Home | History | Annotate | Download | only in common
      1 // Copyright (C) 2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 /*
      4 ******************************************************************************
      5 *
      6 *   Copyright (C) 1997-2016, International Business Machines
      7 *   Corporation and others.  All Rights Reserved.
      8 *
      9 ******************************************************************************
     10 *
     11 * File CMEMORY.H
     12 *
     13 *  Contains stdlib.h/string.h memory functions
     14 *
     15 * @author       Bertrand A. Damiba
     16 *
     17 * Modification History:
     18 *
     19 *   Date        Name        Description
     20 *   6/20/98     Bertrand    Created.
     21 *  05/03/99     stephen     Changed from functions to macros.
     22 *
     23 ******************************************************************************
     24 */
     25 
     26 #ifndef CMEMORY_H
     27 #define CMEMORY_H
     28 
     29 #include "unicode/utypes.h"
     30 
     31 #include <stddef.h>
     32 #include <string.h>
     33 #include "unicode/localpointer.h"
     34 
     35 #if U_DEBUG && defined(UPRV_MALLOC_COUNT)
     36 #include <stdio.h>
     37 #endif
     38 
     39 #if U_DEBUG
     40 
     41 /*
     42  * The C++ standard requires that the source pointer for memcpy() & memmove()
     43  * is valid, not NULL, and not at the end of an allocated memory block.
     44  * In debug mode, we read one byte from the source point to verify that it's
     45  * a valid, readable pointer.
     46  */
     47 
     48 U_CAPI void uprv_checkValidMemory(const void *p, size_t n);
     49 
     50 #define uprv_memcpy(dst, src, size) ( \
     51     uprv_checkValidMemory(src, 1), \
     52     U_STANDARD_CPP_NAMESPACE memcpy(dst, src, size))
     53 #define uprv_memmove(dst, src, size) ( \
     54     uprv_checkValidMemory(src, 1), \
     55     U_STANDARD_CPP_NAMESPACE memmove(dst, src, size))
     56 
     57 #else
     58 
     59 #define uprv_memcpy(dst, src, size) U_STANDARD_CPP_NAMESPACE memcpy(dst, src, size)
     60 #define uprv_memmove(dst, src, size) U_STANDARD_CPP_NAMESPACE memmove(dst, src, size)
     61 
     62 #endif  /* U_DEBUG */
     63 
     64 /**
     65  * \def UPRV_LENGTHOF
     66  * Convenience macro to determine the length of a fixed array at compile-time.
     67  * @param array A fixed length array
     68  * @return The length of the array, in elements
     69  * @internal
     70  */
     71 #define UPRV_LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
     72 #define uprv_memset(buffer, mark, size) U_STANDARD_CPP_NAMESPACE memset(buffer, mark, size)
     73 #define uprv_memcmp(buffer1, buffer2, size) U_STANDARD_CPP_NAMESPACE memcmp(buffer1, buffer2,size)
     74 
     75 U_CAPI void * U_EXPORT2
     76 uprv_malloc(size_t s) U_MALLOC_ATTR U_ALLOC_SIZE_ATTR(1);
     77 
     78 U_CAPI void * U_EXPORT2
     79 uprv_realloc(void *mem, size_t size) U_ALLOC_SIZE_ATTR(2);
     80 
     81 U_CAPI void U_EXPORT2
     82 uprv_free(void *mem);
     83 
     84 U_CAPI void * U_EXPORT2
     85 uprv_calloc(size_t num, size_t size) U_MALLOC_ATTR U_ALLOC_SIZE_ATTR2(1,2);
     86 
     87 /**
     88  * This should align the memory properly on any machine.
     89  * This is very useful for the safeClone functions.
     90  */
     91 typedef union {
     92     long    t1;
     93     double  t2;
     94     void   *t3;
     95 } UAlignedMemory;
     96 
     97 /**
     98  * Get the least significant bits of a pointer (a memory address).
     99  * For example, with a mask of 3, the macro gets the 2 least significant bits,
    100  * which will be 0 if the pointer is 32-bit (4-byte) aligned.
    101  *
    102  * ptrdiff_t is the most appropriate integer type to cast to.
    103  * size_t should work too, since on most (or all?) platforms it has the same
    104  * width as ptrdiff_t.
    105  */
    106 #define U_POINTER_MASK_LSB(ptr, mask) (((ptrdiff_t)(char *)(ptr)) & (mask))
    107 
    108 /**
    109  * Get the amount of bytes that a pointer is off by from
    110  * the previous UAlignedMemory-aligned pointer.
    111  */
    112 #define U_ALIGNMENT_OFFSET(ptr) U_POINTER_MASK_LSB(ptr, sizeof(UAlignedMemory) - 1)
    113 
    114 /**
    115  * Get the amount of bytes to add to a pointer
    116  * in order to get the next UAlignedMemory-aligned address.
    117  */
    118 #define U_ALIGNMENT_OFFSET_UP(ptr) (sizeof(UAlignedMemory) - U_ALIGNMENT_OFFSET(ptr))
    119 
    120 /**
    121   *  Heap clean up function, called from u_cleanup()
    122   *    Clears any user heap functions from u_setMemoryFunctions()
    123   *    Does NOT deallocate any remaining allocated memory.
    124   */
    125 U_CFUNC UBool
    126 cmemory_cleanup(void);
    127 
    128 /**
    129  * A function called by <TT>uhash_remove</TT>,
    130  * <TT>uhash_close</TT>, or <TT>uhash_put</TT> to delete
    131  * an existing key or value.
    132  * @param obj A key or value stored in a hashtable
    133  * @see uprv_deleteUObject
    134  */
    135 typedef void U_CALLCONV UObjectDeleter(void* obj);
    136 
    137 /**
    138  * Deleter for UObject instances.
    139  * Works for all subclasses of UObject because it has a virtual destructor.
    140  */
    141 U_CAPI void U_EXPORT2
    142 uprv_deleteUObject(void *obj);
    143 
    144 #ifdef __cplusplus
    145 
    146 U_NAMESPACE_BEGIN
    147 
    148 /**
    149  * "Smart pointer" class, deletes memory via uprv_free().
    150  * For most methods see the LocalPointerBase base class.
    151  * Adds operator[] for array item access.
    152  *
    153  * @see LocalPointerBase
    154  */
    155 template<typename T>
    156 class LocalMemory : public LocalPointerBase<T> {
    157 public:
    158     using LocalPointerBase<T>::operator*;
    159     using LocalPointerBase<T>::operator->;
    160     /**
    161      * Constructor takes ownership.
    162      * @param p simple pointer to an array of T items that is adopted
    163      */
    164     explicit LocalMemory(T *p=NULL) : LocalPointerBase<T>(p) {}
    165 #if U_HAVE_RVALUE_REFERENCES
    166     /**
    167      * Move constructor, leaves src with isNull().
    168      * @param src source smart pointer
    169      */
    170     LocalMemory(LocalMemory<T> &&src) U_NOEXCEPT : LocalPointerBase<T>(src.ptr) {
    171         src.ptr=NULL;
    172     }
    173 #endif
    174     /**
    175      * Destructor deletes the memory it owns.
    176      */
    177     ~LocalMemory() {
    178         uprv_free(LocalPointerBase<T>::ptr);
    179     }
    180 #if U_HAVE_RVALUE_REFERENCES
    181     /**
    182      * Move assignment operator, leaves src with isNull().
    183      * The behavior is undefined if *this and src are the same object.
    184      * @param src source smart pointer
    185      * @return *this
    186      */
    187     LocalMemory<T> &operator=(LocalMemory<T> &&src) U_NOEXCEPT {
    188         return moveFrom(src);
    189     }
    190 #endif
    191     /**
    192      * Move assignment, leaves src with isNull().
    193      * The behavior is undefined if *this and src are the same object.
    194      *
    195      * Can be called explicitly, does not need C++11 support.
    196      * @param src source smart pointer
    197      * @return *this
    198      */
    199     LocalMemory<T> &moveFrom(LocalMemory<T> &src) U_NOEXCEPT {
    200         delete[] LocalPointerBase<T>::ptr;
    201         LocalPointerBase<T>::ptr=src.ptr;
    202         src.ptr=NULL;
    203         return *this;
    204     }
    205     /**
    206      * Swap pointers.
    207      * @param other other smart pointer
    208      */
    209     void swap(LocalMemory<T> &other) U_NOEXCEPT {
    210         T *temp=LocalPointerBase<T>::ptr;
    211         LocalPointerBase<T>::ptr=other.ptr;
    212         other.ptr=temp;
    213     }
    214     /**
    215      * Non-member LocalMemory swap function.
    216      * @param p1 will get p2's pointer
    217      * @param p2 will get p1's pointer
    218      */
    219     friend inline void swap(LocalMemory<T> &p1, LocalMemory<T> &p2) U_NOEXCEPT {
    220         p1.swap(p2);
    221     }
    222     /**
    223      * Deletes the array it owns,
    224      * and adopts (takes ownership of) the one passed in.
    225      * @param p simple pointer to an array of T items that is adopted
    226      */
    227     void adoptInstead(T *p) {
    228         uprv_free(LocalPointerBase<T>::ptr);
    229         LocalPointerBase<T>::ptr=p;
    230     }
    231     /**
    232      * Deletes the array it owns, allocates a new one and reset its bytes to 0.
    233      * Returns the new array pointer.
    234      * If the allocation fails, then the current array is unchanged and
    235      * this method returns NULL.
    236      * @param newCapacity must be >0
    237      * @return the allocated array pointer, or NULL if the allocation failed
    238      */
    239     inline T *allocateInsteadAndReset(int32_t newCapacity=1);
    240     /**
    241      * Deletes the array it owns and allocates a new one, copying length T items.
    242      * Returns the new array pointer.
    243      * If the allocation fails, then the current array is unchanged and
    244      * this method returns NULL.
    245      * @param newCapacity must be >0
    246      * @param length number of T items to be copied from the old array to the new one;
    247      *               must be no more than the capacity of the old array,
    248      *               which the caller must track because the LocalMemory does not track it
    249      * @return the allocated array pointer, or NULL if the allocation failed
    250      */
    251     inline T *allocateInsteadAndCopy(int32_t newCapacity=1, int32_t length=0);
    252     /**
    253      * Array item access (writable).
    254      * No index bounds check.
    255      * @param i array index
    256      * @return reference to the array item
    257      */
    258     T &operator[](ptrdiff_t i) const { return LocalPointerBase<T>::ptr[i]; }
    259 };
    260 
    261 template<typename T>
    262 inline T *LocalMemory<T>::allocateInsteadAndReset(int32_t newCapacity) {
    263     if(newCapacity>0) {
    264         T *p=(T *)uprv_malloc(newCapacity*sizeof(T));
    265         if(p!=NULL) {
    266             uprv_memset(p, 0, newCapacity*sizeof(T));
    267             uprv_free(LocalPointerBase<T>::ptr);
    268             LocalPointerBase<T>::ptr=p;
    269         }
    270         return p;
    271     } else {
    272         return NULL;
    273     }
    274 }
    275 
    276 
    277 template<typename T>
    278 inline T *LocalMemory<T>::allocateInsteadAndCopy(int32_t newCapacity, int32_t length) {
    279     if(newCapacity>0) {
    280         T *p=(T *)uprv_malloc(newCapacity*sizeof(T));
    281         if(p!=NULL) {
    282             if(length>0) {
    283                 if(length>newCapacity) {
    284                     length=newCapacity;
    285                 }
    286                 uprv_memcpy(p, LocalPointerBase<T>::ptr, (size_t)length*sizeof(T));
    287             }
    288             uprv_free(LocalPointerBase<T>::ptr);
    289             LocalPointerBase<T>::ptr=p;
    290         }
    291         return p;
    292     } else {
    293         return NULL;
    294     }
    295 }
    296 
    297 /**
    298  * Simple array/buffer management class using uprv_malloc() and uprv_free().
    299  * Provides an internal array with fixed capacity. Can alias another array
    300  * or allocate one.
    301  *
    302  * The array address is properly aligned for type T. It might not be properly
    303  * aligned for types larger than T (or larger than the largest subtype of T).
    304  *
    305  * Unlike LocalMemory and LocalArray, this class never adopts
    306  * (takes ownership of) another array.
    307  */
    308 template<typename T, int32_t stackCapacity>
    309 class MaybeStackArray {
    310 public:
    311     /**
    312      * Default constructor initializes with internal T[stackCapacity] buffer.
    313      */
    314     MaybeStackArray() : ptr(stackArray), capacity(stackCapacity), needToRelease(FALSE) {}
    315     /**
    316      * Destructor deletes the array (if owned).
    317      */
    318     ~MaybeStackArray() { releaseArray(); }
    319     /**
    320      * Returns the array capacity (number of T items).
    321      * @return array capacity
    322      */
    323     int32_t getCapacity() const { return capacity; }
    324     /**
    325      * Access without ownership change.
    326      * @return the array pointer
    327      */
    328     T *getAlias() const { return ptr; }
    329     /**
    330      * Returns the array limit. Simple convenience method.
    331      * @return getAlias()+getCapacity()
    332      */
    333     T *getArrayLimit() const { return getAlias()+capacity; }
    334     // No "operator T *() const" because that can make
    335     // expressions like mbs[index] ambiguous for some compilers.
    336     /**
    337      * Array item access (const).
    338      * No index bounds check.
    339      * @param i array index
    340      * @return reference to the array item
    341      */
    342     const T &operator[](ptrdiff_t i) const { return ptr[i]; }
    343     /**
    344      * Array item access (writable).
    345      * No index bounds check.
    346      * @param i array index
    347      * @return reference to the array item
    348      */
    349     T &operator[](ptrdiff_t i) { return ptr[i]; }
    350     /**
    351      * Deletes the array (if owned) and aliases another one, no transfer of ownership.
    352      * If the arguments are illegal, then the current array is unchanged.
    353      * @param otherArray must not be NULL
    354      * @param otherCapacity must be >0
    355      */
    356     void aliasInstead(T *otherArray, int32_t otherCapacity) {
    357         if(otherArray!=NULL && otherCapacity>0) {
    358             releaseArray();
    359             ptr=otherArray;
    360             capacity=otherCapacity;
    361             needToRelease=FALSE;
    362         }
    363     }
    364     /**
    365      * Deletes the array (if owned) and allocates a new one, copying length T items.
    366      * Returns the new array pointer.
    367      * If the allocation fails, then the current array is unchanged and
    368      * this method returns NULL.
    369      * @param newCapacity can be less than or greater than the current capacity;
    370      *                    must be >0
    371      * @param length number of T items to be copied from the old array to the new one
    372      * @return the allocated array pointer, or NULL if the allocation failed
    373      */
    374     inline T *resize(int32_t newCapacity, int32_t length=0);
    375     /**
    376      * Gives up ownership of the array if owned, or else clones it,
    377      * copying length T items; resets itself to the internal stack array.
    378      * Returns NULL if the allocation failed.
    379      * @param length number of T items to copy when cloning,
    380      *        and capacity of the clone when cloning
    381      * @param resultCapacity will be set to the returned array's capacity (output-only)
    382      * @return the array pointer;
    383      *         caller becomes responsible for deleting the array
    384      */
    385     inline T *orphanOrClone(int32_t length, int32_t &resultCapacity);
    386 private:
    387     T *ptr;
    388     int32_t capacity;
    389     UBool needToRelease;
    390     T stackArray[stackCapacity];
    391     void releaseArray() {
    392         if(needToRelease) {
    393             uprv_free(ptr);
    394         }
    395     }
    396     /* No comparison operators with other MaybeStackArray's. */
    397     bool operator==(const MaybeStackArray & /*other*/) {return FALSE;}
    398     bool operator!=(const MaybeStackArray & /*other*/) {return TRUE;}
    399     /* No ownership transfer: No copy constructor, no assignment operator. */
    400     MaybeStackArray(const MaybeStackArray & /*other*/) {}
    401     void operator=(const MaybeStackArray & /*other*/) {}
    402 
    403     // No heap allocation. Use only on the stack.
    404     //   (Declaring these functions private triggers a cascade of problems:
    405     //      MSVC insists on exporting an instantiation of MaybeStackArray, which
    406     //      requires that all functions be defined.
    407     //      An empty implementation of new() is rejected, it must return a value.
    408     //      Returning NULL is rejected by gcc for operator new.
    409     //      The expedient thing is just not to override operator new.
    410     //      While relatively pointless, heap allocated instances will function.
    411     // static void * U_EXPORT2 operator new(size_t size);
    412     // static void * U_EXPORT2 operator new[](size_t size);
    413 #if U_HAVE_PLACEMENT_NEW
    414     // static void * U_EXPORT2 operator new(size_t, void *ptr);
    415 #endif
    416 };
    417 
    418 template<typename T, int32_t stackCapacity>
    419 inline T *MaybeStackArray<T, stackCapacity>::resize(int32_t newCapacity, int32_t length) {
    420     if(newCapacity>0) {
    421 #if U_DEBUG && defined(UPRV_MALLOC_COUNT)
    422       ::fprintf(::stderr,"MaybeStacArray (resize) alloc %d * %lu\n", newCapacity,sizeof(T));
    423 #endif
    424         T *p=(T *)uprv_malloc(newCapacity*sizeof(T));
    425         if(p!=NULL) {
    426             if(length>0) {
    427                 if(length>capacity) {
    428                     length=capacity;
    429                 }
    430                 if(length>newCapacity) {
    431                     length=newCapacity;
    432                 }
    433                 uprv_memcpy(p, ptr, (size_t)length*sizeof(T));
    434             }
    435             releaseArray();
    436             ptr=p;
    437             capacity=newCapacity;
    438             needToRelease=TRUE;
    439         }
    440         return p;
    441     } else {
    442         return NULL;
    443     }
    444 }
    445 
    446 template<typename T, int32_t stackCapacity>
    447 inline T *MaybeStackArray<T, stackCapacity>::orphanOrClone(int32_t length, int32_t &resultCapacity) {
    448     T *p;
    449     if(needToRelease) {
    450         p=ptr;
    451     } else if(length<=0) {
    452         return NULL;
    453     } else {
    454         if(length>capacity) {
    455             length=capacity;
    456         }
    457         p=(T *)uprv_malloc(length*sizeof(T));
    458 #if U_DEBUG && defined(UPRV_MALLOC_COUNT)
    459       ::fprintf(::stderr,"MaybeStacArray (orphan) alloc %d * %lu\n", length,sizeof(T));
    460 #endif
    461         if(p==NULL) {
    462             return NULL;
    463         }
    464         uprv_memcpy(p, ptr, (size_t)length*sizeof(T));
    465     }
    466     resultCapacity=length;
    467     ptr=stackArray;
    468     capacity=stackCapacity;
    469     needToRelease=FALSE;
    470     return p;
    471 }
    472 
    473 /**
    474  * Variant of MaybeStackArray that allocates a header struct and an array
    475  * in one contiguous memory block, using uprv_malloc() and uprv_free().
    476  * Provides internal memory with fixed array capacity. Can alias another memory
    477  * block or allocate one.
    478  * The stackCapacity is the number of T items in the internal memory,
    479  * not counting the H header.
    480  * Unlike LocalMemory and LocalArray, this class never adopts
    481  * (takes ownership of) another memory block.
    482  */
    483 template<typename H, typename T, int32_t stackCapacity>
    484 class MaybeStackHeaderAndArray {
    485 public:
    486     /**
    487      * Default constructor initializes with internal H+T[stackCapacity] buffer.
    488      */
    489     MaybeStackHeaderAndArray() : ptr(&stackHeader), capacity(stackCapacity), needToRelease(FALSE) {}
    490     /**
    491      * Destructor deletes the memory (if owned).
    492      */
    493     ~MaybeStackHeaderAndArray() { releaseMemory(); }
    494     /**
    495      * Returns the array capacity (number of T items).
    496      * @return array capacity
    497      */
    498     int32_t getCapacity() const { return capacity; }
    499     /**
    500      * Access without ownership change.
    501      * @return the header pointer
    502      */
    503     H *getAlias() const { return ptr; }
    504     /**
    505      * Returns the array start.
    506      * @return array start, same address as getAlias()+1
    507      */
    508     T *getArrayStart() const { return reinterpret_cast<T *>(getAlias()+1); }
    509     /**
    510      * Returns the array limit.
    511      * @return array limit
    512      */
    513     T *getArrayLimit() const { return getArrayStart()+capacity; }
    514     /**
    515      * Access without ownership change. Same as getAlias().
    516      * A class instance can be used directly in expressions that take a T *.
    517      * @return the header pointer
    518      */
    519     operator H *() const { return ptr; }
    520     /**
    521      * Array item access (writable).
    522      * No index bounds check.
    523      * @param i array index
    524      * @return reference to the array item
    525      */
    526     T &operator[](ptrdiff_t i) { return getArrayStart()[i]; }
    527     /**
    528      * Deletes the memory block (if owned) and aliases another one, no transfer of ownership.
    529      * If the arguments are illegal, then the current memory is unchanged.
    530      * @param otherArray must not be NULL
    531      * @param otherCapacity must be >0
    532      */
    533     void aliasInstead(H *otherMemory, int32_t otherCapacity) {
    534         if(otherMemory!=NULL && otherCapacity>0) {
    535             releaseMemory();
    536             ptr=otherMemory;
    537             capacity=otherCapacity;
    538             needToRelease=FALSE;
    539         }
    540     }
    541     /**
    542      * Deletes the memory block (if owned) and allocates a new one,
    543      * copying the header and length T array items.
    544      * Returns the new header pointer.
    545      * If the allocation fails, then the current memory is unchanged and
    546      * this method returns NULL.
    547      * @param newCapacity can be less than or greater than the current capacity;
    548      *                    must be >0
    549      * @param length number of T items to be copied from the old array to the new one
    550      * @return the allocated pointer, or NULL if the allocation failed
    551      */
    552     inline H *resize(int32_t newCapacity, int32_t length=0);
    553     /**
    554      * Gives up ownership of the memory if owned, or else clones it,
    555      * copying the header and length T array items; resets itself to the internal memory.
    556      * Returns NULL if the allocation failed.
    557      * @param length number of T items to copy when cloning,
    558      *        and array capacity of the clone when cloning
    559      * @param resultCapacity will be set to the returned array's capacity (output-only)
    560      * @return the header pointer;
    561      *         caller becomes responsible for deleting the array
    562      */
    563     inline H *orphanOrClone(int32_t length, int32_t &resultCapacity);
    564 private:
    565     H *ptr;
    566     int32_t capacity;
    567     UBool needToRelease;
    568     // stackHeader must precede stackArray immediately.
    569     H stackHeader;
    570     T stackArray[stackCapacity];
    571     void releaseMemory() {
    572         if(needToRelease) {
    573             uprv_free(ptr);
    574         }
    575     }
    576     /* No comparison operators with other MaybeStackHeaderAndArray's. */
    577     bool operator==(const MaybeStackHeaderAndArray & /*other*/) {return FALSE;}
    578     bool operator!=(const MaybeStackHeaderAndArray & /*other*/) {return TRUE;}
    579     /* No ownership transfer: No copy constructor, no assignment operator. */
    580     MaybeStackHeaderAndArray(const MaybeStackHeaderAndArray & /*other*/) {}
    581     void operator=(const MaybeStackHeaderAndArray & /*other*/) {}
    582 
    583     // No heap allocation. Use only on the stack.
    584     //   (Declaring these functions private triggers a cascade of problems;
    585     //    see the MaybeStackArray class for details.)
    586     // static void * U_EXPORT2 operator new(size_t size);
    587     // static void * U_EXPORT2 operator new[](size_t size);
    588 #if U_HAVE_PLACEMENT_NEW
    589     // static void * U_EXPORT2 operator new(size_t, void *ptr);
    590 #endif
    591 };
    592 
    593 template<typename H, typename T, int32_t stackCapacity>
    594 inline H *MaybeStackHeaderAndArray<H, T, stackCapacity>::resize(int32_t newCapacity,
    595                                                                 int32_t length) {
    596     if(newCapacity>=0) {
    597 #if U_DEBUG && defined(UPRV_MALLOC_COUNT)
    598       ::fprintf(::stderr,"MaybeStackHeaderAndArray alloc %d + %d * %ul\n", sizeof(H),newCapacity,sizeof(T));
    599 #endif
    600         H *p=(H *)uprv_malloc(sizeof(H)+newCapacity*sizeof(T));
    601         if(p!=NULL) {
    602             if(length<0) {
    603                 length=0;
    604             } else if(length>0) {
    605                 if(length>capacity) {
    606                     length=capacity;
    607                 }
    608                 if(length>newCapacity) {
    609                     length=newCapacity;
    610                 }
    611             }
    612             uprv_memcpy(p, ptr, sizeof(H)+(size_t)length*sizeof(T));
    613             releaseMemory();
    614             ptr=p;
    615             capacity=newCapacity;
    616             needToRelease=TRUE;
    617         }
    618         return p;
    619     } else {
    620         return NULL;
    621     }
    622 }
    623 
    624 template<typename H, typename T, int32_t stackCapacity>
    625 inline H *MaybeStackHeaderAndArray<H, T, stackCapacity>::orphanOrClone(int32_t length,
    626                                                                        int32_t &resultCapacity) {
    627     H *p;
    628     if(needToRelease) {
    629         p=ptr;
    630     } else {
    631         if(length<0) {
    632             length=0;
    633         } else if(length>capacity) {
    634             length=capacity;
    635         }
    636 #if U_DEBUG && defined(UPRV_MALLOC_COUNT)
    637       ::fprintf(::stderr,"MaybeStackHeaderAndArray (orphan) alloc %ul + %d * %lu\n", sizeof(H),length,sizeof(T));
    638 #endif
    639         p=(H *)uprv_malloc(sizeof(H)+length*sizeof(T));
    640         if(p==NULL) {
    641             return NULL;
    642         }
    643         uprv_memcpy(p, ptr, sizeof(H)+(size_t)length*sizeof(T));
    644     }
    645     resultCapacity=length;
    646     ptr=&stackHeader;
    647     capacity=stackCapacity;
    648     needToRelease=FALSE;
    649     return p;
    650 }
    651 
    652 U_NAMESPACE_END
    653 
    654 #endif  /* __cplusplus */
    655 #endif  /* CMEMORY_H */
    656