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 ()

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]
 

Definition at line 442 of file Streambuf.h.

References 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.

00443 {
00444     trace_with_mask("Streambuf::~Streambuf",STRMBUFTRACE);
00445 
00446     if (!(m_flags & USER_BUF)) {
00447         delete [] m_buf_base;
00448         m_buf_base = m_buf_end = 0;
00449     }
00450 }

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 419 of file Streambuf.h.

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

00420 { 
00421     trace_with_mask("Streambuf::Streambuf",STRMBUFTRACE);
00422 
00423     init (); 
00424 }

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 454 of file Streambuf.h.

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

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

00455 { 
00456     trace_with_mask("Streambuf::base",STRMBUFTRACE);
00457 
00458     return m_read_base; 
00459 }

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 249 of file Streambuf.cpp.

00250 {
00251     trace_with_mask("Streambuf::doallocate",STRMBUFTRACE);
00252 
00253     char* buf;
00254     buf = new char [1024];
00255     if (buf == NULL) {
00256         return EOF;
00257     }
00258     setb (buf, buf+1024, 1);
00259 
00260     return 1;
00261 }

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 472 of file Streambuf.h.

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

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

00473 { 
00474     trace_with_mask("Streambuf::egptr",STRMBUFTRACE);
00475 
00476     return m_read_end; 
00477 }

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 497 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().

00498 { 
00499     trace_with_mask("Streambuf::epptr",STRMBUFTRACE);
00500     return m_write_end; 
00501 }

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 463 of file Streambuf.h.

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

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

00464 { 
00465     trace_with_mask("Streambuf::gptr",STRMBUFTRACE);
00466 
00467     return m_read_ptr; 
00468 }

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 389 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().

00390 { 
00391     trace_with_mask("Streambuf::in_avail",STRMBUFTRACE);
00392 
00393     return m_read_end - m_read_ptr; 
00394 }

void ASSA::Streambuf::init  )  [inline, protected]
 

Definition at line 428 of file Streambuf.h.

References ASSA::io_ptrs::m_buf_base, ASSA::io_ptrs::m_buf_end, ASSA::io_ptrs::m_flags, ASSA::io_ptrs::m_read_base, ASSA::io_ptrs::m_read_end, ASSA::io_ptrs::m_read_ptr, ASSA::io_ptrs::m_shortbuf, ASSA::io_ptrs::m_write_base, ASSA::io_ptrs::m_write_end, ASSA::io_ptrs::m_write_ptr, ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by Streambuf().

00429 {
00430     trace_with_mask("Streambuf::init", STRMBUFTRACE);
00431 
00432     m_read_base = m_read_ptr = m_read_end = 0;
00433     m_write_base = m_write_ptr = m_write_end = 0;
00434     m_buf_base = m_buf_end = 0;
00435     m_flags = 0;
00436 
00437     m_shortbuf[0] = 0;
00438 }

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 597 of file Streambuf.h.

References ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by sputc().

00598 {
00599     trace_with_mask("Streambuf::overflow",STRMBUFTRACE);
00600 
00601     return (EOF);
00602 }

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 481 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().

00482 { 
00483     trace_with_mask("Streambuf::pbase",STRMBUFTRACE);
00484     return m_write_base; 
00485 }

void ASSA::Streambuf::pbump int  n_  )  [inline, protected]
 

Advances the next pointer for the output sequence by n_.

Definition at line 505 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().

00506 { 
00507     trace_with_mask("Streambuf::pbump",STRMBUFTRACE);
00508     m_write_ptr += n_; 
00509 }

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 489 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().

00490 { 
00491     trace_with_mask("Streambuf::pptr",STRMBUFTRACE);
00492     return m_write_ptr; 
00493 }

Streambuf * ASSA::Streambuf::pubsetbuf char *  s_,
int  n_
[inline]
 

Set buffer.

Returns:
setbuf(s_, n_)

Definition at line 371 of file Streambuf.h.

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

00372 { 
00373     trace_with_mask("Streambuf::pubsetbuf",STRMBUFTRACE);
00374     
00375     return setbuf (s_, n_); 
00376 }

int ASSA::Streambuf::pubsync  )  [inline]
 

See also:
sync
Returns:
sync()

Definition at line 380 of file Streambuf.h.

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

00381 { 
00382     trace_with_mask("Streambuf::pubsync",STRMBUFTRACE);
00383 
00384     return sync (); 
00385 }

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 529 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().

00530 {
00531     trace_with_mask("Streambuf::sbumpc",STRMBUFTRACE);
00532 
00533     return (m_read_ptr >= m_read_end ? uflow ()
00534             : *(unsigned char *) m_read_ptr++);
00535 }

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 95 of file Streambuf.cpp.

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

00096 {
00097     trace_with_mask("Streambuf::setb",STRMBUFTRACE);
00098 
00099     if (m_buf_base && !(m_flags & USER_BUF))
00100         delete m_buf_base;
00101 
00102     m_buf_base = b_;
00103     m_buf_end = eb_;
00104     
00105     if (del_)
00106         m_flags &= ~ USER_BUF; // clear bit
00107     else
00108         m_flags |= USER_BUF; // set bit
00109 
00110     dump ();
00111 }

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 115 of file Streambuf.cpp.

Referenced by pubsetbuf().

00116 {
00117     trace_with_mask("Streambuf::setb",STRMBUFTRACE);
00118 
00119     if (sync () == EOF) // Flush out all pending bytes before
00120         return NULL;    // resetting buffer. Also, first time around,
00121     // calling sync() suppose to set put area
00122     // pointers.
00123 
00124     if (p_ == NULL || len_ == 0) {
00125         DL((STRMBUF,"Unbuffered IO set.\n"));
00126         unbuffered (1);
00127         // We do it from doalloc instead - vlg
00128         // setb (m_shortbuf, m_shortbuf+1, 0);
00129     }
00130     else {
00131         DL((STRMBUF,"Buffered IO set.\n"));
00132         unbuffered (0);
00133         setb (p_, p_ + len_, 0);
00134     }
00135     setp (0, 0);
00136     setg (0, 0, 0);
00137 
00138     return this;
00139 }

void Streambuf::setg char *  gbeg_,
char *  gnext_,
char *  gend_
[protected]
 

Set get area pointers.

Definition at line 84 of file Streambuf.cpp.

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

00085 {
00086     trace_with_mask("Streambuf::setg",STRMBUFTRACE);
00087 
00088     m_read_base = gbeg_;
00089     m_read_ptr  = gnext_;
00090     m_read_end  = gend_;
00091 }

void ASSA::Streambuf::setp char *  pbeg_,
char *  pend_
[inline, protected]
 

Set put area pointers.

Definition at line 578 of file Streambuf.h.

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

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

00579 {
00580     trace_with_mask("Streambuf::setp",STRMBUFTRACE);
00581 
00582     m_write_base = m_write_ptr = pbeg_;
00583     m_write_end  = pend_;
00584 }

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 539 of file Streambuf.h.

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

00540 {
00541     trace_with_mask("Streambuf::sgetc",STRMBUFTRACE);
00542 
00543     return (m_read_ptr >= m_read_end && underflow () == EOF 
00544             ? EOF : *(unsigned char*) m_read_ptr);
00545 }

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 549 of file Streambuf.h.

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

00550 {
00551     trace_with_mask("Streambuf::sgetn",STRMBUFTRACE);
00552 
00553     return xsgetn (data_, len_);
00554 }

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 521 of file Streambuf.h.

References ASSA::STRMBUFTRACE, and trace_with_mask.

00522 { 
00523     trace_with_mask("Streambuf::showmanyc",STRMBUFTRACE);
00524     return -1; 
00525 }

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 72 of file Streambuf.cpp.

00073 {   
00074     trace_with_mask("Streambuf::snextc",STRMBUFTRACE);
00075 
00076     if (m_read_ptr >= m_read_end && underflow () == EOF) {
00077         return EOF;
00078     }
00079     return m_read_ptr++, sgetc (); 
00080 }

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 558 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().

00559 {
00560     trace_with_mask("Streambuf::sputc",STRMBUFTRACE);
00561 
00562     return (m_write_ptr >= m_write_end
00563             ? overflow (c_)
00564             : (unsigned char) (*m_write_ptr++ = c_));
00565 }

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 569 of file Streambuf.h.

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

00570 {
00571     trace_with_mask("Streambuf::sputn",STRMBUFTRACE);
00572 
00573     return xsputn (b_, len_);
00574 }

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 513 of file Streambuf.h.

References ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by pubsync().

00514 { 
00515     trace_with_mask("Streambuf::sync",STRMBUFTRACE);
00516     return 0; 
00517 }

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 187 of file Streambuf.cpp.

Referenced by sbumpc().

00188 {
00189     trace_with_mask("Streambuf::uflow",STRMBUFTRACE);
00190 
00191     if (underflow () == EOF)
00192         return EOF;
00193     dump ();
00194     return *(unsigned char *) m_read_ptr++;
00195 }

int ASSA::Streambuf::unbuffered  )  [inline]
 

Returns:
true if unbuffered, false otherwise

Definition at line 398 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(), ASSA::Socketbuf::Socketbuf(), and ASSA::Socketbuf::underflow().

00399 { 
00400     trace_with_mask("Streambuf::unbuffered",STRMBUFTRACE);
00401     
00402     return m_flags & UNBUFFERED ? 1 : 0; 
00403 }

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 407 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().

00408 {
00409     trace_with_mask("Streambuf::unbuffered",STRMBUFTRACE);
00410 
00411     if (i_) 
00412         m_flags |= UNBUFFERED; // set
00413     else
00414         m_flags &= ~ UNBUFFERED; // unset
00415 }

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 588 of file Streambuf.h.

References ASSA::STRMBUFTRACE, and trace_with_mask.

Referenced by sgetc().

00589 {
00590     trace_with_mask("Streambuf::underflow",STRMBUFTRACE);
00591 
00592     return (EOF);
00593 }

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 143 of file Streambuf.cpp.

Referenced by sgetn().

00144 {
00145     trace_with_mask("Streambuf::xsgetn",STRMBUFTRACE);
00146 
00147     /*
00148       Get area is empty and nothing is on the socket.
00149     */
00150     int count = m_read_end - m_read_ptr; // Bytes in Get area
00151 
00152     if (count == 0 && underflow () == EOF) {
00153         DL((STRMBUFTRACE,"returning %d. count: %d\n", EOF));
00154         return EOF;
00155     }
00156     count = m_read_end - m_read_ptr; // Adjusted bytes in Get area
00157 
00158     DL((STRMBUFTRACE,"Adjusted bytes in Get Area: %d\n",count));
00159 
00160     if (count > len_) {
00161         count = len_;
00162     }
00163 
00164     if (count <= 0) {
00165         count = 0;  // Peer closed connection
00166     }
00167     else if (count > 20) {
00168         memcpy (data_, m_read_ptr, count);
00169         m_read_ptr += count;
00170     }
00171     else {
00172         char* s = data_;
00173         char* p = m_read_ptr;
00174         int i = count;
00175         while (i-- > 0) {
00176             *s++ = *p++;
00177         }
00178         m_read_ptr = p;
00179     }
00180     DL((STRMBUFTRACE,"Transferred %d bytes to user-space buffer\n", count));
00181 
00182     return (count);
00183 }

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 199 of file Streambuf.cpp.

Referenced by sputn().

00200 {
00201     trace_with_mask("Streambuf::xsputn",STRMBUFTRACE);
00202 
00203     const char* s = data_;
00204     int more = len_;
00205     if (more <= 0) {
00206         return 0;
00207     }
00208 
00209     for (;;) {
00210         int count = m_write_end - m_write_ptr; // Space available
00211 
00212         if (count > 0) {
00213 
00214             if (count > more) // Enough buffer space
00215                 count = more;
00216 
00217             if (count > 20) {
00218                 memcpy (m_write_ptr, s, count);
00219                 s += count;
00220                 m_write_ptr += count;
00221             }
00222             else if (count <= 0) {
00223                 count = 0;
00224             }
00225             else {
00226                 char* p = m_write_ptr;
00227                 int i;
00228 
00229                 for (i=count; --i >= 0;) {
00230                     *p++ = *s++;
00231                 }
00232                 m_write_ptr = p;
00233             }
00234             more -= count;
00235         } // if (count>0)
00236         
00237         if (more == 0 || overflow ((unsigned char) *s++) == EOF) {
00238             break;
00239         }
00240         more--;
00241 
00242     } // for (;;)
00243 
00244     return (len_ - more);
00245 }


The documentation for this class was generated from the following files:
Generated on Mon Dec 19 16:20:20 2005 for libassa by  doxygen 1.4.5