quickjs-tart

quickjs-based runtime for wallet-core logic
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ctr.h (947B)

      1 /**
      2  * \file ctr.h
      3  *
      4  * \brief    This file contains common functionality for counter algorithms.
      5  *
      6  *  Copyright The Mbed TLS Contributors
      7  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
      8  */
      9 
     10 #ifndef MBEDTLS_CTR_H
     11 #define MBEDTLS_CTR_H
     12 
     13 #include "common.h"
     14 
     15 /**
     16  * \brief               Increment a big-endian 16-byte value.
     17  *                      This is quite performance-sensitive for AES-CTR and CTR-DRBG.
     18  *
     19  * \param n             A 16-byte value to be incremented.
     20  */
     21 static inline void mbedtls_ctr_increment_counter(uint8_t n[16])
     22 {
     23     // The 32-bit version seems to perform about the same as a 64-bit version
     24     // on 64-bit architectures, so no need to define a 64-bit version.
     25     for (int i = 3;; i--) {
     26         uint32_t x = MBEDTLS_GET_UINT32_BE(n, i << 2);
     27         x += 1;
     28         MBEDTLS_PUT_UINT32_BE(x, n, i << 2);
     29         if (x != 0 || i == 0) {
     30             break;
     31         }
     32     }
     33 }
     34 
     35 #endif /* MBEDTLS_CTR_H */