stream.cxx

eCos1.31版

//========================================================================
//
//      stream.cxx
//
//      Implementations of internal C library stdio stream functions
//
//========================================================================
//####COPYRIGHTBEGIN####
//                                                                          
// -------------------------------------------                              
// The contents of this file are subject to the Red Hat eCos Public License 
// Version 1.1 (the "License"); you may not use this file except in         
// compliance with the License.  You may obtain a copy of the License at    
// http://www.redhat.com/                                                   
//                                                                          
// Software distributed under the License is distributed on an "AS IS"      
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the 
// License for the specific language governing rights and limitations under 
// the License.                                                             
//                                                                          
// The Original Code is eCos - Embedded Configurable Operating System,      
// released September 30, 1998.                                             
//                                                                          
// The Initial Developer of the Original Code is Red Hat.                   
// Portions created by Red Hat are                                          
// Copyright (C) 1998, 1999, 2000 Red Hat, Inc.                             
// All Rights Reserved.                                                     
// -------------------------------------------                              
//                                                                          
//####COPYRIGHTEND####
//========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):     jlarmour
// Contributors:  jlarmour
// Date:          1999-03-16
// Purpose:     
// Description: 
// Usage:       
//
//####DESCRIPTIONEND####
//
//========================================================================

// CONFIGURATION

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


// Include the C library? And do we want the stdio stuff?
#ifdef CYGPKG_LIBC_STDIO

// 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 "clibincl/stringsupp.hxx" // _memcpy()
#include "clibincl/stream.hxx"     // Header for this file
#include "clibincl/stdiosupp.hxx"  // Stdio support functions
#include <cyg/io/io.h>             // I/O system
#include <cyg/io/config_keys.h>    // CYG_IO_GET_CONFIG_SERIAL_OUTPUT_DRAIN


// FUNCTIONS

Cyg_StdioStream::Cyg_StdioStream(cyg_io_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
    
{

    CYG_CHECK_DATA_PTR(dev, "Attempt to open invalid device!");

#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_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();

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

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

    if (flags.buffering) {
        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_io_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;
    } // 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

#ifdef CYGSEM_LIBC_STDIO_WANT_BUFFERED_IO
    if (flags.buffering) {
        cyg_uint8 *buff_to_read_from;
        cyg_ucount32 bytes_available;
        Cyg_ErrNo err;
    
        // this should really only be called after refill_read_buffer, but
        // just in case
        err = flush_output_unlocked();
        if (ENOERR == err)
            err = cyg_libc_stdio_flush_all_but(this);

        if (err != ENOERR) {
            unlock_me();
            return err;
        }
        
        // we're now reading
        flags.last_buffer_op_was_read = true;
        
        bytes_available = io_buf.get_buffer_addr_to_read(
              (cyg_uint8 **)&buff_to_read_from );
        
        *bytes_read += (bytes_available < buffer_length) ? bytes_available
                                                         : buffer_length;
        if (*bytes_read) {
            memcpy( user_buffer, buff_to_read_from, *bytes_read );
            io_buf.set_bytes_read( *bytes_read );