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      1 /******************************************************************************
      2  *
      3  *  Copyright (C) 2016 Google, Inc.
      4  *
      5  *  Licensed under the Apache License, Version 2.0 (the "License");
      6  *  you may not use this file except in compliance with the License.
      7  *  You may obtain a copy of the License at:
      8  *
      9  *  http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  *  Unless required by applicable law or agreed to in writing, software
     12  *  distributed under the License is distributed on an "AS IS" BASIS,
     13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  *  See the License for the specific language governing permissions and
     15  *  limitations under the License.
     16  *
     17  ******************************************************************************/
     18 
     19 #pragma once
     20 
     21 #include <stdbool.h>
     22 #include <stdint.h>
     23 
     24 #define UNUSED_ATTR __attribute__((unused))
     25 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
     26 #define INVALID_FD (-1)
     27 
     28 #define CONCAT(a, b) a##b
     29 
     30 // Use during compile time to check conditional values
     31 // NOTE: The the failures will present as a generic error
     32 // "error: initialization makes pointer from integer without a cast"
     33 // but the file and line number will present the condition that
     34 // failed.
     35 #define DUMMY_COUNTER(c) CONCAT(__osi_dummy_, c)
     36 #define DUMMY_PTR DUMMY_COUNTER(__COUNTER__)
     37 
     38 // base/macros.h defines a COMPILE_ASSERT macro to the C++11 keyword
     39 // "static_assert" (it undef's COMPILE_ASSERT before redefining it).
     40 // C++ code that includes base and osi/include/osi.h can thus easily default to
     41 // the definition from libbase but we should check here to avoid compile errors.
     42 #ifndef COMPILE_ASSERT
     43 #define COMPILE_ASSERT(COND) \
     44   typedef int failed_compile_assert[(COND) ? 1 : -1] __attribute__((unused))
     45 #endif  // COMPILE_ASSERT
     46 
     47 // Macros for safe integer to pointer conversion. In the C language, data is
     48 // commonly cast to opaque pointer containers and back for generic parameter
     49 // passing in callbacks. These macros should be used sparingly in new code
     50 // (never in C++ code). Whenever integers need to be passed as a pointer, use
     51 // these macros.
     52 #define PTR_TO_UINT(p) ((unsigned int)((uintptr_t)(p)))
     53 #define UINT_TO_PTR(u) ((void*)((uintptr_t)(u)))
     54 
     55 #define PTR_TO_INT(p) ((int)((intptr_t)(p)))
     56 #define INT_TO_PTR(i) ((void*)((intptr_t)(i)))
     57 
     58 // Obtain a random number between 0 and INT_MAX inclusive.
     59 // Taken from a system random source such as /dev/random.
     60 // No guarantees of distribution are made.
     61 // Effort is made for this to come from a real random source.
     62 int osi_rand(void);
     63 
     64 // Re-run |fn| system call until the system call doesn't cause EINTR.
     65 #define OSI_NO_INTR(fn) \
     66   do {                  \
     67   } while ((fn) == -1 && errno == EINTR)
     68