Initial Vexta Core v0.1.0 release
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src/streams.h
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809
src/streams.h
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// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2020 The Bitcoin Core developers
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// Copyright (c) 2014-2020 The DigiByte Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef DIGIBYTE_STREAMS_H
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#define DIGIBYTE_STREAMS_H
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#include <serialize.h>
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#include <span.h>
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#include <support/allocators/zeroafterfree.h>
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#include <algorithm>
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#include <assert.h>
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#include <ios>
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#include <limits>
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#include <optional>
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include <string>
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#include <utility>
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#include <vector>
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template<typename Stream>
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class OverrideStream
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{
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Stream* stream;
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const int nType;
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const int nVersion;
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public:
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OverrideStream(Stream* stream_, int nType_, int nVersion_) : stream(stream_), nType(nType_), nVersion(nVersion_) {}
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template<typename T>
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OverrideStream<Stream>& operator<<(const T& obj)
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{
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// Serialize to this stream
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::Serialize(*this, obj);
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return (*this);
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}
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template<typename T>
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OverrideStream<Stream>& operator>>(T&& obj)
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{
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// Unserialize from this stream
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::Unserialize(*this, obj);
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return (*this);
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}
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void write(const char* pch, size_t nSize)
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{
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stream->write(pch, nSize);
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}
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void read(char* pch, size_t nSize)
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{
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stream->read(pch, nSize);
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}
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int GetVersion() const { return nVersion; }
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int GetType() const { return nType; }
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size_t size() const { return stream->size(); }
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void ignore(size_t size) { return stream->ignore(size); }
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};
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/* Minimal stream for overwriting and/or appending to an existing byte vector
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*
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* The referenced vector will grow as necessary
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*/
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class CVectorWriter
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{
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public:
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/*
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* @param[in] nTypeIn Serialization Type
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* @param[in] nVersionIn Serialization Version (including any flags)
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* @param[in] vchDataIn Referenced byte vector to overwrite/append
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* @param[in] nPosIn Starting position. Vector index where writes should start. The vector will initially
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* grow as necessary to max(nPosIn, vec.size()). So to append, use vec.size().
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*/
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CVectorWriter(int nTypeIn, int nVersionIn, std::vector<unsigned char>& vchDataIn, size_t nPosIn) : nType(nTypeIn), nVersion(nVersionIn), vchData(vchDataIn), nPos(nPosIn)
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{
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if(nPos > vchData.size())
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vchData.resize(nPos);
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}
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/*
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* (other params same as above)
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* @param[in] args A list of items to serialize starting at nPosIn.
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*/
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template <typename... Args>
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CVectorWriter(int nTypeIn, int nVersionIn, std::vector<unsigned char>& vchDataIn, size_t nPosIn, Args&&... args) : CVectorWriter(nTypeIn, nVersionIn, vchDataIn, nPosIn)
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{
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::SerializeMany(*this, std::forward<Args>(args)...);
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}
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void write(const char* pch, size_t nSize)
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{
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assert(nPos <= vchData.size());
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size_t nOverwrite = std::min(nSize, vchData.size() - nPos);
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if (nOverwrite) {
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memcpy(vchData.data() + nPos, reinterpret_cast<const unsigned char*>(pch), nOverwrite);
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}
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if (nOverwrite < nSize) {
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vchData.insert(vchData.end(), reinterpret_cast<const unsigned char*>(pch) + nOverwrite, reinterpret_cast<const unsigned char*>(pch) + nSize);
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}
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nPos += nSize;
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}
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template<typename T>
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CVectorWriter& operator<<(const T& obj)
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{
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// Serialize to this stream
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::Serialize(*this, obj);
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return (*this);
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}
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int GetVersion() const
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{
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return nVersion;
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}
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int GetType() const
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{
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return nType;
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}
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private:
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const int nType;
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const int nVersion;
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std::vector<unsigned char>& vchData;
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size_t nPos;
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};
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/** Minimal stream for reading from an existing vector by reference
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*/
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class VectorReader
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{
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private:
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const int m_type;
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const int m_version;
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const std::vector<unsigned char>& m_data;
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size_t m_pos = 0;
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public:
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/**
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* @param[in] type Serialization Type
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* @param[in] version Serialization Version (including any flags)
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* @param[in] data Referenced byte vector to overwrite/append
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* @param[in] pos Starting position. Vector index where reads should start.
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*/
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VectorReader(int type, int version, const std::vector<unsigned char>& data, size_t pos)
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: m_type(type), m_version(version), m_data(data), m_pos(pos)
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{
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if (m_pos > m_data.size()) {
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throw std::ios_base::failure("VectorReader(...): end of data (m_pos > m_data.size())");
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}
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}
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/**
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* (other params same as above)
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* @param[in] args A list of items to deserialize starting at pos.
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*/
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template <typename... Args>
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VectorReader(int type, int version, const std::vector<unsigned char>& data, size_t pos,
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Args&&... args)
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: VectorReader(type, version, data, pos)
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{
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::UnserializeMany(*this, std::forward<Args>(args)...);
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}
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template<typename T>
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VectorReader& operator>>(T&& obj)
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{
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// Unserialize from this stream
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::Unserialize(*this, obj);
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return (*this);
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}
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int GetVersion() const { return m_version; }
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int GetType() const { return m_type; }
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size_t size() const { return m_data.size() - m_pos; }
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bool empty() const { return m_data.size() == m_pos; }
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void read(char* dst, size_t n)
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{
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if (n == 0) {
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return;
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}
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// Read from the beginning of the buffer
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size_t pos_next = m_pos + n;
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if (pos_next > m_data.size()) {
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throw std::ios_base::failure("VectorReader::read(): end of data");
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}
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memcpy(dst, m_data.data() + m_pos, n);
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m_pos = pos_next;
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}
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};
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/** Double ended buffer combining vector and stream-like interfaces.
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*
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* >> and << read and write unformatted data using the above serialization templates.
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* Fills with data in linear time; some stringstream implementations take N^2 time.
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*/
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class CDataStream
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{
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protected:
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using vector_type = SerializeData;
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vector_type vch;
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unsigned int nReadPos{0};
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int nType;
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int nVersion;
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public:
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typedef vector_type::allocator_type allocator_type;
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typedef vector_type::size_type size_type;
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typedef vector_type::difference_type difference_type;
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typedef vector_type::reference reference;
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typedef vector_type::const_reference const_reference;
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typedef vector_type::value_type value_type;
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typedef vector_type::iterator iterator;
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typedef vector_type::const_iterator const_iterator;
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typedef vector_type::reverse_iterator reverse_iterator;
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explicit CDataStream(int nTypeIn, int nVersionIn)
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: nType{nTypeIn},
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nVersion{nVersionIn} {}
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explicit CDataStream(Span<const uint8_t> sp, int nTypeIn, int nVersionIn)
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: vch(sp.data(), sp.data() + sp.size()),
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nType{nTypeIn},
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nVersion{nVersionIn} {}
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template <typename... Args>
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CDataStream(int nTypeIn, int nVersionIn, Args&&... args)
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: nType{nTypeIn},
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nVersion{nVersionIn}
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{
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::SerializeMany(*this, std::forward<Args>(args)...);
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}
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std::string str() const
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{
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return (std::string(begin(), end()));
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}
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//
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// Vector subset
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//
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const_iterator begin() const { return vch.begin() + nReadPos; }
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iterator begin() { return vch.begin() + nReadPos; }
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const_iterator end() const { return vch.end(); }
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iterator end() { return vch.end(); }
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size_type size() const { return vch.size() - nReadPos; }
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bool empty() const { return vch.size() == nReadPos; }
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void resize(size_type n, value_type c=0) { vch.resize(n + nReadPos, c); }
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void reserve(size_type n) { vch.reserve(n + nReadPos); }
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const_reference operator[](size_type pos) const { return vch[pos + nReadPos]; }
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reference operator[](size_type pos) { return vch[pos + nReadPos]; }
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void clear() { vch.clear(); nReadPos = 0; }
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iterator insert(iterator it, const uint8_t x) { return vch.insert(it, x); }
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void insert(iterator it, size_type n, const uint8_t x) { vch.insert(it, n, x); }
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value_type* data() { return vch.data() + nReadPos; }
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const value_type* data() const { return vch.data() + nReadPos; }
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void insert(iterator it, std::vector<uint8_t>::const_iterator first, std::vector<uint8_t>::const_iterator last)
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{
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if (last == first) return;
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assert(last - first > 0);
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if (it == vch.begin() + nReadPos && (unsigned int)(last - first) <= nReadPos)
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{
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// special case for inserting at the front when there's room
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nReadPos -= (last - first);
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memcpy(&vch[nReadPos], &first[0], last - first);
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}
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else
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vch.insert(it, first, last);
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}
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void insert(iterator it, const char* first, const char* last)
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{
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if (last == first) return;
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assert(last - first > 0);
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if (it == vch.begin() + nReadPos && (unsigned int)(last - first) <= nReadPos)
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{
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// special case for inserting at the front when there's room
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nReadPos -= (last - first);
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memcpy(&vch[nReadPos], &first[0], last - first);
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}
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else
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vch.insert(it, first, last);
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}
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iterator erase(iterator it)
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{
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if (it == vch.begin() + nReadPos)
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{
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// special case for erasing from the front
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if (++nReadPos >= vch.size())
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{
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// whenever we reach the end, we take the opportunity to clear the buffer
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nReadPos = 0;
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return vch.erase(vch.begin(), vch.end());
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}
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return vch.begin() + nReadPos;
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}
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else
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return vch.erase(it);
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}
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iterator erase(iterator first, iterator last)
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{
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if (first == vch.begin() + nReadPos)
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{
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// special case for erasing from the front
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if (last == vch.end())
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{
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nReadPos = 0;
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return vch.erase(vch.begin(), vch.end());
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}
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else
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{
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nReadPos = (last - vch.begin());
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return last;
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}
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}
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else
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return vch.erase(first, last);
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}
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inline void Compact()
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{
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vch.erase(vch.begin(), vch.begin() + nReadPos);
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nReadPos = 0;
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}
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bool Rewind(std::optional<size_type> n = std::nullopt)
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{
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// Total rewind if no size is passed
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if (!n) {
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nReadPos = 0;
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return true;
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}
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// Rewind by n characters if the buffer hasn't been compacted yet
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if (*n > nReadPos)
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return false;
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nReadPos -= *n;
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return true;
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}
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//
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// Stream subset
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//
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bool eof() const { return size() == 0; }
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CDataStream* rdbuf() { return this; }
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int in_avail() const { return size(); }
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void SetType(int n) { nType = n; }
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int GetType() const { return nType; }
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void SetVersion(int n) { nVersion = n; }
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int GetVersion() const { return nVersion; }
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void read(char* pch, size_t nSize)
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{
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if (nSize == 0) return;
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// Read from the beginning of the buffer
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unsigned int nReadPosNext = nReadPos + nSize;
|
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if (nReadPosNext > vch.size()) {
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throw std::ios_base::failure("CDataStream::read(): end of data");
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}
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memcpy(pch, &vch[nReadPos], nSize);
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if (nReadPosNext == vch.size())
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{
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nReadPos = 0;
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vch.clear();
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return;
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}
|
||||
nReadPos = nReadPosNext;
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}
|
||||
|
||||
void ignore(int nSize)
|
||||
{
|
||||
// Ignore from the beginning of the buffer
|
||||
if (nSize < 0) {
|
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throw std::ios_base::failure("CDataStream::ignore(): nSize negative");
|
||||
}
|
||||
unsigned int nReadPosNext = nReadPos + nSize;
|
||||
if (nReadPosNext >= vch.size())
|
||||
{
|
||||
if (nReadPosNext > vch.size())
|
||||
throw std::ios_base::failure("CDataStream::ignore(): end of data");
|
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nReadPos = 0;
|
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vch.clear();
|
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return;
|
||||
}
|
||||
nReadPos = nReadPosNext;
|
||||
}
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||||
|
||||
void write(const char* pch, size_t nSize)
|
||||
{
|
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// Write to the end of the buffer
|
||||
vch.insert(vch.end(), pch, pch + nSize);
|
||||
}
|
||||
|
||||
template<typename Stream>
|
||||
void Serialize(Stream& s) const
|
||||
{
|
||||
// Special case: stream << stream concatenates like stream += stream
|
||||
if (!vch.empty())
|
||||
s.write((char*)vch.data(), vch.size() * sizeof(value_type));
|
||||
}
|
||||
|
||||
template<typename T>
|
||||
CDataStream& operator<<(const T& obj)
|
||||
{
|
||||
// Serialize to this stream
|
||||
::Serialize(*this, obj);
|
||||
return (*this);
|
||||
}
|
||||
|
||||
template<typename T>
|
||||
CDataStream& operator>>(T&& obj)
|
||||
{
|
||||
// Unserialize from this stream
|
||||
::Unserialize(*this, obj);
|
||||
return (*this);
|
||||
}
|
||||
|
||||
/**
|
||||
* XOR the contents of this stream with a certain key.
|
||||
*
|
||||
* @param[in] key The key used to XOR the data in this stream.
|
||||
*/
|
||||
void Xor(const std::vector<unsigned char>& key)
|
||||
{
|
||||
if (key.size() == 0) {
|
||||
return;
|
||||
}
|
||||
|
||||
for (size_type i = 0, j = 0; i != size(); i++) {
|
||||
vch[i] ^= key[j++];
|
||||
|
||||
// This potentially acts on very many bytes of data, so it's
|
||||
// important that we calculate `j`, i.e. the `key` index in this
|
||||
// way instead of doing a %, which would effectively be a division
|
||||
// for each byte Xor'd -- much slower than need be.
|
||||
if (j == key.size())
|
||||
j = 0;
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
template <typename IStream>
|
||||
class BitStreamReader
|
||||
{
|
||||
private:
|
||||
IStream& m_istream;
|
||||
|
||||
/// Buffered byte read in from the input stream. A new byte is read into the
|
||||
/// buffer when m_offset reaches 8.
|
||||
uint8_t m_buffer{0};
|
||||
|
||||
/// Number of high order bits in m_buffer already returned by previous
|
||||
/// Read() calls. The next bit to be returned is at this offset from the
|
||||
/// most significant bit position.
|
||||
int m_offset{8};
|
||||
|
||||
public:
|
||||
explicit BitStreamReader(IStream& istream) : m_istream(istream) {}
|
||||
|
||||
/** Read the specified number of bits from the stream. The data is returned
|
||||
* in the nbits least significant bits of a 64-bit uint.
|
||||
*/
|
||||
uint64_t Read(int nbits) {
|
||||
if (nbits < 0 || nbits > 64) {
|
||||
throw std::out_of_range("nbits must be between 0 and 64");
|
||||
}
|
||||
|
||||
uint64_t data = 0;
|
||||
while (nbits > 0) {
|
||||
if (m_offset == 8) {
|
||||
m_istream >> m_buffer;
|
||||
m_offset = 0;
|
||||
}
|
||||
|
||||
int bits = std::min(8 - m_offset, nbits);
|
||||
data <<= bits;
|
||||
data |= static_cast<uint8_t>(m_buffer << m_offset) >> (8 - bits);
|
||||
m_offset += bits;
|
||||
nbits -= bits;
|
||||
}
|
||||
return data;
|
||||
}
|
||||
};
|
||||
|
||||
template <typename OStream>
|
||||
class BitStreamWriter
|
||||
{
|
||||
private:
|
||||
OStream& m_ostream;
|
||||
|
||||
/// Buffered byte waiting to be written to the output stream. The byte is
|
||||
/// written buffer when m_offset reaches 8 or Flush() is called.
|
||||
uint8_t m_buffer{0};
|
||||
|
||||
/// Number of high order bits in m_buffer already written by previous
|
||||
/// Write() calls and not yet flushed to the stream. The next bit to be
|
||||
/// written to is at this offset from the most significant bit position.
|
||||
int m_offset{0};
|
||||
|
||||
public:
|
||||
explicit BitStreamWriter(OStream& ostream) : m_ostream(ostream) {}
|
||||
|
||||
~BitStreamWriter()
|
||||
{
|
||||
Flush();
|
||||
}
|
||||
|
||||
/** Write the nbits least significant bits of a 64-bit int to the output
|
||||
* stream. Data is buffered until it completes an octet.
|
||||
*/
|
||||
void Write(uint64_t data, int nbits) {
|
||||
if (nbits < 0 || nbits > 64) {
|
||||
throw std::out_of_range("nbits must be between 0 and 64");
|
||||
}
|
||||
|
||||
while (nbits > 0) {
|
||||
int bits = std::min(8 - m_offset, nbits);
|
||||
m_buffer |= (data << (64 - nbits)) >> (64 - 8 + m_offset);
|
||||
m_offset += bits;
|
||||
nbits -= bits;
|
||||
|
||||
if (m_offset == 8) {
|
||||
Flush();
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/** Flush any unwritten bits to the output stream, padding with 0's to the
|
||||
* next byte boundary.
|
||||
*/
|
||||
void Flush() {
|
||||
if (m_offset == 0) {
|
||||
return;
|
||||
}
|
||||
|
||||
m_ostream << m_buffer;
|
||||
m_buffer = 0;
|
||||
m_offset = 0;
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
|
||||
/** Non-refcounted RAII wrapper for FILE*
|
||||
*
|
||||
* Will automatically close the file when it goes out of scope if not null.
|
||||
* If you're returning the file pointer, return file.release().
|
||||
* If you need to close the file early, use file.fclose() instead of fclose(file).
|
||||
*/
|
||||
class CAutoFile
|
||||
{
|
||||
private:
|
||||
const int nType;
|
||||
const int nVersion;
|
||||
|
||||
FILE* file;
|
||||
|
||||
public:
|
||||
CAutoFile(FILE* filenew, int nTypeIn, int nVersionIn) : nType(nTypeIn), nVersion(nVersionIn)
|
||||
{
|
||||
file = filenew;
|
||||
}
|
||||
|
||||
~CAutoFile()
|
||||
{
|
||||
fclose();
|
||||
}
|
||||
|
||||
// Disallow copies
|
||||
CAutoFile(const CAutoFile&) = delete;
|
||||
CAutoFile& operator=(const CAutoFile&) = delete;
|
||||
|
||||
void fclose()
|
||||
{
|
||||
if (file) {
|
||||
::fclose(file);
|
||||
file = nullptr;
|
||||
}
|
||||
}
|
||||
|
||||
/** Get wrapped FILE* with transfer of ownership.
|
||||
* @note This will invalidate the CAutoFile object, and makes it the responsibility of the caller
|
||||
* of this function to clean up the returned FILE*.
|
||||
*/
|
||||
FILE* release() { FILE* ret = file; file = nullptr; return ret; }
|
||||
|
||||
/** Get wrapped FILE* without transfer of ownership.
|
||||
* @note Ownership of the FILE* will remain with this class. Use this only if the scope of the
|
||||
* CAutoFile outlives use of the passed pointer.
|
||||
*/
|
||||
FILE* Get() const { return file; }
|
||||
|
||||
/** Return true if the wrapped FILE* is nullptr, false otherwise.
|
||||
*/
|
||||
bool IsNull() const { return (file == nullptr); }
|
||||
|
||||
//
|
||||
// Stream subset
|
||||
//
|
||||
int GetType() const { return nType; }
|
||||
int GetVersion() const { return nVersion; }
|
||||
|
||||
void read(char* pch, size_t nSize)
|
||||
{
|
||||
if (!file)
|
||||
throw std::ios_base::failure("CAutoFile::read: file handle is nullptr");
|
||||
if (fread(pch, 1, nSize, file) != nSize)
|
||||
throw std::ios_base::failure(feof(file) ? "CAutoFile::read: end of file" : "CAutoFile::read: fread failed");
|
||||
}
|
||||
|
||||
void ignore(size_t nSize)
|
||||
{
|
||||
if (!file)
|
||||
throw std::ios_base::failure("CAutoFile::ignore: file handle is nullptr");
|
||||
unsigned char data[4096];
|
||||
while (nSize > 0) {
|
||||
size_t nNow = std::min<size_t>(nSize, sizeof(data));
|
||||
if (fread(data, 1, nNow, file) != nNow)
|
||||
throw std::ios_base::failure(feof(file) ? "CAutoFile::ignore: end of file" : "CAutoFile::read: fread failed");
|
||||
nSize -= nNow;
|
||||
}
|
||||
}
|
||||
|
||||
void write(const char* pch, size_t nSize)
|
||||
{
|
||||
if (!file)
|
||||
throw std::ios_base::failure("CAutoFile::write: file handle is nullptr");
|
||||
if (fwrite(pch, 1, nSize, file) != nSize)
|
||||
throw std::ios_base::failure("CAutoFile::write: write failed");
|
||||
}
|
||||
|
||||
template<typename T>
|
||||
CAutoFile& operator<<(const T& obj)
|
||||
{
|
||||
// Serialize to this stream
|
||||
if (!file)
|
||||
throw std::ios_base::failure("CAutoFile::operator<<: file handle is nullptr");
|
||||
::Serialize(*this, obj);
|
||||
return (*this);
|
||||
}
|
||||
|
||||
template<typename T>
|
||||
CAutoFile& operator>>(T&& obj)
|
||||
{
|
||||
// Unserialize from this stream
|
||||
if (!file)
|
||||
throw std::ios_base::failure("CAutoFile::operator>>: file handle is nullptr");
|
||||
::Unserialize(*this, obj);
|
||||
return (*this);
|
||||
}
|
||||
};
|
||||
|
||||
/** Non-refcounted RAII wrapper around a FILE* that implements a ring buffer to
|
||||
* deserialize from. It guarantees the ability to rewind a given number of bytes.
|
||||
*
|
||||
* Will automatically close the file when it goes out of scope if not null.
|
||||
* If you need to close the file early, use file.fclose() instead of fclose(file).
|
||||
*/
|
||||
class CBufferedFile
|
||||
{
|
||||
private:
|
||||
const int nType;
|
||||
const int nVersion;
|
||||
|
||||
FILE *src; //!< source file
|
||||
uint64_t nSrcPos; //!< how many bytes have been read from source
|
||||
uint64_t nReadPos; //!< how many bytes have been read from this
|
||||
uint64_t nReadLimit; //!< up to which position we're allowed to read
|
||||
uint64_t nRewind; //!< how many bytes we guarantee to rewind
|
||||
std::vector<char> vchBuf; //!< the buffer
|
||||
|
||||
protected:
|
||||
//! read data from the source to fill the buffer
|
||||
bool Fill() {
|
||||
unsigned int pos = nSrcPos % vchBuf.size();
|
||||
unsigned int readNow = vchBuf.size() - pos;
|
||||
unsigned int nAvail = vchBuf.size() - (nSrcPos - nReadPos) - nRewind;
|
||||
if (nAvail < readNow)
|
||||
readNow = nAvail;
|
||||
if (readNow == 0)
|
||||
return false;
|
||||
size_t nBytes = fread((void*)&vchBuf[pos], 1, readNow, src);
|
||||
if (nBytes == 0) {
|
||||
throw std::ios_base::failure(feof(src) ? "CBufferedFile::Fill: end of file" : "CBufferedFile::Fill: fread failed");
|
||||
}
|
||||
nSrcPos += nBytes;
|
||||
return true;
|
||||
}
|
||||
|
||||
public:
|
||||
CBufferedFile(FILE *fileIn, uint64_t nBufSize, uint64_t nRewindIn, int nTypeIn, int nVersionIn) :
|
||||
nType(nTypeIn), nVersion(nVersionIn), nSrcPos(0), nReadPos(0), nReadLimit(std::numeric_limits<uint64_t>::max()), nRewind(nRewindIn), vchBuf(nBufSize, 0)
|
||||
{
|
||||
if (nRewindIn >= nBufSize)
|
||||
throw std::ios_base::failure("Rewind limit must be less than buffer size");
|
||||
src = fileIn;
|
||||
}
|
||||
|
||||
~CBufferedFile()
|
||||
{
|
||||
fclose();
|
||||
}
|
||||
|
||||
// Disallow copies
|
||||
CBufferedFile(const CBufferedFile&) = delete;
|
||||
CBufferedFile& operator=(const CBufferedFile&) = delete;
|
||||
|
||||
int GetVersion() const { return nVersion; }
|
||||
int GetType() const { return nType; }
|
||||
|
||||
void fclose()
|
||||
{
|
||||
if (src) {
|
||||
::fclose(src);
|
||||
src = nullptr;
|
||||
}
|
||||
}
|
||||
|
||||
//! check whether we're at the end of the source file
|
||||
bool eof() const {
|
||||
return nReadPos == nSrcPos && feof(src);
|
||||
}
|
||||
|
||||
//! read a number of bytes
|
||||
void read(char *pch, size_t nSize) {
|
||||
if (nSize + nReadPos > nReadLimit)
|
||||
throw std::ios_base::failure("Read attempted past buffer limit");
|
||||
while (nSize > 0) {
|
||||
if (nReadPos == nSrcPos)
|
||||
Fill();
|
||||
unsigned int pos = nReadPos % vchBuf.size();
|
||||
size_t nNow = nSize;
|
||||
if (nNow + pos > vchBuf.size())
|
||||
nNow = vchBuf.size() - pos;
|
||||
if (nNow + nReadPos > nSrcPos)
|
||||
nNow = nSrcPos - nReadPos;
|
||||
memcpy(pch, &vchBuf[pos], nNow);
|
||||
nReadPos += nNow;
|
||||
pch += nNow;
|
||||
nSize -= nNow;
|
||||
}
|
||||
}
|
||||
|
||||
//! return the current reading position
|
||||
uint64_t GetPos() const {
|
||||
return nReadPos;
|
||||
}
|
||||
|
||||
//! rewind to a given reading position
|
||||
bool SetPos(uint64_t nPos) {
|
||||
size_t bufsize = vchBuf.size();
|
||||
if (nPos + bufsize < nSrcPos) {
|
||||
// rewinding too far, rewind as far as possible
|
||||
nReadPos = nSrcPos - bufsize;
|
||||
return false;
|
||||
}
|
||||
if (nPos > nSrcPos) {
|
||||
// can't go this far forward, go as far as possible
|
||||
nReadPos = nSrcPos;
|
||||
return false;
|
||||
}
|
||||
nReadPos = nPos;
|
||||
return true;
|
||||
}
|
||||
|
||||
//! prevent reading beyond a certain position
|
||||
//! no argument removes the limit
|
||||
bool SetLimit(uint64_t nPos = std::numeric_limits<uint64_t>::max()) {
|
||||
if (nPos < nReadPos)
|
||||
return false;
|
||||
nReadLimit = nPos;
|
||||
return true;
|
||||
}
|
||||
|
||||
template<typename T>
|
||||
CBufferedFile& operator>>(T&& obj) {
|
||||
// Unserialize from this stream
|
||||
::Unserialize(*this, obj);
|
||||
return (*this);
|
||||
}
|
||||
|
||||
//! search for a given byte in the stream, and remain positioned on it
|
||||
void FindByte(char ch) {
|
||||
while (true) {
|
||||
if (nReadPos == nSrcPos)
|
||||
Fill();
|
||||
if (vchBuf[nReadPos % vchBuf.size()] == ch)
|
||||
break;
|
||||
nReadPos++;
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
#endif // DIGIBYTE_STREAMS_H
|
||||
Loading…
Reference in a new issue