text: /* LibTomCrypt, modular cryptographic library -- Tom St Denis
   *
   * LibTomCrypt is a library that provides various cryptographic
   * algorithms in a highly modular and flexible manner.
   *
   * The library is free for all purposes without any express
   * guarantee it works.
   */
  #include "tomcrypt.h"
  
  /**
    @file xcbc_process.c
    XCBC Support, process blocks with XCBC
  */
  
  #ifdef LTC_XCBC
  
  /** Process data through XCBC-MAC
    @param xcbc     The XCBC-MAC state
    @param in       Input data to process
    @param inlen    Length of input in octets
    Return CRYPT_OK on success
  */
  int xcbc_process(xcbc_state *xcbc, const unsigned char *in, unsigned long inlen)
  {
     int err;
  #ifdef LTC_FAST
     int x;
  #endif
  
     LTC_ARGCHK(xcbc != NULL);
     LTC_ARGCHK(in   != NULL);
  
     /* check structure */
     if ((err = cipher_is_valid(xcbc->cipher)) != CRYPT_OK) {
        return err;
     }
  
     if ((xcbc->blocksize > cipher_descriptor[xcbc->cipher].block_length) || (xcbc->blocksize < 0) ||
         (xcbc->buflen > xcbc->blocksize) || (xcbc->buflen < 0)) {
        return CRYPT_INVALID_ARG;
     }
  
  #ifdef LTC_FAST
     if (xcbc->buflen == 0) {
         while (inlen > (unsigned long)xcbc->blocksize) {
             for (x = 0; x < xcbc->blocksize; x += sizeof(LTC_FAST_TYPE)) {
                *(LTC_FAST_TYPE_PTR_CAST(&(xcbc->IV[x]))) ^= *(LTC_FAST_TYPE_PTR_CAST(&(in[x])));
             }
             cipher_descriptor[xcbc->cipher].ecb_encrypt(xcbc->IV, xcbc->IV, &xcbc->key);
             in    += xcbc->blocksize;
             inlen -= xcbc->blocksize;
         }
     }
  #endif
  
     while (inlen) {
        if (xcbc->buflen == xcbc->blocksize) {
           cipher_descriptor[xcbc->cipher].ecb_encrypt(xcbc->IV, xcbc->IV, &xcbc->key);
           xcbc->buflen = 0;
        }
        xcbc->IV[xcbc->buflen++] ^= *in++;
        --inlen;
     }
     return CRYPT_OK;
  }
  
  #endif
  
  /* ref:         HEAD -> master, tag: v1.18.2 */
  /* git commit:  7e7eb695d581782f04b24dc444cbfde86af59853 */
  /* commit time: 2018-07-01 22:49:01 +0200 */
  
  