| // Copyright 2017 PDFium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com |
| |
| #include "core/fxcrt/fx_random.h" |
| |
| #include "core/fxcrt/fx_memory.h" |
| #include "core/fxcrt/fx_string.h" |
| #include "core/fxcrt/fx_system.h" |
| |
| #define MT_N 848 |
| #define MT_M 456 |
| #define MT_Matrix_A 0x9908b0df |
| #define MT_Upper_Mask 0x80000000 |
| #define MT_Lower_Mask 0x7fffffff |
| |
| #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_ |
| #include <wincrypt.h> |
| #else // _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_ |
| #include <ctime> |
| #endif // _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_ |
| |
| namespace { |
| |
| struct MTContext { |
| MTContext() { |
| mti = MT_N + 1; |
| bHaveSeed = false; |
| } |
| |
| uint32_t mti; |
| bool bHaveSeed; |
| uint32_t mt[MT_N]; |
| }; |
| |
| #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_ |
| bool GenerateCryptoRandom(uint32_t* pBuffer, int32_t iCount) { |
| HCRYPTPROV hCP = 0; |
| if (!::CryptAcquireContext(&hCP, nullptr, nullptr, PROV_RSA_FULL, 0) || |
| !hCP) { |
| return false; |
| } |
| ::CryptGenRandom(hCP, iCount * sizeof(uint32_t), |
| reinterpret_cast<uint8_t*>(pBuffer)); |
| ::CryptReleaseContext(hCP, 0); |
| return true; |
| } |
| #endif |
| |
| } // namespace |
| |
| void* FX_Random_MT_Start(uint32_t dwSeed) { |
| MTContext* pContext = FX_Alloc(MTContext, 1); |
| pContext->mt[0] = dwSeed; |
| uint32_t& i = pContext->mti; |
| uint32_t* pBuf = pContext->mt; |
| for (i = 1; i < MT_N; i++) |
| pBuf[i] = (1812433253UL * (pBuf[i - 1] ^ (pBuf[i - 1] >> 30)) + i); |
| |
| pContext->bHaveSeed = true; |
| return pContext; |
| } |
| |
| uint32_t FX_Random_MT_Generate(void* pContext) { |
| ASSERT(pContext); |
| |
| MTContext* pMTC = static_cast<MTContext*>(pContext); |
| uint32_t v; |
| static uint32_t mag[2] = {0, MT_Matrix_A}; |
| uint32_t& mti = pMTC->mti; |
| uint32_t* pBuf = pMTC->mt; |
| if ((int)mti < 0 || mti >= MT_N) { |
| if (mti > MT_N && !pMTC->bHaveSeed) |
| return 0; |
| |
| uint32_t kk; |
| for (kk = 0; kk < MT_N - MT_M; kk++) { |
| v = (pBuf[kk] & MT_Upper_Mask) | (pBuf[kk + 1] & MT_Lower_Mask); |
| pBuf[kk] = pBuf[kk + MT_M] ^ (v >> 1) ^ mag[v & 1]; |
| } |
| for (; kk < MT_N - 1; kk++) { |
| v = (pBuf[kk] & MT_Upper_Mask) | (pBuf[kk + 1] & MT_Lower_Mask); |
| pBuf[kk] = pBuf[kk + (MT_M - MT_N)] ^ (v >> 1) ^ mag[v & 1]; |
| } |
| v = (pBuf[MT_N - 1] & MT_Upper_Mask) | (pBuf[0] & MT_Lower_Mask); |
| pBuf[MT_N - 1] = pBuf[MT_M - 1] ^ (v >> 1) ^ mag[v & 1]; |
| mti = 0; |
| } |
| v = pBuf[mti++]; |
| v ^= (v >> 11); |
| v ^= (v << 7) & 0x9d2c5680UL; |
| v ^= (v << 15) & 0xefc60000UL; |
| v ^= (v >> 18); |
| return v; |
| } |
| |
| void FX_Random_MT_Close(void* pContext) { |
| ASSERT(pContext); |
| FX_Free(pContext); |
| } |
| |
| void FX_Random_GenerateMT(uint32_t* pBuffer, int32_t iCount) { |
| uint32_t dwSeed; |
| #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_ |
| if (!GenerateCryptoRandom(&dwSeed, 1)) |
| FX_Random_GenerateBase(&dwSeed, 1); |
| #else |
| FX_Random_GenerateBase(&dwSeed, 1); |
| #endif |
| void* pContext = FX_Random_MT_Start(dwSeed); |
| while (iCount-- > 0) |
| *pBuffer++ = FX_Random_MT_Generate(pContext); |
| |
| FX_Random_MT_Close(pContext); |
| } |
| |
| void FX_Random_GenerateBase(uint32_t* pBuffer, int32_t iCount) { |
| #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_ |
| SYSTEMTIME st1, st2; |
| ::GetSystemTime(&st1); |
| do { |
| ::GetSystemTime(&st2); |
| } while (memcmp(&st1, &st2, sizeof(SYSTEMTIME)) == 0); |
| uint32_t dwHash1 = |
| FX_HashCode_GetA(CFX_ByteStringC((uint8_t*)&st1, sizeof(st1)), true); |
| uint32_t dwHash2 = |
| FX_HashCode_GetA(CFX_ByteStringC((uint8_t*)&st2, sizeof(st2)), true); |
| ::srand((dwHash1 << 16) | (uint32_t)dwHash2); |
| #else |
| time_t tmLast = time(nullptr); |
| time_t tmCur; |
| while ((tmCur = time(nullptr)) == tmLast) |
| continue; |
| |
| ::srand((tmCur << 16) | (tmLast & 0xFFFF)); |
| #endif |
| while (iCount-- > 0) |
| *pBuffer++ = static_cast<uint32_t>((::rand() << 16) | (::rand() & 0xFFFF)); |
| } |