323 lines
12 KiB
C++
323 lines
12 KiB
C++
// 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);
|
|
inline istream (const void* p, streamsize n);
|
|
inline explicit istream (const cmemlink& source);
|
|
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); m_Pos = 0; }
|
|
inline void relink (const cmemlink& l) { relink (l.cdata(), l.readable_size()); }
|
|
void unlink (void) noexcept;
|
|
inline streamsize underflow (streamsize = 1) { return (remaining()); }
|
|
inline uoff_t pos (void) const { return (m_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&) { }
|
|
inline void get (char& c) { read(&c, 1); }
|
|
inline char get () { char c; read(&c, 1); return c; }
|
|
|
|
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 m_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;
|
|
public:
|
|
istream_iterator (void) : m_pis (NULL), m_v() {}
|
|
explicit istream_iterator (Stream& is) : m_pis (&is), m_v() { Read(); }
|
|
istream_iterator (const istream_iterator& i) : m_pis (i.m_pis), m_v (i.m_v) {}
|
|
/// Reads and returns the next value.
|
|
inline const T& operator* (void) { return (m_v); }
|
|
inline istream_iterator& operator++ (void) { Read(); return (*this); }
|
|
inline istream_iterator& operator-- (void) { m_pis->seek (m_pis->pos() - 2 * stream_size_of(m_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) { m_pis->seek (m_pis->pos() - (n + 1) * stream_size_of(m_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.m_pis->pos(), m_pis->pos()) / stream_size_of(m_v)); }
|
|
inline bool operator== (const istream_iterator& i) const { return ((!m_pis && !i.m_pis) || (m_pis && i.m_pis && m_pis->pos() == i.m_pis->pos())); }
|
|
inline bool operator< (const istream_iterator& i) const { return (!i.m_pis || (m_pis && m_pis->pos() < i.m_pis->pos())); }
|
|
private:
|
|
void Read (void)
|
|
{
|
|
if (!m_pis)
|
|
return;
|
|
const streamsize rs (required_stream_size (m_v, *m_pis));
|
|
if (m_pis->remaining() < rs && m_pis->underflow (rs) < rs) {
|
|
m_pis = NULL;
|
|
return;
|
|
}
|
|
*m_pis >> m_v;
|
|
if (stream_at_eof (*m_pis))
|
|
m_pis = NULL;
|
|
}
|
|
private:
|
|
Stream* m_pis; ///< The host stream.
|
|
T m_v; ///< Last read value; cached to be returnable as a const reference.
|
|
};
|
|
|
|
//----------------------------------------------------------------------
|
|
|
|
/// \brief Constructs a stream attached to nothing.
|
|
/// A stream attached to nothing is not usable. Call Link() functions
|
|
/// inherited from cmemlink to attach to some memory block.
|
|
///
|
|
inline istream::istream (void)
|
|
: cmemlink (),
|
|
m_Pos (0)
|
|
{
|
|
}
|
|
|
|
/// Attaches the stream to a block at \p p of size \p n.
|
|
inline istream::istream (const void* p, streamsize n)
|
|
: cmemlink (p, n),
|
|
m_Pos (0)
|
|
{
|
|
}
|
|
|
|
/// Attaches to the block pointed to by \p source.
|
|
inline istream::istream (const cmemlink& source)
|
|
: cmemlink (source),
|
|
m_Pos (0)
|
|
{
|
|
}
|
|
|
|
/// 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;
|
|
#else
|
|
assert (newPos <= size());
|
|
#endif
|
|
m_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
|
|
{
|
|
assert (uintptr_t(begin()) % grain == 0 && "Streams should be attached aligned at the maximum element grain to avoid bus errors.");
|
|
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());
|
|
m_Pos += sizeof(T);
|
|
}
|
|
|
|
/// Swaps contents with \p is
|
|
inline void istream::swap (istream& is)
|
|
{
|
|
cmemlink::swap (is);
|
|
::ustl::swap (m_Pos, is.m_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);
|
|
m_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
|