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Public Member Functions | Protected Member Functions | Private Member Functions | Private Attributes
ASSA::Socketbuf Class Reference

#include <Socketbuf.h>

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

List of all members.

Public Member Functions

 Socketbuf (Socket *s_)
virtual ~Socketbuf ()
- Public Member Functions inherited from ASSA::Streambuf
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 ()
- Public Member Functions inherited from ASSA::io_ptrs
 io_ptrs ()
void dump () const

Protected Member Functions

virtual int sync ()
 This function synchronizes the streambuf with its actual stream of characters.
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 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 showmanyc ()
 The morphemes of showmanyc are "es-how-many-see", not "show-man-ic".
virtual int doallocate ()
 This function is called by allocate when unbuffered() is zero and base() is zero.
- Protected Member Functions inherited from ASSA::Streambuf
 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 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 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).

Private Member Functions

int flush_output ()
int sys_read (char *b_, int len_)
int sys_write (char *b_, int len_)
void xput_char (char c_)

Private Attributes

Socketm_s
 Reference to the Socket stream.

Additional Inherited Members

- Static Public Attributes inherited from ASSA::Streambuf
static const int MAXTCPFRAMESZ = 65536
 Size of the internal input/output buffer.

Detailed Description

Definition at line 29 of file Socketbuf.h.


Constructor & Destructor Documentation

Socketbuf::Socketbuf ( Socket s_)

Definition at line 25 of file Socketbuf.cpp.

References ASSA::STRMBUFTRACE, trace_with_mask, and ASSA::Streambuf::unbuffered().

: m_s (s_)
{
trace_with_mask("Socketbuf::Socketbuf",STRMBUFTRACE);
// By default, I am doing buffering IO
}
Socketbuf::~Socketbuf ( )
virtual

Definition at line 59 of file Socketbuf.cpp.

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

{
trace_with_mask("Socketbuf::~Socketbuf",STRMBUFTRACE);
overflow (EOF); // flush put area
}

Member Function Documentation

int Socketbuf::doallocate ( )
protectedvirtual

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 from ASSA::Streambuf.

Definition at line 226 of file Socketbuf.cpp.

References DL, ASSA::io_ptrs::dump(), ASSA::io_ptrs::m_buf_base, ASSA::io_ptrs::m_flags, ASSA::io_ptrs::m_shortbuf, ASSA::Streambuf::MAXTCPFRAMESZ, ASSA::Streambuf::setb(), ASSA::Streambuf::setg(), ASSA::Streambuf::setp(), ASSA::STRMBUF, ASSA::STRMBUFTRACE, trace_with_mask, and ASSA::io_ptrs::UNBUFFERED.

Referenced by overflow(), and underflow().

{
trace_with_mask("Socketbuf::doallocate",STRMBUFTRACE);
// Get area comes first and matches entier buffer area.
// Put area comes right after it. They are two equally-sized
// separate buffers.
//
// ------------ -
// | | ^
// | get area | | buffer area
// | | v
// ------------ -
// | put area |
// | |
// ------------
//
// Return 1 on allocation and 0 if there is no need
return 0;
if ( ! (m_flags & UNBUFFERED) ) {
DL((STRMBUF,"Buffered IO - allocating %d bytes\n",
char* buf = new char [2 * MAXTCPFRAMESZ];
setg (buf, buf + MAXTCPFRAMESZ, buf + MAXTCPFRAMESZ);
setb (buf, buf + MAXTCPFRAMESZ, 1);
buf += MAXTCPFRAMESZ;
setp (buf, buf+MAXTCPFRAMESZ);
}
else {
DL((STRMBUF,"Unbuffered IO - same 1 byte array\n"));
// read_base is pointing to the begining, and
// read_end to one past end of the buffer.
// Because buffer is empty, read_ptr should point
// to the end (same as read_end). This way, calling
// routines will detect that get area needs data from sync.
//
// +- read_base +- read_ptr
// | |- read_end
// | |+----- one past end-of-block
// v vv
// +--------------+-+
// | get area | |
// +--------------+-+
// write_base & write_ptr are pointing to the begining,
// and write_end to one past end of the buffer.
// Because buffer is empty, read_ptr should point
// to the beginning (same as write_base). This way, calling
// routines will detect that put area needs data from sync.
//
// +- write_base +- write_end points one past
// |- write_ptr | end-of-block
// v v
// +--------------+-+
// | put area | |
// +--------------+-+
}
dump ();
return 1;
}
int Socketbuf::flush_output ( )
private

Definition at line 192 of file Socketbuf.cpp.

References ASSA::Streambuf::epptr(), ASSA::Streambuf::MAXTCPFRAMESZ, ASSA::Streambuf::pbase(), ASSA::Streambuf::pbump(), ASSA::Streambuf::pptr(), ASSA::Streambuf::setp(), ASSA::STRMBUFTRACE, sys_write(), trace_with_mask, and ASSA::Streambuf::unbuffered().

Referenced by overflow(), and sync().

{
trace_with_mask("Socketbuf::flush_output",STRMBUFTRACE);
if (pptr () <= pbase ()) { // Nothing to flush
return 0;
}
int requested;
int xmitted;
requested = pptr () - pbase ();
if ((xmitted = sys_write (pbase (), requested)) < 0) {
return EOF;
}
if (unbuffered ()) {
setp (pbase (), epptr ());
return 0;
}
requested -= xmitted;
pbump (requested);
if (requested > 0) {
::memmove (pbase (), pbase () + xmitted, requested);
}
return 0;
}
int Socketbuf::overflow ( int  c = EOF)
protectedvirtual

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 from ASSA::Streambuf.

Definition at line 162 of file Socketbuf.cpp.

References doallocate(), ASSA::io_ptrs::dump(), ASSA::Streambuf::epptr(), flush_output(), ASSA::Streambuf::pbase(), ASSA::Streambuf::pptr(), ASSA::STRMBUFTRACE, trace_with_mask, ASSA::Streambuf::unbuffered(), and xput_char().

Referenced by ~Socketbuf().

{
trace_with_mask("Socketbuf::overflow",STRMBUFTRACE);
// If c == EOF, return flush_output()
// Otherwise, insert c into the buffer
if (c_ == EOF)
return flush_output ();
if (pbase () == 0 && doallocate () == EOF)
return EOF;
if (pptr () >= epptr() && flush_output () == EOF)
return EOF;
xput_char (c_);
dump ();
if ((unbuffered () || pptr () >= epptr ()) && flush_output () == EOF)
return EOF;
dump ();
return c_;
}
int Socketbuf::showmanyc ( )
protectedvirtual

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 from ASSA::Streambuf.

Definition at line 43 of file Socketbuf.cpp.

References ASSA::Socket::getBytesAvail(), m_s, ASSA::STRMBUFTRACE, and trace_with_mask.

{
trace_with_mask("Socketbuf::showmanyc",STRMBUFTRACE);
return m_s->getBytesAvail ();
}
int Socketbuf::sync ( )
protectedvirtual

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 from ASSA::Streambuf.

Definition at line 35 of file Socketbuf.cpp.

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

{
trace_with_mask("Socketbuf::sync",STRMBUFTRACE);
return flush_output ();
}
int Socketbuf::sys_read ( char *  b_,
int  len_ 
)
private

Definition at line 67 of file Socketbuf.cpp.

References DL, ASSA::get_errno(), ASSA::Socket::getHandler(), m_s, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by underflow().

{
trace_with_mask("Socketbuf::sys_read",STRMBUFTRACE);
int ret = ::recv (m_s->getHandler (), b_, len_, 0);
DL((STRMBUFTRACE,"Tried to read %d bytes from fd=%d\n",
len_, m_s->getHandler ()));
DL((STRMBUFTRACE,"::recv() returned %d\n", ret));
if (ret == -1) {
DL((STRMBUFTRACE,"::recv() error: %d (%s)\n",
errno, strerror (get_errno ())));
}
return (ret);
}
int Socketbuf::sys_write ( char *  b_,
int  len_ 
)
private

Definition at line 86 of file Socketbuf.cpp.

References DL, ASSA::Socket::getHandler(), m_s, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by flush_output().

{
trace_with_mask("Socketbuf::sys_write",STRMBUFTRACE);
int ret = ::send (m_s->getHandler (), b_, len_, 0);
DL((STRMBUFTRACE,"Tried to write %d bytes to fd=%d\n",
len_, m_s->getHandler ()));
DL((STRMBUFTRACE,"::send() returned %d\n", ret));
if (ret == -1) {
DL((STRMBUFTRACE,"::send() error: %d\n",errno));
}
return (ret);
}
int Socketbuf::underflow ( )
protectedvirtual

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 from ASSA::Streambuf.

Definition at line 105 of file Socketbuf.cpp.

References ASSA::Streambuf::base(), DL, doallocate(), ASSA::io_ptrs::dump(), ASSA::MemDump::dump_to_log(), ASSA::Streambuf::egptr(), ASSA::io_ptrs::EOF_SEEN, ASSA::get_errno(), ASSA::Streambuf::gptr(), ASSA::io_ptrs::m_flags, ASSA::Streambuf::MAXTCPFRAMESZ, ASSA::Streambuf::setg(), ASSA::STRMBUF, ASSA::STRMBUFTRACE, sys_read(), trace_with_mask, and ASSA::Streambuf::unbuffered().

{
/*
The important thing to note is that this function
returns:
a) pointer to the first character in buffer available.
b) EOF if sys_read () failed.
In case of peer closing its connection, a) will be true.
Caller can always find out number of bytes in buffer
and determine if peer indeed closed connection.
*/
trace_with_mask("Socketbuf::underflow",STRMBUFTRACE);
if (gptr () < egptr ()) // The get area is not empty,
{
return *(unsigned char*) gptr (); // return 1st character
}
if (base () == 0 && // If buffer isn't established,
doallocate () == EOF) // allocate buffer (both buff & unbuff IO)
{
return EOF;
}
int bufsz = unbuffered () ? 1 : MAXTCPFRAMESZ;
/*
Read as much as I can up to the allocated buffer size.
EOF = (-1).
*/
int rval = sys_read (base (), bufsz);
DL((STRMBUF,"Socketbuf::sys_read() returned %d bytes\n", rval));
if (rval == EOF)
{
if (get_errno () != EWOULDBLOCK) {
}
return EOF;
}
DL((STRMBUF,"Having read %d bytes from socket\n",rval));
MemDump::dump_to_log (STRMBUF, "Data received:", base (), rval);
// Set get area pointers according to the data just read
setg (base (), base (), base () + rval);
dump ();
return (*(unsigned char*) gptr ()); // Return front character
}
void Socketbuf::xput_char ( char  c_)
private

Definition at line 51 of file Socketbuf.cpp.

References ASSA::Streambuf::pbump(), ASSA::Streambuf::pptr(), ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by overflow().

{
trace_with_mask("Socketbuf::xput_char",STRMBUFTRACE);
*pptr() = c_;
pbump (1);
}

Member Data Documentation

Socket* ASSA::Socketbuf::m_s
private

Reference to the Socket stream.

Definition at line 51 of file Socketbuf.h.

Referenced by showmanyc(), sys_read(), and sys_write().


The documentation for this class was generated from the following files: