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 22 #include <stddef.h> 23 #include <stdint.h> 24 25 /* 26 * All UTF-8 in art is actually modified UTF-8. Mostly, this distinction 27 * doesn't matter. 28 * 29 * See http://en.wikipedia.org/wiki/UTF-8#Modified_UTF-8 for the details. 30 */ 31 namespace art { 32 33 /* 34 * Returns the number of UTF-16 characters in the given modified UTF-8 string. 35 */ 36 size_t CountModifiedUtf8Chars(const char* utf8); 37 size_t CountModifiedUtf8Chars(const char* utf8, size_t byte_count); 38 39 /* 40 * Returns the number of modified UTF-8 bytes needed to represent the given 41 * UTF-16 string. 42 */ 43 size_t CountUtf8Bytes(const uint16_t* chars, size_t char_count); 44 45 /* 46 * Convert from Modified UTF-8 to UTF-16. 47 */ 48 void ConvertModifiedUtf8ToUtf16(uint16_t* utf16_out, const char* utf8_in); 49 void ConvertModifiedUtf8ToUtf16(uint16_t* utf16_out, size_t out_chars, 50 const char* utf8_in, size_t in_bytes); 51 52 /* 53 * Compare two modified UTF-8 strings as UTF-16 code point values in a non-locale sensitive manner 54 */ 55 ALWAYS_INLINE int CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues(const char* utf8_1, 56 const char* utf8_2); 57 58 /* 59 * Compare a null-terminated modified UTF-8 string with a UTF-16 string (not null-terminated) 60 * as code point values in a non-locale sensitive manner. 61 */ 62 int CompareModifiedUtf8ToUtf16AsCodePointValues(const char* utf8, const uint16_t* utf16, 63 size_t utf16_length); 64 65 /* 66 * Convert from UTF-16 to Modified UTF-8. Note that the output is _not_ 67 * NUL-terminated. You probably need to call CountUtf8Bytes before calling 68 * this anyway, so if you want a NUL-terminated string, you know where to 69 * put the NUL byte. 70 */ 71 void ConvertUtf16ToModifiedUtf8(char* utf8_out, size_t byte_count, 72 const uint16_t* utf16_in, size_t char_count); 73 74 /* 75 * The java.lang.String hashCode() algorithm. 76 */ 77 template<typename MemoryType> 78 int32_t ComputeUtf16Hash(const MemoryType* chars, size_t char_count) { 79 uint32_t hash = 0; 80 while (char_count--) { 81 hash = hash * 31 + *chars++; 82 } 83 return static_cast<int32_t>(hash); 84 } 85 86 int32_t ComputeUtf16HashFromModifiedUtf8(const char* utf8, size_t utf16_length); 87 88 // Compute a hash code of a modified UTF-8 string. Not the standard java hash since it returns a 89 // uint32_t and hashes individual chars instead of codepoint words. 90 uint32_t ComputeModifiedUtf8Hash(const char* chars); 91 92 /* 93 * Retrieve the next UTF-16 character or surrogate pair from a UTF-8 string. 94 * single byte, 2-byte and 3-byte UTF-8 sequences result in a single UTF-16 95 * character (possibly one half of a surrogate) whereas 4-byte UTF-8 sequences 96 * result in a surrogate pair. Use GetLeadingUtf16Char and GetTrailingUtf16Char 97 * to process the return value of this function. 98 * 99 * Advances "*utf8_data_in" to the start of the next character. 100 * 101 * WARNING: If a string is corrupted by dropping a '\0' in the middle 102 * of a multi byte sequence, you can end up overrunning the buffer with 103 * reads (and possibly with the writes if the length was computed and 104 * cached before the damage). For performance reasons, this function 105 * assumes that the string being parsed is known to be valid (e.g., by 106 * already being verified). Most strings we process here are coming 107 * out of dex files or other internal translations, so the only real 108 * risk comes from the JNI NewStringUTF call. 109 */ 110 uint32_t GetUtf16FromUtf8(const char** utf8_data_in); 111 112 /** 113 * Gets the leading UTF-16 character from a surrogate pair, or the sole 114 * UTF-16 character from the return value of GetUtf16FromUtf8. 115 */ 116 ALWAYS_INLINE uint16_t GetLeadingUtf16Char(uint32_t maybe_pair); 117 118 /** 119 * Gets the trailing UTF-16 character from a surrogate pair, or 0 otherwise 120 * from the return value of GetUtf16FromUtf8. 121 */ 122 ALWAYS_INLINE uint16_t GetTrailingUtf16Char(uint32_t maybe_pair); 123 124 } // namespace art 125 126 #endif // ART_RUNTIME_UTF_H_ 127
