/usr/include/libical/icalmemory.h is in libical-dev 3.0.1-5.
This file is owned by root:root, with mode 0o644.
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FILE: icalmemory.h
CREATOR: eric 30 June 1999
(C) COPYRIGHT 2000, Eric Busboom <eric@softwarestudio.org>
http://www.softwarestudio.org
This library is free software; you can redistribute it and/or modify
it under the terms of either:
The LGPL as published by the Free Software Foundation, version
2.1, available at: http://www.gnu.org/licenses/lgpl-2.1.html
Or:
The Mozilla Public License Version 2.0. You may obtain a copy of
the License at http://www.mozilla.org/MPL/
The Initial Developer of the Original Code is Eric Busboom
======================================================================*/
#ifndef ICALMEMORY_H
#define ICALMEMORY_H
/**
* @file icalmemory.h
* @brief Common memory management routines.
*
* libical often passes strings back to the caller. To make these
* interfaces simple, I did not want the caller to have to pass in a
* memory buffer, but having libical pass out newly allocated memory
* makes it difficult to de-allocate the memory.
*
* The ring buffer in this scheme makes it possible for libical to pass out
* references to memory which the caller does not own, and be able to
* de-allocate the memory later. The ring allows libical to have several buffers
* active simultaneously, which is handy when creating string representations of
* components. Methods for working with these temporary buffers are marked with
* `icalmemory_tmp_*()`.
*
* Other memory management routines include wrappers around the system
* management routines like icalmemory_new_buffer() and icalmemory_free_buffer()
* as well as routines to work with strings, like icalmemory_append_string().
*/
#include "libical_ical_export.h"
/**
* @brief Creates a new temporary buffer on the ring and returns it.
* @param size How big (in bytes) the buffer should be
* @return A pointer to the newly created buffer on the ring
*
* Creates a temporary buffer on the ring. Regardless of what @a size you
* specify, the buffer will always be at least ::MIN_BUFFER_SIZE big, and it
* will be zeroed out.
*
* @par Error handling
* If there is a problem allocating memory for the buffer, it sets ::icalerrno
* to ::ICAL_NEWFAILED_ERROR and returns `NULL`.
*
* @par Ownership
* The returned buffer is owned by icalmemory. It must not be freed by the
* caller and the returned memory will be automatically reclaimed as more items
* are added to the ring buffer.
*
* ### Usage
* ```c
* char *str = icalmemory_tmp_buffer(256);
* strcpy(str, "some data");
*
* // use str
* ```
*/
LIBICAL_ICAL_EXPORT void *icalmemory_tmp_buffer(size_t size);
/**
* @brief Creates a copy of the given string, stored on the ring buffer, and
* returns it.
* @param str The string to copy
* @return A copy of @a str, which has been placed on the ring buffer for
* automatic reclamation.
*
* @par Error handling
* The passed string @a str must not be `NULL`, otherwise a segfault might
* ensue, since the routine calls `strlen()` on it.
*
* @par Ownership
* The returned string is owned by icalmemory. It must not be freed by the
* caller, and it will be automatically reclaimed as more items are added to the
* buffer.
*
* ### Usage
* ```c
* const char *str = "Example string";
* char *tmp_copy = icalmemory_tmp_copy(str);
* ```
*/
LIBICAL_ICAL_EXPORT char *icalmemory_tmp_copy(const char *str);
/**
* @brief Add an externally allocated buffer to the ring.
* @param buf The externally allocated buffer to add to the ring
*
* Adds an externally allocated buffer to the ring. This ensures that libical
* will `free()` the buffer automatically, either after ::BUFFER_RING_SIZE other
* buffers have been created or added, or after ::icalmemory_free_ring() has
* been called.
*
* @par Error handling
* No error is raised if @a buf is `NULL`.
*
* @par Ownership
* After adding @a buf to the ring, it becomes owned by icalmemory and must not
* be `free()`d manually anymore, it leads to a double-`free()` when icalmemory
* reclaims the memory.
*
* ### Usage
* ```c
* char *buf = calloc(256, sizeof(char));
*
* icalmemory_add_tmp_buffer(buf);
* ```
*/
LIBICAL_ICAL_EXPORT void icalmemory_add_tmp_buffer(void *buf);
/**
* @brief Free all memory used in the ring
*
* Frees all memory used in the ring. Depending on if ::HAVE_PTHREAD is set or
* not, the ring buffer is allocated on a per-thread basis, meaning that if all
* rings are to be released, it must be called once in every thread.
*
* ### Usage
* ``` c
* void *buf = icalmemory_tmp_buffer(256);
*
* // use buf
*
* // release buf and all other memory in the ring buffer
* icalmemory_free_ring();
* ```
*/
LIBICAL_ICAL_EXPORT void icalmemory_free_ring(void);
/* Non-tmp buffers must be freed. These are mostly wrappers around
* malloc, etc, but are used so the caller can change the memory
* allocators in a future version of the library */
/**
* @brief Creates new buffer with the specified size.
* @param size The size of the buffer that is to be created.
* @return A pointer to the newly-created buffer.
* @sa icalmemory_free_buffer()
*
* @par Error handling
* If there is a problem allocating memory, it sets ::icalerrno to
* ::ICAL_NEWFAILED_ERROR and returns `NULL`.
*
* @par Ownership
* Buffers created with this method are owned by the caller. The must be
* released with the appropriate icalmemory_free_buffer() method.
*
* This creates a new (non-temporary) buffer of the specified @a size. All
* buffers returned by this method are zeroed-out.
*
* ### Usage
* ```c
* // create buffer
* char *buffer = icalmemory_new_buffer(50);
*
* // fill buffer
* strcpy(buffer, "some data");
*
* // release buffer
* icalmemory_free_buffer(buffer);
* ```
*/
LIBICAL_ICAL_EXPORT void *icalmemory_new_buffer(size_t size);
/**
* @brief Resizes a buffer created with icalmemory_new_buffer().
* @param buf The buffer to be resized.
* @param size The new size of the buffer.
* @return The new, resized buffer.
* @sa icalmemory_new_buffer()
* @warn This method may not be used for temporary buffers (buffers allocated
* with icalmemory_tmp_buffer() and related functions)!
*
* @par Error handling
* If there is a problem while reallocating the buffer, the method sets
* ::icalerrno to ::ICAL_NEWFAILED_ERROR and returns `NULL`.
*
* @par Ownership
* The returned buffer is owned by the caller and needs to be released with the
* appropriate icalmemory_free_buffer() method. The old buffer, @a buf, can not
* be used anymore after calling this method.
*
* ### Usage
* ```c
* // create new buffer
* char *buffer = icalmemory_new_buffer(10);
*
* // fill buffer
* strcpy(buffer, "some data");
*
* // expand buffer
* buffer = icalmemory_resize_buffer(buffer, 20);
*
* // fill with more data
* strcpy(buffer, "a lot more data");
*
* // release
* icalmemory_free_buffer(buffer);
* ```
*/
LIBICAL_ICAL_EXPORT void *icalmemory_resize_buffer(void *buf, size_t size);
/**
* @brief Releases a buffer
* @param buf The buffer to release
* @sa icalmemory_new_buffer()
*
* Releases the memory of the buffer.
*/
LIBICAL_ICAL_EXPORT void icalmemory_free_buffer(void *buf);
/* THESE ROUTINES CAN NOT BE USED ON TMP BUFFERS. Only use them on
normally allocated memory, or on buffers created from
icalmemory_new_buffer, never with buffers created by
icalmemory_tmp_buffer. If icalmemory_append_string has to resize a
buffer on the ring, the ring will loose track of it an you will
have memory problems. */
/**
* @brief Append a string to a buffer.
* @param buf The buffer to append the string to.
* @param pos The position to append the string at.
* @param buf_size The size of the buffer (will be changed if buffer is
* reallocated)
* @param string The string to append to the buffer.
* @warn This method may not be used for temporary buffers (buffers allocated
* with icalmemory_tmp_buffer() and related functions)!
*
* @par Error handling
* Sets ::icalerrno to ::ICAL_BADARG_ERROR if @a buf, `*buf`, @a pos, `* pos`,
* @a buf_size or @a string are `NULL`.
*
* This method will copy the string @a string to the buffer @a buf starting at
* position @a pos, reallocing @a buf if it is too small. @a buf_size is the
* size of @a buf and will be changed if @a buf is reallocated. @a pos will
* point to the last byte of the new string in @a buf, usually a `'\0'`
*
* ### Example
* ```c
* // creates a new buffer
* int buffer_len = 15;
* char *buffer = icalmemory_new_buffer(buffer_len);
* strcpy(buffer, "My name is: ");
*
* // append a string to the buffer
* int buffer_end = strlen(buffer);
* char *buffer_end_pos = buffer[buffer_str_end];
* icalmemory_append_string(&buffer, &buffer_end_pos, &buffer_len, "John Doe");
*
* // print string
* printf("%s\n", buffer);
*
* // release memory
* icalmemory_free_buffer(buffer);
* ```
*/
LIBICAL_ICAL_EXPORT void icalmemory_append_string(char **buf, char **pos, size_t *buf_size,
const char *string);
/**
* @brief Append a character to a buffer.
* @param buf The buffer to append the character to.
* @param pos The position to append the character at.
* @param buf_size The size of the buffer (will be changed if buffer is
* reallocated)
* @param ch The character to append to the buffer.
* @warn This method may not be used for temporary buffers (buffers allocated
* with icalmemory_tmp_buffer() and related functions)!
*
* @par Error handling
* Sets ::icalerrno to ::ICAL_BADARG_ERROR if @a buf, `*buf`, @a pos, `* pos`,
* or @a buf_size `NULL`.
*
* This method will copy the character @a ch and a `'\0'` character after it to
* the buffer @a buf starting at position @a pos, reallocing @a buf if it is too
* small. @a buf_size is the size of @a buf and will be changed if @a buf is
* reallocated. @a pos will point to the new terminating `'\0'` character @a
* buf.
*
* ### Example
* ```c
* // creates a new buffer
* int buffer_len = 15;
* char *buffer = icalmemory_new_buffer(buffer_len);
* strcpy(buffer, "My number is: ");
*
* // append a char to the buffer
* int buffer_end = strlen(buffer);
* char *buffer_end_pos = buffer[buffer_str_end];
* icalmemory_append_char(&buffer, &buffer_end_pos, &buffer_len, '7');
*
* // print string
* printf("%s\n", buffer);
*
* // release memory
* icalmemory_free_buffer(buffer);
* ```
*/
LIBICAL_ICAL_EXPORT void icalmemory_append_char(char **buf, char **pos, size_t *buf_size, char ch);
/**
* @brief Create a duplicate of a string.
* @param s The string to duplicate.
* @return A pointer to a string containing the same data as @a s
*
* @par Error handling
* The string @a s must not be `NULL`, otherwise depending on the `libc` used,
* it might lead to undefined behaviour (read: segfaults).
*
* @par Ownership
* The returned string is owned by the caller and needs to be released with the
* appropriate `free()` method.
*
* A wrapper around `strdup()`. Partly to trap calls to `strdup()`, partly
* because in `-ansi`, `gcc` on Red Hat claims that `strdup()` is undeclared.
*
* ### Usage
* ```c
* const char *my_str = "LibIcal";
* char *dup = icalmemory_strdup(my_str);
* printf("%s\n", dup);
* free(dup);
* ```
*/
LIBICAL_ICAL_EXPORT char *icalmemory_strdup(const char *s);
#endif /* !ICALMEMORY_H */
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