Uprating of the passphrase pixie.

[u/mdw/catacomb] / buf.c

/* -*-c-*-
 *
 * $Id$
 *
 * Buffer handling
 *
 * (c) 2001 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * Catacomb 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 Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include <string.h>

#include "mp.h"
#include "ec.h"
#include "buf.h"

/*----- Main code ---------------------------------------------------------*/

/* --- @buf_init@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @void *p@ = pointer to a buffer
 *              @size_t sz@ = size of the buffer
 *
 * Returns:     ---
 *
 * Use:         Initializes the buffer block appropriately.
 */

void buf_init(buf *b, void *p, size_t sz)
{
  b->base = b->p = p;
  b->limit = b->p + sz;
  b->f = 0;
}

/* --- @buf_break@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *
 * Returns:     Some negative value.
 *
 * Use:         Marks a buffer as broken.
 */

int buf_break(buf *b) { b->f |= BF_BROKEN; return (-1); }

/* --- @buf_flip@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *
 * Returns:     ---
 *
 * Use:         Flips a buffer so that if you've just been writing to it,
 *              you can now read from the bit you've written.
 */

void buf_flip(buf *b)
{
  b->limit = b->p;
  b->p = b->base;
}

/* --- @buf_ensure@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @size_t sz@ = size of data wanted
 *
 * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:         Ensures that there are @sz@ bytes still in the buffer.
 */

int buf_ensure(buf *b, size_t sz) { return (BENSURE(b, sz)); }

/* --- @buf_get@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @size_t sz@ = size of the buffer
 *
 * Returns:     Pointer to the place in the buffer.
 *
 * Use:         Reserves a space in the buffer of the requested size, and
 *              returns its start address.
 */

void *buf_get(buf *b, size_t sz)
{
  void *p;
  if (BENSURE(b, sz))
    return (0);
  p = BCUR(b);
  BSTEP(b, sz);
  return (p);
}

/* --- @buf_put@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @const void *p@ = pointer to a buffer
 *              @size_t sz@ = size of the buffer
 *
 * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:         Fetches data from some place and puts it in the buffer
 */

int buf_put(buf *b, const void *p, size_t sz)
{
  if (BENSURE(b, sz))
    return (-1);
  memcpy(BCUR(b), p, sz);
  BSTEP(b, sz);
  return (0);
}

/* --- @buf_getbyte@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *
 * Returns:     A byte, or less than zero if there wasn't a byte there.
 *
 * Use:         Gets a single byte from a buffer.
 */

int buf_getbyte(buf *b)
{
  if (BENSURE(b, 1))
    return (-1);
  return (*b->p++);
}

/* --- @buf_putbyte@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @int ch@ = byte to write
 *
 * Returns:     Zero if OK, nonzero if there wasn't enough space.
 *
 * Use:         Puts a single byte in a buffer.
 */

int buf_putbyte(buf *b, int ch)
{
  if (BENSURE(b, 1))
    return (-1);
  *b->p++ = ch;
  return (0);
}

/* --- @buf_getu16@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @uint16 *w@ = where to put the word
 *
 * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 *
 * Use:         Gets a 16-bit word from a buffer.
 */

int buf_getu16(buf *b, uint16 *w)
{
  if (BENSURE(b, 2))
    return (-1);
  *w = LOAD16(b->p);
  BSTEP(b, 2);
  return (0);
}

/* --- @buf_putu16@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @uint16 w@ = word to write
 *
 * Returns:     Zero if OK, nonzero if there wasn't enough space.
 *
 * Use:         Puts a 16-but word in a buffer.
 */

int buf_putu16(buf *b, uint16 w)
{
  if (BENSURE(b, 2))
    return (-1);
  STORE16(b->p, w);
  BSTEP(b, 2);
  return (0);
}

/* --- @buf_getu32@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @uint32 *w@ = where to put the word
 *
 * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 *
 * Use:         Gets a 32-bit word from a buffer.
 */

int buf_getu32(buf *b, uint32 *w)
{
  if (BENSURE(b, 4))
    return (-1);
  *w = LOAD32(b->p);
  BSTEP(b, 4);
  return (0);
}

/* --- @buf_putu32@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @uint32 w@ = word to write
 *
 * Returns:     Zero if OK, nonzero if there wasn't enough space.
 *
 * Use:         Puts a 32-but word in a buffer.
 */

int buf_putu32(buf *b, uint32 w)
{
  if (BENSURE(b, 4))
    return (-1);
  STORE32(b->p, w);
  BSTEP(b, 4);
  return (0);
}

/* --- @findz@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @size_t *nn@ = where to put the length
 *
 * Returns:     Zero if OK, nonzero if there wasn't a null byte to be found.
 *
 * Use:         Finds a terminating null byte.
 */

static int findz(buf *b, size_t *nn)
{
  octet *p;

  if ((p = memchr(BCUR(b), 0, BLEN(b))) == 0) {
    buf_break(b);
    return (-1);
  }
  *nn = p - BCUR(b);
  return (0);
}

#define DOSUFFIXES(DO) DO(8) DO(16) DO(32) DO(z)

/* --- @buf_getmem{8,16,32,z} --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @size_t *nn@ = where to put the length
 *
 * Returns:     Pointer to the buffer data, or null.
 *
 * Use:         Gets a chunk of memory from a buffer.  The number, @16@ or
 *              @32@, is the width of the length; @z@ means null-terminated.
 */

void *buf_getmem8(buf *b, size_t *nn)
{
  int n;

  if ((n = buf_getbyte(b)) < 0) return (0);
  *nn = n;
  return (buf_get(b, n));
}

void *buf_getmem16(buf *b, size_t *nn)
{
  uint16 n;

  if (buf_getu16(b, &n)) return (0);
  *nn = n;
  return (buf_get(b, n));
}

void *buf_getmem32(buf *b, size_t *nn)
{
  uint32 n;

  if (buf_getu32(b, &n)) return (0);
  *nn = n;
  return (buf_get(b, n));
}
  
void *buf_getmemz(buf *b, size_t *nn)
{
  if (findz(b, nn)) return (0);
  return (buf_get(b, *nn));
}

/* --- @buf_putmem{8,16,32,z} --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @const void *p@ = pointer to data to write
 *              @size_t n@ = length to write
 *
 * Returns:     Zero if OK, nonzero if there wasn't enough space.
 *
 * Use:         Writes a chunk of data to a buffer.  The number, @16@ or
 *              @32@, is the width of the length; @z@ means null-terminated.
 */

int buf_putmem8(buf *b, const void *p, size_t n)
{
  assert(n <= 0xfful);
  if (buf_putbyte(b, n) || buf_put(b, p, n))
    return (-1);
  return (0);
}

int buf_putmem16(buf *b, const void *p, size_t n)
{
  assert(n <= 0xfffful);
  if (buf_putu16(b, n) || buf_put(b, p, n))
    return (-1);
  return (0);
}

int buf_putmem32(buf *b, const void *p, size_t n)
{
  assert(n <= 0xfffffffful);
  if (buf_putu32(b, n) || buf_put(b, p, n))
    return (-1);
  return (0);
}

int buf_putmemz(buf *b, const void *p, size_t n)
{
  octet *q;

  assert(!memchr(p, 0, n));
  if ((q = buf_get(b, n + 1)) == 0)
    return (-1);
  memcpy(q, p, n);
  q[n] = 0;
  return (0);
}

/* --- @buf_getbuf{8,16,32,z}@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @buf *bb@ = where to put the result
 *
 * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:         Gets a block of data from a buffer, and writes its bounds to
 *              another buffer.  The number, @16@ or @32@, is the width of
 *              the length; @z@ means null-terminated.
 */

#define GETBUF(suff) int buf_getbuf##suff(buf *b, buf *bb)              \
{                                                                       \
  void *p;                                                              \
  size_t n;                                                             \
                                                                        \
  if ((p = buf_getmem##suff(b, &n)) == 0)                               \
    return (-1);                                                        \
  buf_init(bb, p, n);                                                   \
  return (0);                                                           \
}
DOSUFFIXES(GETBUF)

/* --- @buf_putbuf{8,16,32,z}@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @buf *bb@ = buffer to write
 *
 * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:         Puts the contents of a buffer to a buffer.  The number, @16@
 *              or @32@, is the width of the length; @z@ means null-
 *              terminated.
 */

#define PUTBUF(suff) int buf_putbuf##suff(buf *b, buf *bb)              \
  { return (buf_putmem##suff(b, BBASE(bb), BLEN(bb))); }
DOSUFFIXES(PUTBUF)  

/* --- @buf_getstr{8,16,32,z}@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @dstr *d@ = where to put the result
 *
 * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:         Gets a block of data from a buffer, and writes its contents
 *              to a string.  The number, @16@ or @32@, is the width of the
 *              length; @z@ means null-terminated.
 */

#define GETSTR(suff) int buf_getstr##suff(buf *b, dstr *d)              \
{                                                                       \
  void *p;                                                              \
  size_t n;                                                             \
                                                                        \
  if ((p = buf_getmem##suff(b, &n)) == 0)                               \
    return (-1);                                                        \
  DPUTM(d, p, n);                                                       \
  return (0);                                                           \
}
DOSUFFIXES(GETSTR)

/* --- @buf_putstr{8,16,32,z}@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @dstr *d@ = string to write
 *
 * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:         Puts a string to a buffer, and writes its bounds to
 *              another buffer.  The number, @16@ or @32@, is the width of
 *              the length; @z@ means null-terminated.
 */

#define PUTSTR(suff) int buf_putstr##suff(buf *b, dstr *d)              \
  { return (buf_putmem##suff(b, d->buf, d->len)); }
DOSUFFIXES(PUTSTR)

/* --- @buf_getmp@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *
 * Returns:     A multiprecision integer, or null if there wasn't one there.
 *
 * Use:         Gets a multiprecision integer from a buffer.
 */

mp *buf_getmp(buf *b)
{
  uint16 sz;
  size_t n;
  mp *m;
  if (buf_getu16(b, &sz) || buf_ensure(b, sz))
    return (0);
  m = mp_loadb(MP_NEW, BCUR(b), sz);
  n = mp_octets(m);
  if (n != sz && n != 0 && sz != 1) {
    mp_drop(m);
    return (0);
  }
  BSTEP(b, sz);
  return (m);
}

/* --- @buf_putmp@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @mp *m@ = a multiprecision integer
 *
 * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:         Puts a multiprecision integer to a buffer.
 */

int buf_putmp(buf *b, mp *m)
{
  size_t sz = mp_octets(m);
  assert(sz < MASK16);
  if (!sz) sz = 1;
  if (buf_putu16(b, sz) || buf_ensure(b, sz))
    return (-1);
  mp_storeb(m, BCUR(b), sz);
  BSTEP(b, sz);
  return (0);
}

/* --- @buf_getec@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @ec *p@ = where to put the point
 *
 * Returns:     Zero if it worked, nonzero if it failed.
 *
 * Use:         Gets a multiprecision integer from a buffer.  The point must
 *              be initialized.
 */

int buf_getec(buf *b, ec *p)
{
  mp *x = 0, *y = 0;
  uint16 n;
  if (buf_ensure(b, 2)) return (-1);
  n = LOAD16(BCUR(b)); if (!n) { BSTEP(b, 2); EC_SETINF(p); return (0); }
  if ((x = buf_getmp(b)) == 0 || (y = buf_getmp(b)) == 0) {
    mp_drop(x); mp_drop(y); return (-1);
  }
  EC_DESTROY(p); p->x = x; p->y = y; p->z = 0;
  return (0);
}

/* --- @buf_putec@ --- *
 *
 * Arguments:   @buf *b@ = pointer to a buffer block
 *              @ec *p@ = an elliptic curve point
 *
 * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 *
 * Use:         Puts an elliptic curve point to a buffer.
 */

int buf_putec(buf *b, ec *p)
{
  if (EC_ATINF(p)) return (buf_putu16(b, 0));
  if (buf_putmp(b, p->x) || buf_putmp(b, p->y)) return (-1);
  return (0);
}

/*----- That's all, folks -------------------------------------------------*/