Add strcasecmp() to string.h

ncc/examples/mini_bbs.c

@@ -352,16 +352,12 @@ void on_incoming_data(u64 socket_id, u64 num_bytes)
 
     if (p_user->state == STATE_WRITE_MSG)
     {
-        bool done = (
-            strcmp(read_buf, "Done\n") == 0     ||
-            strcmp(read_buf, "Done\r\n") == 0   ||
-            strcmp(read_buf, "done\n") == 0     ||
-            strcmp(read_buf, "done\r\n") == 0
-        );
+        // Strip trailing whitespace from the buffer
+        rstrip_ws(read_buf);
 
-        if (done)
+        if (strcasecmp(read_buf, "done") == 0)
         {
-            // Strip trailing whitespace
+            // Strip trailing whitespace in the message buffer
             rstrip_ws(p_user->msg_buf);
 
             // If this is an empty message, do nothing
@@ -386,9 +382,13 @@ void on_incoming_data(u64 socket_id, u64 num_bytes)
             return;
         }
 
+        // Add back a newline on the message buffer because
+        // we stripped whitespace earlier
+        strncat(p_user->msg_buf, "\n", 1);
+
+        // Append new line to the user's message buffer
         size_t msg_len = strlen(p_user->msg_buf);
         size_t len = strlen(read_buf);
-
         size_t max_chars = MAX_MSG_LEN - 1 - msg_len;
         strncat(p_user->msg_buf, read_buf, max_chars);
 

ncc/include/string.h

@@ -2,6 +2,7 @@
 #define __STRING_H__
 
 #include <stddef.h>
+#include <ctype.h>
 
 #ifndef memcpy
 #define memcpy(dst, src, num_bytes) asm (dst, src, num_bytes) -> void { syscall memcpy; }
@@ -37,6 +38,27 @@ int strcmp(char* a, char* b)
     return 0;
 }
 
+// Perform case-insensitive string comparison
+// This function is non-standard, but offered by many compilers.
+int strcasecmp(char* a, char* b)
+{
+    for (size_t i = 0;; ++i)
+    {
+        char ch_a = tolower(a[i]);
+        char ch_b = tolower(b[i]);
+
+        if (ch_a < ch_b)
+            return -1;
+        else if (ch_a > ch_b)
+            return 1;
+
+        if (ch_a == 0)
+            break;
+    }
+
+    return 0;
+}
+
 int strncmp(char* a, char* b, size_t num)
 {
     for (size_t i = 0; i < num; ++i)