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/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#ifndef INCLUDE_git_userbuf_h__
#define INCLUDE_git_userbuf_h__
#include "common.h"
/**
* @file git2/userbuf.h
* @brief Buffer export structure
*
* @ingroup Git
* @{
*/
GIT_BEGIN_DECL
/** An optional initialization macro for `git_userbuf` objects. */
#define GIT_USERBUF_INIT { NULL, 0, 0 }
/** A constant initialization macro for `git_userbuf` objects. */
#define GIT_USERBUF_CONST(str, len) { (char *)(str), 0, (size_t)(len) }
/**
* A data buffer for exporting data from libgit2.
*
* Sometimes libgit2 wants to return an allocated data buffer to the
* caller and allow the caller take responsibility for its lifecycle.
* This requires the caller to free the memory with `git_userbuf_dispose`
* when they have finished using it.
*/
typedef struct {
/**
* The buffer's contents. This is a NUL terminated C string.
*/
char *ptr;
/**
* This is the allocated size of the allocated buffer. For
* buffers returned to you from libgit2, you should not
* modify this value. For any buffer that you pass to
* libgit2, this remain 0.
*/
size_t asize;
/**
* The size (in bytes) of the data in the buffer, not including
* the NUL terminating character.
*/
size_t size;
} git_userbuf;
/**
* Check quickly if buffer looks like it contains binary data
*
* @param buf Buffer to check
* @return 1 if buffer looks like non-text data
*/
GIT_EXTERN(int) git_userbuf_is_binary(const git_userbuf *buf);
/**
* Check quickly if buffer contains a NUL byte
*
* @param buf Buffer to check
* @return 1 if buffer contains a NUL byte
*/
GIT_EXTERN(int) git_userbuf_contains_nul(const git_userbuf *buf);
/**
* Places the given data in the buffer. This is necessary for some
* callback functions that take user data. If there is already data in
* the buffer, you should call `git_userbuf_dispose` before setting the
* buffer data.
*
* @param buf The buffer to place data into
* @param ptr The data to place in the buffer
* @param len The length of the data in bytes
*/
GIT_EXTERN(int) git_userbuf_set(git_userbuf *buf, const void *ptr, size_t len);
/**
* Resize the buffer allocation to make more space.
*
* This will attempt to grow the buffer to accommodate the target size.
*
* If the buffer refers to memory that was not allocated by libgit2 (i.e.
* the `asize` field is zero), then `ptr` will be replaced with a newly
* allocated block of data. Be careful so that memory allocated by the
* caller is not lost. As a special variant, if you pass `target_size` as
* 0 and the memory is not allocated by libgit2, this will allocate a new
* buffer of size `size` and copy the external data into it.
*
* Currently, this will never shrink a buffer, only expand it.
*
* If the allocation fails, this will return an error and the buffer will be
* marked as invalid for future operations, invaliding the contents.
*
* @param buffer The buffer to be resized; may or may not be allocated yet
* @param target_size The desired available size
* @return 0 on success, -1 on allocation failure
*/
GIT_EXTERN(int) git_userbuf_grow(git_userbuf *buffer, size_t target_size);
/**
* Free the memory referred to by the git_userbuf.
*
* @param buf The buffer to deallocate
*/
GIT_EXTERN(void) git_userbuf_dispose(git_userbuf *buf);
GIT_END_DECL
/** @} */
#endif
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