files.cpp

// files.cpp - originally written and placed in the public domain by Wei Dai
 
#include "pch.h"
 
#ifndef CRYPTOPP_IMPORTS
 
#include "files.h"
 
#include <iostream>
#include <fstream>
#include <limits>
 
ANONYMOUS_NAMESPACE_BEGIN
 
class IosExceptionMask
{
public:
        IosExceptionMask(std::istream& stream) : m_stream(stream) {
                m_mask = m_stream.exceptions();
                m_stream.exceptions(static_cast<std::ios::iostate>(0));
        }
 
        IosExceptionMask(std::istream& stream, std::ios::iostate newMask) : m_stream(stream) {
                m_mask = m_stream.exceptions();
                m_stream.exceptions(newMask);
        }
 
        ~IosExceptionMask() {
                m_stream.exceptions(m_mask);
        }
 
private:
        std::istream& m_stream;
        std::ios::iostate m_mask;
};
 
ANONYMOUS_NAMESPACE_END
 
NAMESPACE_BEGIN(CryptoPP)
 
#if defined(CRYPTOPP_DEBUG) && !defined(CRYPTOPP_DOXYGEN_PROCESSING)
void Files_TestInstantiations()
{
        FileStore f0;
        FileSource f1;
        FileSink f2;
}
#endif
 
void FileStore::StoreInitialize(const NameValuePairs &parameters)
{
        m_waiting = false;
        m_stream = NULLPTR;
        m_file.release();
 
        const char *fileName = NULLPTR;
#if defined(CRYPTOPP_UNIX_AVAILABLE) || _MSC_VER >= 1400
        const wchar_t *fileNameWide = NULLPTR;
        if (!parameters.GetValue(Name::InputFileNameWide(), fileNameWide))
#endif
                if (!parameters.GetValue(Name::InputFileName(), fileName))
                {
                        parameters.GetValue(Name::InputStreamPointer(), m_stream);
                        return;
                }
 
        std::ios::openmode binary = parameters.GetValueWithDefault(Name::InputBinaryMode(), true) ? std::ios::binary : std::ios::openmode(0);
        m_file.reset(new std::ifstream);
#ifdef CRYPTOPP_UNIX_AVAILABLE
        std::string narrowed;
        if (fileNameWide)
                fileName = (narrowed = StringNarrow(fileNameWide)).c_str();
#endif
#if _MSC_VER >= 1400
        if (fileNameWide)
        {
                m_file->open(fileNameWide, std::ios::in | binary);
                if (!*m_file)
                        throw OpenErr(StringNarrow(fileNameWide, false));
        }
#endif
        if (fileName)
        {
                m_file->open(fileName, std::ios::in | binary);
                if (!*m_file)
                        throw OpenErr(fileName);
        }
        m_stream = m_file.get();
}
 
lword FileStore::MaxRetrievable() const
{
        if (!m_stream)
                return 0;
 
        // Disable badbit, failbit and eof exceptions
        IosExceptionMask guard(*m_stream);
 
        // Clear error bits due to seekg(). Also see
        // https://github.com/weidai11/cryptopp/pull/968
        std::streampos current = m_stream->tellg();
        std::streampos end = m_stream->seekg(0, std::ios::end).tellg();
        m_stream->clear();
        m_stream->seekg(current);
        m_stream->clear();
 
        // Return max for a non-seekable stream
        // https://www.cplusplus.com/reference/istream/istream/tellg
        if (end == static_cast<std::streampos>(-1))
                return LWORD_MAX;
 
        return end-current;
}
 
size_t FileStore::TransferTo2(BufferedTransformation &target, lword &transferBytes, const std::string &channel, bool blocking)
{
        if (!m_stream)
        {
                transferBytes = 0;
                return 0;
        }
 
        lword size=transferBytes;
        transferBytes = 0;
 
        if (m_waiting)
                goto output;
 
        size_t spaceSize, blockedBytes;
        while (size && m_stream->good())
        {
                spaceSize = 1024;
                m_space = HelpCreatePutSpace(target, channel, 1, UnsignedMin(size_t(SIZE_MAX), size), spaceSize);
                m_stream->read((char *)m_space, (std::streamsize)STDMIN(size, (lword)spaceSize));
                m_len = (size_t)m_stream->gcount();
 
output:
                blockedBytes = target.ChannelPutModifiable2(channel, m_space, m_len, 0, blocking);
                m_waiting = blockedBytes > 0;
                if (m_waiting)
                        return blockedBytes;
                size -= m_len;
                transferBytes += m_len;
        }
 
        if (!m_stream->good() && !m_stream->eof())
                throw ReadErr();
 
        return 0;
}
 
size_t FileStore::CopyRangeTo2(BufferedTransformation &target, lword &begin, lword end, const std::string &channel, bool blocking) const
{
        if (!m_stream)
                return 0;
 
        if (begin == 0 && end == 1)
        {
                int result = m_stream->peek();
                if (result == std::char_traits<char>::eof())
                        return 0;
                else
                {
                        size_t blockedBytes = target.ChannelPut(channel, byte(result), blocking);
                        begin += 1-blockedBytes;
                        return blockedBytes;
                }
        }
 
        // TODO: figure out what happens on cin
        std::streampos current = m_stream->tellg();
        std::streampos endPosition = m_stream->seekg(0, std::ios::end).tellg();
        std::streampos newPosition = current + static_cast<std::streamoff>(begin);
 
        if (newPosition >= endPosition)
        {
                m_stream->seekg(current);
                return 0;       // don't try to seek beyond the end of file
        }
        m_stream->seekg(newPosition);
        try
        {
                CRYPTOPP_ASSERT(!m_waiting);
                lword copyMax = end-begin;
                size_t blockedBytes = const_cast<FileStore *>(this)->TransferTo2(target, copyMax, channel, blocking);
                begin += copyMax;
                if (blockedBytes)
                {
                        const_cast<FileStore *>(this)->m_waiting = false;
                        return blockedBytes;
                }
        }
        catch(...)
        {
                m_stream->clear();
                m_stream->seekg(current);
                throw;
        }
        m_stream->clear();
        m_stream->seekg(current);
 
        return 0;
}
 
lword FileStore::Skip(lword skipMax)
{
        if (!m_stream)
                return 0;
 
        lword oldPos = m_stream->tellg();
        std::istream::off_type offset;
        if (!SafeConvert(skipMax, offset))
                throw InvalidArgument("FileStore: maximum seek offset exceeded");
        m_stream->seekg(offset, std::ios::cur);
        return (lword)m_stream->tellg() - oldPos;
}
 
void FileSink::IsolatedInitialize(const NameValuePairs &parameters)
{
        m_stream = NULLPTR;
        m_file.release();
 
        const char *fileName = NULLPTR;
#if defined(CRYPTOPP_UNIX_AVAILABLE) || _MSC_VER >= 1400
        const wchar_t *fileNameWide = NULLPTR;
        if (!parameters.GetValue(Name::OutputFileNameWide(), fileNameWide))
#endif
                if (!parameters.GetValue(Name::OutputFileName(), fileName))
                {
                        parameters.GetValue(Name::OutputStreamPointer(), m_stream);
                        return;
                }
 
        std::ios::openmode binary = parameters.GetValueWithDefault(Name::OutputBinaryMode(), true) ? std::ios::binary : std::ios::openmode(0);
        m_file.reset(new std::ofstream);
#ifdef CRYPTOPP_UNIX_AVAILABLE
        std::string narrowed;
        if (fileNameWide)
                fileName = (narrowed = StringNarrow(fileNameWide)).c_str();
#elif (CRYPTOPP_MSC_VERSION >= 1400)
        if (fileNameWide)
        {
                m_file->open(fileNameWide, std::ios::out | std::ios::trunc | binary);
                if (!*m_file)
                        throw OpenErr(StringNarrow(fileNameWide, false));
        }
#endif
        if (fileName)
        {
                m_file->open(fileName, std::ios::out | std::ios::trunc | binary);
                if (!*m_file)
                        throw OpenErr(fileName);
        }
        m_stream = m_file.get();
}
 
bool FileSink::IsolatedFlush(bool hardFlush, bool blocking)
{
        CRYPTOPP_UNUSED(hardFlush), CRYPTOPP_UNUSED(blocking);
        if (!m_stream)
                throw Err("FileSink: output stream not opened");
 
        m_stream->flush();
        if (!m_stream->good())
                throw WriteErr();
 
        return false;
}
 
size_t FileSink::Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
{
        CRYPTOPP_UNUSED(blocking);
        if (!m_stream)
                throw Err("FileSink: output stream not opened");
 
        while (length > 0)
        {
                std::streamsize size;
                if (!SafeConvert(length, size))
                        size = ((std::numeric_limits<std::streamsize>::max)());
                m_stream->write((const char *)inString, size);
                inString += size;
                length -= (size_t)size;
        }
 
        if (messageEnd)
                m_stream->flush();
 
        if (!m_stream->good())
                throw WriteErr();
 
        return 0;
}
 
NAMESPACE_END
 
#endif