stream.cxx

ecos实时嵌入式操作系统

//========================================================================
//
//      stream.cxx
//
//      Implementations of internal C library stdio stream functions
//
//========================================================================
//####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:  
// Date:          2000-04-20
// 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 <cyg/infra/cyg_ass.h>     // Assertion infrastructure
#include <stddef.h>                // NULL and size_t from compiler
#include <errno.h>                 // Error codes
#include <string.h>                // memcpy() and memset()
#include <cyg/libc/stdio/stream.hxx>     // Header for this file
#include <cyg/libc/stdio/stdiosupp.hxx>  // Stdio support functions


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


// FUNCTIONS

Cyg_StdioStream::Cyg_StdioStream(cyg_stdio_handle_t dev,
                                 OpenMode open_mode,
                                 cyg_bool append, cyg_bool binary,
                                 int buffer_mode, cyg_ucount32 buffer_size,
                                 cyg_uint8 *buffer_addr )
#ifdef CYGSEM_LIBC_STDIO_WANT_BUFFERED_IO
    : io_buf( buffer_size, buffer_addr )
#endif
{
    initialize( dev, open_mode, append, binary, buffer_mode,
                buffer_size, buffer_addr);
}

void Cyg_StdioStream::initialize(cyg_stdio_handle_t dev,
                                 OpenMode open_mode,
                                 cyg_bool append, cyg_bool binary,
                                 int buffer_mode, cyg_ucount32 buffer_size,
                                 cyg_uint8 *buffer_addr )
{

#ifdef CYGDBG_USE_ASSERTS
    magic_validity_word = 0xbadbad;
#endif

    my_device = dev;

    // Clear all flags
    memset( &flags, 0, sizeof(flags) );

    switch (open_mode) {
    case CYG_STREAM_READ:
        flags.opened_for_read = true;
        break;
    case CYG_STREAM_WRITE:
        flags.opened_for_write = true;
        break;
    case CYG_STREAM_READWRITE:
        flags.opened_for_read = true;
        flags.opened_for_write = true;
        break;
    default:
        error=EINVAL;
        return;
    } // switch
        
    
    if (flags.opened_for_write) {
#if 0
        // FIXME: need some replacement for this
        if (!my_device->write_blocking) {
            error = EDEVNOSUPP;
            return;
        } // if
#endif
#ifdef CYGSEM_LIBC_STDIO_WANT_BUFFERED_IO
        flags.last_buffer_op_was_read = false;
#endif
    } // if


    if (flags.opened_for_read) {
#if 0
        // FIXME: need some replacement for this
        if (!my_device->read_blocking) {
            error = EDEVNOSUPP;
            return;
        } // if
#endif

        // NB also if opened for read AND write, then say last op was read
#ifdef CYGSEM_LIBC_STDIO_WANT_BUFFERED_IO
        flags.last_buffer_op_was_read = true;
#endif
    } // if

    flags.binary = binary ? 1 : 0;

    error = ENOERR;
    
    // in due course we would do an equivalent to fseek(...,0, SEEK_END);
    // when appending. for now, there's nothing, except set eof
    
    flags.at_eof = append ? 1 : 0;

    position = 0;

#ifdef CYGSEM_LIBC_STDIO_WANT_BUFFERED_IO

    switch (buffer_mode) {
    case _IONBF:
        CYG_ASSERT( (buffer_size == 0) && (buffer_addr == NULL),
                    "No buffering wanted but size/address specified!" );
        flags.buffering = flags.line_buffering = false;
        break;
    case _IOLBF:
        flags.buffering = true;
        flags.line_buffering = true;
        break;
    case _IOFBF:
        flags.buffering = true;
        flags.line_buffering = false;
        break;
    default:
        error = EINVAL;
        return;
    } // switch

    // one way of checking the buffer was set up correctly
    if (flags.buffering && io_buf.get_buffer_size()==-1) {
        error = ENOMEM;
        return;
    }

#endif

#if 0 // FIXME - Need to set binary mode.
    if (my_device->open) {
        error = (*my_device->open)( my_device->cookie, 
                                    binary ? CYG_DEVICE_OPEN_MODE_RAW
                                           : CYG_DEVICE_OPEN_MODE_TEXT );
        if (error != ENOERR)
            return; // keep error code the same
    } // if
    
#endif

#ifdef CYGDBG_USE_ASSERTS
    magic_validity_word = 0x7b4321ce;
#endif
    
} // Cyg_StdioStream constructor


Cyg_StdioStream::Cyg_StdioStream( OpenMode open_mode,
                                 cyg_ucount32 buffer_size,
                                  cyg_uint8 *buffer_addr )
#ifdef CYGSEM_LIBC_STDIO_WANT_BUFFERED_IO
    : io_buf( buffer_size, buffer_addr )
#endif
{
    initialize( CYG_STDIO_HANDLE_NULL, open_mode, false, false, _IOFBF,
                buffer_size, buffer_addr );

    if( error != ENOERR )
        return;
    
    switch( open_mode )
    {
    case CYG_STREAM_READ:
        // Fix up the stream so it looks like the buffer contents has just
        // been read in.
#ifdef CYGSEM_LIBC_STDIO_WANT_BUFFERED_IO
        io_buf.set_bytes_written( buffer_size );
#endif
        break;
        
    case CYG_STREAM_WRITE:
        // Fix up the stream so it looks like the buffer is ready to accept
        // new data.
        break;

    default:
        error = EINVAL;
        return;
    }
}


Cyg_ErrNo
Cyg_StdioStream::refill_read_buffer( void )
{
    Cyg_ErrNo read_err;
    cyg_uint8 *buffer;
    cyg_uint32 len;

    CYG_ASSERTCLASS( this, "Stream object is not a valid stream!" );
    
    if (!lock_me())
        return EBADF;  // assume file is now invalid

    // first just check that we _can_ read this device!
    if (!flags.opened_for_read) {
        unlock_me();
        return EINVAL;
    }
    
#ifdef CYGSEM_LIBC_STDIO_WANT_BUFFERED_IO
    // If there is pending output to write, then this will check and
    // write it
    if (flags.buffering) {
        read_err = flush_output_unlocked();

        // we're now reading
        flags.last_buffer_op_was_read = true;

        // flush ALL streams
        if (read_err == ENOERR)
            read_err = cyg_libc_stdio_flush_all_but(this);

        if (read_err != ENOERR) {
            unlock_me();
            return read_err;
        } // if

        len = io_buf.get_buffer_addr_to_write( (cyg_uint8**)&buffer );
        if (!len) { // no buffer space available
            unlock_me();
            return ENOERR;  // isn't an error, just needs user to read out data
        } // if
    }
    else
#endif

    if (!flags.readbuf_char_in_use) {
        len = 1;
        buffer = &readbuf_char;
    }
    else {
        // no buffer space available
        unlock_me();
        return ENOERR;  // isn't an error, just needs user to read out data
    } // else

    read_err = cyg_stdio_read(my_device, buffer, &len);


#ifdef CYGSEM_LIBC_STDIO_WANT_BUFFERED_IO
    if (flags.buffering)
        io_buf.set_bytes_written( len );
    else
#endif
        flags.readbuf_char_in_use = len ? 1 : 0;

    unlock_me();

    if (read_err == ENOERR) {
        if (len == 0) {
            read_err = EAGAIN;
            flags.at_eof = true;
        }
        else
            flags.at_eof = false;
    } // if
    
    return read_err;
} // refill_read_buffer()


Cyg_ErrNo
Cyg_StdioStream::read( cyg_uint8 *user_buffer, cyg_ucount32 buffer_length,
                       cyg_ucount32 *bytes_read )
{
    CYG_ASSERTCLASS( this, "Stream object is not a valid stream!" );
    
    *bytes_read = 0;

    if (!lock_me())
        return EBADF;  // assume file is now invalid

    if (!flags.opened_for_read) {
        unlock_me();
        return EINVAL;
    }

#ifdef CYGFUN_LIBC_STDIO_ungetc
    if (flags.unread_char_buf_in_use && buffer_length) {
        *user_buffer++ = unread_char_buf;
        ++*bytes_read;
        flags.unread_char_buf_in_use = false;
        --buffer_length;
    } // if

#endif // ifdef CYGFUN_LIBC_STDIO_ungetc