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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_RUNTIME_UTF_H_
     18 #define ART_RUNTIME_UTF_H_
     19 
     20 #include "base/macros.h"
     21 #include "base/mutex.h"
     22 
     23 #include <stddef.h>
     24 #include <stdint.h>
     25 
     26 /*
     27  * All UTF-8 in art is actually modified UTF-8. Mostly, this distinction
     28  * doesn't matter.
     29  *
     30  * See http://en.wikipedia.org/wiki/UTF-8#Modified_UTF-8 for the details.
     31  */
     32 namespace art {
     33 
     34 namespace mirror {
     35   template<class T> class PrimitiveArray;
     36   typedef PrimitiveArray<uint16_t> CharArray;
     37 }  // namespace mirror
     38 
     39 /*
     40  * Returns the number of UTF-16 characters in the given modified UTF-8 string.
     41  */
     42 size_t CountModifiedUtf8Chars(const char* utf8);
     43 
     44 /*
     45  * Returns the number of modified UTF-8 bytes needed to represent the given
     46  * UTF-16 string.
     47  */
     48 size_t CountUtf8Bytes(const uint16_t* chars, size_t char_count);
     49 
     50 /*
     51  * Convert from Modified UTF-8 to UTF-16.
     52  */
     53 void ConvertModifiedUtf8ToUtf16(uint16_t* utf16_out, const char* utf8_in);
     54 
     55 /*
     56  * Compare two modified UTF-8 strings as UTF-16 code point values in a non-locale sensitive manner
     57  */
     58 ALWAYS_INLINE int CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues(const char* utf8_1,
     59                                                                           const char* utf8_2);
     60 
     61 /*
     62  * Compare a modified UTF-8 string with a UTF-16 string as code point values in a non-locale
     63  * sensitive manner.
     64  */
     65 int CompareModifiedUtf8ToUtf16AsCodePointValues(const char* utf8_1, const uint16_t* utf8_2);
     66 
     67 /*
     68  * Convert from UTF-16 to Modified UTF-8. Note that the output is _not_
     69  * NUL-terminated. You probably need to call CountUtf8Bytes before calling
     70  * this anyway, so if you want a NUL-terminated string, you know where to
     71  * put the NUL byte.
     72  */
     73 void ConvertUtf16ToModifiedUtf8(char* utf8_out, const uint16_t* utf16_in, size_t char_count);
     74 
     75 /*
     76  * The java.lang.String hashCode() algorithm.
     77  */
     78 int32_t ComputeUtf16Hash(mirror::CharArray* chars, int32_t offset, size_t char_count)
     79     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
     80 int32_t ComputeUtf16Hash(const uint16_t* chars, size_t char_count);
     81 
     82 // Compute a hash code of a modified UTF-8 string. Not the standard java hash since it returns a
     83 // size_t and hashes individual chars instead of codepoint words.
     84 size_t ComputeModifiedUtf8Hash(const char* chars);
     85 
     86 /*
     87  * Retrieve the next UTF-16 character from a UTF-8 string.
     88  *
     89  * Advances "*utf8_data_in" to the start of the next character.
     90  *
     91  * WARNING: If a string is corrupted by dropping a '\0' in the middle
     92  * of a 3-byte sequence, you can end up overrunning the buffer with
     93  * reads (and possibly with the writes if the length was computed and
     94  * cached before the damage). For performance reasons, this function
     95  * assumes that the string being parsed is known to be valid (e.g., by
     96  * already being verified). Most strings we process here are coming
     97  * out of dex files or other internal translations, so the only real
     98  * risk comes from the JNI NewStringUTF call.
     99  */
    100 uint16_t GetUtf16FromUtf8(const char** utf8_data_in);
    101 
    102 }  // namespace art
    103 
    104 #endif  // ART_RUNTIME_UTF_H_
    105