allow line editing via arrow keys in chat/groupchat windows

src/misc_tools.c

@@ -8,6 +8,7 @@
 #include <limits.h>
 
 #include "toxic_windows.h"
+#include "misc_tools.h"
 
 // XXX: FIX
 unsigned char *hex_string_to_bin(char hex_string[])
@@ -158,3 +159,62 @@ bool valid_nick(uint8_t *nick)
 
     return true;
 }
+
+/*
+ * Buffer helper tools. Assumes buffers are no larger than MAX_STR_SIZE
+ */
+
+/* Adds char to buffer at pos */
+void add_char_to_buf(wint_t ch, wchar_t *buf, size_t *pos, size_t *len)
+{
+    if (*pos < 0 || *len >= MAX_STR_SIZE)
+        return;
+
+    /* if cursor is at end of line simply insert char at last position and increment */
+    if (buf[*pos] == L'\0') {
+        buf[(*pos)++] = ch;
+        buf[*pos] = L'\0';
+        ++(*len);
+        return;
+    }
+
+    /* move all chars in front of pos one space forward and insert char in pos */
+    int i;
+
+    for (i = *len; i >= *pos && i >= 0; --i)
+        buf[i+1] = buf[i];
+
+    buf[(*pos)++] = ch;
+    ++(*len);
+}
+
+/* Deletes the character before pos via the backspace key */
+void del_char_from_buf(wint_t ch, wchar_t *buf, size_t *pos, size_t *len)
+{
+    if (*pos <= 0)
+        return;
+
+    /* if cursor is at end of line delete previous char */
+    if (buf[*pos] == L'\0') {
+        buf[--(*pos)] = L'\0';
+        --(*len);
+        return;
+    }
+
+    int i;
+
+    /* similar to add_char_to_buf but deletes a char */
+    for (i = *pos-1; i <= *len; ++i)
+        buf[i] = buf[i+1];
+
+    --(*pos);
+    --(*len);
+}
+
+/* sets pos and len to 0 */
+void reset_buf(wchar_t *buf, size_t *pos, size_t *len)
+{
+    buf[0] = L'\0';
+    *pos = 0;
+    *len = 0;
+}