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      1 /*
      2  * Copyright (C) 2008 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 /*
     18  * UTF-8 and Unicode string manipulation functions, plus convenience
     19  * functions for working with java/lang/String.
     20  */
     21 #ifndef DALVIK_STRING_H_
     22 #define DALVIK_STRING_H_
     23 
     24 #include <string>
     25 #include <vector>
     26 
     27 /*
     28  * (This is private to UtfString.c, but we cheat a bit and also use it
     29  * for InlineNative.c.  Not really worth creating a separate header.)
     30  *
     31  * We can avoid poking around in gDvm by hard-coding the expected values of
     32  * the String field offsets.  This will be annoying if String is in flux
     33  * or the VM field layout is changing, so we use defines here to make it
     34  * easy to switch back to the gDvm version.
     35  *
     36  * The values are checked for correctness during startup.
     37  */
     38 //#define USE_GLOBAL_STRING_DEFS
     39 #ifdef USE_GLOBAL_STRING_DEFS
     40 # define STRING_FIELDOFF_VALUE      gDvm.offJavaLangString_value
     41 # define STRING_FIELDOFF_OFFSET     gDvm.offJavaLangString_offset
     42 # define STRING_FIELDOFF_COUNT      gDvm.offJavaLangString_count
     43 # define STRING_FIELDOFF_HASHCODE   gDvm.offJavaLangString_hashCode
     44 #else
     45 # define STRING_FIELDOFF_VALUE      8
     46 # define STRING_FIELDOFF_HASHCODE   12
     47 # define STRING_FIELDOFF_OFFSET     16
     48 # define STRING_FIELDOFF_COUNT      20
     49 #endif
     50 
     51 /*
     52  * Hash function for modified UTF-8 strings.
     53  */
     54 u4 dvmComputeUtf8Hash(const char* str);
     55 
     56 /*
     57  * Hash function for string objects. Ensures the hash code field is
     58  * populated and returns its value.
     59  */
     60 u4 dvmComputeStringHash(StringObject* strObj);
     61 
     62 /*
     63  * Create a java.lang.String[] from a vector of C++ strings.
     64  *
     65  * The caller must call dvmReleaseTrackedAlloc() on the returned array,
     66  * but not on the individual elements.
     67  *
     68  * Returns NULL and throws an exception on failure.
     69  */
     70 ArrayObject* dvmCreateStringArray(const std::vector<std::string>& strings);
     71 
     72 /*
     73  * Create a java/lang/String from a C string.
     74  *
     75  * The caller must call dvmReleaseTrackedAlloc() on the return value.
     76  *
     77  * Returns NULL and throws an exception on failure.
     78  */
     79 StringObject* dvmCreateStringFromCstr(const char* utf8Str);
     80 
     81 /*
     82  * Create a java/lang/String from a C++ string.
     83  *
     84  * The caller must call dvmReleaseTrackedAlloc() on the return value.
     85  *
     86  * Returns NULL and throws an exception on failure.
     87  */
     88 StringObject* dvmCreateStringFromCstr(const std::string& utf8Str);
     89 
     90 /*
     91  * Create a java/lang/String from a C string, given its UTF-16 length
     92  * (number of UTF-16 code points).
     93  *
     94  * The caller must call dvmReleaseTrackedAlloc() on the return value.
     95  *
     96  * Returns NULL and throws an exception on failure.
     97  */
     98 StringObject* dvmCreateStringFromCstrAndLength(const char* utf8Str,
     99     u4 utf16Length);
    100 
    101 /*
    102  * Compute the number of characters in a "modified UTF-8" string.  This will
    103  * match the result from strlen() so long as there are no multi-byte chars.
    104  */
    105 size_t dvmUtf8Len(const char* utf8Str);
    106 
    107 /*
    108  * Convert a UTF-8 string to UTF-16.  "utf16Str" must have enough room
    109  * to hold the output.
    110  */
    111 void dvmConvertUtf8ToUtf16(u2* utf16Str, const char* utf8Str);
    112 
    113 /*
    114  * Create a java/lang/String from a Unicode string.
    115  *
    116  * The caller must call dvmReleaseTrackedAlloc() on the return value.
    117  */
    118 StringObject* dvmCreateStringFromUnicode(const u2* unichars, int len);
    119 
    120 /*
    121  * Create a UTF-8 C string from a java/lang/String.  Caller must free
    122  * the result.
    123  *
    124  * Returns NULL if "jstr" is NULL.
    125  */
    126 char* dvmCreateCstrFromString(const StringObject* jstr);
    127 
    128 /*
    129  * Create a UTF-8 C string from a region of a java/lang/String.  (Used by
    130  * the JNI GetStringUTFRegion call.)
    131  */
    132 void dvmGetStringUtfRegion(const StringObject* jstr,
    133         int start, int len, char* buf);
    134 
    135 /*
    136  * Compare two string objects.  (This is a dvmHashTableLookup() callback.)
    137  */
    138 int dvmHashcmpStrings(const void* vstrObj1, const void* vstrObj2);
    139 
    140 #endif  // DALVIK_STRING_H_
    141