icuSources/common/cmemory.h

   1 // © 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 */