vsnprintf.cxx

ecos实时嵌入式操作系统

//===========================================================================
//
//      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/io/devtab.h>          // Device table
#include <cyg/libc/stdio/stream.hxx>// Cyg_StdioStream

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

#ifndef CYGPKG_LIBC_STDIO_FILEIO

// FUNCTIONS

static Cyg_ErrNo
str_write(cyg_stdio_handle_t handle, const void *buf, cyg_uint32 *len)
{
    cyg_devtab_entry_t *dev = (cyg_devtab_entry_t *)handle;
    cyg_uint8 **str_p = (cyg_uint8 **)dev->priv;
    cyg_ucount32 i;

    // I suspect most strings passed to vsnprintf will be relatively short,
    // so we just take the simple approach rather than have the overhead
    // of calling memcpy etc.

    // simply copy string until we run out of user space

    for (i = 0; i < *len; i++, (*str_p)++ )
    {
        **str_p = *((cyg_uint8 *)buf + i);
    } // for

    *len = i;

    return ENOERR;
    
} // str_write()

static DEVIO_TABLE(devio_table,
                   str_write,       // write
                   NULL,            // read
                   NULL,            // select
                   NULL,            // get_config
                   NULL);           // set_config

externC int
vsnprintf( char *s, size_t size, const char *format, va_list arg )
{
    int rc;
    // construct a fake device with the address of the string we've
    // been passed as its private data. This way we can use the data
    // directly
    DEVTAB_ENTRY_NO_INIT(strdev,
                         "strdev",       // Name
                         NULL,           // Dependent name (layered device)
                         &devio_table,   // I/O function table
                         NULL,           // Init
                         NULL,           // Lookup
                         &s);            // private
    Cyg_StdioStream my_stream( &strdev, Cyg_StdioStream::CYG_STREAM_WRITE,
                               false, false, _IONBF, 0, NULL );
    
    rc = vfnprintf( (FILE *)&my_stream, size, format, arg );

    // Null-terminate it, but note that s has been changed by str_write(), so
    // that it now points to the end of the string
    s[0] = '\0';

    return rc;

} // vsnprintf()

#else

externC int
vsnprintf( char *s, size_t size, const char *format, va_list arg )
{
    int rc;

    Cyg_StdioStream my_stream( Cyg_StdioStream::CYG_STREAM_WRITE,
                               size, (cyg_uint8 *)s );
    
    rc = vfnprintf( (FILE *)&my_stream, size, format, arg );

    if( rc > 0 )
        s[rc] = '\0';

    return rc;

} // vsnprintf()

#endif

// EOF vsnprintf.cxx