rsc_files.c

vlc stand 0.1.99 ist sehr einfach

/*****************************************************************************
 * rsc_files.c: resources files manipulation functions
 * This library describe a general format used to store 'resources'. Resources
 * can be anything, including pictures, audio streams, and so on.
 *****************************************************************************
 * Copyright (C) 1999, 2000 VideoLAN
 *
 * Authors:
 *
 * This program 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 of the License, or
 * (at your option) any later version.
 * 
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

/*****************************************************************************
 * Format of a resource file:
 *  offset      type        meaning
 *  0           char[2]     "RF" (magic number)
 *  2           char[2]     "VL" (minor magic number, ignored)
 *  4           u16         i_type: resource file type. This is to allow
 *                          different versions of the resources types constants.
 *  6           u16         i_size: number of entries in the resources table.
 * {
 *  +0          char[32]    resource name (ASCIIZ or ASCII[32])
 *  +32         u16         resource type
 *  +34         u64         data offset in bytes, from beginning of file
 *  +42         u64         data size in bytes
 * } * i_size
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include "defs.h"

#include <errno.h>                                                  /* errno */
#include <fcntl.h>                                                 /* open() */
#include <stdlib.h>                                                /* free() */
#include <string.h>                                /* strerror(), strncopy() */
#include <unistd.h>                     /* read(), close(), lseek(), write() */

#include "config.h"
#include "common.h"
#include "mtime.h"

#include "rsc_files.h"

#include "intf_msg.h"

/*****************************************************************************
 * CreateResourceFile: create a new resource file
 *****************************************************************************
 * Creates a new resource file. The file is opened read/write and erased if
 * it already exists.
 *****************************************************************************
 * Messages type: rsc, major code 101
 *****************************************************************************/
resource_file_t *CreateResourceFile( char *psz_filename, int i_type, int i_size,
                                     int i_mode )
{
    resource_file_t *   p_file;                            /* new descriptor */
    int                 i_index;                           /* resource index */

    /* Create descriptor and tables */
    p_file = malloc( sizeof(resource_file_t) );
    if( p_file == NULL )
    {
        intf_ErrMsg("rsc error 101-1: %s\n", strerror(errno));
        return( NULL );
    }
    p_file->p_resource = malloc( sizeof(resource_descriptor_t) * i_size );
    if( p_file->p_resource == NULL )
    {
        intf_ErrMsg("rsc error 101-2: %s\n", strerror(errno));
        free( p_file );
        return( NULL );
    }

    /* Open file */
    p_file->i_file = open( psz_filename, O_CREAT | O_RDWR, i_mode );
    if( p_file->i_file == -1 )                                      /* error */
    {
        intf_ErrMsg("rsc error 101-3: %s: %s\n", psz_filename, strerror(errno) );
        free( p_file->p_resource );
        free( p_file );
    }

    /* Initialize tables */
    p_file->i_type = i_type;
    p_file->i_size = i_size;
    p_file->b_read_only = 0;
    for( i_index = 0; i_index < i_size; i_index++ )
    {
        p_file->p_resource[i_index].i_type = EMPTY_RESOURCE;
    }

    return( p_file );
}

/*****************************************************************************
 * OpenResourceFile: open an existing resource file read-only
 *****************************************************************************
 * Open an existing resource file. i_flags should be O_RDONLY or O_RDWR. An
 * error will occurs if the file does not exists.
 *****************************************************************************
 * Messages type: rsc, major code 102
 *****************************************************************************/
resource_file_t *OpenResourceFile( char *psz_filename, int i_type, int i_flags )
{
    resource_file_t *   p_file;                            /* new descriptor */
    int                 i_index;                           /* resource index */
    byte_t              p_buffer[50];                              /* buffer */

    /* Create descriptor and tables */
    p_file = malloc( sizeof(resource_file_t) );
    if( p_file == NULL )
    {
        intf_ErrMsg("rsc error 102-1: %s\n", strerror(errno));
        return( NULL );
    }

    /* Open file */
    p_file->i_file = open( psz_filename, i_flags );
    if( p_file->i_file == -1 )                                      /* error */
    {
        intf_ErrMsg("rsc error 102-2: %s: %s\n", psz_filename, strerror(errno) );
        free( p_file );
        return( NULL );
    }

    /* Read header */
    if( read( p_file->i_file, p_buffer, 8 ) != 8)
    {
        intf_ErrMsg("rsc error 102-3: %s: unexpected end of file (not a resource file ?)\n");
        close( p_file->i_file );
        free( p_file);
        return( NULL );
    }
    if( (p_buffer[0] != 'R') || (p_buffer[0] != 'F') || (*(u16 *)(p_buffer + 4) != i_type) )
    {
        intf_ErrMsg("rsc error 102-4: %s is not a valid resource file or has incorrect type\n", psz_filename);
        close( p_file->i_file );
        free( p_file );
        return( NULL );
    }
    p_file->i_type = i_type;
    p_file->i_size = *(u16 *)(p_buffer + 6);
    intf_DbgMsg("rsc debug 102-1: %s opened, %d resources\n", psz_filename, p_file->i_size);

    /* Allocate tables */
    p_file->p_resource = malloc( sizeof(resource_descriptor_t) * p_file->i_size );
    if( p_file->p_resource == NULL )
    {
        intf_ErrMsg("rsc error 102-5: %s\n", strerror(errno));
        close( p_file->i_file );
        free( p_file );
        return( NULL );
    }

    /* Initialize table */
    p_file->b_up_to_date = 1;
    p_file->b_read_only = ( i_flags & O_RDWR ) ? 0 : 1;
    for( i_index = 0; i_index < p_file->i_size; i_index++ )
    {
        if( read( p_file->i_file, p_buffer, 50 ) != 50 )
        {
            intf_ErrMsg("rsc error 102-6: %s: unexpected end of file\n", psz_filename);
            close( p_file->i_file );
            free( p_file->p_resource );
            free( p_file );
            return( NULL );
        }
        memcpy( p_file->p_resource[i_index].psz_name, p_buffer, 32 );
        p_file->p_resource[i_index].psz_name[RESOURCE_MAX_NAME] = '\0';
        p_file->p_resource[i_index].i_type =    *(u16 *)(p_buffer + 32 );
        p_file->p_resource[i_index].i_offset =  *(u64 *)(p_buffer + 34 );
        p_file->p_resource[i_index].i_size =    *(u64 *)(p_buffer + 42 );
    }

    return( p_file );
}

/*****************************************************************************
 * UpdateResourceFile: write the resources table in a resource file
 *****************************************************************************
 * This function writes resources table in the resource file. This is
 * automatically done when the file is closed, but can also be done manually.
 *****************************************************************************
 * Messages type: rsc, major code 103
 *****************************************************************************/
int UpdateResourceFile( resource_file_t *p_file )
{
    byte_t      p_buffer[50];                                      /* buffer */
    int         i_index;                                   /* resource index */

#ifdef DEBUG
    if( p_file->b_read_only )
    {
        intf_DbgMsg("rsc debug 103-1: can't update a read-only file\n");
        return( -1 );
    }
#endif

    /* Seek beginning of file */
    if( lseek( p_file->i_file, 0, SEEK_SET ) )