/*
   * Cryptographic API.
   *
   * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
   * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License as published by the Free
   * Software Foundation; either version 2 of the License, or (at your option)
   * any later version.
   *
   */
  
  #ifndef _CRYPTO_SCATTERWALK_H
  #define _CRYPTO_SCATTERWALK_H

  #include <linux/mm.h>

  #include <linux/scatterlist.h>

  #include "internal.h"

  static inline struct scatterlist *sg_next(struct scatterlist *sg)
  {

  	return (++sg)->length ? sg : (void *)sg->page;

  }

  static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
  						struct scatter_walk *walk_out)

  {

  	return !(((walk_in->sg->page - walk_out->sg->page) << PAGE_SHIFT) +
  		 (int)(walk_in->offset - walk_out->offset));
  }
  
  static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
  {
  	unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
  	unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
  	return len_this_page > len ? len : len_this_page;

  }

  static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
  					     unsigned int nbytes)

  {

  	unsigned int len_this_page = scatterwalk_pagelen(walk);
  	return nbytes > len_this_page ? len_this_page : nbytes;

  }
  
  static inline void scatterwalk_advance(struct scatter_walk *walk,
  				       unsigned int nbytes)
  {

  	walk->offset += nbytes;

  }

  static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
  					       unsigned int alignmask)
  {
  	return !(walk->offset & alignmask);
  }

  static inline struct page *scatterwalk_page(struct scatter_walk *walk)
  {
  	return walk->sg->page + (walk->offset >> PAGE_SHIFT);
  }
  
  static inline void scatterwalk_unmap(void *vaddr, int out)
  {
  	crypto_kunmap(vaddr, out);
  }

  void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);

  void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
  			    size_t nbytes, int out);
  void *scatterwalk_map(struct scatter_walk *walk, int out);

  void scatterwalk_done(struct scatter_walk *walk, int out, int more);
  
  #endif  /* _CRYPTO_SCATTERWALK_H */