icuSources/common/putilimp.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 NAME : putilimp.h
  12 *
  13 *   Date        Name        Description
  14 *   10/17/04    grhoten     Move internal functions from putil.h to this file.
  15 ******************************************************************************
  16 */
  17
  18 #ifndef PUTILIMP_H
  19 #define PUTILIMP_H
  20
  21 #include "unicode/utypes.h"
  22 #include "unicode/putil.h"
  23
  24 /**
  25  * \def U_SIGNED_RIGHT_SHIFT_IS_ARITHMETIC
  26  * Nearly all CPUs and compilers implement a right-shift of a signed integer
  27  * as an Arithmetic Shift Right which copies the sign bit (the Most Significant Bit (MSB))
  28  * into the vacated bits (sign extension).
  29  * For example, (int32_t)0xfff5fff3>>4 becomes 0xffff5fff and -1>>1=-1.
  30  *
  31  * This can be useful for storing a signed value in the upper bits
  32  * and another bit field in the lower bits.
  33  * The signed value can be retrieved by simple right-shifting.
  34  *
  35  * This is consistent with the Java language.
  36  *
  37  * However, the C standard allows compilers to implement a right-shift of a signed integer
  38  * as a Logical Shift Right which copies a 0 into the vacated bits.
  39  * For example, (int32_t)0xfff5fff3>>4 becomes 0x0fff5fff and -1>>1=0x7fffffff.
  40  *
  41  * Code that depends on the natural behavior should be guarded with this macro,
  42  * with an alternate path for unusual platforms.
  43  * @internal
  44  */
  45 #ifdef U_SIGNED_RIGHT_SHIFT_IS_ARITHMETIC
  46     /* Use the predefined value. */
  47 #else
  48     /*
  49      * Nearly all CPUs & compilers implement a right-shift of a signed integer
  50      * as an Arithmetic Shift Right (with sign extension).
  51      */
  52 #   define U_SIGNED_RIGHT_SHIFT_IS_ARITHMETIC 1
  53 #endif
  54
  55 /** Define this to 1 if your platform supports IEEE 754 floating point,
  56    to 0 if it does not. */
  57 #ifndef IEEE_754
  58 #   define IEEE_754 1
  59 #endif
  60
  61 /**
  62  * uintptr_t is an optional part of the standard definitions in stdint.h.
  63  * The opengroup.org documentation for stdint.h says
  64  * "On XSI-conformant systems, the intptr_t and uintptr_t types are required;
  65  * otherwise, they are optional."
  66  * We assume that when uintptr_t is defined, UINTPTR_MAX is defined as well.
  67  *
  68  * Do not use ptrdiff_t since it is signed. size_t is unsigned.
  69  */
  70 /* TODO: This check fails on some z environments. Filed a ticket #9357 for this. */
  71 #if !defined(__intptr_t_defined) && !defined(UINTPTR_MAX) && (U_PLATFORM != U_PF_OS390)
  72 typedef size_t uintptr_t;
  73 #endif
  74
  75 /*===========================================================================*/
  76 /** @{ Information about POSIX support                                       */
  77 /*===========================================================================*/
  78
  79 #ifdef U_HAVE_NL_LANGINFO_CODESET
  80     /* Use the predefined value. */
  81 #elif U_PLATFORM_USES_ONLY_WIN32_API || U_PLATFORM == U_PF_ANDROID || U_PLATFORM == U_PF_QNX
  82 #   define U_HAVE_NL_LANGINFO_CODESET 0
  83 #else
  84 #   define U_HAVE_NL_LANGINFO_CODESET 1
  85 #endif
  86
  87 #ifdef U_NL_LANGINFO_CODESET
  88     /* Use the predefined value. */
  89 #elif !U_HAVE_NL_LANGINFO_CODESET
  90 #   define U_NL_LANGINFO_CODESET -1
  91 #elif U_PLATFORM == U_PF_OS400
  92    /* not defined */
  93 #else
  94 #   define U_NL_LANGINFO_CODESET CODESET
  95 #endif
  96
  97 #if defined(U_TZSET) || defined(U_HAVE_TZSET)
  98     /* Use the predefined value. */
  99 #elif U_PLATFORM_USES_ONLY_WIN32_API
 100     // UWP doesn't support tzset or environment variables for tz
 101 #if U_PLATFORM_HAS_WINUWP_API == 0
 102 #   define U_TZSET _tzset
 103 #endif
 104 #elif U_PLATFORM == U_PF_OS400
 105    /* not defined */
 106 #else
 107 #   define U_TZSET tzset
 108 #endif
 109
 110 #if defined(U_TIMEZONE) || defined(U_HAVE_TIMEZONE)
 111     /* Use the predefined value. */
 112 #elif U_PLATFORM == U_PF_ANDROID
 113 #   define U_TIMEZONE timezone
 114 #elif defined(__UCLIBC__)
 115     // uClibc does not have __timezone or _timezone.
 116 #elif defined(_NEWLIB_VERSION)
 117 #   define U_TIMEZONE _timezone
 118 #elif defined(__GLIBC__)
 119     // glibc
 120 #   define U_TIMEZONE __timezone
 121 #elif U_PLATFORM_IS_LINUX_BASED
 122     // not defined
 123 #elif U_PLATFORM_USES_ONLY_WIN32_API
 124 #   define U_TIMEZONE _timezone
 125 #elif U_PLATFORM == U_PF_BSD && !defined(__NetBSD__)
 126    /* not defined */
 127 #elif U_PLATFORM == U_PF_OS400
 128    /* not defined */
 129 #elif U_PLATFORM == U_PF_IPHONE
 130    /* not defined */
 131 #else
 132 #   define U_TIMEZONE timezone
 133 #endif
 134
 135 #if defined(U_TZNAME) || defined(U_HAVE_TZNAME)
 136     /* Use the predefined value. */
 137 #elif U_PLATFORM_USES_ONLY_WIN32_API
 138     /* not usable on all windows platforms */
 139 #if U_PLATFORM_HAS_WINUWP_API == 0
 140 #   define U_TZNAME _tzname
 141 #endif
 142 #elif U_PLATFORM == U_PF_OS400
 143    /* not defined */
 144 #else
 145 #   define U_TZNAME tzname
 146 #endif
 147
 148 #ifdef U_HAVE_MMAP
 149     /* Use the predefined value. */
 150 #elif U_PLATFORM_USES_ONLY_WIN32_API
 151 #   define U_HAVE_MMAP 0
 152 #else
 153 #   define U_HAVE_MMAP 1
 154 #endif
 155
 156 #ifdef U_HAVE_POPEN
 157     /* Use the predefined value. */
 158 #elif U_PLATFORM_USES_ONLY_WIN32_API
 159 #   define U_HAVE_POPEN 0
 160 #elif U_PLATFORM == U_PF_OS400
 161 #   define U_HAVE_POPEN 0
 162 #else
 163 #   define U_HAVE_POPEN 1
 164 #endif
 165
 166 /**
 167  * \def U_HAVE_DIRENT_H
 168  * Defines whether dirent.h is available.
 169  * @internal
 170  */
 171 #ifdef U_HAVE_DIRENT_H
 172     /* Use the predefined value. */
 173 #elif U_PLATFORM_USES_ONLY_WIN32_API
 174 #   define U_HAVE_DIRENT_H 0
 175 #else
 176 #   define U_HAVE_DIRENT_H 1
 177 #endif
 178
 179 /** @} */
 180
 181 /*===========================================================================*/
 182 /** @{ GCC built in functions for atomic memory operations                   */
 183 /*===========================================================================*/
 184
 185 /**
 186  * \def U_HAVE_GCC_ATOMICS
 187  * @internal
 188  */
 189 #ifdef U_HAVE_GCC_ATOMICS
 190     /* Use the predefined value. */
 191 #elif U_PLATFORM == U_PF_MINGW
 192     #define U_HAVE_GCC_ATOMICS 0
 193 #elif U_GCC_MAJOR_MINOR >= 404 || defined(__clang__)
 194     /* TODO: Intel icc and IBM xlc on AIX also support gcc atomics.  (Intel originated them.)
 195      *       Add them for these compilers.
 196      * Note: Clang sets __GNUC__ defines for version 4.2, so misses the 4.4 test here.
 197      */
 198 #   define U_HAVE_GCC_ATOMICS 1
 199 #else
 200 #   define U_HAVE_GCC_ATOMICS 0
 201 #endif
 202
 203 /** @} */
 204
 205 /**
 206  * \def U_HAVE_STD_ATOMICS
 207  * Defines whether to use the C++11 std::atomic functions.
 208  * If false, ICU will fall back to compiler or platform specific alternatives.
 209  * Note: support for these fall back options for atomics will be removed in a future version
 210  *       of ICU, and the use of C++ 11 atomics will be required.
 211  * @internal
 212  */
 213 #ifdef U_HAVE_STD_ATOMICS
 214     /* Use the predefined value. */
 215 #else
 216 #    define U_HAVE_STD_ATOMICS 1
 217 #endif
 218
 219 /**
 220  *  \def U_HAVE_CLANG_ATOMICS
 221  *  Defines whether Clang c11 style built-in atomics are available.
 222  *  These are used in preference to gcc atomics when both are available.
 223  */
 224 #ifdef U_HAVE_CLANG_ATOMICS
 225     /* Use the predefined value. */
 226 #elif __has_builtin(__c11_atomic_load) && \
 227     __has_builtin(__c11_atomic_store) && \
 228     __has_builtin(__c11_atomic_fetch_add) && \
 229     __has_builtin(__c11_atomic_fetch_sub)
 230 #    define U_HAVE_CLANG_ATOMICS 1
 231 #else
 232 #    define U_HAVE_CLANG_ATOMICS 0
 233 #endif
 234
 235
 236 /**
 237  * \def U_HAVE_STD_MUTEX
 238  * Defines whether to use the C++11 std::mutex functions.
 239  * If false, ICU will fall back to compiler or platform specific alternatives.
 240  * std::mutex is preferred, and used by default unless this setting is overridden.
 241  * Note: support for other options for mutexes will be removed in a future version
 242  *       of ICU, and the use of std::mutex will be required.
 243  * @internal
 244  */
 245 #ifdef U_HAVE_STD_MUTEX
 246     /* Use the predefined value. */
 247 #else
 248 #    define U_HAVE_STD_MUTEX 1
 249 #endif
 250
 251 /*===========================================================================*/
 252 /** @{ Programs used by ICU code                                             */
 253 /*===========================================================================*/
 254
 255 /**
 256  * \def U_MAKE_IS_NMAKE
 257  * Defines whether the "make" program is Windows nmake.
 258  */
 259 #ifdef U_MAKE_IS_NMAKE
 260     /* Use the predefined value. */
 261 #elif U_PLATFORM == U_PF_WINDOWS
 262 #   define U_MAKE_IS_NMAKE 1
 263 #else
 264 #   define U_MAKE_IS_NMAKE 0
 265 #endif
 266
 267 /** @} */
 268
 269 /*==========================================================================*/
 270 /* Platform utilities                                                       */
 271 /*==========================================================================*/
 272
 273 /**
 274  * Platform utilities isolates the platform dependencies of the
 275  * library.  For each platform which this code is ported to, these
 276  * functions may have to be re-implemented.
 277  */
 278
 279 /**
 280  * Floating point utility to determine if a double is Not a Number (NaN).
 281  * @internal
 282  */
 283 U_INTERNAL UBool   U_EXPORT2 uprv_isNaN(double d);
 284 /**
 285  * Floating point utility to determine if a double has an infinite value.
 286  * @internal
 287  */
 288 U_INTERNAL UBool   U_EXPORT2 uprv_isInfinite(double d);
 289 /**
 290  * Floating point utility to determine if a double has a positive infinite value.
 291  * @internal
 292  */
 293 U_INTERNAL UBool   U_EXPORT2 uprv_isPositiveInfinity(double d);
 294 /**
 295  * Floating point utility to determine if a double has a negative infinite value.
 296  * @internal
 297  */
 298 U_INTERNAL UBool   U_EXPORT2 uprv_isNegativeInfinity(double d);
 299 /**
 300  * Floating point utility that returns a Not a Number (NaN) value.
 301  * @internal
 302  */
 303 U_INTERNAL double  U_EXPORT2 uprv_getNaN(void);
 304 /**
 305  * Floating point utility that returns an infinite value.
 306  * @internal
 307  */
 308 U_INTERNAL double  U_EXPORT2 uprv_getInfinity(void);
 309
 310 /**
 311  * Floating point utility to truncate a double.
 312  * @internal
 313  */
 314 U_INTERNAL double  U_EXPORT2 uprv_trunc(double d);
 315 /**
 316  * Floating point utility to calculate the floor of a double.
 317  * @internal
 318  */
 319 U_INTERNAL double  U_EXPORT2 uprv_floor(double d);
 320 /**
 321  * Floating point utility to calculate the ceiling of a double.
 322  * @internal
 323  */
 324 U_INTERNAL double  U_EXPORT2 uprv_ceil(double d);
 325 /**
 326  * Floating point utility to calculate the absolute value of a double.
 327  * @internal
 328  */
 329 U_INTERNAL double  U_EXPORT2 uprv_fabs(double d);
 330 /**
 331  * Floating point utility to calculate the fractional and integer parts of a double.
 332  * @internal
 333  */
 334 U_INTERNAL double  U_EXPORT2 uprv_modf(double d, double* pinteger);
 335 /**
 336  * Floating point utility to calculate the remainder of a double divided by another double.
 337  * @internal
 338  */
 339 U_INTERNAL double  U_EXPORT2 uprv_fmod(double d, double y);
 340 /**
 341  * Floating point utility to calculate d to the power of exponent (d^exponent).
 342  * @internal
 343  */
 344 U_INTERNAL double  U_EXPORT2 uprv_pow(double d, double exponent);
 345 /**
 346  * Floating point utility to calculate 10 to the power of exponent (10^exponent).
 347  * @internal
 348  */
 349 U_INTERNAL double  U_EXPORT2 uprv_pow10(int32_t exponent);
 350 /**
 351  * Floating point utility to calculate the maximum value of two doubles.
 352  * @internal
 353  */
 354 U_INTERNAL double  U_EXPORT2 uprv_fmax(double d, double y);
 355 /**
 356  * Floating point utility to calculate the minimum value of two doubles.
 357  * @internal
 358  */
 359 U_INTERNAL double  U_EXPORT2 uprv_fmin(double d, double y);
 360 /**
 361  * Private utility to calculate the maximum value of two integers.
 362  * @internal
 363  */
 364 U_INTERNAL int32_t U_EXPORT2 uprv_max(int32_t d, int32_t y);
 365 /**
 366  * Private utility to calculate the minimum value of two integers.
 367  * @internal
 368  */
 369 U_INTERNAL int32_t U_EXPORT2 uprv_min(int32_t d, int32_t y);
 370
 371 #if U_IS_BIG_ENDIAN
 372 #   define uprv_isNegative(number) (*((signed char *)&(number))<0)
 373 #else
 374 #   define uprv_isNegative(number) (*((signed char *)&(number)+sizeof(number)-1)<0)
 375 #endif
 376
 377 /**
 378  * Return the largest positive number that can be represented by an integer
 379  * type of arbitrary bit length.
 380  * @internal
 381  */
 382 U_INTERNAL double  U_EXPORT2 uprv_maxMantissa(void);
 383
 384 /**
 385  * Floating point utility to calculate the logarithm of a double.
 386  * @internal
 387  */
 388 U_INTERNAL double  U_EXPORT2 uprv_log(double d);
 389
 390 /**
 391  * Does common notion of rounding e.g. uprv_floor(x + 0.5);
 392  * @param x the double number
 393  * @return the rounded double
 394  * @internal
 395  */
 396 U_INTERNAL double  U_EXPORT2 uprv_round(double x);
 397
 398 /**
 399  * Adds the signed integers a and b, storing the result in res.
 400  * Checks for signed integer overflow.
 401  * Similar to the GCC/Clang extension __builtin_add_overflow
 402  *
 403  * @param a The first operand.
 404  * @param b The second operand.
 405  * @param res a + b
 406  * @return true if overflow occurred; false if no overflow occurred.
 407  * @internal
 408  */
 409 U_INTERNAL UBool U_EXPORT2 uprv_add32_overflow(int32_t a, int32_t b, int32_t* res);
 410
 411 /**
 412  * Multiplies the signed integers a and b, storing the result in res.
 413  * Checks for signed integer overflow.
 414  * Similar to the GCC/Clang extension __builtin_mul_overflow
 415  *
 416  * @param a The first multiplicand.
 417  * @param b The second multiplicand.
 418  * @param res a * b
 419  * @return true if overflow occurred; false if no overflow occurred.
 420  * @internal
 421  */
 422 U_INTERNAL UBool U_EXPORT2 uprv_mul32_overflow(int32_t a, int32_t b, int32_t* res);
 423
 424 #if 0
 425 /**
 426  * Returns the number of digits after the decimal point in a double number x.
 427  *
 428  * @param x the double number
 429  * @return the number of digits after the decimal point in a double number x.
 430  * @internal
 431  */
 432 /*U_INTERNAL int32_t  U_EXPORT2 uprv_digitsAfterDecimal(double x);*/
 433 #endif
 434
 435 #if !U_CHARSET_IS_UTF8
 436 /**
 437  * Please use ucnv_getDefaultName() instead.
 438  * Return the default codepage for this platform and locale.
 439  * This function can call setlocale() on Unix platforms. Please read the
 440  * platform documentation on setlocale() before calling this function.
 441  * @return the default codepage for this platform
 442  * @internal
 443  */
 444 U_INTERNAL const char*  U_EXPORT2 uprv_getDefaultCodepage(void);
 445 #endif
 446
 447 /**
 448  * Please use uloc_getDefault() instead.
 449  * Return the default locale ID string by querying the system, or
 450  *     zero if one cannot be found.
 451  * This function can call setlocale() on Unix platforms. Please read the
 452  * platform documentation on setlocale() before calling this function.
 453  * @return the default locale ID string
 454  * @internal
 455  */
 456 U_INTERNAL const char*  U_EXPORT2 uprv_getDefaultLocaleID(void);
 457
 458 /**
 459  * Time zone utilities
 460  *
 461  * Wrappers for C runtime library functions relating to timezones.
 462  * The t_tzset() function (similar to tzset) uses the current setting
 463  * of the environment variable TZ to assign values to three global
 464  * variables: daylight, timezone, and tzname. These variables have the
 465  * following meanings, and are declared in &lt;time.h&gt;.
 466  *
 467  *   daylight   Nonzero if daylight-saving-time zone (DST) is specified
 468  *              in TZ; otherwise, 0. Default value is 1.
 469  *   timezone   Difference in seconds between coordinated universal
 470  *              time and local time. E.g., -28,800 for PST (GMT-8hrs)
 471  *   tzname(0)  Three-letter time-zone name derived from TZ environment
 472  *              variable. E.g., "PST".
 473  *   tzname(1)  Three-letter DST zone name derived from TZ environment
 474  *              variable.  E.g., "PDT". If DST zone is omitted from TZ,
 475  *              tzname(1) is an empty string.
 476  *
 477  * Notes: For example, to set the TZ environment variable to correspond
 478  * to the current time zone in Germany, you can use one of the
 479  * following statements:
 480  *
 481  *   set TZ=GST1GDT
 482  *   set TZ=GST+1GDT
 483  *
 484  * If the TZ value is not set, t_tzset() attempts to use the time zone
 485  * information specified by the operating system. Under Windows NT
 486  * and Windows 95, this information is specified in the Control Panel's
 487  * Date/Time application.
 488  * @internal
 489  */
 490 U_INTERNAL void     U_EXPORT2 uprv_tzset(void);
 491
 492 /**
 493  * Difference in seconds between coordinated universal
 494  * time and local time. E.g., -28,800 for PST (GMT-8hrs)
 495  * @return the difference in seconds between coordinated universal time and local time.
 496  * @internal
 497  */
 498 U_INTERNAL int32_t  U_EXPORT2 uprv_timezone(void);
 499
 500 /**
 501  *   tzname(0)  Three-letter time-zone name derived from TZ environment
 502  *              variable. E.g., "PST".
 503  *   tzname(1)  Three-letter DST zone name derived from TZ environment
 504  *              variable.  E.g., "PDT". If DST zone is omitted from TZ,
 505  *              tzname(1) is an empty string.
 506  * @internal
 507  */
 508 U_INTERNAL const char* U_EXPORT2 uprv_tzname(int n);
 509
 510 /**
 511  * Reset the global tzname cache.
 512  * @internal
 513  */
 514 U_INTERNAL void uprv_tzname_clear_cache();
 515
 516 /**
 517  * Get UTC (GMT) time measured in milliseconds since 0:00 on 1/1/1970.
 518  * This function is affected by 'faketime' and should be the bottleneck for all user-visible ICU time functions.
 519  * @return the UTC time measured in milliseconds
 520  * @internal
 521  */
 522 U_INTERNAL UDate U_EXPORT2 uprv_getUTCtime(void);
 523
 524 /**
 525  * Get UTC (GMT) time measured in milliseconds since 0:00 on 1/1/1970.
 526  * This function is not affected by 'faketime', so it should only be used by low level test functions- not by anything that
 527  * exposes time to the end user.
 528  * @return the UTC time measured in milliseconds
 529  * @internal
 530  */
 531 U_INTERNAL UDate U_EXPORT2 uprv_getRawUTCtime(void);
 532
 533 /**
 534  * Determine whether a pathname is absolute or not, as defined by the platform.
 535  * @param path Pathname to test
 536  * @return TRUE if the path is absolute
 537  * @internal (ICU 3.0)
 538  */
 539 U_INTERNAL UBool U_EXPORT2 uprv_pathIsAbsolute(const char *path);
 540
 541 /**
 542  * Use U_MAX_PTR instead of this function.
 543  * @param void pointer to test
 544  * @return the largest possible pointer greater than the base
 545  * @internal (ICU 3.8)
 546  */
 547 U_INTERNAL void * U_EXPORT2 uprv_maximumPtr(void *base);
 548
 549 /**
 550  * Maximum value of a (void*) - use to indicate the limit of an 'infinite' buffer.
 551  * In fact, buffer sizes must not exceed 2GB so that the difference between
 552  * the buffer limit and the buffer start can be expressed in an int32_t.
 553  *
 554  * The definition of U_MAX_PTR must fulfill the following conditions:
 555  * - return the largest possible pointer greater than base
 556  * - return a valid pointer according to the machine architecture (AS/400, 64-bit, etc.)
 557  * - avoid wrapping around at high addresses
 558  * - make sure that the returned pointer is not farther from base than 0x7fffffff bytes
 559  *
 560  * @param base The beginning of a buffer to find the maximum offset from
 561  * @internal
 562  */
 563 #ifndef U_MAX_PTR
 564 #  if U_PLATFORM == U_PF_OS390 && !defined(_LP64)
 565     /* We have 31-bit pointers. */
 566 #    define U_MAX_PTR(base) ((void *)0x7fffffff)
 567 #  elif U_PLATFORM == U_PF_OS400
 568 #    define U_MAX_PTR(base) uprv_maximumPtr((void *)base)
 569 #  elif 0
 570     /*
 571      * For platforms where pointers are scalar values (which is normal, but unlike i5/OS)
 572      * but that do not define uintptr_t.
 573      *
 574      * However, this does not work on modern compilers:
 575      * The C++ standard does not define pointer overflow, and allows compilers to
 576      * assume that p+u>p for any pointer p and any integer u>0.
 577      * Thus, modern compilers optimize away the ">" comparison.
 578      * (See ICU tickets #7187 and #8096.)
 579      */
 580 #    define U_MAX_PTR(base) \
 581     ((void *)(((char *)(base)+0x7fffffffu) > (char *)(base) \
 582         ? ((char *)(base)+0x7fffffffu) \
 583         : (char *)-1))
 584 #  else
 585     /* Default version. C++ standard compliant for scalar pointers. */
 586 #    define U_MAX_PTR(base) \
 587     ((void *)(((uintptr_t)(base)+0x7fffffffu) > (uintptr_t)(base) \
 588         ? ((uintptr_t)(base)+0x7fffffffu) \
 589         : (uintptr_t)-1))
 590 #  endif
 591 #endif
 592
 593
 594 #ifdef __cplusplus
 595 /**
 596  * Pin a buffer capacity such that doing pointer arithmetic
 597  * on the destination pointer and capacity cannot overflow.
 598  *
 599  * The pinned capacity must fulfill the following conditions (for positive capacities):
 600  *   - dest + capacity is a valid pointer according to the machine arcitecture (AS/400, 64-bit, etc.)
 601  *   - (dest + capacity) >= dest
 602  *   - The size (in bytes) of T[capacity] does not exceed 0x7fffffff
 603  *
 604  * @param dest the destination buffer pointer.
 605  * @param capacity the requested buffer capacity, in units of type T.
 606  * @return the pinned capacity.
 607  * @internal
 608  */
 609 template <typename T>
 610 inline int32_t pinCapacity(T *dest, int32_t capacity) {
 611     if (capacity <= 0) { return capacity; }
 612
 613     uintptr_t destInt = (uintptr_t)dest;
 614     uintptr_t maxInt;
 615
 616 #  if U_PLATFORM == U_PF_OS390 && !defined(_LP64)
 617     // We have 31-bit pointers.
 618     maxInt = 0x7fffffff;
 619 #  elif U_PLATFORM == U_PF_OS400
 620     maxInt = (uintptr_t)uprv_maximumPtr((void *)dest);
 621 #  else
 622     maxInt = destInt + 0x7fffffffu;
 623     if (maxInt < destInt) {
 624         // Less than 2GB to the end of the address space.
 625         // Pin to that to prevent address overflow.
 626         maxInt = (uintptr_t)-1;
 627     }
 628 #  endif
 629
 630     uintptr_t maxBytes = maxInt - destInt;  // max. 2GB
 631     int32_t maxCapacity = (int32_t)(maxBytes / sizeof(T));
 632     return capacity <= maxCapacity ? capacity : maxCapacity;
 633 }
 634 #endif   // __cplusplus
 635
 636 /*  Dynamic Library Functions */
 637
 638 typedef void (UVoidFunction)(void);
 639
 640 #if U_ENABLE_DYLOAD
 641 /**
 642  * Load a library
 643  * @internal (ICU 4.4)
 644  */
 645 U_INTERNAL void * U_EXPORT2 uprv_dl_open(const char *libName, UErrorCode *status);
 646
 647 /**
 648  * Close a library
 649  * @internal (ICU 4.4)
 650  */
 651 U_INTERNAL void U_EXPORT2 uprv_dl_close( void *lib, UErrorCode *status);
 652
 653 /**
 654  * Extract a symbol from a library (function)
 655  * @internal (ICU 4.8)
 656  */
 657 U_INTERNAL UVoidFunction* U_EXPORT2 uprv_dlsym_func( void *lib, const char *symbolName, UErrorCode *status);
 658
 659 /**
 660  * Extract a symbol from a library (function)
 661  * Not implemented, no clients.
 662  * @internal
 663  */
 664 /* U_INTERNAL void * U_EXPORT2 uprv_dlsym_data( void *lib, const char *symbolName, UErrorCode *status); */
 665
 666 #endif
 667
 668 /**
 669  * Define malloc and related functions
 670  * @internal
 671  */
 672 #if U_PLATFORM == U_PF_OS400
 673 # define uprv_default_malloc(x) _C_TS_malloc(x)
 674 # define uprv_default_realloc(x,y) _C_TS_realloc(x,y)
 675 # define uprv_default_free(x) _C_TS_free(x)
 676 /* also _C_TS_calloc(x) */
 677 #else
 678 /* C defaults */
 679 # define uprv_default_malloc(x) malloc(x)
 680 # define uprv_default_realloc(x,y) realloc(x,y)
 681 # define uprv_default_free(x) free(x)
 682 #endif
 683
 684
 685 #endif