/*

 * 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_sys_hashsig_h__

#define INCLUDE_sys_hashsig_h__

#include "git2/common.h"

GIT_BEGIN_DECL

/**

 * Similarity signature of arbitrary text content based on line hashes

 */

typedef struct git_hashsig git_hashsig;

/**

 * Options for hashsig computation

 *

 * The options GIT_HASHSIG_NORMAL, GIT_HASHSIG_IGNORE_WHITESPACE,

 * GIT_HASHSIG_SMART_WHITESPACE are exclusive and should not be combined.

 */

typedef enum {

	/**

	 * Use all data

	 */

	GIT_HASHSIG_NORMAL = 0,

	/**

	 * Ignore whitespace

	 */

	GIT_HASHSIG_IGNORE_WHITESPACE = (1 << 0),

	/**

	 * Ignore \r and all space after \n

	 */

	GIT_HASHSIG_SMART_WHITESPACE = (1 << 1),

	/**

	 * Allow hashing of small files

	 */

	GIT_HASHSIG_ALLOW_SMALL_FILES = (1 << 2)

} git_hashsig_option_t;

/**

 * Compute a similarity signature for a text buffer

 *

 * If you have passed the option GIT_HASHSIG_IGNORE_WHITESPACE, then the

 * whitespace will be removed from the buffer while it is being processed,

 * modifying the buffer in place. Sorry about that!

 *

 * @param out The computed similarity signature.

 * @param buf The input buffer.

 * @param buflen The input buffer size.

 * @param opts The signature computation options (see above).

 * @return 0 on success, GIT_EBUFS if the buffer doesn't contain enough data to

 * compute a valid signature (unless GIT_HASHSIG_ALLOW_SMALL_FILES is set), or

 * error code.

 */

GIT_EXTERN(int) git_hashsig_create(

	git_hashsig **out,

	const char *buf,

	size_t buflen,

	git_hashsig_option_t opts);

/**

 * Compute a similarity signature for a text file

 *

 * This walks through the file, only loading a maximum of 4K of file data at

 * a time. Otherwise, it acts just like `git_hashsig_create`.

 *

 * @param out The computed similarity signature.

 * @param path The path to the input file.

 * @param opts The signature computation options (see above).

 * @return 0 on success, GIT_EBUFS if the buffer doesn't contain enough data to

 * compute a valid signature (unless GIT_HASHSIG_ALLOW_SMALL_FILES is set), or

 * error code.

 */

GIT_EXTERN(int) git_hashsig_create_fromfile(

	git_hashsig **out,

	const char *path,

	git_hashsig_option_t opts);

/**

 * Release memory for a content similarity signature

 *

 * @param sig The similarity signature to free.

 */

GIT_EXTERN(void) git_hashsig_free(git_hashsig *sig);

/**

 * Measure similarity score between two similarity signatures

 *

 * @param a The first similarity signature to compare.

 * @param b The second similarity signature to compare.

 * @return [0 to 100] on success as the similarity score, or error code.

 */

GIT_EXTERN(int) git_hashsig_compare(

	const git_hashsig *a,

	const git_hashsig *b);

GIT_END_DECL

#endif