view packages/language/c/libc/stdio/current/src/common/vsnprintf.cxx @ 2356:52c6a8ead2a6

Speed-up [v]s[n]printf() functions by a factor of about 2+. In particular, sprintf(s, "%s", "") becomes faster 2.8 times, printing of every character -- 1.7 times, and, as a result, e.g., printing of a string of length 50 -- 2.2 times. * include/stream.hxx (class Cyg_OutputStream): New ABC. (class Cyg_StdioStream): inherit from Cyg_OutputStream; make the destructor, write(), and get_error() virtual. * src/output/vfnprintf.cxx (vfnprintf): Use ABC Cyg_OutputStream instead of Cyg_StdioStream. * src/common/vsnprintf.cxx (class Cyg_VsnprintfStream): New class that specializes Cyg_OutputStream for output to a string. (vsnprintf): Use Cyg_VsnprintfStream for printing to a string.
author asl
date Sat, 27 Jan 2007 13:53:37 +0000
parents 871b38a618f4
children 74dbf4c3f2e1
line wrap: on
line source

//===========================================================================
//
//      vsnprintf.cxx
//
//      ANSI Stdio vsnprintf() function
//
//===========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//===========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   jlarmour
// Contributors:  jlarmour
// Date:        1998-02-13
// Purpose:     
// Description: 
// Usage:       
//
//####DESCRIPTIONEND####
//
//===========================================================================

// CONFIGURATION

#include <pkgconf/libc_stdio.h>   // Configuration header

// INCLUDES

#include <cyg/infra/cyg_type.h>     // Common project-wide type definitions
#include <stddef.h>                 // NULL and size_t from compiler
#include <stdio.h>                  // header for this file
#include <errno.h>                  // error codes
#include <cyg/libc/stdio/stream.hxx>// Cyg_StdioStream

#include <cyg/libc/stdio/io.inl>     // I/O system inlines

// FUNCTIONS

class Cyg_VsnprintfStream: public Cyg_OutputStream
{
public:
    Cyg_VsnprintfStream(char* s): s_(s) {}

    virtual ~Cyg_VsnprintfStream() { *s_ = '\0'; }

    virtual Cyg_ErrNo write( const cyg_uint8 *buffer,
        cyg_ucount32 buffer_length, cyg_ucount32 *bytes_written );

    virtual Cyg_ErrNo get_error( void ) { return ENOERR; }

private:
    char* s_;
};

Cyg_ErrNo
Cyg_VsnprintfStream::write(
    const cyg_uint8 *buffer,
    cyg_ucount32 buffer_length,
    cyg_ucount32 *bytes_written )
{
    char *dest = s_;
    char const *src = (char const *)buffer;
    char const *end = src + buffer_length;
    while(src < end)
        *dest++ = *src++;
    s_ = dest;
    *bytes_written = buffer_length;
    return ENOERR;
}

externC int
vsnprintf( char *s, size_t size, const char *format, va_list arg ) __THROW
{
    Cyg_VsnprintfStream stream(s);
    return vfnprintf( (FILE *)(void *)&stream, size, format, arg );
} // vsnprintf()

// EOF vsnprintf.cxx