/* _PDCLIB_open( char const * const, int )

   This file is part of the Public Domain C Library (PDCLib).
   Permission is granted to use, modify, and / or redistribute at will.
*/

/* This is an example implementation of _PDCLIB_open() fit for use with POSIX
   kernels.
*/

#include <stdio.h>

#ifndef REGTEST
#include <_PDCLIB_glue.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#include "/usr/include/errno.h"

int _PDCLIB_open( char const * const filename, unsigned int mode )
{
    /* This is an example implementation of _PDCLIB_open() fit for use with
       POSIX kernels.
    */
    int osmode;
    switch ( mode & ( _PDCLIB_FREAD | _PDCLIB_FWRITE | _PDCLIB_FAPPEND | _PDCLIB_FRW ) )
    {
        case _PDCLIB_FREAD: /* "r" */
            osmode = O_RDONLY;
            break;
        case _PDCLIB_FWRITE: /* "w" */
            osmode = O_WRONLY | O_CREAT | O_TRUNC;
            break;
        case _PDCLIB_FAPPEND: /* "a" */
            osmode = O_WRONLY | O_APPEND | O_CREAT;
            break;
        case _PDCLIB_FREAD | _PDCLIB_FRW: /* "r+" */
            osmode = O_RDWR;
            break;
        case _PDCLIB_FWRITE | _PDCLIB_FRW: /* "w+" */
            osmode = O_RDWR | O_CREAT | O_TRUNC;
            break;
        case _PDCLIB_FAPPEND | _PDCLIB_FRW: /* "a+" */
            osmode = O_RDWR | O_APPEND | O_CREAT;
            break;
        default: /* Invalid mode */
            return -1;
    }
    int rc;
    if ( osmode & O_CREAT )
    {
        rc = open( filename, osmode, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH );
    }
    else
    {
        rc = open( filename, osmode );
    }
    if ( rc == -1 )
    {
        switch ( errno )
        {
            /* See the comments on implementation-defined errno values in
               <_PDCLIB_config.h>.
            */
            case EACCES:
            case EFAULT:
            case EINTR:
            case EISDIR:
            case ELOOP:
            case EMFILE:
            case ENAMETOOLONG:
            case ENFILE:
            case ENODEV:
            case ENOENT:
            case ENOMEM:
            case ENOSPC:
            case ENOTDIR:
            case EOVERFLOW:
            case EROFS:
            case ETXTBSY:
                _PDCLIB_errno = _PDCLIB_ERROR;
                break;
            default:
                /* This should be something like EUNKNOWN. */
                _PDCLIB_errno = _PDCLIB_ERROR;
                break;
        }
    }
    return rc;
}

#endif

#ifdef TEST
#include <_PDCLIB_test.h>

#include <stdlib.h>
#include <string.h>

int main( void )
{
#ifndef REGTEST
    /* This testdriver assumes POSIX, i.e. _PDCLIB_fd_t being int and being
       incremented by one on each successful open.
    */
    int fh;
    char buffer[ 10 ];
    remove( testfile );
    /* Trying to read non-existent file. */
    TESTCASE( _PDCLIB_open( testfile, _PDCLIB_FREAD ) == _PDCLIB_NOHANDLE );
    /* Writing to file, trying to read from it. */
    TESTCASE( ( fh = _PDCLIB_open( testfile, _PDCLIB_FWRITE ) ) != _PDCLIB_NOHANDLE );
    TESTCASE( write( fh, "test", 4 ) == 4 );
    TESTCASE( lseek( fh, 0, SEEK_SET ) == 0 );
    TESTCASE( read( fh, buffer, 4 ) == -1 );
    TESTCASE( _PDCLIB_close( fh ) == 0 );
    /* Reading from file, trying to write to it. */
    TESTCASE( ( fh = _PDCLIB_open( testfile, _PDCLIB_FREAD ) ) != _PDCLIB_NOHANDLE );
    TESTCASE( write( fh, "test", 4 ) == -1 );
    TESTCASE( _PDCLIB_close( fh ) == 0 );
    /* Appending to file, trying to read from it. */
    TESTCASE( ( fh = _PDCLIB_open( testfile, _PDCLIB_FAPPEND ) ) != _PDCLIB_NOHANDLE );
    TESTCASE( write( fh, "app", 3 ) == 3 );
    TESTCASE( lseek( fh, 0, SEEK_SET ) == 0 );
    TESTCASE( read( fh, buffer, 10 ) == -1 );
    TESTCASE( write( fh, "end", 3 ) == 3 );
    TESTCASE( _PDCLIB_close( fh ) == 0 );
    /* Reading and writing from file ("r+"). */
    TESTCASE( ( fh = _PDCLIB_open( testfile, _PDCLIB_FREAD | _PDCLIB_FRW ) ) != _PDCLIB_NOHANDLE );
    TESTCASE( read( fh, buffer, 10 ) == 10 );
    TESTCASE( memcmp( buffer, "testappend", 10 ) == 0 );
    TESTCASE( lseek( fh, 0, SEEK_SET ) == 0 );
    TESTCASE( write( fh, "wedo", 4 ) == 4 );
    TESTCASE( lseek( fh, 0, SEEK_SET ) == 0 );
    TESTCASE( read( fh, buffer, 10 ) == 10 );
    TESTCASE( memcmp( buffer, "wedoappend", 10 ) == 0 );
    TESTCASE( _PDCLIB_close( fh ) == 0 );
    /* Writing and reading from file ("w+"). */
    TESTCASE( ( fh = _PDCLIB_open( testfile, _PDCLIB_FWRITE | _PDCLIB_FRW ) ) != _PDCLIB_NOHANDLE );
    TESTCASE( write( fh, "test", 4 ) == 4 );
    TESTCASE( lseek( fh, 1, SEEK_SET ) == 1 );
    TESTCASE( read( fh, buffer, 2 ) == 2 );
    TESTCASE( memcmp( buffer, "es", 2 ) == 0 );
    TESTCASE( write( fh, "sie", 3 ) == 3 );
    TESTCASE( lseek( fh, 0, SEEK_SET ) == 0 );
    TESTCASE( read( fh, buffer, 6 ) == 6 );
    TESTCASE( memcmp( buffer, "tessie", 6 ) == 0 );
    TESTCASE( _PDCLIB_close( fh ) == 0 );
    /* Appending and reading from file ("a+"). */
    TESTCASE( ( fh = _PDCLIB_open( testfile, _PDCLIB_FAPPEND | _PDCLIB_FRW ) ) != _PDCLIB_NOHANDLE );
    TESTCASE( write( fh, "baby", 4 ) == 4 );
    TESTCASE( lseek( fh, 0, SEEK_SET ) == 0 );
    TESTCASE( read( fh, buffer, 10 ) == 10 );
    TESTCASE( memcmp( buffer, "tessiebaby", 10 ) == 0 );
    TESTCASE( _PDCLIB_close( fh ) == 0 );
    /* Cleaning up. */
    TESTCASE( remove( testfile ) == 0 );
#endif
    return TEST_RESULTS;
}

#endif