(1 . 31)(1 . 33)
/* mpicoder.c  -  Coder for the external representation of MPIs
 * Copyright (C) 1998, 1999, 2005 Free Software Foundation, Inc.
 * Modified by No Such Labs. (C) 2015. See README.
 *
 * This file is part of GnuPG.
 * This file was originally part of Gnu Privacy Guard (GPG), ver. 1.4.10,
 * SHA256(gnupg-1.4.10.tar.gz):
 *        0bfd74660a2f6cedcf7d8256db4a63c996ffebbcdc2cf54397bfb72878c5a85a
 * (C) 1994-2005 Free Software Foundation, Inc.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * 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 3 of the License, or
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * GnuPG is distributed in the hope that it will be useful,
 * This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>

#include "knobs.h"
#include "mpi.h"
#include "mpi-internal.h"
#include "iobuf.h"
#include "memory.h"
#include "util.h"

(35 . 110)(37 . 6)

#define MAX_EXTERN_MPI_BITS 16384

/****************
 * write an mpi to out.
 */
int
mpi_write( IOBUF out, MPI a )
{
    int rc;
    unsigned nbits = mpi_get_nbits(a);
    byte *p, *buf;
    unsigned n;

    if( nbits > MAX_EXTERN_MPI_BITS )
	log_bug("mpi_encode: mpi too large (%u bits)\n", nbits);

    iobuf_put(out, (nbits >>8) );
    iobuf_put(out, (nbits) );

    p = buf = mpi_get_buffer( a, &n, NULL );
    rc = iobuf_write( out, p, n );
    xfree(buf);
    return rc;
}


/****************
 * Read an external representation of an mpi and return the MPI
 * The external format is a 16 bit unsigned value stored in network byte order,
 * giving the number of bits for the following integer. The integer is stored
 * with MSB first (left padded with zeroes to align on a byte boundary).
 */
MPI
#ifdef M_DEBUG
mpi_debug_read(IOBUF inp, unsigned *ret_nread, int secure, const char *info)
#else
mpi_read(IOBUF inp, unsigned *ret_nread, int secure)
#endif
{
    int c, i, j;
    unsigned int nmax = *ret_nread;
    unsigned nbits, nbytes, nlimbs, nread=0;
    mpi_limb_t a;
    MPI val = NULL;

    if (nread == nmax)
        goto overflow;
    if( (c = iobuf_get(inp)) == -1 )
	goto leave;
    nread++;
    nbits = c << 8;

    if (nread == nmax)
        goto overflow;
    if( (c = iobuf_get(inp)) == -1 )
	goto leave;
    nread++;
    nbits |= c;

    if( nbits > MAX_EXTERN_MPI_BITS ) {
	log_error("mpi too large for this implementation (%u bits)\n", nbits);
	goto leave;
    }

    nbytes = (nbits+7) / 8;
    nlimbs = (nbytes+BYTES_PER_MPI_LIMB-1) / BYTES_PER_MPI_LIMB;
#ifdef M_DEBUG
    val = secure? mpi_debug_alloc_secure( nlimbs, info )
		: mpi_debug_alloc( nlimbs, info );
#else
    val = secure? mpi_alloc_secure( nlimbs )
		: mpi_alloc( nlimbs );
#endif
    i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
    i %= BYTES_PER_MPI_LIMB;
    val->nbits = nbits;
    j= val->nlimbs = nlimbs;
    val->sign = 0;
    for( ; j > 0; j-- ) {
	a = 0;
	for(; i < BYTES_PER_MPI_LIMB; i++ ) {
            if (nread == nmax) {
#ifdef M_DEBUG
                mpi_debug_free (val);
#else
                mpi_free (val);
#endif
                val = NULL;
                goto overflow;
            }
	    a <<= 8;
	    a |= iobuf_get(inp) & 0xff; nread++;
	}
	i = 0;
	val->d[j-1] = a;
    }

  leave:
    *ret_nread = nread;
    return val;
  overflow:
    log_error ("mpi larger than indicated length (%u bytes)\n", nmax);
    *ret_nread = nread;
    return val;
}


MPI
mpi_read_from_buffer(byte *buffer, unsigned int *ret_nread, int secure)
(309 . 6)(207 . 7)
}


/*
void
g10_log_mpidump( const char *text, MPI a )
{
(318 . 31)(217 . 7)
    mpi_print(fp, a, 1 );
    fputc('\n', fp);
}

/****************
 * Special function to get the low 8 bytes from an mpi.
 * This can be used as a keyid; KEYID is an 2 element array.
 * Return the low 4 bytes.
 */
u32
mpi_get_keyid( MPI a, u32 *keyid )
{
#if BYTES_PER_MPI_LIMB == 4
    if( keyid ) {
	keyid[0] = a->nlimbs >= 2? a->d[1] : 0;
	keyid[1] = a->nlimbs >= 1? a->d[0] : 0;
    }
    return a->nlimbs >= 1? a->d[0] : 0;
#elif BYTES_PER_MPI_LIMB == 8
    if( keyid ) {
	keyid[0] = a->nlimbs? (u32)(a->d[0] >> 32) : 0;
	keyid[1] = a->nlimbs? (u32)(a->d[0] & 0xffffffff) : 0;
    }
    return a->nlimbs? (u32)(a->d[0] & 0xffffffff) : 0;
#else
#error Make this function work with other LIMB sizes
#endif
}
*/


/****************