libassa 3.5.0
Public Member Functions | Static Public Attributes | Protected Member Functions

ASSA::Streambuf Class Reference

Streambuf class. More...

#include <Streambuf.h>

Inheritance diagram for ASSA::Streambuf:
ASSA::io_ptrs ASSA::Socketbuf

List of all members.

Public Member Functions

virtual ~Streambuf ()
Streambufpubsetbuf (char *s_, int n_)
 Set buffer.
int pubsync ()
int in_avail ()
 This function returns the number of characters immediately available in the get area.
int snextc ()
 This function moves the get pointer forward one position, then returns the character after the get pointer's new position.
int sbumpc ()
 This function should probably have been called ``sgetc''.
int sgetc ()
 This function returns the character after the get pointer, or EOF if the get pointer is at the end of the sequence.
int sgetn (char *b_, int len_)
 This function gets the next len_ characters following the get pointer, copying them to the char array pointed to by b_; it advances the get pointer past the last character fetched.
int sputc (char c_)
 This function stores c just after the put pointer, and advances the pointer one position, possibly extending the sequence.
int sputn (char *b_, int len_)
 From the location pointed to by ptr, stores exactly len characters after the put pointer, advancing the put pointer just past the last character.
void unbuffered (int i_)
 If i_ is non-zero, then all IO operations are buffered.
int unbuffered ()

Static Public Attributes

static const int MAXTCPFRAMESZ = 65536
 Size of the internal input/output buffer.

Protected Member Functions

 Streambuf ()
 The default constructor is protected for class Streambuf to asssure that only objects for classes derived from this class may be constructed.
 Streambuf (const Streambuf &)
Streambufoperator= (const Streambuf &)
char * base () const
 Returns the lowest possible value for gptr() - the beginning of the get area.
char * gptr () const
 Returns a pointer to the beginning of the get area, and thus to the next character to be fetched (if there are any).
char * egptr () const
 Returns a pointer just past the end of the get area, the maximum possible value for gptr().
void setg (char *gbeg_, char *gnext_, char *gend_)
 Set get area pointers.
char * pbase () const
 Returns a pointer to the beginning fo the space available for the put area, the lowest possible value for pptr().
char * pptr () const
 Returns a pointer to the beginning of the put area, and thus to the location of the next character that is stored (if possible).
char * epptr () const
 Returns a pointer just past the end of the put area, the maximum possible value for pptr().
void setp (char *pbeg_, char *pend_)
 Set put area pointers.
void pbump (int n_)
 Advances the next pointer for the output sequence by n_.
void setb (char *b_, char *eb_, int del_)
 Establish the reserve area (buffer).
void init ()
virtual Streambufsetbuf (char *p_, int len_)
 Performs an operation that is defined separately for each class derived from Streambuf.
virtual int sync ()
 This function synchronizes the streambuf with its actual stream of characters.
virtual int showmanyc ()
 The morphemes of showmanyc are "es-how-many-see", not "show-man-ic".
virtual int xsgetn (char *b_, int len_)
 Assigns up to len_ characters to successive elements of the array whose first element is designated by b_.
virtual int underflow ()
 This function is called to supply characters for input (from some source) when the get area is empty, although it may be called at other times.
virtual int uflow ()
 Reads the characters from the input sequence, if possible, and moves the stream position past it, as follows:
virtual int xsputn (const char *b_, int len_)
 Writes up to len_ characters to the output sequence as if by repeated calls to sputc (c).
virtual int overflow (int c=EOF)
 This function is called to consume characters (flush them to output), typically when the put area is full and an attempt is made to store another character.
virtual int doallocate ()
 This function is called by allocate when unbuffered() is zero and base() is zero.

Detailed Description

Streambuf class.

Streambuf class is based on Standard C++ iostream streambuf class.

Extending std::streambuf is always pain due to the obscurity and complexity of its interface, and in general, lack of the source code needed to efficiently understand its implementation.

I wrote my own Streambuf that implements a subset of std::streambuf functions - a bare minimum to get by for Socket buffering.

The buffer of a Streambuf may be considered to have three parts: the get area, the put area, and the reserve area (which is the same as the buffer area).

The get area contains the characters immediately available for input.

The put area holds characters stored for output but not yet consumed by (flushed to) their ultimate destination. The get and put areas may be disjoint or may overlap (in my implementation they are two disjoined buffers). The reserve area is the entire buffer, overlapped by the get and put areas (in my implementation, reserve area covers get area only). The get and put areas may expand into the remainder of the reserve area. In the course of input and output operations, the sizes of the get and put areas expand and shrink, always bounded by the total buffer size.

Definition at line 90 of file Streambuf.h.


Constructor & Destructor Documentation

ASSA::Streambuf::~Streambuf ( ) [inline, virtual]
ASSA::Streambuf::Streambuf ( ) [inline, protected]

The default constructor is protected for class Streambuf to asssure that only objects for classes derived from this class may be constructed.

Definition at line 429 of file Streambuf.h.

References init(), ASSA::STRMBUFTRACE, and trace_with_mask.

{ 
    trace_with_mask("Streambuf::Streambuf",STRMBUFTRACE);

    init (); 
}
ASSA::Streambuf::Streambuf ( const Streambuf ) [protected]

Member Function Documentation

char * ASSA::Streambuf::base ( ) const [inline, protected]

Returns the lowest possible value for gptr() - the beginning of the get area.

Definition at line 464 of file Streambuf.h.

References ASSA::io_ptrs::m_read_base, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by ASSA::Socketbuf::underflow().

{ 
    trace_with_mask("Streambuf::base",STRMBUFTRACE);

    return m_read_base; 
}
int Streambuf::doallocate ( ) [protected, virtual]

This function is called by allocate when unbuffered() is zero and base() is zero.

It attempts to make a buffer of suitable size available. On success it must call setb to establish the reserve area, then return a value greater than zero. On failure it returns EOF. The default behavior is to allocate a buffer using new.

Reimplemented in ASSA::Socketbuf.

Definition at line 234 of file Streambuf.cpp.

References setb(), ASSA::STRMBUFTRACE, and trace_with_mask.

{
    trace_with_mask("Streambuf::doallocate",STRMBUFTRACE);

    char* buf;
    buf = new char [1024];
    if (buf == NULL) {
        return EOF;
    }
    setb (buf, buf+1024, 1);

    return 1;
}
char * ASSA::Streambuf::egptr ( ) const [inline, protected]

Returns a pointer just past the end of the get area, the maximum possible value for gptr().

Definition at line 482 of file Streambuf.h.

References ASSA::io_ptrs::m_read_end, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by ASSA::Socketbuf::underflow().

{ 
    trace_with_mask("Streambuf::egptr",STRMBUFTRACE);

    return m_read_end; 
}
char * ASSA::Streambuf::epptr ( ) const [inline, protected]

Returns a pointer just past the end of the put area, the maximum possible value for pptr().

The space from pptr() through epptr() is immediately available for storing characters without a flush operation.

Definition at line 507 of file Streambuf.h.

References ASSA::io_ptrs::m_write_end, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by ASSA::Socketbuf::flush_output(), and ASSA::Socketbuf::overflow().

{ 
    trace_with_mask("Streambuf::epptr",STRMBUFTRACE);
    return m_write_end; 
}
char * ASSA::Streambuf::gptr ( ) const [inline, protected]

Returns a pointer to the beginning of the get area, and thus to the next character to be fetched (if there are any).

The characters immediately available are from gptr() through egptr()-1. If egptr()<=gptr(), no char- acters are available.

Definition at line 473 of file Streambuf.h.

References ASSA::io_ptrs::m_read_ptr, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by ASSA::Socketbuf::underflow().

{ 
    trace_with_mask("Streambuf::gptr",STRMBUFTRACE);

    return m_read_ptr; 
}
int ASSA::Streambuf::in_avail ( ) [inline]

This function returns the number of characters immediately available in the get area.

It is certain that i characters may be fetched without error, and without accessing any external device.

Definition at line 399 of file Streambuf.h.

References ASSA::io_ptrs::m_read_end, ASSA::io_ptrs::m_read_ptr, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by ASSA::IPv4Socket::clone(), ASSA::IPv4Socket::close(), ASSA::Socket::getBytesAvail(), and ASSA::IPv4Socket::in_avail().

{ 
    trace_with_mask("Streambuf::in_avail",STRMBUFTRACE);

    return m_read_end - m_read_ptr; 
}
void ASSA::Streambuf::init ( ) [inline, protected]
Streambuf& ASSA::Streambuf::operator= ( const Streambuf ) [protected]
int ASSA::Streambuf::overflow ( int  c = EOF) [inline, protected, virtual]

This function is called to consume characters (flush them to output), typically when the put area is full and an attempt is made to store another character.

If c is not EOF, overflow must either store or consume the character, following those already in the put area. It returns EOF on error, any other value on success. The default behavior of the base class version is undefined, so each derived class must define its own overflow. The normal action for a derived class version is to consume the characters in the put area (those between pbase() and pptr()), call setp() to set up a new put area, then store c (using sputc()) if it is not EOF.

Reimplemented in ASSA::Socketbuf.

Definition at line 607 of file Streambuf.h.

References ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by sputc(), and xsputn().

{
    trace_with_mask("Streambuf::overflow",STRMBUFTRACE);

    return (EOF);
}
char * ASSA::Streambuf::pbase ( ) const [inline, protected]

Returns a pointer to the beginning fo the space available for the put area, the lowest possible value for pptr().

The area from pbase() through pptr()-1 represents characters which have been stored int the buffer but not yet consumed.

Definition at line 491 of file Streambuf.h.

References ASSA::io_ptrs::m_write_base, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by ASSA::Socketbuf::flush_output(), and ASSA::Socketbuf::overflow().

{ 
    trace_with_mask("Streambuf::pbase",STRMBUFTRACE);
    return m_write_base; 
}
void ASSA::Streambuf::pbump ( int  n_) [inline, protected]

Advances the next pointer for the output sequence by n_.

Definition at line 515 of file Streambuf.h.

References ASSA::io_ptrs::m_write_ptr, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by ASSA::Socketbuf::flush_output(), and ASSA::Socketbuf::xput_char().

{ 
    trace_with_mask("Streambuf::pbump",STRMBUFTRACE);
    m_write_ptr += n_; 
}
char * ASSA::Streambuf::pptr ( ) const [inline, protected]

Returns a pointer to the beginning of the put area, and thus to the location of the next character that is stored (if possible).

Definition at line 499 of file Streambuf.h.

References ASSA::io_ptrs::m_write_ptr, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by ASSA::Socketbuf::flush_output(), ASSA::Socketbuf::overflow(), and ASSA::Socketbuf::xput_char().

{ 
    trace_with_mask("Streambuf::pptr",STRMBUFTRACE);
    return m_write_ptr; 
}
Streambuf * ASSA::Streambuf::pubsetbuf ( char *  s_,
int  n_ 
) [inline]

Set buffer.

Returns:
setbuf(s_, n_)

Definition at line 381 of file Streambuf.h.

References setbuf(), ASSA::STRMBUFTRACE, and trace_with_mask.

{ 
    trace_with_mask("Streambuf::pubsetbuf",STRMBUFTRACE);
    
    return setbuf (s_, n_); 
}
int ASSA::Streambuf::pubsync ( ) [inline]
See also:
sync
Returns:
sync()

Definition at line 390 of file Streambuf.h.

References ASSA::STRMBUFTRACE, sync(), and trace_with_mask.

{ 
    trace_with_mask("Streambuf::pubsync",STRMBUFTRACE);

    return sync (); 
}
int ASSA::Streambuf::sbumpc ( ) [inline]

This function should probably have been called ``sgetc''.

It moves the get pointer forward one posi- tion and returns the character it moved past. If the get pointer is currently at the end of the sequence, this function returns EOF.

Definition at line 539 of file Streambuf.h.

References ASSA::io_ptrs::m_read_end, ASSA::io_ptrs::m_read_ptr, ASSA::STRMBUFTRACE, trace_with_mask, and uflow().

Referenced by ASSA::IPv4Socket::close(), and ASSA::IPv4Socket::read().

{
    trace_with_mask("Streambuf::sbumpc",STRMBUFTRACE);

    return (m_read_ptr >= m_read_end ? uflow ()
            : *(unsigned char *) m_read_ptr++);
}
void Streambuf::setb ( char *  b_,
char *  eb_,
int  del_ 
) [protected]

Establish the reserve area (buffer).

Set base() to b_, ebuf() to eb_. If del_ is non-zero, the buffer will be deleted whenever base() is changed by another call to setb(), or when Streambuf destructor is invoked. If del_ is zero, the buffer will not be deleted automatically.

Parameters:
b_pointer to the buffer's first byte
eb_pointer to the byte one past the buffer's last byte
del_0 - external memory management, 1 - delete on swap/destruction

Definition at line 80 of file Streambuf.cpp.

References ASSA::io_ptrs::dump(), ASSA::io_ptrs::m_buf_base, ASSA::io_ptrs::m_buf_end, ASSA::io_ptrs::m_flags, ASSA::STRMBUFTRACE, trace_with_mask, and ASSA::io_ptrs::USER_BUF.

Referenced by doallocate(), ASSA::Socketbuf::doallocate(), and setbuf().

{
    trace_with_mask("Streambuf::setb",STRMBUFTRACE);

    if (m_buf_base && !(m_flags & USER_BUF))
        delete m_buf_base;

    m_buf_base = b_;
    m_buf_end = eb_;
    
    if (del_)
        m_flags &= ~ USER_BUF; // clear bit
    else
        m_flags |= USER_BUF; // set bit

    dump ();
}
Streambuf * Streambuf::setbuf ( char *  p_,
int  len_ 
) [protected, virtual]

Performs an operation that is defined separately for each class derived from Streambuf.

Default behavior is to set internal buffer to p_. If p_ is NULL or len_ is 0, then unbuffered I/O (one byte at a time) is assumed.

Parameters:
p_buffer to use
len_length of the buffer

Definition at line 100 of file Streambuf.cpp.

References DL, setb(), setg(), setp(), ASSA::STRMBUF, ASSA::STRMBUFTRACE, sync(), trace_with_mask, and unbuffered().

Referenced by pubsetbuf().

{
    trace_with_mask("Streambuf::setb",STRMBUFTRACE);

    if (sync () == EOF) // Flush out all pending bytes before
        return NULL;    // resetting buffer. Also, first time around,
    // calling sync() suppose to set put area
    // pointers.

    if (p_ == NULL || len_ == 0) {
        DL((STRMBUF,"Unbuffered IO set.\n"));
        unbuffered (1);
        // We do it from doalloc instead - vlg
        // setb (m_shortbuf, m_shortbuf+1, 0);
    }
    else {
        DL((STRMBUF,"Buffered IO set.\n"));
        unbuffered (0);
        setb (p_, p_ + len_, 0);
    }
    setp (0, 0);
    setg (0, 0, 0);

    return this;
}
void Streambuf::setg ( char *  gbeg_,
char *  gnext_,
char *  gend_ 
) [protected]
void ASSA::Streambuf::setp ( char *  pbeg_,
char *  pend_ 
) [inline, protected]
int ASSA::Streambuf::sgetc ( ) [inline]

This function returns the character after the get pointer, or EOF if the get pointer is at the end of the sequence.

Despite its name, this function does NOT move the get pointer.

Definition at line 549 of file Streambuf.h.

References ASSA::io_ptrs::m_read_end, ASSA::io_ptrs::m_read_ptr, ASSA::STRMBUFTRACE, trace_with_mask, and underflow().

Referenced by snextc().

{
    trace_with_mask("Streambuf::sgetc",STRMBUFTRACE);

    return (m_read_ptr >= m_read_end && underflow () == EOF 
            ? EOF : *(unsigned char*) m_read_ptr);
}
int ASSA::Streambuf::sgetn ( char *  b_,
int  len_ 
) [inline]

This function gets the next len_ characters following the get pointer, copying them to the char array pointed to by b_; it advances the get pointer past the last character fetched.

If fewer than len characters are left, it gets as many as are available.

Returns:
the number of characters fetched.

Definition at line 559 of file Streambuf.h.

References ASSA::STRMBUFTRACE, trace_with_mask, and xsgetn().

Referenced by ASSA::IPv4Socket::read().

{
    trace_with_mask("Streambuf::sgetn",STRMBUFTRACE);

    return xsgetn (data_, len_);
}
int ASSA::Streambuf::showmanyc ( ) [inline, protected, virtual]

The morphemes of showmanyc are "es-how-many-see", not "show-man-ic".

Return an estimate of the number of characters available in the sequence, or -1. If it returns a positive value, then successive calls to underflow() will not return EOF until at least that number of characters have been supplied. If showmanyc() returns -1, then calls to underflow() or uflow() will fail. The intention is not only that these calls will not return EOF, but that they will return ``immediately.''

Reimplemented in ASSA::Socketbuf.

Definition at line 531 of file Streambuf.h.

References ASSA::STRMBUFTRACE, and trace_with_mask.

{ 
    trace_with_mask("Streambuf::showmanyc",STRMBUFTRACE);
    return -1; 
}
int Streambuf::snextc ( )

This function moves the get pointer forward one position, then returns the character after the get pointer's new position.

If the get pointer is at the end of the sequence before or after the call to this function (no character is available), this function returns EOF. Example: Suppose the input buffer looks like this: abc|def where `|' marks the position of the get pointer. This function will advance the get pointer and return `e'.

Definition at line 57 of file Streambuf.cpp.

References ASSA::io_ptrs::m_read_end, ASSA::io_ptrs::m_read_ptr, sgetc(), ASSA::STRMBUFTRACE, trace_with_mask, and underflow().

{   
    trace_with_mask("Streambuf::snextc",STRMBUFTRACE);

    if (m_read_ptr >= m_read_end && underflow () == EOF) {
        return EOF;
    }
    return m_read_ptr++, sgetc (); 
}
int ASSA::Streambuf::sputc ( char  c_) [inline]

This function stores c just after the put pointer, and advances the pointer one position, possibly extending the sequence.

It returns c, or EOF on error. What constitutes an error depends on the actual derived buffer class.

Definition at line 568 of file Streambuf.h.

References ASSA::io_ptrs::m_write_end, ASSA::io_ptrs::m_write_ptr, overflow(), ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by ASSA::IPv4Socket::write().

{
    trace_with_mask("Streambuf::sputc",STRMBUFTRACE);

    return (m_write_ptr >= m_write_end
            ? overflow (c_)
            : (unsigned char) (*m_write_ptr++ = c_));
}
int ASSA::Streambuf::sputn ( char *  b_,
int  len_ 
) [inline]

From the location pointed to by ptr, stores exactly len characters after the put pointer, advancing the put pointer just past the last character.

It returns the number of characters stored, which ought to be len. Fewer than len characters stored indicates some sort of error.

Definition at line 579 of file Streambuf.h.

References ASSA::STRMBUFTRACE, trace_with_mask, and xsputn().

Referenced by ASSA::IPv4Socket::write().

{
    trace_with_mask("Streambuf::sputn",STRMBUFTRACE);

    return xsputn (b_, len_);
}
int ASSA::Streambuf::sync ( ) [inline, protected, virtual]

This function synchronizes the streambuf with its actual stream of characters.

The derived class version should flush any characters in the put area to their final destination, and if possible give back any characters in the input buffer to their source. It should return EOF on any error, zero on success. The default behavior of the base class version is to return zero if there are no pending input or output characters (in_avail() and out_waiting() are both zero), and return EOF otherwise.

Reimplemented in ASSA::Socketbuf.

Definition at line 523 of file Streambuf.h.

References ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by pubsync(), and setbuf().

{ 
    trace_with_mask("Streambuf::sync",STRMBUFTRACE);
    return 0; 
}
int Streambuf::uflow ( ) [protected, virtual]

Reads the characters from the input sequence, if possible, and moves the stream position past it, as follows:

1) If the input sequence has a read position available the function signals success by returning (unsigned char)*gnext++.

2) Otherwise, if the function can read the character x directly from the associated input sequence, it signals succes by returning (unsigned char) x. If the function makes a read position available, it also assigns x to *gnext.

The default behavior is to call underflow () and, if that function returns EOF or fails to make a read position available, return EOF. Otherwise, the function signals success by returning (unsigned char)*gnext++.

Definition at line 172 of file Streambuf.cpp.

References ASSA::io_ptrs::dump(), ASSA::io_ptrs::m_read_ptr, ASSA::STRMBUFTRACE, trace_with_mask, and underflow().

Referenced by sbumpc().

{
    trace_with_mask("Streambuf::uflow",STRMBUFTRACE);

    if (underflow () == EOF)
        return EOF;
    dump ();
    return *(unsigned char *) m_read_ptr++;
}
void ASSA::Streambuf::unbuffered ( int  i_) [inline]

If i_ is non-zero, then all IO operations are buffered.

If i_ is zero, then unbuffered IO is performed (one character at a time.

Definition at line 417 of file Streambuf.h.

References ASSA::io_ptrs::m_flags, ASSA::STRMBUFTRACE, trace_with_mask, and ASSA::io_ptrs::UNBUFFERED.

Referenced by ASSA::IPv4Socket::read(), and ASSA::IPv4Socket::write().

{
    trace_with_mask("Streambuf::unbuffered",STRMBUFTRACE);

    if (i_) 
        m_flags |= UNBUFFERED; // set
    else
        m_flags &= ~ UNBUFFERED; // unset
}
int ASSA::Streambuf::unbuffered ( ) [inline]
Returns:
true if unbuffered, false otherwise

Definition at line 408 of file Streambuf.h.

References ASSA::io_ptrs::m_flags, ASSA::STRMBUFTRACE, trace_with_mask, and ASSA::io_ptrs::UNBUFFERED.

Referenced by ASSA::Socketbuf::flush_output(), ASSA::Socketbuf::overflow(), setbuf(), ASSA::Socketbuf::Socketbuf(), and ASSA::Socketbuf::underflow().

{ 
    trace_with_mask("Streambuf::unbuffered",STRMBUFTRACE);
    
    return m_flags & UNBUFFERED ? 1 : 0; 
}
int ASSA::Streambuf::underflow ( ) [inline, protected, virtual]

This function is called to supply characters for input (from some source) when the get area is empty, although it may be called at other times.

If the get area is not empty, it should just return the first character (without advancing the get pointer). If the get area is empty, it should establish a new get area, aquire new input, and return the first character, if any. If no input characters are available, it should leave an empty get area and return EOF. The default behavior of the base class version is undefined, so each derived class must define its own underflow.

Reimplemented in ASSA::Socketbuf.

Definition at line 598 of file Streambuf.h.

References ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by sgetc(), snextc(), uflow(), and xsgetn().

{
    trace_with_mask("Streambuf::underflow",STRMBUFTRACE);

    return (EOF);
}
int Streambuf::xsgetn ( char *  b_,
int  len_ 
) [protected, virtual]

Assigns up to len_ characters to successive elements of the array whose first element is designated by b_.

The characters assigned are read from the input sequence as if by repeated calls to sbumpc(). Assigning stops when either len_ characters have been assigned or a call to sbumpc() would return EOF.

Returns:
The number of characters assigned.

Definition at line 128 of file Streambuf.cpp.

References DL, ASSA::io_ptrs::m_read_end, ASSA::io_ptrs::m_read_ptr, ASSA::STRMBUFTRACE, trace_with_mask, and underflow().

Referenced by sgetn().

{
    trace_with_mask("Streambuf::xsgetn",STRMBUFTRACE);

    /*
      Get area is empty and nothing is on the socket.
    */
    int count = m_read_end - m_read_ptr; // Bytes in Get area

    if (count == 0 && underflow () == EOF) {
        DL((STRMBUFTRACE,"returning %d. count: %d\n", EOF));
        return EOF;
    }
    count = m_read_end - m_read_ptr; // Adjusted bytes in Get area

    DL((STRMBUFTRACE,"Adjusted bytes in Get Area: %d\n",count));

    if (count > len_) {
        count = len_;
    }

    if (count <= 0) {
        count = 0;  // Peer closed connection
    }
    else if (count > 20) {
        memcpy (data_, m_read_ptr, count);
        m_read_ptr += count;
    }
    else {
        char* s = data_;
        char* p = m_read_ptr;
        int i = count;
        while (i-- > 0) {
            *s++ = *p++;
        }
        m_read_ptr = p;
    }
    DL((STRMBUFTRACE,"Transferred %d bytes to user-space buffer\n", count));

    return (count);
}
int Streambuf::xsputn ( const char *  b_,
int  len_ 
) [protected, virtual]

Writes up to len_ characters to the output sequence as if by repeated calls to sputc (c).

The characters written are obtained from successive elements of the array whose first element is designated by b_. Writing stops when either len_ characters have been written or a call to sputc(c) would return EOF.

Returns:
The number of characters written.

Definition at line 184 of file Streambuf.cpp.

References ASSA::io_ptrs::m_write_end, ASSA::io_ptrs::m_write_ptr, overflow(), ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by sputn().

{
    trace_with_mask("Streambuf::xsputn",STRMBUFTRACE);

    const char* s = data_;
    int more = len_;
    if (more <= 0) {
        return 0;
    }

    for (;;) {
        int count = m_write_end - m_write_ptr; // Space available

        if (count > 0) {

            if (count > more) // Enough buffer space
                count = more;

            if (count > 20) {
                memcpy (m_write_ptr, s, count);
                s += count;
                m_write_ptr += count;
            }
            else if (count <= 0) {
                count = 0;
            }
            else {
                char* p = m_write_ptr;
                int i;

                for (i=count; --i >= 0;) {
                    *p++ = *s++;
                }
                m_write_ptr = p;
            }
            more -= count;
        } // if (count>0)
        
        if (more == 0 || overflow ((unsigned char) *s++) == EOF) {
            break;
        }
        more--;

    } // for (;;)

    return (len_ - more);
}

Member Data Documentation

const int ASSA::Streambuf::MAXTCPFRAMESZ = 65536 [static]

Size of the internal input/output buffer.

You can use this constant to do application code read/writes to the socket.

Definition at line 106 of file Streambuf.h.

Referenced by ASSA::Socketbuf::doallocate(), ASSA::Socketbuf::flush_output(), and ASSA::Socketbuf::underflow().


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