ b/k&r/04-funcs-and-prog-struct/04-find/04-find-opt.c
@@ -7,14 +7,17 @@ int getln(char line[], int lim);
 int strindex(char source[], char searchfor[], int slen);
 
 /* find: prints lines containing pattern, returns number of matching lines */
-int find(char *pattern)
+int find(char *pattern, char lineno_flag, char except_flag)
 {
     char line[MAXLINE];
     int found = 0;
     int slen = strlen(pattern);
+    long lineno;
 
-    while (getln(line, MAXLINE) > 0)
-        if (strindex(line, pattern, slen) >= 0) {
+    for (lineno = 1; getln(line, MAXLINE) > 0; lineno++)
+        if ((strindex(line, pattern, slen) >= 0) != except_flag) {
+            if (lineno_flag)
+                printf("%ld:", lineno);
             printf("%s", line);
             found++;
         }
diff --git a/k&r/04-funcs-and-prog-struct/04-find/04-find.c b/k&r/04-funcs-and-prog-struct/04-find/04-find.c
index 276d28b..6b9d993 100644
--- a/k&r/04-funcs-and-prog-struct/04-find/04-find.c
+++ b/k&r/04-funcs-and-prog-struct/04-find/04-find.c
@@ -3,7 +3,7 @@
 /* compile with 04-find-no-overflow.c or 04-find-opt.c
  * gcc 04-find.c [04-find-no-overflow.c | 04-find-opt.c] */
 
-int find(char *pattern);
+int find(char *pattern, char lineno_flag, char except_flag);
 
 #define ARG_FLAGS X('n', lineno) X('x', except)
 
@@ -17,7 +17,7 @@ int main(int argc, char *argv[])
     char c;
 
     /* declare flag variables  */
-#define X(c, flag_var) int flag_var = 0;
+#define X(c, flag) char flag##_flag = 0;
     ARG_FLAGS
 #undef X
     char **parg = argv;
@@ -29,7 +29,7 @@ int main(int argc, char *argv[])
         }
         while (c = *++parg[0])
             switch (c) {
-        #define X(C, flag_var) case C: flag_var = 1; break;
+        #define X(C, flag) case C: flag##_flag = 1; break;
             ARG_FLAGS
         #undef X
             default: 
@@ -40,6 +40,7 @@ int main(int argc, char *argv[])
         --argc;
     }
 
+    /* illegal arguments */
     if (argc != 2) {
         printf("usage: find ");
     #define X(c, _) printf("[-%c] ", c);
@@ -57,6 +58,6 @@ int main(int argc, char *argv[])
             return -2;
         }
 
-    int found = find(pattern);
+    int found = find(pattern, lineno_flag, except_flag);
     return found;
 }