/* -*-C-*-

$Id: prmhash.c,v 11.12 2007/04/22 16:31:23 cph Exp $

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme 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.

MIT/GNU Scheme is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
USA.

*/

/* Interface to mhash library */

#include "scheme.h"
#include "prims.h"
#include "usrdef.h"
#include "os.h"

/* If mhash.h unavailable, ignore it.  This helps
   "makegen/makegen.scm" work properly on systems lacking this
   library.  */
#ifdef HAVE_MHASH_H
#  include <mhash.h>
#endif

#define UNARY_OPERATION(name, get_arg, cvt_val)				\
{									\
  PRIMITIVE_HEADER (1);							\
  PRIMITIVE_RETURN (cvt_val (name (get_arg (1))));			\
}

static SCHEME_OBJECT
cp2s (void * cp)
{
  if (cp == 0)
    return (SHARP_F);
  else
    {
      SCHEME_OBJECT s = (char_pointer_to_string (cp));
      free (cp);
      return (s);
    }
}

typedef struct
{
  MHASH context;
  hashid id;
} context_entry;

static size_t context_table_length = 0;
static context_entry * context_table = 0;

static size_t
search_context_table (MHASH context)
{
  size_t i;
  for (i = 0; (i < context_table_length); i += 1)
    if (((context_table[i]) . context) == context)
      break;
  return (i);
}

static size_t
allocate_context_entry (void)
{
  size_t i = (search_context_table (0));
  if (i < context_table_length)
    return (i);
  if (i == 0)
    {
      context_table_length = 256;
      context_table
	= (OS_malloc ((sizeof (context_entry)) * context_table_length));
    }
  else
    {
      context_table_length *= 2;
      context_table
	= (OS_realloc (context_table,
		       ((sizeof (context_entry)) * context_table_length)));
    }
  {
    size_t j;
    for (j = i; (j < context_table_length); j += 1)
      ((context_table[j]) . context) = 0;
  }
  return (i);
}

static SCHEME_OBJECT
store_context (MHASH context, hashid id)
{
  if (context == MHASH_FAILED)
    return (SHARP_F);
  {
    size_t i = (allocate_context_entry ());
    ((context_table[i]) . context) = context;
    ((context_table[i]) . id) = id;
    return (ulong_to_integer (i));
  }
}

static void
forget_context (size_t index)
{
  ((context_table[index]) . context) = 0;
}

static size_t
arg_context_index (unsigned int arg)
{
  unsigned long n = (arg_ulong_index_integer (arg, context_table_length));
  if (((context_table[n]) . context) == 0)
    error_bad_range_arg (arg);
  return (n);
}

static MHASH
arg_context (unsigned int arg)
{
  return ((context_table [arg_context_index (arg)]) . context);
}

static size_t hashid_count;
static hashid * hashid_map = 0;

static void
initialize_hashid_map (void)
{
  if (hashid_map == 0)
    {
      size_t i = 0;
      size_t j = 0;
      hashid_count = (mhash_count ());
      hashid_map = (OS_malloc ((sizeof (hashid)) * hashid_count));
      while (i <= hashid_count)
	{
	  if ((mhash_get_block_size (i)) != 0)
	    (hashid_map[j++]) = ((hashid) i);
	  i += 1;
	}
    }
}

static hashid
arg_hashid (unsigned int arg)
{
  initialize_hashid_map ();
  return (hashid_map [arg_ulong_index_integer (arg, hashid_count)]);
}

DEFINE_PRIMITIVE ("MHASH_COUNT", Prim_mhash_count, 0, 0, 0)
{
  PRIMITIVE_HEADER (0);
  initialize_hashid_map ();
  PRIMITIVE_RETURN (ulong_to_integer (hashid_count));
}

DEFINE_PRIMITIVE ("MHASH_GET_BLOCK_SIZE", Prim_mhash_get_block_size, 1, 1, 0)
  UNARY_OPERATION (mhash_get_block_size, arg_hashid, ulong_to_integer)
DEFINE_PRIMITIVE ("MHASH_GET_HASH_PBLOCK", Prim_mhash_get_hash_pblock, 1, 1, 0)
  UNARY_OPERATION (mhash_get_hash_pblock, arg_hashid, ulong_to_integer)
DEFINE_PRIMITIVE ("MHASH_GET_HASH_NAME", Prim_mhash_get_hash_name, 1, 1, 0)
  UNARY_OPERATION (mhash_get_hash_name, arg_hashid, cp2s)

DEFINE_PRIMITIVE ("MHASH_INIT", Prim_mhash_init, 1, 1, 0)
{
  PRIMITIVE_HEADER (1);
  {
    hashid id = (arg_hashid (1));
    PRIMITIVE_RETURN (store_context ((mhash_init (id)), id));
  }
}

DEFINE_PRIMITIVE ("MHASH_HMAC_INIT", Prim_mhash_hmac_init, 3, 3, 0)
{
  PRIMITIVE_HEADER (3);
  CHECK_ARG (2, STRING_P);
  {
    hashid id = (arg_hashid (1));
    SCHEME_OBJECT key = (ARG_REF (2));
    PRIMITIVE_RETURN
      (store_context ((mhash_hmac_init (id,
					(STRING_POINTER (key)),
					(STRING_LENGTH (key)),
					(arg_ulong_integer (3)))),
		      id));
  }
}

DEFINE_PRIMITIVE ("MHASH", Prim_mhash, 4, 4, 0)
{
  PRIMITIVE_HEADER (4);
  CHECK_ARG (2, STRING_P);
  {
    SCHEME_OBJECT string = (ARG_REF (2));
    unsigned long l = (STRING_LENGTH (string));
    unsigned long start = (arg_ulong_index_integer (3, l));
    unsigned long end = (arg_integer_in_range (4, start, (l + 1)));
    mhash ((arg_context (1)), (STRING_LOC (string, start)), (end - start));
  }
  PRIMITIVE_RETURN (UNSPECIFIC);
}

DEFINE_PRIMITIVE ("MHASH_END", Prim_mhash_end, 1, 1, 0)
{
  PRIMITIVE_HEADER (1);
  {
    size_t index = (arg_context_index (1));
    MHASH context = ((context_table[index]) . context);
    hashid id = ((context_table[index]) . id);
    size_t block_size = (mhash_get_block_size (id));
    /* Must allocate string _before_ calling mhash_end.  */
    SCHEME_OBJECT sd = (allocate_string (block_size));
    void * digest = (mhash_end (context));
    forget_context (index);
    memcpy ((STRING_POINTER (sd)), digest, block_size);
    free (digest);
    PRIMITIVE_RETURN (sd);
  }
}

DEFINE_PRIMITIVE ("MHASH_HMAC_END", Prim_mhash_hmac_end, 1, 1, 0)
{
  PRIMITIVE_HEADER (1);
  {
    size_t index = (arg_context_index (1));
    MHASH context = ((context_table[index]) . context);
    hashid id = ((context_table[index]) . id);
    size_t block_size = (mhash_get_block_size (id));
    /* Must allocate string _before_ calling mhash_hmac_end.  */
    SCHEME_OBJECT sd = (allocate_string (block_size));
    void * digest = (mhash_hmac_end (context));
    forget_context (index);
    memcpy ((STRING_POINTER (sd)), digest, block_size);
    free (digest);
    PRIMITIVE_RETURN (sd);
  }
}

static size_t keygenid_count;
static keygenid * keygenid_map = 0;

static void
initialize_keygenid_map (void)
{
  if (keygenid_map == 0)
    {
      size_t i = 0;
      size_t j = 0;
      keygenid_count = (mhash_keygen_count ());
      keygenid_map = (OS_malloc ((sizeof (keygenid)) * keygenid_count));
      while (j < keygenid_count)
	{
	  void * name = (mhash_get_keygen_name (i));
	  if (name != 0)
	    {
	      (keygenid_map[j++]) = ((keygenid) i);
	      free (name);
	    }
	  i += 1;
	}
    }
}

static keygenid
arg_keygenid (unsigned int arg)
{
  initialize_keygenid_map ();
  return (keygenid_map [arg_ulong_index_integer (arg, keygenid_count)]);
}

DEFINE_PRIMITIVE ("MHASH_KEYGEN_COUNT", Prim_mhash_keygen_count, 0, 0, 0)
{
  PRIMITIVE_HEADER (0);
  initialize_keygenid_map ();
  PRIMITIVE_RETURN (ulong_to_integer (keygenid_count));
}

DEFINE_PRIMITIVE ("MHASH_GET_KEYGEN_NAME", Prim_mhash_get_keygen_name, 1, 1, 0)
  UNARY_OPERATION (mhash_get_keygen_name, arg_keygenid, cp2s)
DEFINE_PRIMITIVE ("MHASH_KEYGEN_USES_SALT", Prim_mhash_keygen_uses_salt, 1, 1, 0)
  UNARY_OPERATION (mhash_keygen_uses_salt, arg_keygenid, BOOLEAN_TO_OBJECT)
DEFINE_PRIMITIVE ("MHASH_KEYGEN_USES_COUNT", Prim_mhash_keygen_uses_count, 1, 1, 0)
  UNARY_OPERATION (mhash_keygen_uses_count, arg_keygenid, BOOLEAN_TO_OBJECT)
DEFINE_PRIMITIVE ("MHASH_KEYGEN_USES_HASH_ALGORITHM", Prim_mhash_keygen_uses_hash_algorithm, 1, 1, 0)
  UNARY_OPERATION (mhash_keygen_uses_hash_algorithm, arg_keygenid, long_to_integer)
DEFINE_PRIMITIVE ("MHASH_GET_KEYGEN_SALT_SIZE", Prim_mhash_get_keygen_salt_size, 1, 1, 0)
  UNARY_OPERATION (mhash_get_keygen_salt_size, arg_keygenid, ulong_to_integer)
DEFINE_PRIMITIVE ("MHASH_GET_KEYGEN_MAX_KEY_SIZE", Prim_mhash_get_keygen_max_key_size, 1, 1, 0)
  UNARY_OPERATION (mhash_get_keygen_max_key_size, arg_keygenid, ulong_to_integer)

DEFINE_PRIMITIVE ("MHASH_KEYGEN", Prim_mhash_keygen, 4, 4, 0)
{
  /* keygen-id #(salt count hashid ...) keyword passphrase */
  PRIMITIVE_HEADER (4);
  CHECK_ARG (2, VECTOR_P);
  CHECK_ARG (3, STRING_P);
  CHECK_ARG (4, STRING_P);
  {
    keygenid id = (arg_keygenid (1));
    SCHEME_OBJECT parameters = (ARG_REF (2));
    SCHEME_OBJECT keyword = (ARG_REF (3));
    SCHEME_OBJECT passphrase = (ARG_REF (4));
    unsigned int n_algs = (mhash_keygen_uses_hash_algorithm (id));
    SCHEME_OBJECT salt;
    SCHEME_OBJECT count;
    KEYGEN cparms;
    {
      size_t max_key_size = (mhash_get_keygen_max_key_size (id));
      if ((max_key_size != 0) && ((STRING_LENGTH (keyword)) > max_key_size))
	error_bad_range_arg (4);
    }
    if ((VECTOR_LENGTH (parameters)) != (2 + n_algs))
      error_bad_range_arg (2);
    salt = (VECTOR_REF (parameters, 0));
    count = (VECTOR_REF (parameters, 1));
    if (mhash_keygen_uses_salt (id))
      {
	if (!STRING_P (salt))
	  error_bad_range_arg (2);
	{
	  size_t salt_size = (mhash_get_keygen_salt_size (id));
	  if ((salt_size != 0) && ((STRING_LENGTH (salt)) != salt_size))
	    error_bad_range_arg (2);
	}
	(cparms . salt) = (STRING_BYTE_PTR (salt));
	(cparms . salt_size) = (STRING_LENGTH (salt));
      }
    else if (salt != SHARP_F)
      error_bad_range_arg (2);
    if (mhash_keygen_uses_count (id))
      {
	if (!integer_to_ulong_p (count))
	  error_bad_range_arg (2);
	(cparms . count) = (integer_to_ulong (count));
      }
    else if (count != SHARP_F)
      error_bad_range_arg (2);
    {
      unsigned int i;
      initialize_hashid_map ();
      for (i = 0; (i < n_algs); i += 1)
	{
	  SCHEME_OBJECT a = (VECTOR_REF (parameters, (2 + i)));
	  if (!integer_to_ulong_p (a))
	    error_bad_range_arg (2);
	  {
	    unsigned long ia = (integer_to_ulong (a));
	    if (ia < hashid_count)
	      ((cparms . hash_algorithm) [i]) = (hashid_map[ia]);
	    else
	      error_bad_range_arg (2);
	  }
	}
    }
    PRIMITIVE_RETURN
      (BOOLEAN_TO_OBJECT
       ((mhash_keygen_ext (id, cparms,
			   (STRING_POINTER (keyword)),
			   (STRING_LENGTH (keyword)),
			   (STRING_BYTE_PTR (passphrase)),
			   (STRING_LENGTH (passphrase))))
	== 0));
  }
}

#ifdef COMPILE_AS_MODULE

char *
dload_initialize_file (void)
{
  declare_primitive
    ("MHASH_COUNT", Prim_mhash_count, 0, 0, 0);
  declare_primitive
    ("MHASH_GET_BLOCK_SIZE", Prim_mhash_get_block_size, 1, 1, 0);
  declare_primitive
    ("MHASH_GET_HASH_PBLOCK", Prim_mhash_get_hash_pblock, 1, 1, 0);
  declare_primitive
    ("MHASH_GET_HASH_NAME", Prim_mhash_get_hash_name, 1, 1, 0);
  declare_primitive
    ("MHASH_INIT", Prim_mhash_init, 1, 1, 0);
  declare_primitive
    ("MHASH_HMAC_INIT", Prim_mhash_hmac_init, 3, 3, 0);
  declare_primitive
    ("MHASH", Prim_mhash, 4, 4, 0);
  declare_primitive
    ("MHASH_END", Prim_mhash_end, 1, 1, 0);
  declare_primitive
    ("MHASH_HMAC_END", Prim_mhash_hmac_end, 1, 1, 0);
  declare_primitive
    ("MHASH_KEYGEN_COUNT", Prim_mhash_keygen_count, 0, 0, 0);
  declare_primitive
    ("MHASH_GET_KEYGEN_NAME", Prim_mhash_get_keygen_name, 1, 1, 0);
  declare_primitive
    ("MHASH_KEYGEN_USES_SALT", Prim_mhash_keygen_uses_salt, 1, 1, 0);
  declare_primitive
    ("MHASH_KEYGEN_USES_COUNT", Prim_mhash_keygen_uses_count, 1, 1, 0);
  declare_primitive
    ("MHASH_KEYGEN_USES_HASH_ALGORITHM", Prim_mhash_keygen_uses_hash_algorithm, 1, 1, 0);
  declare_primitive
    ("MHASH_GET_KEYGEN_SALT_SIZE", Prim_mhash_get_keygen_salt_size, 1, 1, 0);
  declare_primitive
    ("MHASH_GET_KEYGEN_MAX_KEY_SIZE", Prim_mhash_get_keygen_max_key_size, 1, 1, 0);
  declare_primitive
     ("MHASH_KEYGEN", Prim_mhash_keygen, 4, 4, 0);
  return "#prmd5";
}

#endif /* COMPILE_AS_MODULE */
