text: /*
   * 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 line hashes for a buffer
   */
  typedef struct git_hashsig git_hashsig;
  
  typedef enum {
  	GIT_HASHSIG_NORMAL = 0, /* use all data */
  	GIT_HASHSIG_IGNORE_WHITESPACE = 1, /* ignore whitespace */
  	GIT_HASHSIG_SMART_WHITESPACE = 2, /* ignore \r and all space after \n */
  } git_hashsig_option_t;
  
  /**
   * Build a similarity signature for a buffer
   *
   * If you have passed a whitespace-ignoring buffer, then the whitespace
   * will be removed from the buffer while it is being processed, modifying
   * the buffer in place.  Sorry about that!
   *
   * This will return an error if the buffer doesn't contain enough data to
   * compute a valid signature.
   *
   * @param out The array of hashed runs representing the file content
   * @param buf The contents of the file to hash
   * @param buflen The length of the data at `buf`
   * @param generate_pairwise_hashes Should pairwise runs be hashed
   */
  GIT_EXTERN(int) git_hashsig_create(
  	git_hashsig **out,
  	const char *buf,
  	size_t buflen,
  	git_hashsig_option_t opts);
  
  /**
   * Build a similarity signature from a 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`.
   *
   * This will return an error if the file doesn't contain enough data to
   * compute a valid signature.
   */
  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
   */
  GIT_EXTERN(void) git_hashsig_free(git_hashsig *sig);
  
  /**
   * Measure similarity between two files
   *
   * @return <0 for error, [0 to 100] as similarity score
   */
  GIT_EXTERN(int) git_hashsig_compare(
  	const git_hashsig *a,
  	const git_hashsig *b);
  
  GIT_END_DECL
  
  #endif
  