dyn_string.c

/*
 * Dynomite - A thin, distributed replication layer for multi non-distributed
 * storages. Copyright (C) 2014 Netflix, Inc.
 */

/*
 * twemproxy - A fast and lightweight proxy for memcached protocol.
 * Copyright (C) 2011 Twitter, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdlib.h>
#include <string.h>

#include "dyn_core.h"

/*
 * String (struct string) is a sequence of unsigned char objects terminated
 * by the null character '\0'. The length of the string is pre-computed and
 * made available explicitly as an additional field. This means that we don't
 * have to walk the entire character sequence until the null terminating
 * character every time that the length of the String is requested
 *
 * The only way to create a String is to initialize it using, string_init()
 * and duplicate an existing String - string_duplicate() or copy an existing
 * raw sequence of character bytes - string_copy(). Such String's must be
 * freed using string_deinit()
 *
 * We can also create String as reference to raw string - string_set_raw()
 * or to text string - string_set_text() or string(). Such String don't have
 * to be freed.
 */

void string_init(struct string *str) {
  str->len = 0;
  str->data = NULL;
}

void string_deinit(struct string *str) {
  ASSERT((str->len == 0 && str->data == NULL) ||
         (str->len != 0 && str->data != NULL));

  if (str->data != NULL) {
    dn_free(str->data);
    string_init(str);
  }
}

bool string_empty(const struct string *str) {
  ASSERT((str->len == 0 && str->data == NULL) ||
         (str->len != 0 && str->data != NULL));
  return str->len == 0 ? true : false;
}

rstatus_t string_duplicate(struct string *dst, const struct string *src) {
  ASSERT(dst->len == 0 && dst->data == NULL);
  ASSERT(src->len != 0 && src->data != NULL);

  dst->data = dn_strndup(src->data, src->len);
  if (dst->data == NULL) {
    return DN_ENOMEM;
  }

  dst->len = dn_strlen(dst->data);
  return DN_OK;
}

rstatus_t string_copy(struct string *dst, const uint8_t *src, uint32_t srclen) {
  // ASSERT(dst->len == 0 && dst->data == NULL);
  ASSERT(src != NULL && srclen != 0);

  dst->data = dn_strndup(src, srclen);
  if (dst->data == NULL) {
    return DN_ENOMEM;
  }

  dst->len = dn_strlen(dst->data);

  return DN_OK;
}

/* For copying constant string into dst */
rstatus_t string_copy_c(struct string *dst, const uint8_t *src) {
  return string_copy(dst, src, (uint32_t)dn_strlen(src));
}

int string_compare(const struct string *s1, const struct string *s2) {
  if (s1->len != s2->len) {
    return s1->len - s2->len > 0 ? 1 : -1;
  }

  return dn_strncmp(s1->data, s2->data, s1->len);
}

/*
char *
strndup (const char *s, size_t n)
{
  char *result;
  size_t len = strlen (s);

  if (n < len)
    len = n;

  result = (char *) malloc (len + 1);
  if (!result)
    return 0;

  result[len] = '\0';
  return (char *) memcpy (result, s, len);
}
*/