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// 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/fx_stream.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 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() > 99;
}
void CFX_ChecksumContext::FinishChecksum() {
m_pSAXReader.reset();
if (m_pByteContext) {
uint8_t digest[20];
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();
}
}
ByteString CFX_ChecksumContext::GetChecksum() const {
return m_bsChecksum;
}
void CFX_ChecksumContext::Update(const ByteStringView& bsText) {
if (!m_pByteContext)
return;
CRYPT_SHA1Update(m_pByteContext.get(), bsText.raw_str(), bsText.GetLength());
}
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