/*  MiniDLNA media server
 *  Copyright (C) 2009  Justin Maggard
 *
 *  This program 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.
 *
 *  This program 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 "config.h"
#ifdef TIVO_SUPPORT
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <linux/types.h> // Defines __u32
#include <sqlite3.h>
#include "tivo_utils.h"

/* This function based on byRequest */
char *
decodeString(char * string, int inplace)
{
	if( !string )
		return NULL;
	int alloc = (int)strlen(string)+1;
	char * ns = NULL;
	unsigned char in;
	int strindex=0;
	long hex;

	if( !inplace )
	{
		if( !(ns = malloc(alloc)) )
			return NULL;
	}

	while(--alloc > 0)
	{
		in = *string;
		if((in == '%') && isxdigit(string[1]) && isxdigit(string[2]))
		{
			/* this is two hexadecimal digits following a '%' */
			char hexstr[3];
			char *ptr;
			hexstr[0] = string[1];
			hexstr[1] = string[2];
			hexstr[2] = 0;

			hex = strtol(hexstr, &ptr, 16);

			in = (unsigned char)hex; /* this long is never bigger than 255 anyway */
			if( inplace )
			{
				*string = in;
				memmove(string+1, string+3, alloc-2);
			}
			else
			{
				string+=2;
			}
			alloc-=2;
		}
		if( !inplace )
			ns[strindex++] = in;
		string++;
	}
	if( inplace )
	{
		return string;
	}
	else
	{
		ns[strindex] = '\0'; /* terminate it */
		return ns;
	}
}

/* These next functions implement a repeatable random function with a user-provided seed */
static int
seedRandomByte(__u32 seed) {
  unsigned char t;
  if( !sqlite3Prng.isInit )
  {
    int i;
    char k[256];
    sqlite3Prng.j = 0;
    sqlite3Prng.i = 0;
    memset(&k, 0, 256);
    memcpy(&k, &seed, 4);
    for(i=0; i<256; i++){
      sqlite3Prng.s[i] = i;
    }
    for(i=0; i<256; i++){
      sqlite3Prng.j += sqlite3Prng.s[i] + k[i];
      t = sqlite3Prng.s[sqlite3Prng.j];
      sqlite3Prng.s[sqlite3Prng.j] = sqlite3Prng.s[i];
      sqlite3Prng.s[i] = t;
    }
    sqlite3Prng.isInit = 1;
  }
  /* Generate and return single random byte */
  sqlite3Prng.i++;
  t = sqlite3Prng.s[sqlite3Prng.i];
  sqlite3Prng.j += t;
  sqlite3Prng.s[sqlite3Prng.i] = sqlite3Prng.s[sqlite3Prng.j];
  sqlite3Prng.s[sqlite3Prng.j] = t;
  t += sqlite3Prng.s[sqlite3Prng.i];

  return sqlite3Prng.s[t];
}

void
seedRandomness(int N, void *pBuf, __u32 seed){
  unsigned char *zBuf = pBuf;

  while( N-- ){
    *(zBuf++) = seedRandomByte(seed);
  }
}

void
TiVoRandomSeedFunc(sqlite3_context *context, int argc, sqlite3_value **argv)
{
  sqlite_int64 r, seed;
  if( argc != 1 || sqlite3_value_type(argv[0]) != SQLITE_INTEGER )
	return;
  seed = sqlite3_value_int64(argv[0]);
  seedRandomness(sizeof(r), &r, seed);
  sqlite3_result_int64(context, r);
}
#endif