text: /******************************************************************************
   * Copyright (C) 2014-2020 Zhifeng Gong <gozfree@163.com>
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   ******************************************************************************/
  #ifndef _GNU_SOURCE
  #define _GNU_SOURCE
  #endif
  #include "libmacro.h"
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #if defined (__linux__) || defined (__CYGWIN__)
  #include <unistd.h>
  #endif
  
  #include <stdint.h>
  #include <signal.h>
  #include <errno.h>
  
  void *memdup(const void *src, size_t len)
  {
      void *dst = calloc(1, len);
      if (LIKELY(dst != NULL)) {
          memcpy(dst, src, len);
      }
      return dst;
  }
  
  struct iovec *iovec_create(size_t len)
  {
      struct iovec *vec = CALLOC(1, struct iovec);
      if (LIKELY(vec != NULL)) {
          vec->iov_len = len;
          vec->iov_base = calloc(1, len);
          if (UNLIKELY(vec->iov_base == NULL)) {
              free(vec);
              vec = NULL;
          }
      }
      return vec;
  }
  
  void iovec_destroy(struct iovec *vec)
  {
      if (LIKELY(vec != NULL)) {
          /* free(NULL) do nop */
          free(vec->iov_base);
          free(vec);
      }
  }
  
  /**
   * Fast little endian check
   * NOTE: not applicable for PDP endian
   */
  bool is_little_endian(void)
  {
      static uint16_t x = 0x01;
      return *((uint8_t *) &x);
  }
  
  