/*
  This file is part of SLL.
  Copyright (C) 2008 Sebastien LUTTRINGER <contact@seblu.net>

  SLL 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; version 2 of the License.

  SLL 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 SLL; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "slm.hh"
#include "cypher.hh"
#include "error.hh"

#include <openssl/sha.h>
#include <openssl/bio.h>
#include <openssl/buffer.h>
#include <openssl/evp.h>
#include <openssl/md5.h>

/**
 * return sha1 of data with base64 encoding
 *
 * @param data data to sha1 and base64
 * @param size size of data
 *
 * @return malloc'ed sha1 size
 */
string Cypher::sha1_64(const char *data, size_t size) {
  unsigned char md[SHA_DIGEST_LENGTH];
  BIO *bmem, *b64;
  BUF_MEM *bptr;
  string ret;

  // compute sha1
  SHA1((const unsigned char *) data, size, md);

  // compute b64
  b64 = BIO_new(BIO_f_base64());
  bmem = BIO_new(BIO_s_mem());
  b64 = BIO_push(b64, bmem);
  BIO_write(b64, md, SHA_DIGEST_LENGTH);
  BIO_flush(b64);
  BIO_get_mem_ptr(b64, &bptr);

  if (bptr->length > 0)
    ret.insert(0, bptr->data, bptr->length - 1);
  else
    throw Error(ERR_CYPHER, "Unable to compute sha1_64");

  BIO_free_all(b64);

  return ret;
}

/**
 * return md5 hexa digest of file @param file.
 *
 * @return malloc'ed md5 digest in hexadecimal
 */
string Cypher::md5_16(const string &file) {
  MD5_CTX ctx;
  FILE *fs;
  size_t len;
  char buf[512];
  char md[MD5_DIGEST_LENGTH];
  char digest[MD5_DIGEST_LENGTH * 2 + 1];

  if (!MD5_Init(&ctx))
    throw Error(ERR_CYPHER, (string) "Unable to compute md5_16 on file " + file);

  if ((fs = fopen(file.c_str(), "r")) == 0)
    throw Error(ERR_CYPHER, (string) "Unable to compute md5_16 on file " + file);

  while ((len = fread(buf, 1, 512, fs)) > 0)
    if (!MD5_Update(&ctx, buf, len))
      break;

  if (!MD5_Final((unsigned char*)md, &ctx))
    throw Error(ERR_CYPHER, (string) "Unable to compute md5_16 on file " + file);

  for(len = 0; len < MD5_DIGEST_LENGTH; ++len)
    sprintf(digest + (len * 2), "%02x", (unsigned char) md[len]);

  digest[MD5_DIGEST_LENGTH * 2] = 0;

  return digest;
}