hash.c

/*
 * hash - one-way hash routines
 *
 * Copyright (C) 1999-2007,2021-2023  Landon Curt Noll
 *
 * Calc is open software; you can redistribute it and/or modify it under
 * the terms of the version 2.1 of the GNU Lesser General Public License
 * as published by the Free Software Foundation.
 *
 * Calc 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 Lesser General
 * Public License for more details.
 *
 * A copy of version 2.1 of the GNU Lesser General Public License is
 * distributed with calc under the filename COPYING-LGPL.  You should have
 * received a copy with calc; if not, write to Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Under source code control:   1995/11/23 05:13:11
 * File existed as early as:    1995
 *
 * chongo <was here> /\oo/\     http://www.isthe.com/chongo/
 * Share and enjoy!  :-)        http://www.isthe.com/chongo/tech/comp/calc/
 */


#include <stdio.h>
#include "have_string.h"
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include "calc.h"
#include "alloc.h"
#include "value.h"
#include "zrand.h"
#include "zrandom.h"
#include "hash.h"


#include "errtbl.h"
#include "banned.h"     /* include after system header <> includes */


/*
 * external hash_setup functions
 */
E_FUNC void shs_init_state(HASH*);
E_FUNC void sha1_init_state(HASH*);
E_FUNC void MD5_init_state(HASH*);


/*
 * hash_long can deal with bool's, int's, FLAGS's and LEN's
 */
#define hash_bool(type, val, state) (hash_long((type), (long)(val), (state)))
#define hash_int(type, val, state) (hash_long((type), (long)(val), (state)))
#define hash_flag(type, val, state) (hash_long((type), (long)(val), (state)))
#define hash_len(type, val, state) (hash_long((type), (long)(val), (state)))


/*
 * hash_setup - setup the hash state for a given hash
 */
STATIC struct hash_setup {
        int type;               /* hash type (see XYZ_HASH_TYPE below) */
        void (*init_state)(HASH*);      /* initialize a hash state */
} htbl[] = {
        { SHA1_HASH_TYPE, sha1_init_state },    /* SHA-1 / SHA-1 */
        { -1, NULL }            /* must be last */
};


/*
 * hash_init - initialize a hash state
 *
 * given:
 *      type    - hash type (see hash.h)
 *      state   - the state to initialize, or NULL to malloc it
 *
 * returns:
 *      initialized state
 */
HASH *
hash_init(int type, HASH *state)
{
        int i;

        /*
         * malloc if needed
         */
        if (state == NULL) {
                state = (HASH *)malloc(sizeof(HASH));
                if (state == NULL) {
                        math_error("hash_init: cannot malloc HASH");
                        not_reached();
                }
        }

        /*
         * clear hash value
         */
        memset((void*)state, 0, sizeof(HASH));
        state->bytes = true;

        /*
         * search for the hash_setup function
         */
        for (i=0; htbl[i].init_state != NULL; ++i) {

                /* if we found the state that we were looking for */
                if (type == htbl[i].type) {

                        /* initialize state and return */
                        (htbl[i].init_state)(state);

                        /* firewall - MAX_CHUNKSIZE must be >= chunksize */
                        if (state->chunksize > MAX_CHUNKSIZE) {
                                math_error(
                                  "internal error: MAX_CHUNKSIZE is too small");
                                not_reached();
                        }
                        return state;
                }
        }

        /*
         * no such hash state
         */
        math_error("internal error: hash type not found in htbl[]");
        return NULL;
}


/*
 * hash_free - free the hash state
 */
void
hash_free(HASH *state)
{
        /*
         * do nothing if state is NULL
         */
        if (state == NULL) {
                return;
        }

        /*
         * free main state and return
         */
        free(state);
        return;
}


/*
 * hash_copy - copy a hash state
 *
 * given:
 *      state   - the state to copy
 *
 * returns:
 *      pointer to copy of state
 */
HASH *
hash_copy(HASH *state)
{
        HASH *hnew;             /* copy of state */

        /*
         * malloc new state
         */
        hnew = (HASH *)malloc(sizeof(HASH));
        if (hnew == NULL) {
                math_error("hash_init: cannot malloc HASH");
                not_reached();
        }

        /*
         * duplicate state
         */
        memcpy((void *)hnew, (void *)state, sizeof(HASH));
        return hnew;
}


/*
 * hash_cmp - compare hash values
 *
 * given:
 *      a       first hash state
 *      b       second hash state
 *
 * returns:
 *      true => hash states are different
 *      false => hash states are the same
 */
int
hash_cmp(HASH *a, HASH *b)
{
        /*
         * firewall and quick check
         */
        if (a == b) {
                /* pointers to the same object */
                return false;
        }
        if (a == NULL || b == NULL) {
                /* one pointer is NULL, so they differ */
                return true;
        }
        if (a->cmp == NULL || b->cmp == NULL) {
                /* one cmp function is NULL, so they differ */
                return true;
        }

        /*
         * compare hash types
         */
        if (a->hashtype != b->hashtype) {
                /* different hash types are different */
                return true;
        }

        /*
         * perform the hash specific comparison
         */
        return ((a->cmp)(a,b));
}


/*
 * hash_print - print the name and value of a hash
 *
 * given:
 *      state   the hash state to print name and value of
 */
void
hash_print(HASH *state)
{
        /* print the hash */
        (state->print)(state);
        return;
}


/*
 * hash_final - finalize the state of a hash and return a ZVALUE
 *
 * given:
 *      state   the hash state to finalize
 *
 * returns:
 *      hash state as a ZVALUE
 */
ZVALUE
hash_final(HASH *state)
{
        /* return the finalized the hash value */
        return (state->final)(state);
}


/*
 * hash_long - note a long value
 *
 * given:
 *      type    - hash type (see hash.h)
 *      longval - a long value
 *      state   - the state to hash
 *
 * returns:
 *      the new state
 *
 * This function will hash a long value as if it were a 64 bit value.
 * The input is a long.  If a long is smaller than 64 bits, we will
 * hash a final 32 bits of zeros.
 *
 * This function is OK to hash bool's, unsigned long's, unsigned int's
 * signed int's as well as FLAG's and LEN's.
 */
HASH *
hash_long(int type, long longval, HASH *state)
{
        long lval[64/LONG_BITS];        /* 64 bits of longs */

        /*
         * initialize if state is NULL
         */
        if (state == NULL) {
                state = hash_init(type, NULL);
        }

        /*
         * setup for the hash_long
         */
        (state->chkpt)(state);
        state->bytes = false;   /* data to be read as words */

        /*
         * catch the zero numeric value special case
         */
        if (longval == 0) {
                /* note a zero numeric value and return */
                (state->note)(HASH_ZERO(state->base), state);
                return state;
        }

        /*
         * prep for a long value hash
         */
        (state->note)(state->base, state);

        /*
         * hash as if we have a 64 bit value
         */
        memset((char *)lval, 0, sizeof(lval));
        lval[0] = longval;
        (state->update)(state, (USB8 *)lval, sizeof(lval));

        /*
         * all done
         */
        return state;
}


/*
 * hash_zvalue - hash a ZVALUE
 *
 * given:
 *      type    - hash type (see hash.h)
 *      zval    - the ZVALUE
 *      state   - the state to hash or NULL
 *
 * returns:
 *      the new state
 */
HASH *
hash_zvalue(int type, ZVALUE zval, HASH *state)
{

#if CALC_BYTE_ORDER == BIG_ENDIAN && BASEB == 16
        int full_lim;           /* HALFs in whole chunks in zval */
        int chunkhalf;          /* size of half buffer in HALFs */
        int i;
        int j;
#endif
#if BASEB == 16
        HALF half[MAX_CHUNKSIZE];       /* For endian reversal */
#endif

        /*
         * initialize if state is NULL
         */
        if (state == NULL) {
                state = hash_init(type, NULL);
        }

        /*
         * setup for the ZVALUE hash
         */
        (state->chkpt)(state);
        state->bytes = false;   /* data to be read as words */

        /*
         * catch the zero numeric value special case
         */
        if (ziszero(zval)) {
                /* note a zero numeric value and return */
                (state->note)(HASH_ZERO(state->base), state);
                return state;
        }

        /*
         * prep for a ZVALUE hash
         */
        (state->note)(HASH_ZVALUE(state->base), state);
        /* note if we have a negative value */
        if (zisneg(zval)) {
                (state->note)(HASH_NEG(state->base), state);
        }

#if CALC_BYTE_ORDER == BIG_ENDIAN && BASEB == 16

        /*
         * hash full chunks
         *
         * We need to convert the array of HALFs into canonical architectural
         * independent form -- 32 bit arrays.  Because we have 16 bit values
         * in Big Endian form, we need to swap 16 bit values so that they
         * appear as 32 bit Big Endian values.
         */
        chunkhalf = state->chunksize/sizeof(HALF);
        full_lim = (zval.len / chunkhalf) * chunkhalf;
        for (i=0; i < full_lim; i += chunkhalf) {
                /* HALF swap copy a chunk into a data buffer */
                for (j=0; j < chunkhalf; j += 2) {
                        half[j] = zval.v[i+j+1];
                        half[j+1] = zval.v[i+j];
                }
                (state->update)(state, (USB8*) half, state->chunksize);
        }

        /*
         * hash the final partial chunk (if any)
         *
         * We need to convert the array of HALFs into canonical architectural
         * independent form -- 32 bit arrays.  Because we have 16 bit values
         * in Big Endian form, we need to swap 16 bit values so that they
         * appear as 32 bit Big Endian values.
         */
        if (zval.len > full_lim) {
                for (j=0; j < zval.len-full_lim-1; j += 2) {
                        half[j] = zval.v[full_lim+j+1];
                        half[j+1] = zval.v[full_lim+j];
                }
                if (j < zval.len-full_lim) {
                        half[j] = (HALF)0;
                        half[j+1] = zval.v[zval.len-1];
                        --full_lim;
                }
                (state->update)(state, (USB8 *) half,
                          (zval.len-full_lim)*sizeof(HALF));
        }

#else

        /*
         * hash the array of HALFs
         *
         * The array of HALFs is equivalent to the canonical architectural
         * independent form.  We either have 32 bit HALFs (in which case
         * we do not case the byte order) or we have 16 bit HALFs in Little
         * Endian order (which happens to be laid out in the same order as
         * 32 bit values).
         */
        (state->update)(state, (USB8 *)zval.v, zval.len*sizeof(HALF));

#if BASEB == 16
        if (zval.len & 1) {             /* padding to complete word */
                half[0] = 0;
                (state->update)(state, (USB8 *) half, 2);
        }
#endif

#endif

        /*
         * all done
         */
        return state;
}


/*
 * hash_number - hash a NUMBER
 *
 * given:
 *      type    - hash type (see hash.h)
 *      n       - the NUMBER
 *      state   - the state to hash or NULL
 *
 * returns:
 *      the new state
 */
HASH *
hash_number(int type, void *n, HASH *state)
{
        NUMBER *number = (NUMBER *)n;   /* n as a NUMBER pointer */
        bool sign;                      /* sign of the denominator */

        /*
         * initialize if state is NULL
         */
        if (state == NULL) {
                state = hash_init(type, NULL);
        }

        /*
         * setup for the NUMBER hash
         */
        (state->chkpt)(state);
        state->bytes = false;

        /*
         * process the numerator
         */
        state = hash_zvalue(type, number->num, state);

        /*
         * if the NUMBER is not an integer, process the denominator
         */
        if (qisfrac(number)) {

                /* note the division */
                (state->note)(HASH_DIV(state->base), state);

                /* hash denominator as positive -- just in case */
                sign = number->den.sign;
                number->den.sign = 0;

                /* hash the denominator */
                state = hash_zvalue(type, number->den, state);

                /* restore the sign */
                number->den.sign = sign;
        }

        /*
         * all done
         */
        return state;
}


/*
 * hash_complex - hash a COMPLEX
 *
 * given:
 *      type    - hash type (see hash.h)
 *      c       - the COMPLEX
 *      state   - the state to hash or NULL
 *
 * returns:
 *      the new state
 */
HASH *
hash_complex(int type, void *c, HASH *state)
{
        COMPLEX *complex = (COMPLEX *)c;        /* c as a COMPLEX pointer */

        /*
         * initialize if state is NULL
         */
        if (state == NULL) {
                state = hash_init(type, NULL);
        }

        /*
         * setup for the COMPLEX hash
         */
        (state->chkpt)(state);
        state->bytes = false;

        /*
         * catch the zero special case
         */
        if (ciszero(complex)) {
                /* note a zero numeric value and return */
                (state->note)(HASH_ZERO(state->base), state);
                return state;
        }

        /*
         * process the real value if not pure imaginary
         *
         * We will ignore the real part if the value is of the form 0+xi.
         */
        if (!qiszero(complex->real)) {
                state = hash_number(type, complex->real, state);
        }

        /*
         * if the NUMBER is not real, process the imaginary value
         *
         * We will ignore the imaginary part of the value is of the form x+0i.
         */
        if (!cisreal(complex)) {

                /* note the sqrt(-1) */
                (state->note)(HASH_COMPLEX(state->base), state);

                /* hash the imaginary value */
                state = hash_number(type, complex->imag, state);
        }

        /*
         * all done
         */
        return state;
}


/*
 * hash_str - hash a null-terminated string
 *
 * given:
 *      type    - hash type (see hash.h)
 *      str     - the string
 *      state   - the state to hash or NULL
 *
 * returns:
 *      the new state
 */
HASH *
hash_str(int type, char *str, HASH *state)
{
        size_t len;             /* string length */

        /*
         * initialize if state is NULL
         */
        if (state == NULL) {
                state = hash_init(type, NULL);
        }

        /*
         * setup for the string hash
         */
        if (!state->bytes) {
                (state->chkpt)(state);
                state->bytes = true;
        }

        len = strlen(str);

        /*
         * hash the string
         */
        (state->update)(state, (USB8*)str, len);

        /*
         * all done
         */
        return state;
}


/*
 * hash_STR - hash a STRING
 *
 * given:
 *      type    - hash type (see hash.h)
 *      str     - the STRING
 *      state   - the state to hash or NULL
 *
 * returns:
 *      the new state
 */
HASH *
hash_STR(int type, STRING *str, HASH *state)
{
        /*
         * initialize if state is NULL
         */
        if (state == NULL) {
                state = hash_init(type, NULL);
        }

        /*
         * setup for the string hash
         */
        if (!state->bytes) {
                (state->chkpt)(state);
                state->bytes = true;
        }

        /*
         * hash the string
         */
        (state->update)(state, (USB8*) str->s_str, (USB32) str->s_len);

        /*
         * all done
         */
        return state;
}


/*
 * hash_usb8 - hash an array of USB8s
 *
 * given:
 *      type    - hash type (see hash.h)
 *      byte    - pointer to an array of USB8s
 *      len     - number of USB8s to hash
 *      state   - the state to hash or NULL
 *
 * returns:
 *      the new state
 */
HASH *
hash_usb8(int type, USB8 *byte, int len, HASH *state)
{
        /*
         * initialize if state is NULL
         */
        if (state == NULL) {
                state = hash_init(type, NULL);
        }

        /*
         * setup for the string hash
         */
        if (!state->bytes) {
                (state->chkpt)(state);
                state->bytes = true;
        }

        /*
         * hash the array of octets
         */
        (state->update)(state, byte, (USB32)len);

        /*
         * all done
         */
        return state;
}


/*
 * hash_value - hash a value
 *
 * given:
 *      type    - hash type (see hash.h)
 *      v       - the value
 *      state   - the state to hash or NULL
 *
 * returns:
 *      the new state
 */
HASH *
hash_value(int type, void *v, HASH *state)
{
        LISTELEM *ep;           /* list element pointer */
        ASSOCELEM **assochead;  /* association chain head */
        ASSOCELEM *aep;         /* current association value */
        ASSOCELEM *nextaep;     /* next association value */
        VALUE *value = (VALUE *)v;      /* v cast to a VALUE */
        VALUE *vp;              /* pointer to next OBJ table value */
        ZVALUE fileval;         /* size, position, dev, inode of a file */
        int i;

        /*
         * initialize if state is NULL
         */
        if (state == NULL) {
                state = hash_init(type, NULL);
        }

        /*
         * process the value type
         */
        switch (value->v_type) {
        case V_NULL:
                (state->chkpt)(state);
                state->bytes = true;
                break;

        case V_INT:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);

                /* hash as if we have a 64 bit value */
                state = hash_int(type, value->v_int, state);
                break;

        case V_NUM:
                /* hash this type */
                state = hash_number(type, value->v_num, state);
                break;

        case V_COM:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);

                /* hash this type */
                state = hash_complex(type, value->v_com, state);
                break;

        case V_ADDR:
                /* there is nothing to setup, simply hash what we point at */
                state = hash_value(type, value->v_addr, state);
                break;

        case V_STR:
                /* strings have no setup */

                /* hash this type */
                state = hash_STR(type, value->v_str, state);
                break;

        case V_MAT:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);
                state->bytes = true;

                /* hash all the elements of the matrix */
                for (i=0; i < value->v_mat->m_size; ++i) {

                        /* hash the next matrix value */
                        state = hash_value(type,
                                        value->v_mat->m_table+i, state);
                        state->bytes = false;   /* as if reading words */
                }
                break;

        case V_LIST:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);

                /* hash all the elements of the list */
                for (i=0, ep = value->v_list->l_first;
                     ep != NULL && i < value->v_list->l_count;
                     ++i, ep = ep->e_next) {

                        /* hash the next list value */
                        state = hash_value(type, &ep->e_value, state);
                        state->bytes = false;   /* as if reading words */
                }
                break;

        case V_ASSOC:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);
                state->bytes = true;

                /* hash the association */
                assochead = value->v_assoc->a_table;
                for (i = 0; i < value->v_assoc->a_size; i++) {
                        nextaep = *assochead;
                        while (nextaep) {
                                aep = nextaep;
                                nextaep = aep->e_next;

                                /* hash the next association value */
                                state = hash_value(type, &aep->e_value, state);
                                state->bytes = false; /* as if reading words */
                        }
                        assochead++;
                }
                break;

        case V_OBJ:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);
                state->bytes = true;    /* reading bytes */

                /* hash the object name and then the element values */

                state = hash_str(type, objtypename(
                        value->v_obj->o_actions->oa_index), state);
                (state->chkpt)(state);

                for (i=value->v_obj->o_actions->oa_count,
                     vp=value->v_obj->o_table;
                     i-- > 0;
                     vp++) {

                        /* hash the next object value */
                        state = hash_value(type, vp, state);
                        state->bytes = false;   /* as if reading words */
                }
                break;

        case V_FILE:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);

                /* hash file length if possible */
                if (getsize(value->v_file, &fileval) == 0) {
                        state = hash_zvalue(type, fileval, state);
                        zfree(fileval);
                } else {
                        /* hash -1 for invalid length */
                        state = hash_long(type, (long)-1, state);
                }
                /* hash the file position if possible */
                if (getloc(value->v_file, &fileval) == 0) {
                        state = hash_zvalue(type, fileval, state);
                        zfree(fileval);
                } else {
                        /* hash -1 for invalid location */
                        state = hash_long(type, (long)-1, state);
                }
                /* hash the file device if possible */
                if (get_device(value->v_file, &fileval) == 0) {
                        state = hash_zvalue(type, fileval, state);
                        zfree(fileval);
                } else {
                        /* hash -1 for invalid device */
                        state = hash_long(type, (long)-1, state);
                }
                /* hash the file inode if possible */
                if (get_inode(value->v_file, &fileval) == 0) {
                        state = hash_zvalue(type, fileval, state);
                        zfree(fileval);
                } else {
                        /* hash -1 for invalid inode */
                        state = hash_long(type, (long)-1, state);
                }
                break;

        case V_RAND:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);

                /* hash the RAND state */
                state = hash_int(type, value->v_rand->seeded, state);
                state = hash_int(type, value->v_rand->bits, state);
                (state->update)(state,
                        (USB8 *)value->v_rand->buffer, SLEN*FULL_BITS/8);
                state = hash_int(type, value->v_rand->j, state);
                state = hash_int(type, value->v_rand->k, state);
                state = hash_int(type, value->v_rand->need_to_skip, state);
                (state->update)(state,
                        (USB8 *)value->v_rand->slot, SCNT*FULL_BITS/8);
                (state->update)(state,
                        (USB8*)value->v_rand->shuf, SHUFLEN*FULL_BITS/8);
                state->bytes = false;   /* as if reading words */
                break;

        case V_RANDOM:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);

                /* hash the RANDOM state */
                state = hash_int(type, value->v_random->seeded, state);
                state = hash_int(type, value->v_random->bits, state);
                (state->update)(state,
                        (USB8 *)&(value->v_random->buffer), BASEB/8);
                state = hash_zvalue(type, value->v_random->r, state);
                state = hash_zvalue(type, value->v_random->n, state);
                state->bytes = false;   /* as if reading words */
                break;

        case V_CONFIG:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);

                /* hash the CONFIG state */
                state = hash_int(type, value->v_config->outmode, state);
                state = hash_int(type, value->v_config->outmode2, state);
                state = hash_long(type,(long)value->v_config->outdigits, state);
                state = hash_number(type, value->v_config->epsilon, state);
                state = hash_long(type,
                        (long)value->v_config->epsilonprec, state);
                state = hash_flag(type, value->v_config->traceflags, state);
                state = hash_long(type, (long)value->v_config->maxprint, state);
                state = hash_len(type, value->v_config->mul2, state);
                state = hash_len(type, value->v_config->sq2, state);
                state = hash_len(type, value->v_config->pow2, state);
                state = hash_len(type, value->v_config->redc2, state);
                state = hash_bool(type, value->v_config->tilde_ok, state);
                state = hash_bool(type, value->v_config->tilde_space, state);
                state = hash_bool(type, value->v_config->tab_ok, state);
                state = hash_long(type, (long)value->v_config->quomod, state);
                state = hash_long(type, (long)value->v_config->quo, state);
                state = hash_long(type, (long)value->v_config->mod, state);
                state = hash_long(type, (long)value->v_config->sqrt, state);
                state = hash_long(type, (long)value->v_config->appr, state);
                state = hash_long(type, (long)value->v_config->cfappr, state);
                state = hash_long(type, (long)value->v_config->cfsim, state);
                state = hash_long(type, (long)value->v_config->outround, state);
                state = hash_long(type, (long)value->v_config->round, state);
                state = hash_long(type, (long)value->v_config->triground, state);
                state = hash_bool(type, value->v_config->leadzero, state);
                state = hash_bool(type, value->v_config->fullzero, state);
                state = hash_long(type,
                        (long)value->v_config->maxscancount, state);
                state = hash_str(type, value->v_config->prompt1, state);
                state->bytes = false;   /* as if just read words */
                state = hash_str(type, value->v_config->prompt2, state);
                state->bytes = false;   /* as if just read words */
                state = hash_int(type, value->v_config->blkmaxprint, state);
                state = hash_bool(type, value->v_config->blkverbose, state);
                state = hash_int(type, value->v_config->blkbase, state);
                state = hash_int(type, value->v_config->blkfmt, state);
                state = hash_long(type,
                        (long)value->v_config->resource_debug, state);
                state = hash_long(type,
                        (long)value->v_config->calc_debug, state);
                state = hash_long(type,
                        (long)value->v_config->user_debug, state);
                state = hash_bool(type, value->v_config->verbose_quit, state);
                state = hash_int(type, value->v_config->ctrl_d, state);
                state = hash_str(type, value->v_config->program, state);
                state = hash_str(type, value->v_config->base_name, state);
                state = hash_bool(type, value->v_config->windows, state);
                state = hash_bool(type, value->v_config->cygwin, state);
                state = hash_bool(type, value->v_config->compile_custom, state);
                if (value->v_config->allow_custom != NULL &&
                    *(value->v_config->allow_custom)) {
                        state = hash_bool(type, true, state);
                } else {
                        state = hash_bool(type, false, state);
                }
                state = hash_str(type, value->v_config->version, state);
                state = hash_int(type, value->v_config->baseb, state);
                state = hash_bool(type, value->v_config->redecl_warn, state);
                state = hash_bool(type, value->v_config->dupvar_warn, state);
                state = hash_bool(type, value->v_config->fraction_space, state);
                break;

        case V_HASH:
                /* setup for the this value type */
                (state->chkpt)(state);
                (state->type)(value->v_type, state);

                /* hash the HASH state */
                state = hash_int(type, value->v_hash->type, state);
                state = hash_bool(type, value->v_hash->bytes,state);
                state = hash_int(type, value->v_hash->base, state);
                state = hash_int(type, value->v_hash->chunksize, state);
                state = hash_int(type, value->v_hash->unionsize, state);
                (state->update)(state,
                    value->v_hash->h_union.data, state->unionsize);
                state->bytes = false;   /* as if reading words */
                break;

        case V_BLOCK:
                /* there is no setup for a BLOCK */

                /* hash the octets in the BLOCK */
                if (value->v_block->datalen > 0) {
                        state = hash_usb8(type, value->v_block->data,
                                           value->v_block->datalen, state);
                }
                break;

        case V_OCTET:
                /* there is no setup for an OCTET */

                /* hash the OCTET */
                state = hash_usb8(type, value->v_octet, 1, state);
                break;

        case V_NBLOCK:
                /* there is no setup for a NBLOCK */

                /* hash the octets in the NBLOCK */
                if (value->v_nblock->blk->datalen > 0) {
                        state = hash_usb8(type, value->v_nblock->blk->data,
                                           value->v_nblock->blk->datalen,
                                           state);
                }
                break;

        default:
                math_error("hashing an unknown value");
                not_reached();
        }
        return state;
}