as_string.h

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/* 
 * Copyright 2008-2018 Aerospike, Inc.
 *
 * Portions may be licensed to Aerospike, Inc. under one or more contributor
 * license agreements.
 *
 * 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.
 */
 
#pragma once
 
#include <aerospike/as_std.h>
#include <aerospike/as_util.h>
#include <aerospike/as_val.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
/******************************************************************************
 *  TYPES
 ******************************************************************************/
 
/**
 *  Container for NULL-terminates string values.
 *
 *  ## Initialization
 *  
 *  An as_string should be initialized via one of the provided function.
 *  - as_string_init()
 *  - as_string_new()
 *
 *  To initialize a stack allocated as_string, use as_string_init():
 *
 *  ~~~~~~~~~~{.c}
 *  as_string s;
 *  as_string_init(&s, "abc", false);
 *  ~~~~~~~~~~
 *
 *  The 3rd argument indicates whether the string value should be `free()`d 
 *  when as_string is destroyed.
 *
 *  To create and initialize a heap allocated as_string, use as_string_new():
 *  
 *  ~~~~~~~~~~{.c}
 *  as_string * s = as_string_new("abc", false);
 *  ~~~~~~~~~~
 *
 *  ## Destruction
 *
 *  When the as_string instance is no longer required, then you should
 *  release the resources associated with it via as_string_destroy():
 *
 *  ~~~~~~~~~~{.c}
 *  as_string_destroy(s);
 *  ~~~~~~~~~~
 *  
 *  ## Usage
 *
 *  There are two functions for getting the boxed value contained by 
 *  as_string:
 *
 *  as_string_get() returns the contained value. If an error occurred, then
 *  NULL is returned. Possible errors is the as_string instance is NULL.
 *
 *  ~~~~~~~~~~{.c}
 *  char * sval = as_string_get(i);
 *  ~~~~~~~~~~
 *
 *  as_string_getorelse() allows you to return a default value if an error 
 *  occurs:
 *
 *  ~~~~~~~~~~{.c}
 *  char * sval = as_string_getorelse(i, "oops!");
 *  ~~~~~~~~~~
 *
 *  ## Conversions
 *
 *  as_string is derived from as_val, so it is generally safe to down cast:
 *
 *  ~~~~~~~~~~{.c}
 *  as_val val = (as_val) s;
 *  ~~~~~~~~~~
 *  
 *  However, upcasting is more error prone. When doing so, you should use 
 *  as_string_fromval(). If conversion fails, then the return value is NULL.
 *
 *  ~~~~~~~~~~{.c}
 *  as_string * i = as_string_fromval(val);
 *  ~~~~~~~~~~
 *
 *  @extends as_val
 *  @ingroup aerospike_t
 */
typedef struct as_string_s {
    
    /**
     *  @private
     *  as_boolean is a subtype of as_val.
     *  You can cast as_boolean to as_val.
     */
    as_val _;
 
    /**
     *  If true, then `as_string.value` can be freed.
     */
    bool free;
 
    /**
     *  The string value.
     */
    char * value;
 
    /**
     *  The length of the string.
     */
    size_t len;
 
} as_string;
 
/******************************************************************************
 *  INSTANCE FUNCTIONS
 ******************************************************************************/
 
/**
 *  Initialize a stack allocated `as_string`.
 *
 *  If free is true, then the string value will be freed when the as_string is destroyed.
 *
 *  @param string   The stack allocated as_string to initialize
 *  @param value    The NULL terminated string of character.
 *  @param free     If true, then the value will be freed when as_string is destroyed.
 *
 *  @return On success, the initialized string. Otherwise NULL.
 *
 *  @relatesalso as_string
 */
AS_EXTERN as_string * as_string_init(as_string * string, char * value, bool free);
 
/**
 *  Initialize a stack allocated `as_string` and its length.
 *
 *  If free is true, then the string value will be freed when the as_string is destroyed.
 *
 *  @param string   The stack allocated as_string to initialize
 *  @param value    The NULL terminated string of character.
 *  @param len      The length of the string.
 *  @param free     If true, then the value will be freed when as_string is destroyed.
 *
 *  @return On success, the initialized string. Otherwise NULL.
 *
 *  @relatesalso as_string
 */
AS_EXTERN as_string * as_string_init_wlen(as_string * string, char * value, size_t len, bool free);
 
/**
 *  Create and initialize a new heap allocated `as_string`.
 *
 *  If free is true, then the string value will be freed when the as_string is destroyed.
 *
 *  @param value    The NULL terminated string of character.
 *  @param free     If true, then the value will be freed when as_string is destroyed.
 *
 *  @return On success, the new string. Otherwise NULL.
 *
 *  @relatesalso as_string
 */
AS_EXTERN as_string * as_string_new(char * value, bool free);
 
/**
 *  Create and initialize a new heap allocated `as_string` and its length.
 *
 *  If free is true, then the string value will be freed when the as_string is destroyed.
 *
 *  @param value    The NULL terminated string of character.
 *  @param len      The length of the string.
 *  @param free     If true, then the value will be freed when as_string is destroyed.
 *
 *  @return On success, the new string. Otherwise NULL.
 *
 *  @relatesalso as_string
 */
AS_EXTERN as_string * as_string_new_wlen(char * value, size_t len, bool free);
 
/**
 *  Create and initialize a new heap allocated `as_string`.
 *
 *  Value is cf_strdup()'d and will be freed when the as_string is destroyed.
 *
 *  @param value    The NULL terminated string of character.
 *
 *  @return On success, the new string. Otherwise NULL.
 */
AS_EXTERN as_string * as_string_new_strdup(const char * value);
 
/**
 *  Destroy the as_string and associated resources.
 *
 *  @relatesalso as_string
 */
static inline void as_string_destroy(as_string * string) 
{
    as_val_destroy((as_val *) string);
}
 
/******************************************************************************
 *  VALUE FUNCTIONS
 ******************************************************************************/
 
/**
 *  The length of the string
 *
 *  @param string The string to get the length of. 
 *
 *  @return the length of the string in bytes.
 *
 *  @relatesalso as_string
 */
AS_EXTERN size_t as_string_len(as_string * string);
 
/**
 *  Get the string value. If string is NULL, then return the fallback value.
 *
 *  @relatesalso as_string
 */
static inline char * as_string_getorelse(const as_string * string, char * fallback) 
{
    return string ? string->value : fallback;
}
 
/**
 *  Get the string value.
 *
 *  @relatesalso as_string
 */
static inline char * as_string_get(const as_string * string) 
{
    return as_string_getorelse(string, NULL);
}
 
/**
 *  Get the string value.
 *  @deprecated Use as_string_get() instead
 *
 *  @relatesalso as_string
 */
static inline char * as_string_tostring(const as_string * string) 
{
    return as_string_getorelse(string, NULL);
}
 
/**
 *  Return filename component of full path.
 *
 *  If path is empty, the current directory is returned.
 *  If path contains trailing directory slashes, create new string to hold
 *  filename without slashes.  The input path is guaranteed not to be modified.
 *  as_string_destroy() must be called when finished with filename.
 *
 *  @relatesalso as_string
 */
AS_EXTERN const char* as_basename(as_string * filename, const char* path);
 
/******************************************************************************
 *  CONVERSION FUNCTIONS
 ******************************************************************************/
 
/**
 *  Convert to an as_val.
 *
 *  @relatesalso as_string
 */
static inline as_val * as_string_toval(const as_string * s) 
{
    return (as_val *) s;
}
 
/**
 *  Convert from an as_val.
 *
 *  @relatesalso as_string
 */
static inline as_string * as_string_fromval(const as_val * v) 
{
    return as_util_fromval(v, AS_STRING, as_string);
}
 
/******************************************************************************
 *  as_val FUNCTIONS
 ******************************************************************************/
 
/**
 *  @private
 *  Internal helper function for destroying an as_val.
 */
AS_EXTERN void as_string_val_destroy(as_val * v);
 
/**
 *  @private
 *  Internal helper function for getting the hashcode of an as_val.
 */
AS_EXTERN uint32_t as_string_val_hashcode(const as_val * v);
 
/**
 *  @private
 *  Internal helper function for getting the string representation of an as_val.
 */
AS_EXTERN char * as_string_val_tostring(const as_val * v);
 
/******************************************************************************
 *  String utilities
 ******************************************************************************/
 
/**
 *  @private
 *  Copy null terminated src to trg up to a maximum size.
 *  If maximum size reached, null terminate last character and
 *  and return true that truncation occurred.
 *
 *  as_strncpy does not pad unused bytes with zeroes like the
 *  standard strncpy.
 *
 *  ~~~~~~~~~~{.c}
 *      char target[64];
 *      as_strncpy(target, "source string", sizeof(target));
 *  ~~~~~~~~~~
 *
 *  @relatesalso as_string
 */
AS_EXTERN bool as_strncpy(char* trg, const char* src, int size);
 
#ifdef __cplusplus
} // end extern "C"
#endif