/*-
 * Copyright (c) 2014 Pedro Souza <pedrosouza@freebsd.org>
 * 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 "lstd.h"
#include "math.h"

#ifdef LOADER_VERIEXEC
#include <verify_file.h>
#endif

FILE *
fopen(const char *filename, const char *mode)
{
        struct stat     st;
        int             fd, m, o;
        FILE            *f;

        if (mode == NULL)
                return NULL;

        switch (*mode++) {
        case 'r':       /* open for reading */
                m = O_RDONLY;
                o = 0;
                break;

        case 'w':       /* open for writing */
                m = O_WRONLY;
                /* These are not actually implemented yet */
                o = O_CREAT | O_TRUNC;
                break;

        default:        /* illegal mode */
                return (NULL);
        }

        if (*mode == '+')
                m = O_RDWR;

        fd = open(filename, m | o);
        if (fd < 0)
                return NULL;

        f = malloc(sizeof(FILE));
        if (f == NULL) {
                close(fd);
                return NULL;
        }

        if (fstat(fd, &st) != 0) {
                free(f);
                close(fd);
                return (NULL);
        }

#ifdef LOADER_VERIEXEC
        /* only regular files and only reading makes sense */
        if (S_ISREG(st.st_mode) && !(m & O_WRONLY)) {
                if (verify_file(fd, filename, 0, VE_GUESS, __func__) < 0) {
                        free(f);
                        close(fd);
                        return (NULL);
                }
        }
#endif

        f->fd = fd;
        f->offset = 0;
        f->size = st.st_size;

        return (f);
}


FILE *
freopen(const char *filename, const char *mode, FILE *stream)
{
        fclose(stream);
        return (fopen(filename, mode));
}

size_t
fread(void *ptr, size_t size, size_t count, FILE *stream)
{
        size_t r;

        if (stream == NULL)
                return 0;
        r = (size_t)read(stream->fd, ptr, size * count);
        stream->offset += r;

        return (r);
}

size_t
fwrite(const void *ptr, size_t size, size_t count, FILE *stream)
{
        ssize_t w;

        if (stream == NULL || ptr == NULL)
                return (0);
        w = write(stream->fd, ptr, size * count);
        if (w == -1)
                return (0);

        stream->offset += w;
        return ((size_t)w);
}

int
fclose(FILE *stream)
{
        if (stream == NULL)
                return EOF;
        close(stream->fd);
        free(stream);

        return (0);
}

int
ferror(FILE *stream)
{

        return (stream == NULL || stream->fd < 0);
}

int
feof(FILE *stream)
{

        if (stream == NULL)
                return 1;

        return (stream->offset >= stream->size);
}

int
getc(FILE *stream)
{
        char    ch;
        size_t  r;

        if (stream == NULL)
                return EOF;
        r = read(stream->fd, &ch, 1);
        if (r == 1)
                return ch;
        return EOF;
}

DIR *
opendir(const char *name)
{
        DIR *dp;
        int fd;

        fd = open(name, O_RDONLY);
        if (fd < 0)
                return NULL;
        dp = fdopendir(fd);
        if (dp == NULL)
                close(fd);
        return dp;
}

DIR *
fdopendir(int fd)
{
        DIR *dp;

        dp = malloc(sizeof(*dp));
        if (dp == NULL)
                return NULL;
        dp->fd = fd;
        return dp;
}

int
closedir(DIR *dp)
{
        close(dp->fd);
        dp->fd = -1;
        free(dp);
        return 0;
}

void
luai_writestring(const char *s, int i)
{

        while (i-- > 0)
                putchar(*s++);
}

/*
 * These routines from here on down are to implement the lua math
 * library, but that's not presently included by default. They are
 * little more than placeholders to allow compilation due to linkage
 * issues with upstream Lua.
 */

int64_t
lstd_pow(int64_t x, int64_t y)
{
        int64_t rv = 1;

        if (y < 0)
                return 0;
        rv = x;
        while (--y)
                rv *= x;

        return rv;
}

int64_t
lstd_floor(int64_t x)
{

        return (x);
}

int64_t
lstd_fmod(int64_t a, int64_t b)
{

        return (a % b);
}

/*
 * This can't be implemented, so maybe it should just abort.
 */
int64_t
lstd_frexp(int64_t a, int *y)
{
        *y = 0;

        return 0;
}