1 files changed, 151 insertions, 0 deletions
diff --git a/core/fxcrt/cfx_checksumcontext.cpp b/core/fxcrt/cfx_checksumcontext.cpp
new file mode 100644
index 0000000000..994d18604a
--- /dev/null
+++ b/core/fxcrt/cfx_checksumcontext.cpp
@@ -0,0 +1,151 @@
+// Copyright 2014 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/cfx_checksumcontext.h"
+
+#include "core/fdrm/crypto/fx_crypt.h"
+#include "core/fxcrt/xml/cfx_saxreaderhandler.h"
+#include "third_party/base/ptr_util.h"
+
+namespace {
+
+struct FX_BASE64DATA {
+  uint32_t data1 : 2;
+  uint32_t data2 : 6;
+  uint32_t data3 : 4;
+  uint32_t data4 : 4;
+  uint32_t data5 : 6;
+  uint32_t data6 : 2;
+  uint32_t data7 : 8;
+};
+
+const char g_FXBase64EncoderMap[64] = {
+    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
+    'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
+    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
+    'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
+    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/',
+};
+
+void Base64EncodePiece(const FX_BASE64DATA& src, int32_t iBytes, char dst[4]) {
+  dst[0] = g_FXBase64EncoderMap[src.data2];
+  uint32_t b = src.data1 << 4;
+  if (iBytes > 1) {
+    b |= src.data4;
+  }
+  dst[1] = g_FXBase64EncoderMap[b];
+  if (iBytes > 1) {
+    b = src.data3 << 2;
+    if (iBytes > 2) {
+      b |= src.data6;
+    }
+    dst[2] = g_FXBase64EncoderMap[b];
+    if (iBytes > 2) {
+      dst[3] = g_FXBase64EncoderMap[src.data5];
+    } else {
+      dst[3] = '=';
+    }
+  } else {
+    dst[2] = dst[3] = '=';
+  }
+}
+
+int32_t Base64EncodeA(const uint8_t* pSrc, int32_t iSrcLen, char* pDst) {
+  ASSERT(pSrc);
+  if (iSrcLen < 1) {
+    return 0;
+  }
+  if (!pDst) {
+    int32_t iDstLen = iSrcLen / 3 * 4;
+    if ((iSrcLen % 3) != 0) {
+      iDstLen += 4;
+    }
+    return iDstLen;
+  }
+  FX_BASE64DATA srcData;
+  int32_t iBytes = 3;
+  char* pDstEnd = pDst;
+  while (iSrcLen > 0) {
+    if (iSrcLen > 2) {
+      ((uint8_t*)&srcData)[0] = *pSrc++;
+      ((uint8_t*)&srcData)[1] = *pSrc++;
+      ((uint8_t*)&srcData)[2] = *pSrc++;
+      iSrcLen -= 3;
+    } else {
+      *((uint32_t*)&srcData) = 0;
+      ((uint8_t*)&srcData)[0] = *pSrc++;
+      if (iSrcLen > 1) {
+        ((uint8_t*)&srcData)[1] = *pSrc++;
+      }
+      iBytes = iSrcLen;
+      iSrcLen = 0;
+    }
+    Base64EncodePiece(srcData, iBytes, pDstEnd);
+    pDstEnd += 4;
+  }
+  return pDstEnd - pDst;
+}
+
+}  // namespace
+
+CFX_ChecksumContext::CFX_ChecksumContext() {}
+
+CFX_ChecksumContext::~CFX_ChecksumContext() {}
+
+void CFX_ChecksumContext::StartChecksum() {
+  FinishChecksum();
+  m_pByteContext = pdfium::MakeUnique<CRYPT_sha1_context>();
+  CRYPT_SHA1Start(m_pByteContext.get());
+  m_bsChecksum.clear();
+  m_pSAXReader = pdfium::MakeUnique<CFX_SAXReader>();
+}
+
+bool CFX_ChecksumContext::UpdateChecksum(
+    const CFX_RetainPtr<IFX_SeekableReadStream>& pSrcFile,
+    FX_FILESIZE offset,
+    size_t size) {
+  if (!m_pSAXReader || !pSrcFile)
+    return false;
+
+  if (size < 1)
+    size = pSrcFile->GetSize();
+
+  CFX_SAXReaderHandler handler(this);
+  m_pSAXReader->SetHandler(&handler);
+  if (m_pSAXReader->StartParse(
+          pSrcFile, (uint32_t)offset, (uint32_t)size,
+          CFX_SaxParseMode_NotSkipSpace | CFX_SaxParseMode_NotConvert_amp |
+              CFX_SaxParseMode_NotConvert_lt | CFX_SaxParseMode_NotConvert_gt |
+              CFX_SaxParseMode_NotConvert_sharp) < 0) {
+    return false;
+  }
+  return m_pSAXReader->ContinueParse(nullptr) > 99;
+}
+
+void CFX_ChecksumContext::FinishChecksum() {
+  m_pSAXReader.reset();
+  if (m_pByteContext) {
+    uint8_t digest[20];
+    FXSYS_memset(digest, 0, 20);
+    CRYPT_SHA1Finish(m_pByteContext.get(), digest);
+    int32_t nLen = Base64EncodeA(digest, 20, nullptr);
+    char* pBuffer = m_bsChecksum.GetBuffer(nLen);
+    Base64EncodeA(digest, 20, pBuffer);
+    m_bsChecksum.ReleaseBuffer(nLen);
+    m_pByteContext.reset();
+  }
+}
+
+CFX_ByteString CFX_ChecksumContext::GetChecksum() const {
+  return m_bsChecksum;
+}
+
+void CFX_ChecksumContext::Update(const CFX_ByteStringC& bsText) {
+  if (!m_pByteContext)
+    return;
+
+  CRYPT_SHA1Update(m_pByteContext.get(), bsText.raw_str(), bsText.GetLength());
+}