/*-
 * Copyright (c) 2016 Colin Granville. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <stddef.h>
#include <stdio.h>
#include <stdbool.h>
#include <stdarg.h>
#include "swis.h"
#include "file.h"

int file_open(int dir, const char* format, ...)
{
        char data[256];
        va_list va;
        va_start(va, format);
        int size = vsnprintf(data, sizeof(data), format, va);
        va_end(va);
        if (size == sizeof(data) - 1) return 0;
        
        int handle = 0;
        
        if (dir == FILE_OPEN_WRITE)
        {
                if (_swix(OS_Find, _INR(0,1) | _OUT(0), 0x8f, data, &handle)) return 0;
        }
        else if (dir == FILE_OPEN_READ)
        {      
                if (_swix(OS_Find, _INR(0,1) | _OUT(0), 0x4f, data, &handle)) return 0;
        }
        
        return handle;
}

bool file_read(int file_handle, char* buf, size_t size, size_t* size_read)
{
        if (file_handle == 0) return false;
        _kernel_swi_regs regs;
        regs.r[0] = 4;
        regs.r[1] = file_handle;
        regs.r[2] = (int) buf;
        regs.r[3] = size;
        regs.r[4] = 0;
        if (_kernel_swi(OS_GBPB, &regs, &regs)) return false;
        
        if ( size_read != NULL) *size_read = size - regs.r[3];
        return true;                
}

bool file_write(int file_handle, char* buf, size_t size, size_t* size_written)
{
        if (file_handle == 0) return false;
        _kernel_swi_regs regs;
        regs.r[0] = 2;
        regs.r[1] = file_handle;
        regs.r[2] = (int) buf;
        regs.r[3] = size;
        regs.r[4] = 0;
        if (_kernel_swi(OS_GBPB, &regs, &regs)) return false;
        
        if (size_written != NULL) *size_written = size - regs.r[3];
        return true;                
}

_kernel_oserror* file_close(int file_handle)
{
        if (file_handle == 0) return NULL;
        return _swix(OS_Find, _INR(0,1), 0, file_handle);
}

bool file_set_ptr(int file_handle, size_t ptr)
{
        if (file_handle == 0) return false;
        return _swix(OS_Args, _INR(0,2), 1, file_handle, ptr) == NULL;
}


bool file_get_ptr(int file_handle, size_t* ptr)
{
        if (file_handle == 0) return false;
        return _swix(OS_Args, _INR(0,1) | _OUT(2), 0, file_handle, ptr) == NULL;
} 

