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_LIBDEXFILE_DEX_UTF_H_ 18 #define ART_LIBDEXFILE_DEX_UTF_H_ 19 20 #include "base/macros.h" 21 22 #include <stddef.h> 23 #include <stdint.h> 24 25 #include <string> 26 27 /* 28 * All UTF-8 in art is actually modified UTF-8. Mostly, this distinction 29 * doesn't matter. 30 * 31 * See http://en.wikipedia.org/wiki/UTF-8#Modified_UTF-8 for the details. 32 */ 33 namespace art { 34 35 /* 36 * Returns the number of UTF-16 characters in the given modified UTF-8 string. 37 */ 38 size_t CountModifiedUtf8Chars(const char* utf8); 39 size_t CountModifiedUtf8Chars(const char* utf8, size_t byte_count); 40 41 /* 42 * Returns the number of modified UTF-8 bytes needed to represent the given 43 * UTF-16 string. 44 */ 45 size_t CountUtf8Bytes(const uint16_t* chars, size_t char_count); 46 47 /* 48 * Convert from Modified UTF-8 to UTF-16. 49 */ 50 void ConvertModifiedUtf8ToUtf16(uint16_t* utf16_out, const char* utf8_in); 51 void ConvertModifiedUtf8ToUtf16(uint16_t* utf16_out, size_t out_chars, 52 const char* utf8_in, size_t in_bytes); 53 54 /* 55 * Compare two modified UTF-8 strings as UTF-16 code point values in a non-locale sensitive manner 56 */ 57 ALWAYS_INLINE int CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues(const char* utf8_1, 58 const char* utf8_2); 59 60 /* 61 * Compare a null-terminated modified UTF-8 string with a UTF-16 string (not null-terminated) 62 * as code point values in a non-locale sensitive manner. 63 */ 64 int CompareModifiedUtf8ToUtf16AsCodePointValues(const char* utf8, const uint16_t* utf16, 65 size_t utf16_length); 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, size_t byte_count, 74 const uint16_t* utf16_in, size_t char_count); 75 76 /* 77 * The java.lang.String hashCode() algorithm. 78 */ 79 template<typename MemoryType> 80 int32_t ComputeUtf16Hash(const MemoryType* chars, size_t char_count) { 81 uint32_t hash = 0; 82 while (char_count--) { 83 hash = hash * 31 + *chars++; 84 } 85 return static_cast<int32_t>(hash); 86 } 87 88 int32_t ComputeUtf16HashFromModifiedUtf8(const char* utf8, size_t utf16_length); 89 90 // Compute a hash code of a modified UTF-8 string. Not the standard java hash since it returns a 91 // uint32_t and hashes individual chars instead of codepoint words. 92 uint32_t ComputeModifiedUtf8Hash(const char* chars); 93 94 /* 95 * Retrieve the next UTF-16 character or surrogate pair from a UTF-8 string. 96 * single byte, 2-byte and 3-byte UTF-8 sequences result in a single UTF-16 97 * character (possibly one half of a surrogate) whereas 4-byte UTF-8 sequences 98 * result in a surrogate pair. Use GetLeadingUtf16Char and GetTrailingUtf16Char 99 * to process the return value of this function. 100 * 101 * Advances "*utf8_data_in" to the start of the next character. 102 * 103 * WARNING: If a string is corrupted by dropping a '\0' in the middle 104 * of a multi byte sequence, you can end up overrunning the buffer with 105 * reads (and possibly with the writes if the length was computed and 106 * cached before the damage). For performance reasons, this function 107 * assumes that the string being parsed is known to be valid (e.g., by 108 * already being verified). Most strings we process here are coming 109 * out of dex files or other internal translations, so the only real 110 * risk comes from the JNI NewStringUTF call. 111 */ 112 uint32_t GetUtf16FromUtf8(const char** utf8_data_in); 113 114 /** 115 * Gets the leading UTF-16 character from a surrogate pair, or the sole 116 * UTF-16 character from the return value of GetUtf16FromUtf8. 117 */ 118 ALWAYS_INLINE uint16_t GetLeadingUtf16Char(uint32_t maybe_pair); 119 120 /** 121 * Gets the trailing UTF-16 character from a surrogate pair, or 0 otherwise 122 * from the return value of GetUtf16FromUtf8. 123 */ 124 ALWAYS_INLINE uint16_t GetTrailingUtf16Char(uint32_t maybe_pair); 125 126 // Returns a printable (escaped) version of a character. 127 std::string PrintableChar(uint16_t ch); 128 129 // Returns an ASCII string corresponding to the given UTF-8 string. 130 // Java escapes are used for non-ASCII characters. 131 std::string PrintableString(const char* utf8); 132 133 } // namespace art 134 135 #endif // ART_LIBDEXFILE_DEX_UTF_H_ 136
