Improve performance of search in the list of the magic strings.

JerryScript-DCO-1.0-Signed-off-by: Robert Sipka [email protected]

Author: robertsipka

jerry-core/lit/lit-magic-strings.c

@@ -145,22 +145,52 @@ lit_is_utf8_string_magic (const lit_utf8_byte_t *string_p, /**< utf-8 string */
                           lit_utf8_size_t string_size, /**< string size in bytes */
                           lit_magic_string_id_t *out_id_p) /**< [out] magic string's id */
 {
-  /* TODO: Improve performance of search */
+  static const lit_utf8_byte_t * const magic_strings[] JERRY_CONST_DATA =
+  {
+#define LIT_MAGIC_STRING_DEF(id, utf8_string) \
+    (const lit_utf8_byte_t *) utf8_string,
+#include "lit-magic-strings.inc.h"
+#undef LIT_MAGIC_STRING_DEF
+  };
 
-  for (lit_magic_string_id_t id = (lit_magic_string_id_t) 0;
-       id < LIT_MAGIC_STRING__COUNT;
-       id = (lit_magic_string_id_t) (id + 1))
+  *out_id_p = LIT_MAGIC_STRING__COUNT;
+
+  int first = 0; /**< First magic string element */
+  int last = (int) (LIT_MAGIC_STRING__COUNT - 1); /**< Last magic string element */
+  int middle; /**< mid point of search */
+
+  while (first <= last)
   {
-    if (lit_compare_utf8_string_and_magic_string (string_p, string_size, id))
-    {
-      *out_id_p = id;
+    middle = ((first + last) / 2);
 
-      return true;
+    int compare = memcmp (magic_strings[middle], string_p, string_size);
+    if (compare == 0)
+    {
+      lit_utf8_size_t id_size = lit_zt_utf8_string_size (magic_strings[middle]);
+      if (id_size == string_size)
+      {
+        *out_id_p = (lit_magic_string_id_t) middle;
+        return true;
+      }
+      else if (id_size > string_size)
+      {
+        last = middle -1;
+      }
+      else
+      {
+        return false;
+      }
+    }
+    else if (compare > 0)
+    {
+      last = middle - 1;
+    }
+    else
+    {
+      first = middle + 1;
     }
   }
 
-  *out_id_p = LIT_MAGIC_STRING__COUNT;
-
   return false;
 } /* lit_is_utf8_string_magic */
 
@@ -194,22 +224,6 @@ bool lit_is_ex_utf8_string_magic (const lit_utf8_byte_t *string_p, /**< utf-8 st
   return false;
 } /* lit_is_ex_utf8_string_magic */
 
-/**
- * Compare utf-8 string and magic string for equality
- *
- * @return true if strings are equal
- *         false otherwise
- */
-bool
-lit_compare_utf8_string_and_magic_string (const lit_utf8_byte_t *string_p, /**< utf-8 string */
-                                          lit_utf8_size_t string_size, /**< string size in bytes */
-                                          lit_magic_string_id_t magic_string_id) /**< magic string's id */
-{
-  return lit_compare_utf8_strings (string_p,
-                                   string_size,
-                                   lit_get_magic_string_utf8 (magic_string_id),
-                                   lit_get_magic_string_size (magic_string_id));
-} /* lit_compare_utf8_string_and_magic_string */
 
 /**
  * Compare utf-8 string and external magic string for equality

jerry-core/lit/lit-magic-strings.h

@@ -52,10 +52,8 @@ extern lit_utf8_size_t lit_get_magic_string_ex_size (lit_magic_string_ex_id_t);
 extern void lit_magic_strings_ex_set (const lit_utf8_byte_t **, uint32_t, const lit_utf8_size_t *);
 
 extern bool lit_is_utf8_string_magic (const lit_utf8_byte_t *, lit_utf8_size_t, lit_magic_string_id_t *);
-extern bool lit_is_ex_utf8_string_magic (const lit_utf8_byte_t *, lit_utf8_size_t, lit_magic_string_ex_id_t *);
 
-extern bool lit_compare_utf8_string_and_magic_string (const lit_utf8_byte_t *, lit_utf8_size_t,
-                                                      lit_magic_string_id_t);
+extern bool lit_is_ex_utf8_string_magic (const lit_utf8_byte_t *, lit_utf8_size_t, lit_magic_string_ex_id_t *);
 
 extern bool lit_compare_utf8_string_and_magic_string_ex (const lit_utf8_byte_t *, lit_utf8_size_t,
                                                          lit_magic_string_ex_id_t);