/* GStreamer
 * Copyright (C) <2005,2006> Wim Taymans <wim@fluendo.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */
/* Element-Checklist-Version: 5 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif

#include <string.h>

#include <gst/gst.h>

#include "realhash.h"

void rtsp_ext_real_calc_response_and_checksum (char *response,
    char *chksum, char *challenge);

/*
 * The following code has been copied from
 * xine-lib-1.1.1/src/input/libreal/real.c.
 */

static const unsigned char xor_table[] = {
  0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
  0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
  0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
  0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
  0x10, 0x57, 0x05, 0x18, 0x54, 0x00, 0x00, 0x00
};

#define LE_32(x) GST_READ_UINT32_LE(x)
#define BE_32C(x,y) GST_WRITE_UINT32_BE(x,y)
#define LE_32C(x,y) GST_WRITE_UINT32_LE(x,y)

static void
hash (char *field, char *param)
{
  uint32_t a, b, c, d;

  /* fill variables */
  a = LE_32 (field);
  b = LE_32 (field + 4);
  c = LE_32 (field + 8);
  d = LE_32 (field + 12);

  a = ((b & c) | (~b & d)) + LE_32 ((param + 0x00)) + a - 0x28955B88;
  a = ((a << 0x07) | (a >> 0x19)) + b;
  d = ((a & b) | (~a & c)) + LE_32 ((param + 0x04)) + d - 0x173848AA;
  d = ((d << 0x0c) | (d >> 0x14)) + a;
  c = ((d & a) | (~d & b)) + LE_32 ((param + 0x08)) + c + 0x242070DB;
  c = ((c << 0x11) | (c >> 0x0f)) + d;
  b = ((c & d) | (~c & a)) + LE_32 ((param + 0x0c)) + b - 0x3E423112;
  b = ((b << 0x16) | (b >> 0x0a)) + c;
  a = ((b & c) | (~b & d)) + LE_32 ((param + 0x10)) + a - 0x0A83F051;
  a = ((a << 0x07) | (a >> 0x19)) + b;
  d = ((a & b) | (~a & c)) + LE_32 ((param + 0x14)) + d + 0x4787C62A;
  d = ((d << 0x0c) | (d >> 0x14)) + a;
  c = ((d & a) | (~d & b)) + LE_32 ((param + 0x18)) + c - 0x57CFB9ED;
  c = ((c << 0x11) | (c >> 0x0f)) + d;
  b = ((c & d) | (~c & a)) + LE_32 ((param + 0x1c)) + b - 0x02B96AFF;
  b = ((b << 0x16) | (b >> 0x0a)) + c;
  a = ((b & c) | (~b & d)) + LE_32 ((param + 0x20)) + a + 0x698098D8;
  a = ((a << 0x07) | (a >> 0x19)) + b;
  d = ((a & b) | (~a & c)) + LE_32 ((param + 0x24)) + d - 0x74BB0851;
  d = ((d << 0x0c) | (d >> 0x14)) + a;
  c = ((d & a) | (~d & b)) + LE_32 ((param + 0x28)) + c - 0x0000A44F;
  c = ((c << 0x11) | (c >> 0x0f)) + d;
  b = ((c & d) | (~c & a)) + LE_32 ((param + 0x2C)) + b - 0x76A32842;
  b = ((b << 0x16) | (b >> 0x0a)) + c;
  a = ((b & c) | (~b & d)) + LE_32 ((param + 0x30)) + a + 0x6B901122;
  a = ((a << 0x07) | (a >> 0x19)) + b;
  d = ((a & b) | (~a & c)) + LE_32 ((param + 0x34)) + d - 0x02678E6D;
  d = ((d << 0x0c) | (d >> 0x14)) + a;
  c = ((d & a) | (~d & b)) + LE_32 ((param + 0x38)) + c - 0x5986BC72;
  c = ((c << 0x11) | (c >> 0x0f)) + d;
  b = ((c & d) | (~c & a)) + LE_32 ((param + 0x3c)) + b + 0x49B40821;
  b = ((b << 0x16) | (b >> 0x0a)) + c;

  a = ((b & d) | (~d & c)) + LE_32 ((param + 0x04)) + a - 0x09E1DA9E;
  a = ((a << 0x05) | (a >> 0x1b)) + b;
  d = ((a & c) | (~c & b)) + LE_32 ((param + 0x18)) + d - 0x3FBF4CC0;
  d = ((d << 0x09) | (d >> 0x17)) + a;
  c = ((d & b) | (~b & a)) + LE_32 ((param + 0x2c)) + c + 0x265E5A51;
  c = ((c << 0x0e) | (c >> 0x12)) + d;
  b = ((c & a) | (~a & d)) + LE_32 ((param + 0x00)) + b - 0x16493856;
  b = ((b << 0x14) | (b >> 0x0c)) + c;
  a = ((b & d) | (~d & c)) + LE_32 ((param + 0x14)) + a - 0x29D0EFA3;
  a = ((a << 0x05) | (a >> 0x1b)) + b;
  d = ((a & c) | (~c & b)) + LE_32 ((param + 0x28)) + d + 0x02441453;
  d = ((d << 0x09) | (d >> 0x17)) + a;
  c = ((d & b) | (~b & a)) + LE_32 ((param + 0x3c)) + c - 0x275E197F;
  c = ((c << 0x0e) | (c >> 0x12)) + d;
  b = ((c & a) | (~a & d)) + LE_32 ((param + 0x10)) + b - 0x182C0438;
  b = ((b << 0x14) | (b >> 0x0c)) + c;
  a = ((b & d) | (~d & c)) + LE_32 ((param + 0x24)) + a + 0x21E1CDE6;
  a = ((a << 0x05) | (a >> 0x1b)) + b;
  d = ((a & c) | (~c & b)) + LE_32 ((param + 0x38)) + d - 0x3CC8F82A;
  d = ((d << 0x09) | (d >> 0x17)) + a;
  c = ((d & b) | (~b & a)) + LE_32 ((param + 0x0c)) + c - 0x0B2AF279;
  c = ((c << 0x0e) | (c >> 0x12)) + d;
  b = ((c & a) | (~a & d)) + LE_32 ((param + 0x20)) + b + 0x455A14ED;
  b = ((b << 0x14) | (b >> 0x0c)) + c;
  a = ((b & d) | (~d & c)) + LE_32 ((param + 0x34)) + a - 0x561C16FB;
  a = ((a << 0x05) | (a >> 0x1b)) + b;
  d = ((a & c) | (~c & b)) + LE_32 ((param + 0x08)) + d - 0x03105C08;
  d = ((d << 0x09) | (d >> 0x17)) + a;
  c = ((d & b) | (~b & a)) + LE_32 ((param + 0x1c)) + c + 0x676F02D9;
  c = ((c << 0x0e) | (c >> 0x12)) + d;
  b = ((c & a) | (~a & d)) + LE_32 ((param + 0x30)) + b - 0x72D5B376;
  b = ((b << 0x14) | (b >> 0x0c)) + c;

  a = (b ^ c ^ d) + LE_32 ((param + 0x14)) + a - 0x0005C6BE;
  a = ((a << 0x04) | (a >> 0x1c)) + b;
  d = (a ^ b ^ c) + LE_32 ((param + 0x20)) + d - 0x788E097F;
  d = ((d << 0x0b) | (d >> 0x15)) + a;
  c = (d ^ a ^ b) + LE_32 ((param + 0x2c)) + c + 0x6D9D6122;
  c = ((c << 0x10) | (c >> 0x10)) + d;
  b = (c ^ d ^ a) + LE_32 ((param + 0x38)) + b - 0x021AC7F4;
  b = ((b << 0x17) | (b >> 0x09)) + c;
  a = (b ^ c ^ d) + LE_32 ((param + 0x04)) + a - 0x5B4115BC;
  a = ((a << 0x04) | (a >> 0x1c)) + b;
  d = (a ^ b ^ c) + LE_32 ((param + 0x10)) + d + 0x4BDECFA9;
  d = ((d << 0x0b) | (d >> 0x15)) + a;
  c = (d ^ a ^ b) + LE_32 ((param + 0x1c)) + c - 0x0944B4A0;
  c = ((c << 0x10) | (c >> 0x10)) + d;
  b = (c ^ d ^ a) + LE_32 ((param + 0x28)) + b - 0x41404390;
  b = ((b << 0x17) | (b >> 0x09)) + c;
  a = (b ^ c ^ d) + LE_32 ((param + 0x34)) + a + 0x289B7EC6;
  a = ((a << 0x04) | (a >> 0x1c)) + b;
  d = (a ^ b ^ c) + LE_32 ((param + 0x00)) + d - 0x155ED806;
  d = ((d << 0x0b) | (d >> 0x15)) + a;
  c = (d ^ a ^ b) + LE_32 ((param + 0x0c)) + c - 0x2B10CF7B;
  c = ((c << 0x10) | (c >> 0x10)) + d;
  b = (c ^ d ^ a) + LE_32 ((param + 0x18)) + b + 0x04881D05;
  b = ((b << 0x17) | (b >> 0x09)) + c;
  a = (b ^ c ^ d) + LE_32 ((param + 0x24)) + a - 0x262B2FC7;
  a = ((a << 0x04) | (a >> 0x1c)) + b;
  d = (a ^ b ^ c) + LE_32 ((param + 0x30)) + d - 0x1924661B;
  d = ((d << 0x0b) | (d >> 0x15)) + a;
  c = (d ^ a ^ b) + LE_32 ((param + 0x3c)) + c + 0x1fa27cf8;
  c = ((c << 0x10) | (c >> 0x10)) + d;
  b = (c ^ d ^ a) + LE_32 ((param + 0x08)) + b - 0x3B53A99B;
  b = ((b << 0x17) | (b >> 0x09)) + c;

  a = ((~d | b) ^ c) + LE_32 ((param + 0x00)) + a - 0x0BD6DDBC;
  a = ((a << 0x06) | (a >> 0x1a)) + b;
  d = ((~c | a) ^ b) + LE_32 ((param + 0x1c)) + d + 0x432AFF97;
  d = ((d << 0x0a) | (d >> 0x16)) + a;
  c = ((~b | d) ^ a) + LE_32 ((param + 0x38)) + c - 0x546BDC59;
  c = ((c << 0x0f) | (c >> 0x11)) + d;
  b = ((~a | c) ^ d) + LE_32 ((param + 0x14)) + b - 0x036C5FC7;
  b = ((b << 0x15) | (b >> 0x0b)) + c;
  a = ((~d | b) ^ c) + LE_32 ((param + 0x30)) + a + 0x655B59C3;
  a = ((a << 0x06) | (a >> 0x1a)) + b;
  d = ((~c | a) ^ b) + LE_32 ((param + 0x0C)) + d - 0x70F3336E;
  d = ((d << 0x0a) | (d >> 0x16)) + a;
  c = ((~b | d) ^ a) + LE_32 ((param + 0x28)) + c - 0x00100B83;
  c = ((c << 0x0f) | (c >> 0x11)) + d;
  b = ((~a | c) ^ d) + LE_32 ((param + 0x04)) + b - 0x7A7BA22F;
  b = ((b << 0x15) | (b >> 0x0b)) + c;
  a = ((~d | b) ^ c) + LE_32 ((param + 0x20)) + a + 0x6FA87E4F;
  a = ((a << 0x06) | (a >> 0x1a)) + b;
  d = ((~c | a) ^ b) + LE_32 ((param + 0x3c)) + d - 0x01D31920;
  d = ((d << 0x0a) | (d >> 0x16)) + a;
  c = ((~b | d) ^ a) + LE_32 ((param + 0x18)) + c - 0x5CFEBCEC;
  c = ((c << 0x0f) | (c >> 0x11)) + d;
  b = ((~a | c) ^ d) + LE_32 ((param + 0x34)) + b + 0x4E0811A1;
  b = ((b << 0x15) | (b >> 0x0b)) + c;
  a = ((~d | b) ^ c) + LE_32 ((param + 0x10)) + a - 0x08AC817E;
  a = ((a << 0x06) | (a >> 0x1a)) + b;
  d = ((~c | a) ^ b) + LE_32 ((param + 0x2c)) + d - 0x42C50DCB;
  d = ((d << 0x0a) | (d >> 0x16)) + a;
  c = ((~b | d) ^ a) + LE_32 ((param + 0x08)) + c + 0x2AD7D2BB;
  c = ((c << 0x0f) | (c >> 0x11)) + d;
  b = ((~a | c) ^ d) + LE_32 ((param + 0x24)) + b - 0x14792C6F;
  b = ((b << 0x15) | (b >> 0x0b)) + c;

  a += LE_32 (field);
  b += LE_32 (field + 4);
  c += LE_32 (field + 8);
  d += LE_32 (field + 12);

  LE_32C (field, a);
  LE_32C (field + 4, b);
  LE_32C (field + 8, c);
  LE_32C (field + 12, d);
}

static void
call_hash (char *key, char *challenge, int len)
{
  uint8_t *ptr1, *ptr2;
  uint32_t a, b, c, d, tmp;

  ptr1 = (uint8_t *) (key + 16);
  ptr2 = (uint8_t *) (key + 20);

  a = LE_32 (ptr1);
  b = (a >> 3) & 0x3f;
  a += len * 8;
  LE_32C (ptr1, a);

  if (a < (len << 3))
    ptr2 += 4;

  tmp = LE_32 (ptr2) + (len >> 0x1d);
  LE_32C (ptr2, tmp);
  a = 64 - b;
  c = 0;
  if (a <= len) {

    memcpy (key + b + 24, challenge, a);
    hash (key, key + 24);
    c = a;
    d = c + 0x3f;

    while (d < len) {
      hash (key, challenge + d - 0x3f);
      d += 64;
      c += 64;
    }
    b = 0;
  }

  memcpy (key + b + 24, challenge + c, len - c);
}

void
gst_rtsp_ext_real_calc_response_and_checksum (char *response, char *chksum,
    char *challenge)
{
  int ch_len, table_len, resp_len;
  int i;
  char *ptr;
  char buf[128];
  char field[128];
  char zres[20];
  char buf1[128];
  char buf2[128];

  /* initialize return values */
  memset (response, 0, 64);
  memset (chksum, 0, 34);

  /* initialize buffer */
  memset (buf, 0, 128);
  ptr = buf;
  BE_32C (ptr, 0xa1e9149d);
  ptr += 4;
  BE_32C (ptr, 0x0e6b3b59);
  ptr += 4;

  if ((ch_len = MIN (strlen (challenge), 56)) == 40) {
    challenge[32] = 0;
    ch_len = 32;
  }
  memcpy (ptr, challenge, ch_len);

  /* xor challenge bytewise with xor_table */
  table_len = MIN (strlen ((char *) xor_table), 56);
  for (i = 0; i < table_len; i++)
    ptr[i] = ptr[i] ^ xor_table[i];

  /* initialize our field */
  BE_32C (field, 0x01234567);
  BE_32C (field + 4, 0x89ABCDEF);
  BE_32C (field + 8, 0xFEDCBA98);
  BE_32C (field + 12, 0x76543210);
  BE_32C (field + 16, 0x00000000);
  BE_32C (field + 20, 0x00000000);

  /* calculate response */
  call_hash (field, buf, 64);
  memset (buf1, 0, 64);
  *buf1 = (char) 128;
  memcpy (buf2, field + 16, 8);
  i = (LE_32 ((buf2)) >> 3) & 0x3f;
  if (i < 56)
    i = 56 - i;
  else
    i = 120 - i;
  call_hash (field, buf1, i);
  call_hash (field, buf2, 8);
  memcpy (zres, field, 16);

  /* convert zres to ascii string */
  for (i = 0; i < 16; i++) {
    char a, b;

    a = (zres[i] >> 4) & 15;
    b = zres[i] & 15;

    response[i * 2] = ((a < 10) ? (a + 48) : (a + 87)) & 255;
    response[i * 2 + 1] = ((b < 10) ? (b + 48) : (b + 87)) & 255;
  }

  /* add tail */
  resp_len = strlen (response);
  strcpy (&response[resp_len], "01d0a8e3");

  /* calculate checksum */
  for (i = 0; i < resp_len / 4; i++)
    chksum[i] = response[i * 4];
}