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authorDan Sinclair <dsinclair@chromium.org>2017-09-05 11:19:35 -0400
committerChromium commit bot <commit-bot@chromium.org>2017-09-05 16:12:08 +0000
commit13ea3ff1e33313c7775013acaff4ec218bc632ff (patch)
tree6c0b5efdd062076f1bb87adf51c870fd9d90a3d1 /core/fxcrt/fx_rand.cpp
parent4fde70e28c6aff85ad30a958823e658678f5cfb6 (diff)
downloadpdfium-13ea3ff1e33313c7775013acaff4ec218bc632ff.tar.xz
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 <hnakashima@chromium.org> Commit-Queue: dsinclair <dsinclair@chromium.org>
Diffstat (limited to 'core/fxcrt/fx_rand.cpp')
-rw-r--r--core/fxcrt/fx_rand.cpp141
1 files changed, 141 insertions, 0 deletions
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 <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));
+}