From c98cb65373ad83a01d0ccbe25996b1edaf68fd93 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A1szl=C3=B3=20Lang=C3=B3?=
 <llango.u-szeged@partner.samsung.com>
Date: Thu, 31 Mar 2016 10:17:50 +0200
Subject: [PATCH] Use 'const' in string iterations.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

JerryScript-DCO-1.0-Signed-off-by: László Langó llango.u-szeged@partner.samsung.com
---
 .../ecma/base/ecma-helpers-conversion.c       |  2 +-
 .../ecma/builtin-objects/ecma-builtin-date.c  |  4 +-
 .../builtin-objects/ecma-builtin-global.c     | 22 ++++-----
 .../builtin-objects/ecma-builtin-helpers.c    |  8 ++--
 .../ecma/builtin-objects/ecma-builtin-json.c  |  2 +-
 .../ecma-builtin-string-prototype.c           |  4 +-
 jerry-core/ecma/operations/ecma-eval.c        |  1 +
 .../ecma/operations/ecma-regexp-object.c      | 46 +++++++++----------
 .../ecma/operations/ecma-regexp-object.h      |  2 +-
 jerry-core/lit/lit-char-helpers.c             |  2 +-
 jerry-core/lit/lit-char-helpers.h             |  2 +-
 jerry-core/lit/lit-strings.c                  | 19 ++++----
 jerry-core/lit/lit-strings.h                  |  9 ++--
 jerry-core/parser/regexp/re-parser.c          |  4 +-
 jerry-core/parser/regexp/re-parser.h          |  2 +-
 tests/unit/test-strings.c                     |  7 +--
 16 files changed, 70 insertions(+), 66 deletions(-)

diff --git a/jerry-core/ecma/base/ecma-helpers-conversion.c b/jerry-core/ecma/base/ecma-helpers-conversion.c
index 158446863..2ee12a037 100644
--- a/jerry-core/ecma/base/ecma-helpers-conversion.c
+++ b/jerry-core/ecma/base/ecma-helpers-conversion.c
@@ -355,7 +355,7 @@ ecma_utf8_string_to_number (const lit_utf8_byte_t *str_p, /**< utf-8 string */
     return ECMA_NUMBER_ZERO;
   }
 
-  lit_utf8_byte_t *str_curr_p = (lit_utf8_byte_t *) str_p;
+  const lit_utf8_byte_t *str_curr_p = str_p;
   const lit_utf8_byte_t *str_end_p = str_p + str_size;
   ecma_char_t code_unit;
 
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-date.c b/jerry-core/ecma/builtin-objects/ecma-builtin-date.c
index 846ae66c5..e7d3eaedf 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-date.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-date.c
@@ -53,7 +53,7 @@
  * @return NaN if cannot read from string, ToNumber() otherwise
  */
 static ecma_number_t
-ecma_date_parse_date_chars (lit_utf8_byte_t **str_p, /**< pointer to the cesu8 string */
+ecma_date_parse_date_chars (const lit_utf8_byte_t **str_p, /**< pointer to the cesu8 string */
                             const lit_utf8_byte_t *str_end_p, /**< pointer to the end of the string */
                             uint32_t num_of_chars) /**< number of characters to read and convert */
 {
@@ -207,7 +207,7 @@ ecma_builtin_date_parse (ecma_value_t this_arg __attr_unused___, /**< this argum
 
   ECMA_STRING_TO_UTF8_STRING (date_str_p, date_start_p, date_start_size);
 
-  lit_utf8_byte_t *date_str_curr_p = (lit_utf8_byte_t *) date_start_p;
+  const lit_utf8_byte_t *date_str_curr_p = date_start_p;
   const lit_utf8_byte_t *date_str_end_p = date_start_p + date_start_size;
 
   /* 1. read year */
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-global.c b/jerry-core/ecma/builtin-objects/ecma-builtin-global.c
index 2d913d718..fad9a4bfd 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-global.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-global.c
@@ -88,7 +88,7 @@ ecma_builtin_global_object_print (ecma_value_t this_arg __attr_unused___, /**< t
     lit_utf8_size_t actual_sz = ecma_string_to_utf8_string (str_p, utf8_str_p, utf8_str_size);
     JERRY_ASSERT (actual_sz == utf8_str_size);
 
-    lit_utf8_byte_t *utf8_str_curr_p = utf8_str_p;
+    const lit_utf8_byte_t *utf8_str_curr_p = utf8_str_p;
     const lit_utf8_byte_t *utf8_str_end_p = utf8_str_p + utf8_str_size;
 
     while (utf8_str_curr_p < utf8_str_end_p)
@@ -207,13 +207,13 @@ ecma_builtin_global_object_parse_int (ecma_value_t this_arg __attr_unused___, /*
 
   if (string_buff_size > 0)
   {
-    lit_utf8_byte_t *string_curr_p = (lit_utf8_byte_t *) string_buff;
+    const lit_utf8_byte_t *string_curr_p = (lit_utf8_byte_t *) string_buff;
     const lit_utf8_byte_t *string_end_p = string_buff + string_buff_size;
 
     /* 2. Remove leading whitespace. */
 
-    lit_utf8_byte_t *start_p = (lit_utf8_byte_t *) string_end_p;
-    lit_utf8_byte_t *end_p = start_p;
+    const lit_utf8_byte_t *start_p = string_end_p;
+    const lit_utf8_byte_t *end_p = start_p;
 
     while (string_curr_p < string_end_p)
     {
@@ -426,11 +426,11 @@ ecma_builtin_global_object_parse_float (ecma_value_t this_arg __attr_unused___,
 
   if (string_buff_size > 0)
   {
-    lit_utf8_byte_t *str_curr_p = (lit_utf8_byte_t *) string_buff;
+    const lit_utf8_byte_t *str_curr_p = string_buff;
     const lit_utf8_byte_t *str_end_p = string_buff + string_buff_size;
 
-    lit_utf8_byte_t *start_p = (lit_utf8_byte_t *) str_end_p;
-    lit_utf8_byte_t *end_p = (lit_utf8_byte_t *) str_end_p;
+    const lit_utf8_byte_t *start_p = str_end_p;
+    const lit_utf8_byte_t *end_p = str_end_p;
 
     /* 2. Find first non whitespace char and set starting position. */
     while (str_curr_p < str_end_p)
@@ -1263,8 +1263,8 @@ ecma_builtin_global_object_escape (ecma_value_t this_arg __attr_unused___, /**<
    * The escape routine has two major phases: first we compute
    * the length of the output, then we encode the input.
    */
-  lit_utf8_byte_t *input_curr_p = input_start_p;
-  lit_utf8_byte_t *input_end_p = input_start_p + input_size;
+  const lit_utf8_byte_t *input_curr_p = input_start_p;
+  const lit_utf8_byte_t *input_end_p = input_start_p + input_size;
   lit_utf8_size_t output_length = 0;
 
   while (input_curr_p < input_end_p)
@@ -1377,8 +1377,8 @@ ecma_builtin_global_object_unescape (ecma_value_t this_arg __attr_unused___, /**
   lit_utf8_size_t sz = ecma_string_to_utf8_string (input_string_p, input_start_p, input_size);
   JERRY_ASSERT (sz == input_size);
 
-  lit_utf8_byte_t *input_curr_p = input_start_p;
-  lit_utf8_byte_t *input_end_p = input_start_p + input_size;
+  const lit_utf8_byte_t *input_curr_p = input_start_p;
+  const lit_utf8_byte_t *input_end_p = input_start_p + input_size;
   /* 4. */
   /* The length of input string is always greater than output string
    * so we re-use the input string buffer.
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c
index 8915396f4..56e66e5fa 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c
@@ -582,7 +582,7 @@ ecma_builtin_helper_string_find_index (ecma_string_t *original_str_p, /**< index
 
       ecma_length_t index = start_pos;
 
-      lit_utf8_byte_t *original_str_curr_p = (lit_utf8_byte_t *) original_str_utf8_p;
+      const lit_utf8_byte_t *original_str_curr_p = original_str_utf8_p;
       for (ecma_length_t idx = 0; idx < index; idx++)
       {
         lit_utf8_incr (&original_str_curr_p);
@@ -591,7 +591,7 @@ ecma_builtin_helper_string_find_index (ecma_string_t *original_str_p, /**< index
       /* create utf8 string from search string */
       ECMA_STRING_TO_UTF8_STRING (search_str_p, search_str_utf8_p, search_str_size);
 
-      lit_utf8_byte_t *search_str_curr_p = (lit_utf8_byte_t *) search_str_utf8_p;
+      const lit_utf8_byte_t *search_str_curr_p = search_str_utf8_p;
 
       /* iterate original string and try to match at each position */
       bool searching = true;
@@ -600,13 +600,13 @@ ecma_builtin_helper_string_find_index (ecma_string_t *original_str_p, /**< index
       {
         /* match as long as possible */
         ecma_length_t match_len = 0;
-        lit_utf8_byte_t *stored_original_str_curr_p = original_str_curr_p;
+        const lit_utf8_byte_t *stored_original_str_curr_p = original_str_curr_p;
 
         if (match_len < search_len &&
             index + match_len < original_len &&
             lit_utf8_read_next (&original_str_curr_p) == first_char)
         {
-          lit_utf8_byte_t *nested_search_str_curr_p = search_str_curr_p;
+          const lit_utf8_byte_t *nested_search_str_curr_p = search_str_curr_p;
           match_len++;
 
           while (match_len < search_len &&
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-json.c b/jerry-core/ecma/builtin-objects/ecma-builtin-json.c
index cfc88bbcc..32d55f834 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-json.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-json.c
@@ -1059,7 +1059,7 @@ ecma_builtin_json_quote (ecma_string_t *string_p) /**< string that should be quo
 
   ECMA_STRING_TO_UTF8_STRING (string_p, string_buff, string_buff_size);
 
-  lit_utf8_byte_t *str_p = (lit_utf8_byte_t *) string_buff;
+  const lit_utf8_byte_t *str_p = string_buff;
   const lit_utf8_byte_t *str_end_p = string_buff + string_buff_size;
 
   while (str_p < str_end_p)
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c b/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c
index 98f426b13..e88b8676c 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c
@@ -2074,7 +2074,7 @@ ecma_builtin_string_prototype_object_conversion_helper (ecma_value_t this_arg, /
    */
 
   lit_utf8_size_t output_length = 0;
-  lit_utf8_byte_t *input_str_curr_p = (lit_utf8_byte_t *) input_start_p;
+  const lit_utf8_byte_t *input_str_curr_p = input_start_p;
   const lit_utf8_byte_t *input_str_end_p = input_start_p + input_start_size;
 
   while (input_str_curr_p < input_str_end_p)
@@ -2114,7 +2114,7 @@ ecma_builtin_string_prototype_object_conversion_helper (ecma_value_t this_arg, /
   lit_utf8_byte_t *output_char_p = output_start_p;
 
   /* Encoding the output. */
-  input_str_curr_p = (lit_utf8_byte_t *) input_start_p;
+  input_str_curr_p = input_start_p;
 
   while (input_str_curr_p < input_str_end_p)
   {
diff --git a/jerry-core/ecma/operations/ecma-eval.c b/jerry-core/ecma/operations/ecma-eval.c
index 0e7f12c98..a1975a877 100644
--- a/jerry-core/ecma/operations/ecma-eval.c
+++ b/jerry-core/ecma/operations/ecma-eval.c
@@ -1,4 +1,5 @@
 /* Copyright 2015-2016 Samsung Electronics Co., Ltd.
+ * Copyright 2016 University of Szeged.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
diff --git a/jerry-core/ecma/operations/ecma-regexp-object.c b/jerry-core/ecma/operations/ecma-regexp-object.c
index 6e2cab6af..037334ede 100644
--- a/jerry-core/ecma/operations/ecma-regexp-object.c
+++ b/jerry-core/ecma/operations/ecma-regexp-object.c
@@ -380,13 +380,13 @@ re_canonicalize (ecma_char_t ch, /**< character */
 static ecma_value_t
 re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
                  uint8_t *bc_p, /**< pointer to the current RegExp bytecode */
-                 lit_utf8_byte_t *str_p, /**< input string pointer */
-                 lit_utf8_byte_t **out_str_p) /**< [out] matching substring iterator */
+                 const lit_utf8_byte_t *str_p, /**< input string pointer */
+                 const lit_utf8_byte_t **out_str_p) /**< [out] matching substring iterator */
 {
   ecma_value_t ret_value = ecma_make_simple_value (ECMA_SIMPLE_VALUE_EMPTY);
   re_opcode_t op;
 
-  lit_utf8_byte_t *str_curr_p = str_p;
+  const lit_utf8_byte_t *str_curr_p = str_p;
 
   while ((op = re_get_opcode (&bc_p)))
   {
@@ -541,7 +541,7 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
       case RE_OP_LOOKAHEAD_NEG:
       {
         ecma_value_t match_value = ecma_make_simple_value (ECMA_SIMPLE_VALUE_EMPTY);
-        lit_utf8_byte_t *sub_str_p = NULL;
+        const lit_utf8_byte_t *sub_str_p = NULL;
 
         uint32_t array_size = re_ctx_p->num_of_captures + re_ctx_p->num_of_non_captures;
         MEM_DEFINE_LOCAL_ARRAY (saved_bck_p, array_size, lit_utf8_byte_t *);
@@ -668,7 +668,7 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
           break; /* capture is 'undefined', always matches! */
         }
 
-        lit_utf8_byte_t *sub_str_p = re_ctx_p->saved_p[backref_idx];
+        const lit_utf8_byte_t *sub_str_p = re_ctx_p->saved_p[backref_idx];
 
         while (sub_str_p < re_ctx_p->saved_p[backref_idx + 1])
         {
@@ -697,13 +697,13 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
         uint8_t *old_bc_p;
 
         JERRY_DDLOG ("Execute RE_OP_SAVE_AT_START\n");
-        lit_utf8_byte_t *old_start_p = re_ctx_p->saved_p[RE_GLOBAL_START_IDX];
+        const lit_utf8_byte_t *old_start_p = re_ctx_p->saved_p[RE_GLOBAL_START_IDX];
         re_ctx_p->saved_p[RE_GLOBAL_START_IDX] = str_curr_p;
 
         do
         {
           uint32_t offset = re_get_value (&bc_p);
-          lit_utf8_byte_t *sub_str_p = NULL;
+          const lit_utf8_byte_t *sub_str_p = NULL;
           ecma_value_t match_value = re_match_regexp (re_ctx_p, bc_p, str_curr_p, &sub_str_p);
 
           if (ecma_is_value_true (match_value))
@@ -760,8 +760,8 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
         *  after the group first, if zero iteration is allowed.
         */
         uint32_t start_idx, iter_idx, offset;
-        lit_utf8_byte_t *old_start_p = NULL;
-        lit_utf8_byte_t *sub_str_p = NULL;
+        const lit_utf8_byte_t *old_start_p = NULL;
+        const lit_utf8_byte_t *sub_str_p = NULL;
         uint8_t *old_bc_p;
 
         old_bc_p = bc_p; /* save the bytecode start position of the group start */
@@ -814,7 +814,7 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
       case RE_OP_NON_CAPTURE_GREEDY_ZERO_GROUP_START:
       {
         uint32_t start_idx, iter_idx, old_iteration_cnt, offset;
-        lit_utf8_byte_t *sub_str_p = NULL;
+        const lit_utf8_byte_t *sub_str_p = NULL;
         uint8_t *old_bc_p;
         uint8_t *end_bc_p = NULL;
         start_idx = re_get_value (&bc_p);
@@ -839,7 +839,7 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
           start_idx += re_ctx_p->num_of_captures;
         }
 
-        lit_utf8_byte_t *old_start_p = re_ctx_p->saved_p[start_idx];
+        const lit_utf8_byte_t *old_start_p = re_ctx_p->saved_p[start_idx];
         old_iteration_cnt = re_ctx_p->num_of_iterations_p[iter_idx];
         re_ctx_p->saved_p[start_idx] = str_curr_p;
         re_ctx_p->num_of_iterations_p[iter_idx] = 0;
@@ -921,10 +921,10 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
         if (re_ctx_p->num_of_iterations_p[iter_idx] >= min
             && re_ctx_p->num_of_iterations_p[iter_idx] <= max)
         {
-          lit_utf8_byte_t *old_end_p = re_ctx_p->saved_p[end_idx];
+          const lit_utf8_byte_t *old_end_p = re_ctx_p->saved_p[end_idx];
           re_ctx_p->saved_p[end_idx] = str_curr_p;
 
-          lit_utf8_byte_t *sub_str_p = NULL;
+          const lit_utf8_byte_t *sub_str_p = NULL;
           ecma_value_t match_value = re_match_regexp (re_ctx_p, bc_p, str_curr_p, &sub_str_p);
 
           if (ecma_is_value_true (match_value))
@@ -949,9 +949,9 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
       case RE_OP_NON_CAPTURE_GREEDY_GROUP_END:
       {
         uint32_t start_idx, end_idx, iter_idx, min, max, offset;
-        lit_utf8_byte_t *old_start_p = NULL;
-        lit_utf8_byte_t *old_end_p = NULL;
-        lit_utf8_byte_t *sub_str_p = NULL;
+        const lit_utf8_byte_t *old_start_p = NULL;
+        const lit_utf8_byte_t *old_end_p = NULL;
+        const lit_utf8_byte_t *sub_str_p = NULL;
         uint8_t *old_bc_p;
 
         end_idx = re_get_value (&bc_p);
@@ -1060,7 +1060,7 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
       case RE_OP_NON_GREEDY_ITERATOR:
       {
         uint32_t min, max, offset, num_of_iter;
-        lit_utf8_byte_t *sub_str_p = NULL;
+        const lit_utf8_byte_t *sub_str_p = NULL;
 
         min = re_get_value (&bc_p);
         max = re_get_value (&bc_p);
@@ -1107,7 +1107,7 @@ re_match_regexp (re_matcher_ctx_t *re_ctx_p, /**< RegExp matcher context */
       case RE_OP_GREEDY_ITERATOR:
       {
         uint32_t min, max, offset, num_of_iter;
-        lit_utf8_byte_t *sub_str_p = NULL;
+        const lit_utf8_byte_t *sub_str_p = NULL;
 
         min = re_get_value (&bc_p);
         max = re_get_value (&bc_p);
@@ -1271,18 +1271,18 @@ ecma_regexp_exec_helper (ecma_value_t regexp_value, /**< RegExp object */
   }
 
   re_matcher_ctx_t re_ctx;
-  lit_utf8_byte_t *input_curr_p = NULL;
+  const lit_utf8_byte_t *input_curr_p = NULL;
 
   ecma_string_t *input_string_p = ecma_get_string_from_value (input_string);
   ECMA_STRING_TO_UTF8_STRING (input_string_p, input_buffer_p, input_buffer_size);
 
   if (input_buffer_size == 0u)
   {
-    input_curr_p = (lit_utf8_byte_t *) lit_get_magic_string_utf8 (LIT_MAGIC_STRING__EMPTY);
+    input_curr_p = lit_get_magic_string_utf8 (LIT_MAGIC_STRING__EMPTY);
   }
   else
   {
-    input_curr_p = (lit_utf8_byte_t *) input_buffer_p;
+    input_curr_p = input_buffer_p;
   }
 
   re_ctx.input_start_p = input_curr_p;
@@ -1306,7 +1306,7 @@ ecma_regexp_exec_helper (ecma_value_t regexp_value, /**< RegExp object */
   JERRY_ASSERT (re_ctx.num_of_captures % 2 == 0);
   re_ctx.num_of_non_captures = bc_p->num_of_non_captures;
 
-  MEM_DEFINE_LOCAL_ARRAY (saved_p, re_ctx.num_of_captures + re_ctx.num_of_non_captures, lit_utf8_byte_t *);
+  MEM_DEFINE_LOCAL_ARRAY (saved_p, re_ctx.num_of_captures + re_ctx.num_of_non_captures, const lit_utf8_byte_t *);
 
   for (uint32_t i = 0; i < re_ctx.num_of_captures + re_ctx.num_of_non_captures; i++)
   {
@@ -1356,7 +1356,7 @@ ecma_regexp_exec_helper (ecma_value_t regexp_value, /**< RegExp object */
   }
 
   /* 2. Try to match */
-  lit_utf8_byte_t *sub_str_p = NULL;
+  const lit_utf8_byte_t *sub_str_p = NULL;
   uint8_t *bc_start_p = (uint8_t *) (bc_p + 1);
 
   while (ecma_is_value_empty (ret_value))
diff --git a/jerry-core/ecma/operations/ecma-regexp-object.h b/jerry-core/ecma/operations/ecma-regexp-object.h
index 9443dbe58..274366515 100644
--- a/jerry-core/ecma/operations/ecma-regexp-object.h
+++ b/jerry-core/ecma/operations/ecma-regexp-object.h
@@ -44,7 +44,7 @@ typedef enum
  */
 typedef struct
 {
-  lit_utf8_byte_t **saved_p;            /**< saved result string pointers, ECMA 262 v5, 15.10.2.1, State */
+  const lit_utf8_byte_t **saved_p;      /**< saved result string pointers, ECMA 262 v5, 15.10.2.1, State */
   const lit_utf8_byte_t *input_start_p; /**< start of input pattern string */
   const lit_utf8_byte_t *input_end_p;   /**< end of input pattern string */
   uint32_t num_of_captures;             /**< number of capture groups */
diff --git a/jerry-core/lit/lit-char-helpers.c b/jerry-core/lit/lit-char-helpers.c
index d82343c9c..0ca179415 100644
--- a/jerry-core/lit/lit-char-helpers.c
+++ b/jerry-core/lit/lit-char-helpers.c
@@ -290,7 +290,7 @@ lit_char_hex_to_int (ecma_char_t c) /**< code unit, corresponding to
  * @return true if decoding was successful, false otherwise
  */
 bool
-lit_read_code_unit_from_hex (lit_utf8_byte_t *buf_p, /**< buffer with characters */
+lit_read_code_unit_from_hex (const lit_utf8_byte_t *buf_p, /**< buffer with characters */
                              lit_utf8_size_t number_of_characters, /**< number of characters to be read */
                              ecma_char_ptr_t out_code_unit_p) /**< [out] decoded result */
 {
diff --git a/jerry-core/lit/lit-char-helpers.h b/jerry-core/lit/lit-char-helpers.h
index 779293553..5a44b3af6 100644
--- a/jerry-core/lit/lit-char-helpers.h
+++ b/jerry-core/lit/lit-char-helpers.h
@@ -216,7 +216,7 @@ extern bool lit_char_is_hex_digit (ecma_char_t);
 extern uint32_t lit_char_hex_to_int (ecma_char_t);
 
 /* read a hex encoded code point from a zero terminated buffer */
-bool lit_read_code_unit_from_hex (lit_utf8_byte_t *, lit_utf8_size_t, ecma_char_ptr_t);
+bool lit_read_code_unit_from_hex (const lit_utf8_byte_t *, lit_utf8_size_t, ecma_char_ptr_t);
 
 /**
  * Null character
diff --git a/jerry-core/lit/lit-strings.c b/jerry-core/lit/lit-strings.c
index 5a8bc893a..29ed3ccba 100644
--- a/jerry-core/lit/lit-strings.c
+++ b/jerry-core/lit/lit-strings.c
@@ -1,4 +1,5 @@
 /* Copyright 2015-2016 Samsung Electronics Co., Ltd.
+ * Copyright 2016 University of Szeged.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -591,10 +592,8 @@ lit_read_prev_code_unit_from_utf8 (const lit_utf8_byte_t *buf_p, /**< buffer wit
 {
   JERRY_ASSERT (buf_p);
 
-  lit_utf8_byte_t *current_p = (lit_utf8_byte_t *) buf_p;
-
-  lit_utf8_decr (&current_p);
-  return lit_read_code_unit_from_utf8 (current_p, code_point);
+  lit_utf8_decr (&buf_p);
+  return lit_read_code_unit_from_utf8 (buf_p, code_point);
 } /* lit_read_prev_code_unit_from_utf8 */
 
 /**
@@ -603,7 +602,7 @@ lit_read_prev_code_unit_from_utf8 (const lit_utf8_byte_t *buf_p, /**< buffer wit
  * @return next code unit
  */
 ecma_char_t
-lit_utf8_read_next (lit_utf8_byte_t **buf_p) /**< [in,out] buffer with characters */
+lit_utf8_read_next (const lit_utf8_byte_t **buf_p) /**< [in,out] buffer with characters */
 {
   JERRY_ASSERT (*buf_p);
   ecma_char_t ch;
@@ -619,7 +618,7 @@ lit_utf8_read_next (lit_utf8_byte_t **buf_p) /**< [in,out] buffer with character
  * @return previous code unit
  */
 ecma_char_t
-lit_utf8_read_prev (lit_utf8_byte_t **buf_p) /**< [in,out] buffer with characters */
+lit_utf8_read_prev (const lit_utf8_byte_t **buf_p) /**< [in,out] buffer with characters */
 {
   JERRY_ASSERT (*buf_p);
   ecma_char_t ch;
@@ -666,7 +665,7 @@ lit_utf8_peek_prev (const lit_utf8_byte_t *buf_p) /**< [in,out] buffer with char
  * Increase cesu-8 encoded string pointer by one code unit.
  */
 void
-lit_utf8_incr (lit_utf8_byte_t **buf_p) /**< [in,out] buffer with characters */
+lit_utf8_incr (const lit_utf8_byte_t **buf_p) /**< [in,out] buffer with characters */
 {
   JERRY_ASSERT (*buf_p);
 
@@ -677,15 +676,17 @@ lit_utf8_incr (lit_utf8_byte_t **buf_p) /**< [in,out] buffer with characters */
  * Decrease cesu-8 encoded string pointer by one code unit.
  */
 void
-lit_utf8_decr (lit_utf8_byte_t **buf_p) /**< [in,out] buffer with characters */
+lit_utf8_decr (const lit_utf8_byte_t **buf_p) /**< [in,out] buffer with characters */
 {
   JERRY_ASSERT (*buf_p);
-  lit_utf8_byte_t *current_p = *buf_p;
+  const lit_utf8_byte_t *current_p = *buf_p;
+
   do
   {
     current_p--;
   }
   while ((*(current_p) & LIT_UTF8_EXTRA_BYTE_MASK) == LIT_UTF8_EXTRA_BYTE_MARKER);
+
   *buf_p = current_p;
 } /* lit_utf8_decr */
 
diff --git a/jerry-core/lit/lit-strings.h b/jerry-core/lit/lit-strings.h
index 2b62944d0..3c9d2657e 100644
--- a/jerry-core/lit/lit-strings.h
+++ b/jerry-core/lit/lit-strings.h
@@ -1,4 +1,5 @@
 /* Copyright 2015-2016 Samsung Electronics Co., Ltd.
+ * Copyright 2016 University of Szeged.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -181,12 +182,12 @@ lit_utf8_size_t lit_read_code_unit_from_utf8 (const lit_utf8_byte_t *,
 lit_utf8_size_t lit_read_prev_code_unit_from_utf8 (const lit_utf8_byte_t *,
                                                    ecma_char_t *);
 
-ecma_char_t lit_utf8_read_next (lit_utf8_byte_t **);
-ecma_char_t lit_utf8_read_prev (lit_utf8_byte_t **);
+ecma_char_t lit_utf8_read_next (const lit_utf8_byte_t **);
+ecma_char_t lit_utf8_read_prev (const lit_utf8_byte_t **);
 ecma_char_t lit_utf8_peek_next (const lit_utf8_byte_t *);
 ecma_char_t lit_utf8_peek_prev (const lit_utf8_byte_t *);
-void lit_utf8_incr (lit_utf8_byte_t **);
-void lit_utf8_decr (lit_utf8_byte_t **);
+void lit_utf8_incr (const lit_utf8_byte_t **);
+void lit_utf8_decr (const lit_utf8_byte_t **);
 
 /* print */
 void lit_put_ecma_char (ecma_char_t);
diff --git a/jerry-core/parser/regexp/re-parser.c b/jerry-core/parser/regexp/re-parser.c
index 46d16de9d..02ca4f1dd 100644
--- a/jerry-core/parser/regexp/re-parser.c
+++ b/jerry-core/parser/regexp/re-parser.c
@@ -45,7 +45,7 @@ re_hex_lookup (re_parser_ctx_t *parser_ctx_p, /**< RegExp parser context */
                uint32_t lookup) /**< size of lookup */
 {
   bool is_digit = true;
-  lit_utf8_byte_t *curr_p = parser_ctx_p->input_curr_p;
+  const lit_utf8_byte_t *curr_p = parser_ctx_p->input_curr_p;
 
   for (uint32_t i = 0; is_digit && i < lookup; i++)
   {
@@ -259,7 +259,7 @@ re_count_num_of_groups (re_parser_ctx_t *parser_ctx_p) /**< RegExp parser contex
 {
   int char_class_in = 0;
   parser_ctx_p->num_of_groups = 0;
-  lit_utf8_byte_t *curr_p = (lit_utf8_byte_t *) parser_ctx_p->input_start_p;
+  const lit_utf8_byte_t *curr_p = parser_ctx_p->input_start_p;
 
   while (curr_p < parser_ctx_p->input_end_p)
   {
diff --git a/jerry-core/parser/regexp/re-parser.h b/jerry-core/parser/regexp/re-parser.h
index 31bb03432..25e237416 100644
--- a/jerry-core/parser/regexp/re-parser.h
+++ b/jerry-core/parser/regexp/re-parser.h
@@ -93,7 +93,7 @@ typedef struct
 typedef struct
 {
   const lit_utf8_byte_t *input_start_p; /**< start of input pattern */
-  lit_utf8_byte_t *input_curr_p;  /**< current position in input pattern */
+  const lit_utf8_byte_t *input_curr_p;  /**< current position in input pattern */
   const lit_utf8_byte_t *input_end_p;   /**< end of input pattern */
   int num_of_groups;              /**< number of groups */
   uint32_t num_of_classes;        /**< number of character classes */
diff --git a/tests/unit/test-strings.c b/tests/unit/test-strings.c
index a37c20cc4..958e0db00 100644
--- a/tests/unit/test-strings.c
+++ b/tests/unit/test-strings.c
@@ -1,4 +1,5 @@
-/* Copyright 2015 Samsung Electronics Co., Ltd.
+/* Copyright 2015-2016 Samsung Electronics Co., Ltd.
+ * Copyright 2016 University of Szeged.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -112,7 +113,7 @@ main (int __attr_unused___ argc,
 
   lit_utf8_byte_t cesu8_string[max_bytes_in_string];
   ecma_char_t code_units[max_code_units_in_string];
-  lit_utf8_byte_t *saved_positions[max_code_units_in_string];
+  const lit_utf8_byte_t *saved_positions[max_code_units_in_string];
 
   for (int i = 0; i < test_iters; i++)
   {
@@ -126,7 +127,7 @@ main (int __attr_unused___ argc,
 
     JERRY_ASSERT (lit_utf8_string_length (cesu8_string, cesu8_string_size) == length);
 
-    lit_utf8_byte_t *curr_p = cesu8_string;
+    const lit_utf8_byte_t *curr_p = cesu8_string;
     const lit_utf8_byte_t *end_p = cesu8_string + cesu8_string_size;
 
     ecma_length_t calculated_length = 0;