#include "des_core.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static void rk_crypto_cfb128_encrypt(void *ctx, const unsigned char *in,
                                     unsigned char *out, size_t len,
                                     unsigned char ivec[DES_BLOCK_SIZE],
                                     int *num, int enc, block128_f block) {
  unsigned int n;
  size_t l = 0;

  n = *num;
  if (enc) {

    while (l < len) {
      if (n == 0) {
        (*block)(ivec, ivec, ctx);
      }
      out[l] = ivec[n] ^= in[l];
      ++l;
      n = (n + 1) % DES_BLOCK_SIZE;
    }
    *num = n;
  } else {
    while (l < len) {
      unsigned char c;
      if (n == 0) {
        (*block)(ivec, ivec, ctx);
      }
      out[l] = ivec[n] ^ (c = in[l]);
      ivec[n] = c;
      ++l;
      n = (n + 1) % DES_BLOCK_SIZE;
    }
    *num = n;
  }
}

int rk_des_cfb_encrypt(const unsigned char *in, unsigned char *out,
                       unsigned long length, const unsigned char *key,
                       const int key_len, unsigned char *ivec, const int enc) {
  rk_des_context ctx;
  rk_des3_context ctx3;
  int num = 0;

  if (in == NULL || out == NULL || key == NULL)
    return -1;

  if (key_len != 8 && key_len != 16 && key_len != 24)
    return -2;

  if (length == 0)
    return -3;

  switch (key_len) {
  case 8:
    rk_des_setkey_enc(&ctx, key);
    rk_crypto_cfb128_encrypt((void *)&ctx, in, out, length, ivec, &num, enc,
                             rk_des_crypt_ecb);
    break;
  case 16:
    rk_des3_set2key_enc(&ctx3, key);
    rk_crypto_cfb128_encrypt((void *)&ctx3, in, out, length, ivec, &num, enc,
                             rk_des3_crypt_ecb);
    break;
  case 24:
    rk_des3_set3key_enc(&ctx3, key);
    rk_crypto_cfb128_encrypt((void *)&ctx3, in, out, length, ivec, &num, enc,
                             rk_des3_crypt_ecb);
    break;
  default:
    return -1;
  }

  return 0;
}