/*
 * mfile.c -- memory buffered file
 * (C)Copyright 2000 by TAJIRI Yasuhiro
 * This file is part of Enfle.
 *
 * Last Modified: Thu Aug 10 07:20:25 2000.
 * $Id: mfile.c,v 1.1 2000/08/09 22:20:34 sian Exp $
 *
 * Enfle 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.
 *
 * Enfle 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 02111-1307, USA
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "mfile.h"

#define min(x,y) ((x) < (y) ? (x) : (y))
#define max(x,y) ((x) > (y) ? (x) : (y))

MFILE* mopen(int init_size)
{
    MFILE* mp = (MFILE*)malloc(sizeof(MFILE));
    if(mp==NULL)return NULL;
    mp->buf=malloc(init_size);
    if(mp->buf==NULL ){
        free(mp);
        return NULL;
    }
    mp->size=init_size;
    mp->pos=0;
    return mp;
}
int mclose(MFILE* stream)
{
    free(stream->buf);
    free(stream);
    return 0;
}

size_t mread(char* buf,size_t size, size_t nmemb,  MFILE*stream)
{
    int pos = stream->pos;
    int count=stream->size;
    char* b = (stream->buf)+pos;
    size_t len=size*nmemb;
    
    if (pos >= count) {
	    return -1;
	}
	if (pos + len > count) {
	    len = count - pos;
	}
	if (len <= 0) {
	    return 0;
	}
	stream->pos = pos+len;
//	memmove(buf, b, len);
    for(pos=0;pos<len;pos++)
    {
        *buf++=*b++;
    }
    

	return len;
}
int mputc(int c, MFILE *stream)
{
    int count=stream->pos;
    int newcount = count + 1;
	if (newcount > stream->size) {
        stream->size=max(stream->size << 1, newcount);
        printf("new size=%d\n",stream->size);
        
        stream->buf = realloc(stream->buf,stream->size);
        if(stream->buf==NULL){
            stream->size=0;
            return -1;
        }
	}
    stream->pos = newcount;
	return (stream->buf[count] = (unsigned char)c);
    
}
int mputcn(int c, MFILE *stream,size_t len)
{
    int count=stream->pos;
    /* char* b = stream->buf+count; */
    int newcount = count + len;

    if (newcount > stream->size) {
      stream->size=max(stream->size << 1, newcount);
      printf("new size=%d\n",stream->size);

      stream->buf = realloc(stream->buf,stream->size);
      if(stream->buf==NULL){
	stream->size=0;
	return -1;
      }
    }
    stream->pos = newcount;
    memset(stream->buf+count, c, len);
    stream->pos = newcount;
    return len;
}

size_t mwrite(char* buf,size_t size, size_t nmemb,  MFILE*stream)
{
    int count=stream->pos;
    char* b = stream->buf+count;
    size_t len=size*nmemb;

    int newcount = count + len;
    if (newcount > stream->size) {
      stream->size=max(stream->size << 1, newcount);
      stream->buf = realloc(stream->buf,stream->size);
      if(stream->buf==NULL){
	stream->size=0;
	return 0;
      }
      b = stream->buf+count;
    }
    memmove(b, buf, len);
    stream->pos = newcount;

    return nmemb;
}
    
int mseek( MFILE *stream, long offset, int whence)
{
    if (stream == NULL)
        return -1;

    switch (whence) {
        case SEEK_SET:
            stream->pos=offset;
            break;
        case SEEK_CUR:
            stream->pos+=offset;
            break;
        case SEEK_END:
            stream->pos=stream->size-offset;
            break;
        default:
            fprintf(stderr, "archive_seek: FATAL: Invalid whence specified: %d\n", whence);
    }

    return stream->pos;
}

long mtell( MFILE *stream)
{
    if (stream == NULL)
        return -1;
    return stream->pos;
}