gctf2023/pwn/flipper/dist/common/include/ustl/mistream.h

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// This file is part of the uSTL library, an STL implementation.
//
// Copyright (c) 2005 by Mike Sharov <msharov@users.sourceforge.net>
// This file is free software, distributed under the MIT License.
#pragma once
#include "memlink.h"
#include "strmsize.h"
#include "utf8.h"
#include "uios.h"
#if WANT_STREAM_BOUNDS_CHECKING
#include "typeinfo.h"
#endif
namespace ustl {
class ostream;
class memlink;
class string;
/// \class istream mistream.h ustl.h
/// \ingroup BinaryStreams
///
/// \brief Helper class to read packed binary streams.
///
/// This class contains a set of functions to read integral types from an
/// unstructured memory block. Unpacking binary file data can be done this
/// way, for instance. aligning the data is your responsibility, and can
/// be accomplished by proper ordering of reads and by calling the align()
/// function. Unaligned access is usually slower by orders of magnitude and,
/// on some architectures, such as PowerPC, can cause your program to crash.
/// Therefore, all read functions have asserts to check alignment.
/// Overreading the end of the stream will also cause a crash (an assert in
/// debug builds). Oh, and don't be intimidated by the size of the inlines
/// here. In the assembly code the compiler will usually chop everything down
/// to five instructions each.
///
/// Alignment rules for your objects:
/// - Assume your writes start off 4-byte aligned.
/// - After completion, \ref istream::align the stream to at least 4.
/// - If data portability between 32bit and 64bit platforms is important
/// (it often is not, in config files and the like), ensure you are always
/// using fixed-size types and are aligning to a fixed grain. Avoid writing
/// 8-byte types, and if you do, manually align before doing so.
/// - Non-default alignment is allowed if you plan to frequently write this
/// object in array form and alignment would be costly. For example, an
/// array of uint16_t-sized objects may leave the stream uint16_t aligned
/// as long as you know about it and will default-align the stream after
/// writing the array (note: \ref vector will already do this for you)
///
/// Example code:
/// \code
/// memblock b;
/// b.read_file ("test.file");
/// ostream is (b);
/// is >> boolVar >> ios::talign<int>();
/// is >> intVar >> floatVar;
/// is.read (binaryData, binaryDataSize);
/// is.align();
/// \endcode
///
class istream : public cmemlink, public ios_base {
public:
inline istream (void) : cmemlink(), _pos (0) {}
inline istream (const void* p, streamsize n) : cmemlink(p, n), _pos (0) {}
inline explicit istream (const cmemlink& source) : cmemlink (source), _pos (0) {}
explicit istream (const ostream& source) noexcept;
inline iterator end (void) const { return cmemlink::end(); }
inline void link (const void* p, streamsize n) { cmemlink::link (p, n); }
inline void link (const cmemlink& l) { cmemlink::link (l.cdata(), l.readable_size()); }
inline void link (const void* f, const void* l) { cmemlink::link (f, l); }
inline void relink (const void* p, streamsize n) { cmemlink::relink (p, n); _pos = 0; }
inline void relink (const cmemlink& l) { relink (l.cdata(), l.readable_size()); }
virtual void unlink (void) noexcept override;
virtual streamsize underflow (streamsize = 1);
inline uoff_t pos (void) const { return _pos; }
inline const_iterator ipos (void) const { return begin() + pos(); }
inline streamsize remaining (void) const { return size() - pos(); }
inline void seek (uoff_t newPos);
inline void iseek (const_iterator newPos);
inline void skip (streamsize nBytes);
inline bool aligned (streamsize grain = c_DefaultAlignment) const;
inline bool verify_remaining (const char* op, const char* type, streamsize n);
inline streamsize align_size (streamsize grain = c_DefaultAlignment) const;
inline void align (streamsize grain = c_DefaultAlignment);
inline void swap (istream& is);
inline void read (void* buffer, streamsize size);
inline void read (memlink& buf) { read (buf.begin(), buf.writable_size()); }
void read_strz (string& str);
streamsize readsome (void* s, streamsize n);
inline void read (istream&) { }
void write (ostream& os) const;
void text_write (ostringstream& os) const;
inline streamsize stream_size (void) const { return remaining(); }
template <typename T>
inline void iread (T& v);
inline void ungetc (void) { seek (pos() - 1); }
inline off_t tellg (void) const { return pos(); }
inline void seekg (off_t p, seekdir d = beg);
private:
streamoff _pos; ///< The current read position.
};
//----------------------------------------------------------------------
template <typename T, typename Stream>
inline streamsize required_stream_size (T, const Stream&) { return 1; }
template <typename T>
inline streamsize required_stream_size (T v, const istream&) { return stream_size_of(v); }
template <typename Stream>
inline bool stream_at_eof (const Stream& stm) { return stm.eof(); }
template <>
inline bool stream_at_eof (const istream&) { return false; }
/// \class istream_iterator
/// \ingroup BinaryStreamIterators
///
/// \brief An iterator over an istream to use with uSTL algorithms.
///
template <typename T, typename Stream = istream>
class istream_iterator {
public:
typedef T value_type;
typedef ptrdiff_t difference_type;
typedef const value_type* pointer;
typedef const value_type& reference;
typedef typename Stream::size_type size_type;
typedef input_iterator_tag iterator_category;
public:
istream_iterator (void) : _pis (nullptr), _v() {}
explicit istream_iterator (Stream& is) : _pis (&is), _v() { Read(); }
istream_iterator (const istream_iterator& i) : _pis (i._pis), _v (i._v) {}
/// Reads and returns the next value.
inline const T& operator* (void) { return _v; }
inline istream_iterator& operator++ (void) { Read(); return *this; }
inline istream_iterator& operator-- (void) { _pis->seek (_pis->pos() - 2 * stream_size_of(_v)); return operator++(); }
inline istream_iterator operator++ (int) { istream_iterator old (*this); operator++(); return old; }
inline istream_iterator operator-- (int) { istream_iterator old (*this); operator--(); return old; }
inline istream_iterator& operator+= (streamsize n) { while (n--) operator++(); return *this; }
inline istream_iterator& operator-= (streamsize n) { _pis->seek (_pis->pos() - (n + 1) * stream_size_of(_v)); return operator++(); }
inline istream_iterator operator- (streamoff n) const { istream_iterator result (*this); return result -= n; }
inline difference_type operator- (const istream_iterator& i) const { return distance (i._pis->pos(), _pis->pos()) / stream_size_of(_v); }
inline bool operator== (const istream_iterator& i) const { return (!_pis && !i._pis) || (_pis && i._pis && _pis->pos() == i._pis->pos()); }
inline bool operator< (const istream_iterator& i) const { return !i._pis || (_pis && _pis->pos() < i._pis->pos()); }
private:
void Read (void)
{
if (!_pis)
return;
const streamsize rs (required_stream_size (_v, *_pis));
if (_pis->remaining() < rs && _pis->underflow (rs) < rs) {
_pis = nullptr;
return;
}
*_pis >> _v;
if (stream_at_eof (*_pis))
_pis = nullptr;
}
private:
Stream* _pis; ///< The host stream.
T _v; ///< Last read value; cached to be returnable as a const reference.
};
//----------------------------------------------------------------------
/// Checks that \p n bytes are available in the stream, or else throws.
inline bool istream::verify_remaining (const char* op, const char* type, streamsize n)
{
const streamsize rem = remaining();
bool enough = n <= rem;
if (!enough) overrun (op, type, n, pos(), rem);
return enough;
}
/// Sets the current read position to \p newPos
inline void istream::seek (uoff_t newPos)
{
#if WANT_STREAM_BOUNDS_CHECKING
if (newPos > size())
return overrun ("seekg", "byte", newPos, pos(), size());
#else
assert (newPos <= size());
#endif
_pos = newPos;
}
/// Sets the current read position to \p newPos
inline void istream::iseek (const_iterator newPos)
{
seek (distance (begin(), newPos));
}
/// Sets the current write position to \p p based on \p d.
inline void istream::seekg (off_t p, seekdir d)
{
switch (d) {
case beg: seek (p); break;
case cur: seek (pos() + p); break;
case ios_base::end: seek (size() - p); break;
}
}
/// Skips \p nBytes without reading them.
inline void istream::skip (streamsize nBytes)
{
seek (pos() + nBytes);
}
/// Returns the number of bytes to skip to be aligned on \p grain.
inline streamsize istream::align_size (streamsize grain) const
{
return Align (pos(), grain) - pos();
}
/// Returns \c true if the read position is aligned on \p grain
inline bool istream::aligned (streamsize grain) const
{
return pos() % grain == 0;
}
/// aligns the read position on \p grain
inline void istream::align (streamsize grain)
{
seek (Align (pos(), grain));
}
/// Reads type T from the stream via a direct pointer cast.
template <typename T>
inline void istream::iread (T& v)
{
assert (aligned (stream_align_of (v)));
#if WANT_STREAM_BOUNDS_CHECKING
if (!verify_remaining ("read", typeid(v).name(), sizeof(T)))
return;
#else
assert (remaining() >= sizeof(T));
#endif
v = *reinterpret_cast<const T*>(ipos());
_pos += sizeof(T);
}
/// Swaps contents with \p is
inline void istream::swap (istream& is)
{
cmemlink::swap (is);
::ustl::swap (_pos, is._pos);
}
/// Reads \p n bytes into \p buffer.
inline void istream::read (void* buffer, size_type n)
{
#if WANT_STREAM_BOUNDS_CHECKING
if (!verify_remaining ("read", "binary data", n))
return;
#else
assert (remaining() >= n && "Reading past end of buffer. Make sure you are reading the right format.");
#endif
memcpy (reinterpret_cast<value_type*>(buffer), ipos(), n);
_pos += n;
}
//----------------------------------------------------------------------
template <typename T> struct object_reader {
inline void operator()(istream& is, T& v) const { v.read (is); }
};
template <typename T> struct integral_object_reader {
inline void operator()(istream& is, T& v) const { is.iread (v); }
};
template <typename T>
inline istream& operator>> (istream& is, T& v) {
typedef typename tm::Select <numeric_limits<T>::is_integral,
integral_object_reader<T>, object_reader<T> >::Result object_reader_t;
object_reader_t()(is, v);
return is;
}
template <typename T>
inline istream& operator>> (istream& is, const T& v) { v.read (is); return is; }
//----------------------------------------------------------------------
typedef istream_iterator<utf8subchar_t> istream_iterator_for_utf8;
typedef utf8in_iterator<istream_iterator_for_utf8> utf8istream_iterator;
/// Returns a UTF-8 adaptor reading from \p is.
inline utf8istream_iterator utf8in (istream& is)
{
istream_iterator_for_utf8 si (is);
return utf8istream_iterator (si);
}
//----------------------------------------------------------------------
} // namespace ustl