Geografic-Information-System/lib/gis/quant.c

/**********************************************************************
 *
 *  G_quant_init (quant)
 *       struct Quant *quant;
 *
 *  initializes new quantization structure. calls
 *  G_quant_clear() before it returns.
 *  
 *  note: dies if G_malloc dies.
 *
 **********************************************************************
 *
 *  G_quant_is_truncate (quant)
 *       struct Quant *quant;
 *
 *  Returns wether or not quant rules are set to truncate map
 *  
 **********************************************************************
 *
 *  G_quant_is_round (quant)
 *       struct Quant *quant;
 *
 *  Returns wether or not quant rules are set to round map
 *  
 **********************************************************************
 *
 *  G_quant_truncate (quant)
 *       struct Quant *quant;
 *
 *  sets the quant rules to perform simple truncation on floats.
 *  
 **********************************************************************
 *
 *  G_quant_round (quant)
 *       struct Quant *quant;
 *
 *  sets the quant rules to perform simple rounding on floats.
 *  
 **********************************************************************
 *
 *  G_quant_organize_fp_lookup (quant)
 *       struct Quant *quant;
 *
 *  Organizes fp_lookup table for faster (logarithmic) lookup time
 *  G_quant_organize_fp_lookup() creates a list of min and max for
 *  each quant rule, sorts this list, and stores the pointer to quant
 *  rule that should be used inbetween any 2 numbers in this list.
 *  Also it stores extreme points for 2 infinite rules, if exist.
 *  After the call to G_quant_organize_fp_lookup()
 *  instead of linearly searching through list of rules to find
 *  a rule to apply, quant lookup will perform a binary search
 *  to find an interval containing floating point value, and then use
 *  the rule associated with this interval.
 *  when the value doesn't fall within any interval, check for the
 *  infinite rules.
 *  
 **********************************************************************
 *
 *  void
 *  G_quant_free (q)
 *  
 *       struct Quant *q;
 *
 *  resets the number of defined rules to 0 and free's space allocated
 *  for rules. calls G_quant_clear ().
 *
 **********************************************************************
 *
 *  void
 *  G_quant_clear (q)
 *  
 *       struct Quant *q;
 *
 *  resets the number of defined rules and number of infinite rules to 0. 
 *
 **********************************************************************
 *
 *  int
 *  G_quant_get_limits (q, dMin, dMax, cMin, cMax)
 *  
 *       struct Quant *q;
 *       DCELL *dMin, *dMax;
 *       CELL *cMin, *cMax;
 *
 *  returns the minimum and maximum cell and dcell values of all
 *  the ranges defined.
 *  
 *  returns: -1 if q->truncate or q->round are true or
		   after G_quant_init (), or any call to 
 *                 G_quant_clear () or G_quant_free () 
 *                 no explicit rules have been added
 *                 In this case the returned minimum and maximum 
 *                 CELL and DCELL values are null.
 *            1 otherwise. in this case the values returned correspond
 *                 to the extreme values of the defined rules 
 *
 **********************************************************************
 *  
 *  int
 *  G_quant_nof_rules (q)
 *  
 *       struct Quant *q;
 *  
 *  returns the number of quantization rules defined. This number does
 *  not include the 2 infinite intervals.
 *  
 **********************************************************************
 *  
 *  void
 *  G_quant_get_ith_rule (q, i, dLow, dHigh, cLow, cHigh)
 *  
 *       struct Quant *q;
 *       int i;
 *       DCELL *dLow, *dHigh;
 *       CELL *cLow, *cHigh;
 *  
 *  returns the i'th quantization rule, for 0 <= i < G_quant_nof_rules().
 *  a larger value for i means that the rule has been added later.
 *  
 **********************************************************************
 *   void
 *   G_quant_set_neg_infinite_rule (q, dLeft, c)
 *
 *       struct Quant *q;
 *       DCELL dLeft;
 *       CELL c;
 *
 *   defines a rule for values "dLeft" and smaller. values in this range
 *   are mapped to "c" if none of the "finite" quantization rules applies.
 *
 * **********************************************************************
 *
 *  int
 *  G_quant_get_neg_infinite_rule (q, dLeft, c)
 *
 *       struct Quant *q;
 *       DCELL *dLeft;
 *       CELL *c;
 *
 *  returns in "dLeft" and "c" the rule values for the negative infinite
 *  interval (see G_quant_set_neg_infinite_rule ()).
 *
 *  returns: 0 if this rule is not defined
 *           1 otherwise.
 *
 * **********************************************************************
 *
 *  struct Quant_table *
 *  G__quant_get_rule_for_d_raster_val (q, val)
 *
 *       struct Quant *q;
 *       DCELL val;
 *
 *  returns quant rule which will be applied when looking up  the
 *  integer quant value for val. (used when organizing fp_lookup.
 *
 *  returns: pointer to the Quant_table (color rule)
 *           NULL otherwise.
 *
 **********************************************************************
 *   void
 *   G_quant_set_pos_infinite_rule (q, dRight, c)
 *
 *       struct Quant *q;
 *       DCELL dRight;
 *       CELL c;
 *
 *   defines a rule for values "dRight" and larger. values in this range
 *   are mapped to "c" if none of the "finite" quantization rules or the
 *   negative infinite rule applies.
 *
 * **********************************************************************
 *
 *  int
 *  G_quant_get_pos_infinite_rule (q, dRight, c)
 *
 *       struct Quant *q;
 *       DCELL *dRight;
 *       CELL *c;
 *
 *  returns in "dRight" and "c" the rule values for the positive infinite
 *  interval (see G_quant_set_pos_infinite_rule ()).
 *
 *  returns: 0 if this rule is not defined
 *           1 otherwise.
 *
 **********************************************************************
 *  
 *  void
 *  G_quant_reverse_rule_order (q)
 *
 *        struct Quant *q;
 *
 *  reverses the order in which the qunatization rules are stored. (see
 *  also G_quant_get_ith_rule () and G_quant_perform_d ()).
 *  
 **********************************************************************
 *  
 *  void
 *  G_quant_add_rule (q, dLow, dHigh, cLow, cHigh)
 *  
 *       struct Quant *q;
 *       DCELL dLow, dHigh;
 *       CELL cLow, cHigh;
 *  
 *  adds a new rule to the set of quantization rules. if dLow < dHigh
 *  the rule will be stored with the low and high values interchanged.
 *  
 *  Note: currently no cleanup of rules is performed, i.e. redundant
 *        rules are not removed. This can't be changed because Categories
 *        structure HEAVILY depends of quant rules stored in exactly the
 *        same order they are entered. So if the cleanup or rearrangement 
 *        is done in the future make a flag for add_rule wether or not
 *        to do it, then quant will not set this flag.
 *  
 **********************************************************************
 *  
 *  CELL
 *  G_quant_get_cell_value (q, cellValue)
 *  
 *       struct Quant *q;
 *       DCELL *cellValue;
 *  
 *  returns in "cell" the quantized CELL values corresponding to the
 *  DCELL value "cellValue".
 *
 *  if several quantization rules apply for cellValue, the one which has 
 *  been inserted latest (i.e. the one of them which is returned by 
 *  G_quant_get_ith_rule() for the largest i) is used. if no such rule
 *  applies the cellValue is first tested against the negative infinite
 *  rule, and finally against the positive infinite rule. if none of
 *  these rules apply, NO_DATA is returned. the actual value of NO_DATA 
 *  is found by calling G_c_set_null_value().
 *
 *  NOTE: see G_quant_organize_fp_lookup() for details on how
 *  the values are looked up from fp_lookup table when it is active.
 *  
 *  if after G_quant_init (), or any call to G_quant_clear () or 
 *  G_quant_free () neither G_quant_add_rule (),
 *  G_quant_set_neg_infinite_rule (),  G_quant_set_pos_infinite_rule ()
 *  are used NO_DATA is returned independently 
 *  of cellValue.
 *
 **********************************************************************
 *  
 *  void
 *  G_quant_perform_d (q, dcell, cell, n)
 *  
 *       struct Quant *q;
 *       DCELL *dcell;
 *       CELL *cell;
 *       int n;
 *  
 *  returns in "cell" the quantized CELL values corresponding to the
 *  DCELL values stored in "dcell". the number of elements quantized
 *  is n. quantization is performed by repeated application of 
 *  G_quant_get_cell_value ().
 *  
 **********************************************************************
 *  
 *  void
 *  G_quant_perform_f (q, fcell, cell, n)
 *  
 *       struct Quant *q;
 *       FCELL *fcell;
 *       CELL *cell;
 *       int n;
 *  
 *  same as G_quant_perform_d (), except the type.
 *  
 **********************************************************************/

/*--------------------------------------------------------------------------*/

/*
   the quantization table is stored as a linear array. rules are added starting
   from index 0. redundant rules are not eliminated. rules are tested from the 
   highest index downto 0. there are two "infinite" rules. support is provided 
   to reverse the order of the rules.
 */

/*--------------------------------------------------------------------------*/

#include <stdlib.h>
#include <grass/gis.h>

/*--------------------------------------------------------------------------*/
static int double_comp(const void *, const void *);

#define USE_LOOKUP 1
#define MAX_LOOKUP_TABLE_SIZE 2048
#define MIN(a,b) (a < b ? a : b)
#define MAX(a,b) (a > b ? a : b)
#define NO_DATA (G_set_c_null_value (&tmp, 1), (CELL) tmp)

#define NO_LEFT_INFINITE_RULE (! q->infiniteLeftSet)
#define NO_RIGHT_INFINITE_RULE (! q->infiniteRightSet)
#define NO_FINITE_RULE (q->nofRules <= 0)
#define NO_EXPLICIT_RULE (NO_FINITE_RULE && \
			  NO_LEFT_INFINITE_RULE && NO_RIGHT_INFINITE_RULE)

/*--------------------------------------------------------------------------*/

void G_quant_clear(struct Quant *q)
{
    q->nofRules = 0;
    q->infiniteRightSet = q->infiniteLeftSet = 0;
}

/*--------------------------------------------------------------------------*/

void G_quant_free(struct Quant *q)
{
    G_quant_clear(q);

    if (q->maxNofRules > 0)
	G_free(q->table);
    if (q->fp_lookup.active) {
	G_free(q->fp_lookup.vals);
	G_free(q->fp_lookup.rules);
	q->fp_lookup.nalloc = 0;
	q->fp_lookup.active = 0;
    }
    q->maxNofRules = 0;
}

/*--------------------------------------------------------------------------*/

int G__quant_organize_fp_lookup(struct Quant *q)
{
    int i;
    DCELL val;
    CELL tmp;
    struct Quant_table *p;

    if (q->nofRules * 2 > MAX_LOOKUP_TABLE_SIZE)
	return -1;
    if (q->nofRules == 0)
	return -1;
    q->fp_lookup.vals = (DCELL *)
	G_calloc(q->nofRules * 2, sizeof(DCELL));
    /* 2 endpoints for each rule */
    q->fp_lookup.rules = (struct Quant_table **)
	G_calloc(q->nofRules * 2, sizeof(struct Quant_table *));

    /* first we organize finite rules into a table */
    if (!NO_FINITE_RULE) {
	i = 0;
	/* get the list of DCELL values from set of all dLows and dHighs
	   of all rules */
	/* NOTE: if dLow==DHigh in a rule, the value appears twice in a list 
	   but if dLow==DHigh of the previous, rule the value appears only once */

	for (p = &(q->table[q->nofRules - 1]); p >= q->table; p--) {
	    /* check if the min is the same as previous maximum */
	    if (i == 0 || p->dLow != q->fp_lookup.vals[i - 1])
		q->fp_lookup.vals[i++] = p->dLow;
	    q->fp_lookup.vals[i++] = p->dHigh;
	}
	q->fp_lookup.nalloc = i;

	/* now sort the values */
	qsort((char *)q->fp_lookup.vals, q->fp_lookup.nalloc,
	      sizeof(DCELL), double_comp);

	/* now find the rule to apply inbetween each 2 values in a list */
	for (i = 0; i < q->fp_lookup.nalloc - 1; i++) {
	    /*debug
	       fprintf (stderr, "%lf %lf ", q->fp_lookup.vals[i], q->fp_lookup.vals[i+1]);
	     */
	    val = (q->fp_lookup.vals[i] + q->fp_lookup.vals[i + 1]) / 2.;
	    q->fp_lookup.rules[i] =
		G__quant_get_rule_for_d_raster_val(q, val);
	    /* debug 
	       if(q->fp_lookup.rules[i])
	       fprintf (stderr, "%lf %lf %d %d\n", q->fp_lookup.rules[i]->dLow, q->fp_lookup.rules[i]->dHigh, q->fp_lookup.rules[i]->cLow, q->fp_lookup.rules[i]->cHigh); 
	       else fprintf (stderr, "null\n");
	     */

	}
    }				/* organizing finite rules */

    if (!NO_LEFT_INFINITE_RULE) {
	q->fp_lookup.inf_dmin = q->infiniteDLeft;
	q->fp_lookup.inf_min = q->infiniteCLeft;
    }
    else {
	if (q->fp_lookup.nalloc)
	    q->fp_lookup.inf_dmin = q->fp_lookup.vals[0];
	q->fp_lookup.inf_min = NO_DATA;
    }

    if (!NO_RIGHT_INFINITE_RULE) {
	if (q->fp_lookup.nalloc)
	    q->fp_lookup.inf_dmax = q->infiniteDRight;
	q->fp_lookup.inf_max = q->infiniteCRight;
    }
    else {
	q->fp_lookup.inf_dmax = q->fp_lookup.vals[q->fp_lookup.nalloc - 1];
	q->fp_lookup.inf_max = NO_DATA;
    }
    q->fp_lookup.active = 1;
    return 1;
}

/*--------------------------------------------------------------------------*/


/*!
 * \brief 
 *
 * Initializes the <em>q</em> struct.
 *
 *  \param q
 *  \return int
 */

int G_quant_init(struct Quant *quant)
{
    quant->fp_lookup.active = 0;
    quant->maxNofRules = 0;
    quant->truncate_only = 0;
    quant->round_only = 0;
    G_quant_clear(quant);

    return 1;
}

/*--------------------------------------------------------------------------*/

int G_quant_is_truncate(const struct Quant *quant)
{
    return quant->truncate_only;
}

/*--------------------------------------------------------------------------*/

int G_quant_is_round(const struct Quant *quant)
{
    return quant->round_only;
}

/*--------------------------------------------------------------------------*/


/*!
 * \brief 
 *
 * sets the quant for <em>q</em>
 * rules to perform simple truncation on floats.
 *
 *  \param q
 *  \return int
 */


/*!
 * \brief 
 *
 * sets the quant for <em>q</em>
 * rules to perform simple rounding on floats.
 *
 *  \param q
 *  \return int
 */

int G_quant_truncate(struct Quant *quant)
{
    quant->truncate_only = 1;
    return 1;
}

/*--------------------------------------------------------------------------*/

int G_quant_round(struct Quant *quant)
{
    quant->round_only = 1;
    return 1;
}

/*--------------------------------------------------------------------------*/

static void quant_set_limits(struct Quant *q,
			     DCELL dLow, DCELL dHigh, CELL cLow, CELL cHigh)
{
    q->dMin = dLow;
    q->dMax = dHigh;
    q->cMin = cLow;
    q->cMax = cHigh;
}

/*--------------------------------------------------------------------------*/

static void quant_update_limits(struct Quant *q,
				DCELL dLow, DCELL dHigh,
				CELL cLow, DCELL cHigh)
{
    if (NO_EXPLICIT_RULE) {
	quant_set_limits(q, dLow, dHigh, cLow, cHigh);
	return;
    }

    q->dMin = MIN(q->dMin, MIN(dLow, dHigh));
    q->dMax = MAX(q->dMax, MAX(dLow, dHigh));
    q->cMin = MIN(q->cMin, MIN(cLow, cHigh));
    q->cMax = MAX(q->cMax, MAX(cLow, cHigh));
}

/*--------------------------------------------------------------------------*/


/*!
 * \brief 
 *
 * Extracts the minimum and maximum floating-point
 * and integer values from all the rules (except the <tt>"infinite"</tt> rules)
 * in <em>q</em> into <em>dmin</em>, <em>dmax</em>, <em>cmin</em>, and <em>cmax</em>. Returns 1
 * if there are any explicit rules. If there are no explicit rules, (this
 * includes cases when q is set to truncate or round map), it returns 0 and sets
 * <em>dmin</em>, <em>dmax</em>, <em>cmin</em>, and <em>cmax</em> to NULL.
 *
 *  \param q
 *  \param dmin
 *  \param dmax
 *  \param cmin
 *  \param cmax
 *  \return int
 */

int G_quant_get_limits(const struct Quant *q,
		       DCELL * dMin, DCELL * dMax, CELL * cMin, CELL * cMax)
{
    if (NO_EXPLICIT_RULE) {
	G_set_c_null_value(cMin, 1);
	G_set_c_null_value(cMax, 1);
	G_set_d_null_value(dMin, 1);
	G_set_d_null_value(dMax, 1);
	return -1;
    }

    *dMin = q->dMin;
    *dMax = q->dMax;
    *cMin = q->cMin;
    *cMax = q->cMax;

    return 1;
}

/*--------------------------------------------------------------------------*/

int G_quant_nof_rules(const struct Quant *q)
{
    return q->nofRules;
}

/*--------------------------------------------------------------------------*/

void G_quant_get_ith_rule(const struct Quant *q,
			  int i,
			  DCELL * dLow, DCELL * dHigh,
			  CELL * cLow, CELL * cHigh)
{
    *dLow = q->table[i].dLow;
    *dHigh = q->table[i].dHigh;
    *cLow = q->table[i].cLow;
    *cHigh = q->table[i].cHigh;
}

/*--------------------------------------------------------------------------*/

static void quant_table_increase(struct Quant *q)
{
    if (q->nofRules < q->maxNofRules)
	return;

    if (q->maxNofRules == 0) {
	q->maxNofRules = 50;
	q->table = (struct Quant_table *)
	    G_malloc(q->maxNofRules * sizeof(struct Quant_table));
    }
    else {
	q->maxNofRules += 50;
	q->table = (struct Quant_table *)
	    G_realloc((char *)q->table,
		      q->maxNofRules * sizeof(struct Quant_table));
    }
}

/*--------------------------------------------------------------------------*/

void G_quant_set_neg_infinite_rule(struct Quant *q, DCELL dLeft, CELL c)
{
    q->infiniteDLeft = dLeft;
    q->infiniteCLeft = c;
    quant_update_limits(q, dLeft, dLeft, c, c);

    /* update lookup table */
    if (q->fp_lookup.active) {
	q->fp_lookup.inf_dmin = q->infiniteDLeft;
	q->fp_lookup.inf_min = q->infiniteCLeft;
    }
    q->infiniteLeftSet = 1;
}

/*--------------------------------------------------------------------------*/

int G_quant_get_neg_infinite_rule(const struct Quant *q,
				  DCELL * dLeft, CELL * c)
{
    if (q->infiniteLeftSet == 0)
	return 0;

    *dLeft = q->infiniteDLeft;
    *c = q->infiniteCLeft;

    return 1;
}

/*--------------------------------------------------------------------------*/

void G_quant_set_pos_infinite_rule(struct Quant *q, DCELL dRight, CELL c)
{
    q->infiniteDRight = dRight;
    q->infiniteCRight = c;
    quant_update_limits(q, dRight, dRight, c, c);

    /* update lookup table */
    if (q->fp_lookup.active) {
	q->fp_lookup.inf_dmax = q->infiniteDRight;
	q->fp_lookup.inf_max = q->infiniteCRight;
    }
    q->infiniteRightSet = 1;
}

/*--------------------------------------------------------------------------*/

int G_quant_get_pos_infinite_rule(const struct Quant *q,
				  DCELL * dRight, CELL * c)
{
    if (q->infiniteRightSet == 0)
	return 0;

    *dRight = q->infiniteDRight;
    *c = q->infiniteCRight;

    return 1;
}

/*--------------------------------------------------------------------------*/

void G_quant_add_rule(struct Quant *q,
		      DCELL dLow, DCELL dHigh, CELL cLow, CELL cHigh)
{
    int i;
    struct Quant_table *p;

    quant_table_increase(q);

    i = q->nofRules;

    p = &(q->table[i]);
    if (dHigh >= dLow) {
	p->dLow = dLow;
	p->dHigh = dHigh;
	p->cLow = cLow;
	p->cHigh = cHigh;
    }
    else {
	p->dLow = dHigh;
	p->dHigh = dLow;
	p->cLow = cHigh;
	p->cHigh = cLow;
    }

    /* destroy lookup table, it has to be rebuilt */
    if (q->fp_lookup.active) {
	G_free(q->fp_lookup.vals);
	G_free(q->fp_lookup.rules);
	q->fp_lookup.active = 0;
	q->fp_lookup.nalloc = 0;
    }

    quant_update_limits(q, dLow, dHigh, cLow, cHigh);

    q->nofRules++;
}

/*--------------------------------------------------------------------------*/

void G_quant_reverse_rule_order(struct Quant *q)
{
    struct Quant_table tmp;
    struct Quant_table *pLeft, *pRight;

    pLeft = q->table;
    pRight = &(q->table[q->nofRules - 1]);

    while (pLeft < pRight) {
	tmp.dLow = pLeft->dLow;
	tmp.dHigh = pLeft->dHigh;
	tmp.cLow = pLeft->cLow;
	tmp.cHigh = pLeft->cHigh;

	pLeft->dLow = pRight->dLow;
	pLeft->dHigh = pRight->dHigh;
	pLeft->cLow = pRight->cLow;
	pLeft->cHigh = pRight->cHigh;

	pRight->dLow = tmp.dLow;
	pRight->dHigh = tmp.dHigh;
	pRight->cLow = tmp.cLow;
	pRight->cHigh = tmp.cHigh;

	pLeft++;
	pRight--;
    }
}

/*--------------------------------------------------------------------------*/

static CELL quant_interpolate(DCELL dLow, DCELL dHigh,
			      CELL cLow, CELL cHigh, DCELL dValue)
{
    if (cLow == cHigh)
	return cLow;
    if (dLow == dHigh)
	return cLow;

    return (CELL) ((dValue - dLow) / (dHigh - dLow) * (DCELL) (cHigh - cLow) +
		   (DCELL) cLow);
}

/*--------------------------------------------------------------------------*/
static int less_or_equal(double x, double y)
{
    if (x <= y)
	return 1;
    else
	return 0;
}

static int less(double x, double y)
{
    if (x < y)
	return 1;
    else
	return 0;
}


/*!
 * \brief 
 *
 * 
 * Returns a CELL category for the floating-point <em>value</em> based on the
 * quantization rules in <em>q</em>. The first rule found that applies is used.
 * The rules are searched in the reverse order they are added to <em>q</em>.  If no
 * rule is found, the <em>value</em> is first tested against the negative infinite
 * rule, and finally against the positive infinite rule. if none of these rules
 * apply, the NULL-value is returned.
 * <b>NOTE.</b> See G_quant_organize_fp_lookup() for details on how the
 * values are looked up from fp_lookup table when it is active. (Right now
 * fp_lookup is automatically organized during the first call to
 * G_quant_get_cell_value()
 *
 *  \param q
 *  \param value
 *  \return CELL
 */

CELL G_quant_get_cell_value(struct Quant * q, DCELL dcellVal)
{
    CELL tmp;
    DCELL dtmp;
    int try, min_ind, max_ind;
    struct Quant_table *p;
    int (*lower) ();

    dtmp = dcellVal;
    /* I know the functions which call me already check for null values,
       but I am a public function, and can be called from outside */
    if (G_is_d_null_value(&dtmp))
	return NO_DATA;

    if (q->truncate_only)
	return (CELL) dtmp;

    if (q->round_only) {
	if (dcellVal > 0)
	    return (CELL) (dcellVal + .5);
	return (CELL) (dcellVal - .5);
    }

    if (NO_EXPLICIT_RULE)
	return NO_DATA;
    if (NO_EXPLICIT_RULE)
	return NO_DATA;

    if (USE_LOOKUP &&
	(q->fp_lookup.active || G__quant_organize_fp_lookup(q) > 0)) {
	/* first check if values fall within range */
	/* if value is below the range */
	if (dcellVal < q->fp_lookup.vals[0]) {
	    if (dcellVal <= q->fp_lookup.inf_dmin)
		return q->fp_lookup.inf_min;
	    else
		return NO_DATA;
	}
	/* if value is below above range */
	if (dcellVal > q->fp_lookup.vals[q->fp_lookup.nalloc - 1]) {
	    if (dcellVal >= q->fp_lookup.inf_dmax)
		return q->fp_lookup.inf_max;
	    else
		return NO_DATA;
	}
	/* make binary search to find which interval our value belongs to
	   and apply the rule for this interval */
	try = (q->fp_lookup.nalloc - 1) / 2;
	min_ind = 0;
	max_ind = q->fp_lookup.nalloc - 2;
	while (1) {
	    /* DEBUG 
	       fprintf (stderr, "%d %d %d\n", min_ind, max_ind, try); 
	     */
	    /* when the ruke for the interval is NULL, we exclude the end points.
	       when it exists, we include the end-points */
	    if (q->fp_lookup.rules[try])
		lower = less;
	    else
		lower = less_or_equal;

	    if (lower(q->fp_lookup.vals[try + 1], dcellVal)) {	/* recurse to the second half */
		min_ind = try + 1;
		/* must be still < nalloc-1, since number is within the range */
		try = (max_ind + min_ind) / 2;
		continue;
	    }
	    if (lower(dcellVal, q->fp_lookup.vals[try])) {	/* recurse to the second half */
		max_ind = try - 1;
		/* must be still >= 0, since number is within the range */
		try = (max_ind + min_ind) / 2;
		continue;
	    }
	    /* the value fits into the interval! */
	    p = q->fp_lookup.rules[try];
	    if (p)
		return quant_interpolate(p->dLow, p->dHigh, p->cLow, p->cHigh,
					 dcellVal);
	    /* otherwise when finite rule for this interval doesn't exist */
	    else {		/* first check if maybe infinite rule applies */
		if (dcellVal <= q->fp_lookup.inf_dmin)
		    return q->fp_lookup.inf_min;
		if (dcellVal >= q->fp_lookup.inf_dmax)
		    return q->fp_lookup.inf_max;
		else
		    return NO_DATA;
	    }
	}			/* while */
    }				/* looking up in fp_lookup */

    if (!NO_FINITE_RULE) {
	p = G__quant_get_rule_for_d_raster_val(q, dcellVal);
	if (!p)
	    return NO_DATA;
	return quant_interpolate(p->dLow, p->dHigh, p->cLow, p->cHigh,
				 dcellVal);
    }

    if ((!NO_LEFT_INFINITE_RULE) && (dcellVal <= q->infiniteDLeft))
	return q->infiniteCLeft;

    if ((NO_RIGHT_INFINITE_RULE) || (dcellVal < q->infiniteDRight))
	return NO_DATA;

    return q->infiniteCRight;
}

/*--------------------------------------------------------------------------*/

void G_quant_perform_d(struct Quant *q,
		       const DCELL * dcell, CELL * cell, int n)
{
    int i;

    for (i = 0; i < n; i++, dcell++)
	if (!G_is_d_null_value(dcell))
	    *cell++ = G_quant_get_cell_value(q, *dcell);
	else
	    G_set_c_null_value(cell++, 1);
}

/*--------------------------------------------------------------------------*/

void G_quant_perform_f(struct Quant *q,
		       const FCELL * fcell, CELL * cell, int n)
{
    int i;

    for (i = 0; i < n; i++, fcell++)
	if (!G_is_f_null_value(fcell))
	    *cell++ = G_quant_get_cell_value(q, (DCELL) * fcell);
	else
	    G_set_c_null_value(cell++, 1);
}

/*--------------------------------------------------------------------------*/

static int double_comp(const void *xx, const void *yy)
{
    const DCELL *x = xx;
    const DCELL *y = yy;

    if (G_is_d_null_value(x))
	return 0;
    if (*x < *y)
	return -1;
    else if (*x == *y)
	return 0;
    else
	return 1;
}

/*--------------------------------------------------------------------------*/

struct Quant_table *G__quant_get_rule_for_d_raster_val(const struct Quant *q,
						       DCELL val)
{
    const struct Quant_table *p;

    for (p = &(q->table[q->nofRules - 1]); p >= q->table; p--)
	if ((val >= p->dLow) && (val <= p->dHigh))
	    break;
    if (p >= q->table)
	return (struct Quant_table *)p;
    else
	return (struct Quant_table *)NULL;
}

/*--------------------------------------------------------------------------*/

/*--------------------------------------------------------------------------*/

/*--------------------------------------------------------------------------*/