From 13ea3ff1e33313c7775013acaff4ec218bc632ff Mon Sep 17 00:00:00 2001 From: Dan Sinclair Date: Tue, 5 Sep 2017 11:19:35 -0400 Subject: Split random code from fx_extension.h This CL moves the code invovled in random number generation into fx_rand.h from fx_extension.h. Change-Id: I6c644d7ec0323f32ef6e23c2e2548a9c792e3a72 Reviewed-on: https://pdfium-review.googlesource.com/13070 Reviewed-by: Henrique Nakashima Commit-Queue: dsinclair --- core/fxcrt/fx_rand.cpp | 141 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+) create mode 100644 core/fxcrt/fx_rand.cpp (limited to 'core/fxcrt/fx_rand.cpp') diff --git a/core/fxcrt/fx_rand.cpp b/core/fxcrt/fx_rand.cpp new file mode 100644 index 0000000000..7a0c3e4d9b --- /dev/null +++ b/core/fxcrt/fx_rand.cpp @@ -0,0 +1,141 @@ +// 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_rand.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 +#else // _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_ +#include +#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(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(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((::rand() << 16) | (::rand() & 0xFFFF)); +} -- cgit v1.2.3