Power-Programmierung/CD1.mdf/magazine/drdobbs/c_spec/sources/mv.c

C/C++ Source or Header | 1986-02-20 | 5KB | 216 lines

#include <stdio.h>
#include <errno.h>

/*    MV.C        A Unix style rename function. Useage is
 *
 *            mv <file|directory> [filelist] <file|directory>
 *
 *    [filelist] may be present only if the rightmost argument is
 *    a directory. If the file already exists, it is deleted.
 *
 *    -i    Verfify before overwriting an existing file
 *    -e    Do not echo actions to screen as they are done (this will
 *        make cp behave like the unix version, which is silent).
 *
 *    Exit status:    0 on success, 1 if a file couldn't be moved.
 */

extern char    *cpy    (char*, char*);
extern void    perror    (char*);

/*---------------------------------------------------------------------*/

int    Verify = 0;    /* Verify before overwriting existing file     */
int    Echo   = 1;    /* Say what we're doing as we do it           */

/*---------------------------------------------------------------------*/

#define E(str)        fprintf(stderr, "%s\n", str)
#define exists(file)    (!access(file,0))

/*---------------------------------------------------------------------*/

args(argc, argv)
char    **argv;
{
    /*    Process command line arguments. If -i iv found set
     *    Verify true, if -e is found set Echo false. Return
     *    1 if we found an argument, 0 otherwise
     */

    register char    *p;

    if( argv[1][0] == '-' )
    {
        if( --argc < 3 )
            usage("Too few arguments");

        for( p = *++argv + 1 ; *p ; p++ )
        {
            if      ( *p == 'i' )        Verify = 1;
            else if ( *p == 'e' )        Echo   = 0;
            else    usage("Illegal argument %c", *p );
        }

        return 1;
    }

    return 0;
}

/*---------------------------------------------------------------------*/

overwrite(targ)
char    *targ;
{
    /*    Return true if a file exists and we should overwrite
     *    it. If Verfify is set, ask the user.
     */

    if( exists( targ ))
    {
        /* Target file exists */

        if( Verify )
        {
            fprintf(stderr,"Mv: %s exists, overwrite (y/n)?",
                            targ);
            if( getchar() == 'n' )
            return 0;
        }

        if( unlink(targ) < 0 )    /* Delete the target file */
        {
            fprintf(stderr,
                "File marked read only or is directory\n" );
            return 0;
        }
    }

    return 1;
}

/*---------------------------------------------------------------------*/

char        *get_fname( src )
register char    *src;
{
    /* Return a pointer to the filename part of src */

    register char    *start ;

    for(start = src ; *src ; src++ )
         if( *src == '/' || *src == '\\' )
            start = src + 1;

    return( start );
}

/*---------------------------------------------------------------------*/

main(argc, argv)
char    **argv;
{
    char        targ[128];
    register char    *end = targ;
    register int    moving_to_dir = 0;
    int        err ;
    int        exit_status   = 0;

    ctlc();
    reargv(&argc, &argv);

    if( argc < 3 )
        usage("Too few arguments");

    if( args(argc,argv) )    /* Process command line arguments */
    {
        argc--;
        argv++;
    }

    argc -= 2;    /* Remove the file and target names from argv */
    argv++;

    /* Copy the target name into targ. If the target is a directory
     * add a trailing slash as well. If it's not a directory and
     * argc is > 1 then the command line syntax is wrong.
     */

    end = cpy( targ, argv[argc] );

    if( isdir(targ) )
    {
        *end++ = '/';
        moving_to_dir = 1;
    }
    else if( argc > 1 )
        usage("Can't move multiple files into one file");


    for(; --argc >= 0; argv++ )
    {
        if( moving_to_dir )
        {
            /* If we're moving to a directory append
             * the source name onto the end of the
             * target name.
             */

            strcpy(end, get_fname(*argv) );
        }

        /* If we're moving a file to itself, we're already
         * done. Similarly if we are told not to overwrite
         * an existing file, we're done.
         */

        if( !strcmp(*argv, targ) )
            continue;

        if( !overwrite(targ) )
            continue;

        if( Echo )
            printf("Moving: %20s to %s", *argv, targ );

        if( err = rename(targ, *argv) )
        {
            if( err == EXDEV )
                printf(": May not move to another disk\n");

            else if( err == ENOENT )
                printf(": %s not found\n", *argv );
            else
                printf("Can't move to another directory or disk\n");

            exit_status = 1;
        }
        else if( Echo )
            printf("\n");
    }

    exit( exit_status );
}

/*---------------------------------------------------------------------*/

usage(str, i)
char    *str;
{
    E("Mv: Copyright (c) 1986, Allen I. Holub. All rights reserved.\n");
    fprintf(stderr, str, i );
    E("");
    E("Usage: mv [-ie] oldname newname");
    E("       mv [-ie] file  [... file] directory\n");
    E("-i     ask before over-writing existing files");
    E("-e     don't echo names as they're copied\n");
    E("Rename a file (the top syntax above) or move a file or group");
    E("of files to another directory. A directory may be renamed,");
    E("but not moved to another directory. A target directory must");
    E("be named (unlike the DOS copy command), . (the current directory)");
    E("and .. (the parent directory) alone or in combination");
    E("(ie. \"mv file ../..\"  or  \"mv /dir/file .\") are acceptable.");
    exit(1);
}