CE Implement line editing

libstring/string.c

@@ -118,3 +118,25 @@ int isxdigit (int c) { return isdigit (c) || (c >= 'A' && c <= 'F') || (c >= 'a'
 int isascii (int c) { return (c >= 0 && c <= 127); }
 
 int isblank (int c) { return (c == ' ' || c == '\t'); }
+
+/* SOURCE: https://aticleworld.com/memmove-function-implementation-in-c/ */
+void* memmove (void* dest, const void* src, unsigned int n) {
+  unsigned char isCopyRequire = 0; // flag bit
+  char* pcSource = (char*)src;
+  char* pcDstn = (char*)dest;
+  // return if pcDstn and pcSource is NULL
+  if ((pcSource == NULL) || (pcDstn == NULL)) {
+    return NULL;
+  }
+  // overlap buffer
+  if ((pcSource < pcDstn) && (pcDstn < pcSource + n)) {
+    for (pcDstn += n, pcSource += n; n--;) {
+      *--pcDstn = *--pcSource;
+    }
+  } else {
+    while (n--) {
+      *pcDstn++ = *pcSource++;
+    }
+  }
+  return dest;
+}