/* vim: set ts=4 sw=4 tw=99 et:

  *

  * Copyright (C) 2012 David Anderson

  *

  * This file is part of JITCraft.

  *

  * JITCraft is free software: you can redistribute it and/or modify it under

  * the terms of the GNU General Public License as published by the Free

  * Software Foundation, either version 3 of the License, or (at your option)

  * any later version.

  * 

  * Foobar is distributed in the hope that it will be useful, but WITHOUT ANY

  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License along with

  * JITCraft. If not, see http://www.gnu.org/licenses/.

  */

 #ifndef _include_jitcraft_utility_h_

 #define _include_jitcraft_utility_h_

 #include <assert.h>

 #include <stdint.h>

 #ifdef _MSC_VER

 # include <intrin.h>

 #endif

 #ifdef _MSC_VER

 # pragma warning(disable:4355)

 #endif

 namespace jc {

 static const size_t kMallocAlignment = sizeof(void *) * 2;

 typedef uint8_t uint8;

 typedef int32_t int32;

 typedef uint32_t uint32;

 typedef uint8 * Address;

 static const size_t kKB = 1024;

 static const size_t kMB = 1024 * kKB;

 static const size_t kGB = 1024 * kMB;

 template <typename T>

 class AutoVec

 {

     T *t_;

   public:

     AutoVec()

       : t_(NULL)

     {

     }

     AutoVec(T *t)

       : t_(t)

     {

     }

     ~AutoVec() {

         delete [] t_;

     }

     operator T *() {

         return t_;

     }

     void operator =(T *t) {

         if (t_)

             delete [] t_;

         t_ = t;

     }

 };

 // Bob Jenkin's one-at-a-time hash function[1].

 //

 // [1] http://burtleburtle.net/bob/hash/doobs.html

 class CharacterStreamHasher

 {

     uint32 hash;

   public:

     CharacterStreamHasher()

       : hash(0)

     { }

     void add(char c) {

         hash += c;

         hash += (hash << 10);

         hash ^= (hash >> 6);

     }

     void add(const char *s, size_t length) {

         for (size_t i = 0; i < length; i++)

             add(s[i]);

     }

     uint32 result() {

         hash += (hash << 3);

         hash ^= (hash >> 11);

         hash += (hash << 15);

         return hash;

     }

 };

 static inline uint32

 HashCharSequence(const char *s, size_t length)

 {

     CharacterStreamHasher hasher;

     hasher.add(s, length);

     return hasher.result();

 }

 static inline size_t

 Log2(size_t number)

 {

     assert(number != 0);

 #ifdef _MSC_VER

     unsigned long rval;

     _BitScanReverse(&rval, number);

     return rval;

 #else

 	size_t bit;

 	asm("bsr %1, %0\n"

 		: "=r" (bit)

 		: "rm" (number));

 	return bit;

 #endif

 }

 static inline size_t

 FindRightmostBit(size_t number)

 {

     assert(number != 0);

 #ifdef _MSC_VER

     unsigned long rval;

     _BitScanForward(&rval, number);

     return rval;

 #else

 	size_t bit;

 	asm("bsf %1, %0\n"

 		: "=r" (bit)

 		: "rm" (number));

 	return bit;

 #endif

 }

 static inline bool

 IsPowerOfTwo(size_t value)

 {

     if (value == 0)

         return false;

     return !(value & (value - 1));

 }

 static inline size_t

 Align(size_t count, size_t alignment)

 {

     assert(IsPowerOfTwo(alignment));

     return count + (alignment - (count % alignment)) % alignment;

 }

 static inline bool

 IsUint32AddSafe(unsigned a, unsigned b)

 {

     if (!a || !b)

         return true;

     unsigned log2_a = Log2(a);

     unsigned log2_b = Log2(b);

     return (log2_a < sizeof(unsigned) * 8) &&

            (log2_b < sizeof(unsigned) * 8);

 }

 static inline bool

 IsUintPtrAddSafe(size_t a, size_t b)

 {

     if (!a || !b)

         return true;

     size_t log2_a = Log2(a);

     size_t log2_b = Log2(b);

     return (log2_a < sizeof(size_t) * 8) &&

            (log2_b < sizeof(size_t) * 8);

 }

 static inline bool

 IsUint32MultiplySafe(unsigned a, unsigned b)

 {

     if (a <= 1 || b <= 1)

         return true;

     unsigned log2_a = Log2(a);

     unsigned log2_b = Log2(b);

     return log2_a + log2_b <= sizeof(unsigned) * 8;

 }

 static inline bool

 IsUintPtrMultiplySafe(size_t a, size_t b)

 {

     if (a <= 1 || b <= 1)

         return true;

     size_t log2_a = Log2(a);

     size_t log2_b = Log2(b);

     return log2_a + log2_b <= sizeof(size_t) * 8;

 }

 #define ARRAY_LENGTH(array) (sizeof(array) / sizeof(array[0]))

 #define STATIC_ASSERT(cond) extern int static_assert_f(int a[(cond) ? 1 : -1])

 #define IS_ALIGNED(addr, alignment)	(!(uintptr_t(addr) & ((alignment) - 1)))

 template <typename T>

 static inline bool

 IsAligned(T addr, size_t alignment)

 {

     assert(IsPowerOfTwo(alignment));

     return !(uintptr_t(addr) & (alignment - 1));

 }

 static inline Address

 AlignedBase(Address addr, size_t alignment)

 {

     assert(IsPowerOfTwo(alignment));

     return Address(uintptr_t(addr) & ~(alignment - 1));

 }

 template <typename T> static inline T

 Min(const T &t1, const T &t2)

 {

     return t1 < t2 ? t1 : t2;

 }

 }

 #endif // _include_jitcraft_utility_h_