blender-archive/source/blender/blenkernel/intern/unit.c

/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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 2
 * of the License, or (at your option) any later version.
 *
 * 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, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Contributor(s): Campbell Barton
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/blenkernel/intern/unit.c
 *  \ingroup bke
 */

#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>
#include "BKE_unit.h"

#include "BLI_math.h"
#include "BLI_string.h"
#include "BLI_winstuff.h"


#define TEMP_STR_SIZE 256

#define SEP_CHR		'#'
#define SEP_STR		"#"

#define EPS 0.00001

#define UN_SC_KM	1000.0f
#define UN_SC_HM	100.0f
#define UN_SC_DAM	10.0f
#define UN_SC_M		1.0f
#define UN_SC_DM	0.1f
#define UN_SC_CM	0.01f
#define UN_SC_MM	0.001f
#define UN_SC_UM	0.000001f

#define UN_SC_MI	1609.344f
#define UN_SC_FUR	201.168f
#define UN_SC_CH	20.1168f
#define UN_SC_YD	0.9144f
#define UN_SC_FT	0.3048f
#define UN_SC_IN	0.0254f
#define UN_SC_MIL	0.0000254f

#define UN_SC_MTON	1000.0f /* metric ton */
#define UN_SC_QL	100.0f
#define UN_SC_KG	1.0f
#define UN_SC_HG	0.1f
#define UN_SC_DAG	0.01f
#define UN_SC_G		0.001f

#define UN_SC_ITON	907.18474f /* imperial ton */
#define UN_SC_CWT	45.359237f
#define UN_SC_ST	6.35029318f
#define UN_SC_LB	0.45359237f
#define UN_SC_OZ	0.028349523125f

/* define a single unit */
typedef struct bUnitDef {
	const char *name;
	const char *name_plural;	/* abused a bit for the display name */
	const char *name_short;	/* this is used for display*/
	const char *name_alt;		/* keyboard-friendly ASCII-only version of name_short, can be NULL */
						/* if name_short has non-ASCII chars, name_alt should be present */
	
	const char *name_display;		/* can be NULL */

	double scalar;
	double bias;		/* not used yet, needed for converting temperature */
	int flag;
} bUnitDef;

#define B_UNIT_DEF_NONE 0
#define B_UNIT_DEF_SUPPRESS 1 /* Use for units that are not used enough to be translated into for common use */

/* define a single unit */
typedef struct bUnitCollection {
	struct bUnitDef *units;
	int base_unit;				/* basic unit index (when user doesn't specify unit explicitly) */
	int flag;					/* options for this system */
	int length;					/* to quickly find the last item */
} bUnitCollection;

/* Dummy */
static struct bUnitDef buDummyDef[] = {
	{"",	NULL, "",	NULL, NULL, 1.0, 0.0},
	{NULL,	NULL, NULL,	NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buDummyCollecton = {buDummyDef, 0, 0, sizeof(buDummyDef)};


/* Lengths */
static struct bUnitDef buMetricLenDef[] = {
	{"kilometer", "kilometers",		"km", NULL,	"Kilometers", UN_SC_KM, 0.0,	B_UNIT_DEF_NONE},
	{"hectometer", "hectometers",	"hm", NULL,	"100 Meters", UN_SC_HM, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"dekameter", "dekameters",		"dam",NULL,	"10 Meters",  UN_SC_DAM, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"meter", "meters",				"m",  NULL,	"Meters",     UN_SC_M, 0.0, 	B_UNIT_DEF_NONE}, /* base unit */
	{"decimetre", "decimetres",		"dm", NULL,	"10 Centimeters", UN_SC_DM, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"centimeter", "centimeters",	"cm", NULL,	"Centimeters", UN_SC_CM, 0.0,	B_UNIT_DEF_NONE},
	{"millimeter", "millimeters",	"mm", NULL,	"Millimeters", UN_SC_MM, 0.0,	B_UNIT_DEF_NONE},
	{"micrometer", "micrometers",	"µm", "um",	"Micrometers", UN_SC_UM, 0.0,	B_UNIT_DEF_NONE}, // micron too?

	/* These get displayed because of float precision problems in the transform header,
	 * could work around, but for now probably people wont use these */
	/*
	{"nanometer", "Nanometers",		"nm", NULL,	0.000000001, 0.0,	B_UNIT_DEF_NONE},
	{"picometer", "Picometers",		"pm", NULL,	0.000000000001, 0.0,B_UNIT_DEF_NONE},
	*/
	{NULL, NULL, NULL,	NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buMetricLenCollecton = {buMetricLenDef, 3, 0, sizeof(buMetricLenDef)/sizeof(bUnitDef)};

static struct bUnitDef buImperialLenDef[] = {
	{"mile", "miles",		"mi", "m", "Miles",		UN_SC_MI, 0.0,	B_UNIT_DEF_NONE},
	{"furlong", "furlongs",	"fur", NULL, "Furlongs",UN_SC_FUR, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"chain", "chains",		"ch", NULL, "Chains",	UN_SC_CH, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"yard", "yards",		"yd", NULL, "Yards",	UN_SC_YD, 0.0,	B_UNIT_DEF_NONE},
	{"foot", "feet",		"'", "ft", "Feet",		UN_SC_FT, 0.0,	B_UNIT_DEF_NONE}, /* base unit */
	{"inch", "inches",		"\"", "in", "Inches",	UN_SC_IN, 0.0,	B_UNIT_DEF_NONE},
	{"thou", "thou",		"thou", "mil", "Thou",	UN_SC_MIL, 0.0,	B_UNIT_DEF_NONE}, /* plural for thou has no 's' */
	{NULL, NULL, NULL, NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buImperialLenCollecton = {buImperialLenDef, 4, 0, sizeof(buImperialLenDef)/sizeof(bUnitDef)};

/* Areas */
static struct bUnitDef buMetricAreaDef[] = {
	{"square kilometer", "square kilometers",	"km²", "km2",	"Square Kilometers", UN_SC_KM*UN_SC_KM, 0.0,	B_UNIT_DEF_NONE},
	{"square hectometer","square hectometers",	"hm²", "hm2",	"Square Hectometers", UN_SC_HM*UN_SC_HM, 0.0,	B_UNIT_DEF_NONE}, /* hectare */
	{"square dekameter", "square dekameters",	"dam²","dam2",	"Square Dekameters", UN_SC_DAM*UN_SC_DAM, 0.0,	B_UNIT_DEF_SUPPRESS}, /* are */
	{"square meter", "square meters",			"m²",  "m2",	"Square Meters", UN_SC_M*UN_SC_M, 0.0, 			B_UNIT_DEF_NONE}, /* base unit */
	{"square decimetre", "square decimetres",	"dm²", "dm2",	"Square Decimetres", UN_SC_DM*UN_SC_DM, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"square centimeter", "square centimeters",	"cm²", "cm2",	"Square Centimeters", UN_SC_CM*UN_SC_CM, 0.0,	B_UNIT_DEF_NONE},
	{"square millimeter", "square millimeters",	"mm²", "mm2",	"Square Millimeters", UN_SC_MM*UN_SC_MM, 0.0,	B_UNIT_DEF_NONE},
	{"square micrometer", "square micrometers",	"µm²", "um2",	"Square Micrometers", UN_SC_UM*UN_SC_UM, 0.0,	B_UNIT_DEF_NONE},
	{NULL, NULL, NULL,	NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buMetricAreaCollecton = {buMetricAreaDef, 3, 0, sizeof(buMetricAreaDef)/sizeof(bUnitDef)};

static struct bUnitDef buImperialAreaDef[] = {
	{"square mile", "square miles",			"sq mi", "sq m","Square Miles", UN_SC_MI*UN_SC_MI, 0.0,		B_UNIT_DEF_NONE},
	{"square furlong", "square furlongs",	"sq fur",NULL,	"Square Furlongs", UN_SC_FUR*UN_SC_FUR, 0.0,B_UNIT_DEF_SUPPRESS},
	{"square chain", "square chains",		"sq ch", NULL,	"Square Chains", UN_SC_CH*UN_SC_CH, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"square yard", "square yards",			"sq yd", NULL,	"Square Yards", UN_SC_YD*UN_SC_YD, 0.0,		B_UNIT_DEF_NONE},
	{"square foot", "square feet",			"sq ft", NULL,	"Square Feet", UN_SC_FT*UN_SC_FT, 0.0,		B_UNIT_DEF_NONE}, /* base unit */
	{"square inch", "square inches",		"sq in", NULL,	"Square Inches", UN_SC_IN*UN_SC_IN, 0.0,	B_UNIT_DEF_NONE},
	{"square thou", "square thous",			"sq mil",NULL,	"Square Thous", UN_SC_MIL*UN_SC_MIL, 0.0,	B_UNIT_DEF_NONE},
	{NULL, NULL, NULL, NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buImperialAreaCollecton = {buImperialAreaDef, 4, 0, sizeof(buImperialAreaDef)/sizeof(bUnitDef)};

/* Volumes */
static struct bUnitDef buMetricVolDef[] = {
	{"cubic kilometer", "cubic kilometers",		"km³", "km3",	"Cubic Kilometers", UN_SC_KM*UN_SC_KM*UN_SC_KM, 0.0,	B_UNIT_DEF_NONE},
	{"cubic hectometer","cubic hectometers",	"hm³", "hm3",	"Cubic Hectometers", UN_SC_HM*UN_SC_HM*UN_SC_HM, 0.0,	B_UNIT_DEF_NONE},
	{"cubic dekameter", "cubic dekameters",		"dam³","dam3",	"Cubic Dekameters", UN_SC_DAM*UN_SC_DAM*UN_SC_DAM, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"cubic meter", "cubic meters",				"m³",  "m3",	"Cubic Meters", UN_SC_M*UN_SC_M*UN_SC_M, 0.0, 			B_UNIT_DEF_NONE}, /* base unit */
	{"cubic decimetre", "cubic decimetres",		"dm³", "dm3",	"Cubic Decimetres", UN_SC_DM*UN_SC_DM*UN_SC_DM, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"cubic centimeter", "cubic centimeters",	"cm³", "cm3",	"Cubic Centimeters", UN_SC_CM*UN_SC_CM*UN_SC_CM, 0.0,	B_UNIT_DEF_NONE},
	{"cubic millimeter", "cubic millimeters",	"mm³", "mm3",	"Cubic Millimeters", UN_SC_MM*UN_SC_MM*UN_SC_MM, 0.0,	B_UNIT_DEF_NONE},
	{"cubic micrometer", "cubic micrometers",	"µm³", "um3",	"Cubic Micrometers", UN_SC_UM*UN_SC_UM*UN_SC_UM, 0.0,	B_UNIT_DEF_NONE},
	{NULL, NULL, NULL,	NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buMetricVolCollecton = {buMetricVolDef, 3, 0, sizeof(buMetricVolDef)/sizeof(bUnitDef)};

static struct bUnitDef buImperialVolDef[] = {
	{"cubic mile", "cubic miles",		"cu mi", "cu m","Cubic Miles", UN_SC_MI*UN_SC_MI*UN_SC_MI, 0.0,		B_UNIT_DEF_NONE},
	{"cubic furlong", "cubic furlongs",	"cu fur",NULL,	"Cubic Furlongs", UN_SC_FUR*UN_SC_FUR*UN_SC_FUR, 0.0,B_UNIT_DEF_SUPPRESS},
	{"cubic chain", "cubic chains",		"cu ch", NULL,	"Cubic Chains", UN_SC_CH*UN_SC_CH*UN_SC_CH, 0.0,	B_UNIT_DEF_SUPPRESS},
	{"cubic yard", "cubic yards",		"cu yd", NULL,	"Cubic Yards", UN_SC_YD*UN_SC_YD*UN_SC_YD, 0.0,		B_UNIT_DEF_NONE},
	{"cubic foot", "cubic feet",		"cu ft", NULL,	"Cubic Feet", UN_SC_FT*UN_SC_FT*UN_SC_FT, 0.0,		B_UNIT_DEF_NONE}, /* base unit */
	{"cubic inch", "cubic inches",		"cu in", NULL,	"Cubic Inches", UN_SC_IN*UN_SC_IN*UN_SC_IN, 0.0,	B_UNIT_DEF_NONE},
	{"cubic thou", "cubic thous",		"cu mil",NULL,	"Cubic Thous", UN_SC_MIL*UN_SC_MIL*UN_SC_MIL, 0.0,	B_UNIT_DEF_NONE},
	{NULL, NULL, NULL, NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buImperialVolCollecton = {buImperialVolDef, 4, 0, sizeof(buImperialVolDef)/sizeof(bUnitDef)};

/* Mass */
static struct bUnitDef buMetricMassDef[] = {
	{"ton", "tonnes",			"ton", "t", "1000 Kilograms", UN_SC_MTON, 0.0,	B_UNIT_DEF_NONE},
	{"quintal", "quintals",		"ql", "q",	"100 Kilograms", UN_SC_QL, 0.0,		B_UNIT_DEF_NONE},
	{"kilogram", "kilograms",	"kg", NULL,	"Kilograms", UN_SC_KG, 0.0,			B_UNIT_DEF_NONE}, /* base unit */
	{"hectogram", "hectograms",	"hg", NULL,	"Hectograms", UN_SC_HG, 0.0,		B_UNIT_DEF_NONE},
	{"dekagram", "dekagrams",	"dag",NULL,	"10 Grams", UN_SC_DAG, 0.0,			B_UNIT_DEF_SUPPRESS},
	{"gram", "grams",			"g",  NULL,	"Grams", UN_SC_G, 0.0,				B_UNIT_DEF_NONE},
	{NULL, NULL, NULL,	NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buMetricMassCollecton = {buMetricMassDef, 2, 0, sizeof(buMetricMassDef)/sizeof(bUnitDef)};

static struct bUnitDef buImperialMassDef[] = {
	{"ton", "tonnes",	"ton", "t",	"Tonnes", UN_SC_ITON, 0.0,		B_UNIT_DEF_NONE},
	{"centum weight", "centum weights", "cwt", NULL, "Centum weights", UN_SC_CWT, 0.0, B_UNIT_DEF_NONE},
	{"stone", "stones",	"st", NULL,		"Stones", UN_SC_ST, 0.0,	B_UNIT_DEF_NONE},
	{"pound", "pounds",	"lb", NULL,		"Pounds", UN_SC_LB, 0.0,	B_UNIT_DEF_NONE}, /* base unit */
	{"ounce", "ounces",	"oz", NULL,		"Ounces", UN_SC_OZ, 0.0,	B_UNIT_DEF_NONE},
	{NULL, NULL, NULL, NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buImperialMassCollecton = {buImperialMassDef, 3, 0, sizeof(buImperialMassDef)/sizeof(bUnitDef)};

/* Even if user scales the system to a point where km^3 is used, velocity and
 * acceleration aren't scaled: that's why we have so few units for them */

/* Velocity */
static struct bUnitDef buMetricVelDef[] = {
	{"meter per second", "meters per second",		"m/s",  NULL,	"Meters per second", UN_SC_M, 0.0,			  B_UNIT_DEF_NONE}, /* base unit */
	{"kilometer per hour", "kilometers per hour",	"km/h", NULL,	"Kilometers per hour", UN_SC_KM/3600.0f, 0.0, B_UNIT_DEF_SUPPRESS},
	{NULL, NULL, NULL,	NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buMetricVelCollecton = {buMetricVelDef, 0, 0, sizeof(buMetricVelDef)/sizeof(bUnitDef)};

static struct bUnitDef buImperialVelDef[] = {
	{"foot per second", "feet per second",	"ft/s", "fps",	"Feet per second", UN_SC_FT, 0.0,		B_UNIT_DEF_NONE}, /* base unit */
	{"mile per hour", "miles per hour",		"mph", NULL,	"Miles per hour", UN_SC_MI/3600.0f, 0.0,B_UNIT_DEF_SUPPRESS},
	{NULL, NULL, NULL, NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buImperialVelCollecton = {buImperialVelDef, 0, 0, sizeof(buImperialVelDef)/sizeof(bUnitDef)};

/* Acceleration */
static struct bUnitDef buMetricAclDef[] = {
	{"meter per second squared", "meters per second squared", "m/s²", "m/s2", "Meters per second squared", UN_SC_M, 0.0, B_UNIT_DEF_NONE}, /* base unit */
	{NULL, NULL, NULL,	NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buMetricAclCollecton = {buMetricAclDef, 0, 0, sizeof(buMetricAclDef)/sizeof(bUnitDef)};

static struct bUnitDef buImperialAclDef[] = {
	{"foot per second squared", "feet per second squared", "ft/s²", "ft/s2", "Feet per second squared", UN_SC_FT, 0.0, B_UNIT_DEF_NONE}, /* base unit */
	{NULL, NULL, NULL, NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buImperialAclCollecton = {buImperialAclDef, 0, 0, sizeof(buImperialAclDef)/sizeof(bUnitDef)};

/* Time */
static struct bUnitDef buNaturalTimeDef[] = {
	/* weeks? - probably not needed for blender */
	{"day", "days",					"d", NULL,	"Days",			90000.0, 0.0,	B_UNIT_DEF_NONE},
	{"hour", "hours",				"hr", "h",	"Hours",		3600.0, 0.0,	B_UNIT_DEF_NONE},
	{"minute", "minutes",			"min", "m",	"Minutes",		60.0, 0.0,		B_UNIT_DEF_NONE},
	{"second", "seconds",			"sec", "s",	"Seconds",		1.0, 0.0,		B_UNIT_DEF_NONE}, /* base unit */
	{"millisecond", "milliseconds",	"ms", NULL,	"Milliseconds",	0.001, 0.0	,	B_UNIT_DEF_NONE},
	{"microsecond", "microseconds",	"µs", "us",	"Microseconds",	0.000001, 0.0,	B_UNIT_DEF_NONE},
	{NULL, NULL, NULL, NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buNaturalTimeCollecton = {buNaturalTimeDef, 3, 0, sizeof(buNaturalTimeDef)/sizeof(bUnitDef)};


static struct bUnitDef buNaturalRotDef[] = {
	{"degree", "degrees",			"°", NULL, "Degrees",		M_PI/180.0, 0.0,	B_UNIT_DEF_NONE},
//	{"radian", "radians",			"r", NULL, "Radians",		1.0, 0.0,			B_UNIT_DEF_NONE},
//	{"turn", "turns",				"t", NULL, "Turns",			1.0/(M_PI*2.0), 0.0,B_UNIT_DEF_NONE},
	{NULL, NULL, NULL, NULL, NULL, 0.0, 0.0}
};
static struct bUnitCollection buNaturalRotCollection = {buNaturalRotDef, 0, 0, sizeof(buNaturalRotDef)/sizeof(bUnitDef)};

#define UNIT_SYSTEM_TOT (((sizeof(bUnitSystems) / 9) / sizeof(void *)) - 1)
static struct bUnitCollection *bUnitSystems[][9] = {
	{NULL, NULL, NULL, NULL, NULL, &buNaturalRotCollection, &buNaturalTimeCollecton, NULL, NULL},
	{NULL, &buMetricLenCollecton, &buMetricAreaCollecton, &buMetricVolCollecton, &buMetricMassCollecton, &buNaturalRotCollection, &buNaturalTimeCollecton, &buMetricVelCollecton, &buMetricAclCollecton}, /* metric */
	{NULL, &buImperialLenCollecton, &buImperialAreaCollecton, &buImperialVolCollecton, &buImperialMassCollecton, &buNaturalRotCollection, &buNaturalTimeCollecton, &buImperialVelCollecton, &buImperialAclCollecton}, /* imperial */
	{NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL}
};



/* internal, has some option not exposed */
static bUnitCollection *unit_get_system(int system, int type)
{
	assert((system > -1) && (system < UNIT_SYSTEM_TOT) && (type > -1) && (type < B_UNIT_TYPE_TOT));
	return bUnitSystems[system][type]; /* select system to use, metric/imperial/other? */
}

static bUnitDef *unit_default(bUnitCollection *usys)
{
	return &usys->units[usys->base_unit];
}

static bUnitDef *unit_best_fit(double value, bUnitCollection *usys, bUnitDef *unit_start, int suppress)
{
	bUnitDef *unit;
	double value_abs= value>0.0?value:-value;

	for(unit= unit_start ? unit_start:usys->units; unit->name; unit++) {

		if(suppress && (unit->flag & B_UNIT_DEF_SUPPRESS))
			continue;

		/* scale down scalar so 1cm doesnt convert to 10mm because of float error */
		if (value_abs >= unit->scalar*(1.0-EPS))
			return unit;
	}

	return unit_default(usys);
}



/* convert into 2 units and 2 values for "2ft, 3inch" syntax */
static void unit_dual_convert(double value, bUnitCollection *usys,
		bUnitDef **unit_a, bUnitDef **unit_b, double *value_a, double *value_b)
{
	bUnitDef *unit= unit_best_fit(value, usys, NULL, 1);

	*value_a=  (value < 0.0 ? ceil:floor)(value/unit->scalar) * unit->scalar;
	*value_b= value - (*value_a);

	*unit_a=	unit;
	*unit_b=	unit_best_fit(*value_b, usys, *unit_a, 1);
}

static int unit_as_string(char *str, int len_max, double value, int prec, bUnitCollection *usys,
		/* non exposed options */
		bUnitDef *unit, char pad)
{
	double value_conv;
	int len, i;
	
	if(unit) {
		/* use unit without finding the best one */
	}
	else if(value == 0.0) {
		/* use the default units since there is no way to convert */
		unit= unit_default(usys);
	}
	else {
		unit= unit_best_fit(value, usys, NULL, 1);
	}

	value_conv= value/unit->scalar;

	/* Convert to a string */
	{
		len= BLI_snprintf(str, len_max, "%.*f", prec, value_conv);

		if(len >= len_max)
			len= len_max;
	}
	
	/* Add unit prefix and strip zeros */

	/* replace trailing zero's with spaces
	 * so the number is less complicated but allignment in a button wont
	 * jump about while dragging */
	i= len-1;

	while(i>0 && str[i]=='0') { /* 4.300 -> 4.3 */
		str[i--]= pad;
	}

	if(i>0 && str[i]=='.') { /* 10. -> 10 */
		str[i--]= pad;
	}
	
	/* Now add the suffix */
	if(i<len_max) {
		int j=0;
		i++;
		while(unit->name_short[j] && (i < len_max)) {
			str[i++]= unit->name_short[j++];
		}

		if(pad) {
			/* this loop only runs if so many zeros were removed that
			 * the unit name only used padded chars,
			 * In that case add padding for the name. */

			while(i<=len+j && (i < len_max)) {
				str[i++]= pad;
			}
		}
	}

	/* terminate no matter whats done with padding above */
	if(i >= len_max)
		i= len_max-1;

	str[i] = '\0';
	return i;
}


/* Used for drawing number buttons, try keep fast */
void bUnit_AsString(char *str, int len_max, double value, int prec, int system, int type, int split, int pad)
{
	bUnitCollection *usys = unit_get_system(system, type);

	if(usys==NULL || usys->units[0].name==NULL)
		usys= &buDummyCollecton;
   
	/* split output makes sense only for length, mass and time */
	if(split && (type==B_UNIT_LENGTH || type==B_UNIT_MASS || type==B_UNIT_TIME)) {
		bUnitDef *unit_a, *unit_b;
		double value_a, value_b;

		unit_dual_convert(value, usys,		&unit_a, &unit_b, &value_a, &value_b);

		/* check the 2 is a smaller unit */
		if(unit_b > unit_a) {
			int i= unit_as_string(str, len_max, value_a, prec, usys,  unit_a, '\0');

			/* is there enough space for at least 1 char of the next unit? */
			if(i+2 < len_max) {
				str[i++]= ' ';

				/* use low precision since this is a smaller unit */
				unit_as_string(str+i, len_max-i, value_b, prec?1:0, usys,  unit_b, '\0');
			}
			return;
		}
	}

	unit_as_string(str, len_max, value, prec, usys,    NULL, pad?' ':'\0');
}


static const char *unit_find_str(const char *str, const char *substr)
{
	const char *str_found;

	if(substr && substr[0] != '\0') {
		str_found= strstr(str, substr);
		if(str_found) {
			/* previous char cannot be a letter */
			if (str_found == str || isalpha(*(str_found-1))==0) {
				/* next char cannot be alphanum */
				int len_name = strlen(substr);

				if (!isalpha(*(str_found+len_name))) {
					return str_found;
				}
			}
		}

	}
	return NULL;

}

/* Note that numbers are added within brackets
 * ") " - is used to detect numbers we added so we can detect if commas need to be added
 *
 * "1m1cm+2mm"				- Original value
 * "1*1#1*0.01#+2*0.001#"	- Replace numbers
 * "1*1,1*0.01 +2*0.001 "	- Add comma's if ( - + * / % ^ < > ) not found in between
 *
 */

/* not too strict, (- = * /) are most common  */
static int ch_is_op(char op)
{
	switch(op) {
	case '+':
	case '-':
	case '*':
	case '/':
	case '|':
	case '&':
	case '~':
	case '<':
	case '>':
	case '^':
	case '!':
	case '=':
	case '%':
		return 1;
	default:
		return 0;
	}
}

static int unit_scale_str(char *str, int len_max, char *str_tmp,
                          double scale_pref, bUnitDef *unit, const char *replace_str)
{
	char *str_found;

	if((len_max>0) && (str_found= (char *)unit_find_str(str, replace_str))) {
		/* XXX - investigate, does not respect len_max properly  */

		int len, len_num, len_name, len_move, found_ofs;

		found_ofs = (int)(str_found-str);

		len= strlen(str);

		len_name = strlen(replace_str);
		len_move= (len - (found_ofs+len_name)) + 1; /* 1+ to copy the string terminator */
		len_num= BLI_snprintf(str_tmp, TEMP_STR_SIZE, "*%g"SEP_STR, unit->scalar/scale_pref); /* # removed later */

		if(len_num > len_max)
			len_num= len_max;

		if(found_ofs+len_num+len_move > len_max) {
			/* can't move the whole string, move just as much as will fit */
			len_move -= (found_ofs+len_num+len_move) - len_max;
		}

		if(len_move>0) {
			/* resize the last part of the string */
			memmove(str_found+len_num, str_found+len_name, len_move); /* may grow or shrink the string */
		}

		if(found_ofs+len_num > len_max) {
			/* not even the number will fit into the string, only copy part of it */
			len_num -= (found_ofs+len_num) - len_max;
		}

		if(len_num > 0) {
			/* its possible none of the number could be copied in */
			memcpy(str_found, str_tmp, len_num); /* without the string terminator */
		}

		/* since the null terminator wont be moved if the stringlen_max
		 * was not long enough to fit everything in it */
		str[len_max-1]= '\0';
		return found_ofs + len_num;
	}
	return 0;
}

static int unit_replace(char *str, int len_max, char *str_tmp, double scale_pref, bUnitDef *unit)
{	
	int ofs= 0;
	ofs += unit_scale_str(str+ofs, len_max-ofs, str_tmp, scale_pref, unit, unit->name_short);
	ofs += unit_scale_str(str+ofs, len_max-ofs, str_tmp, scale_pref, unit, unit->name_plural);
	ofs += unit_scale_str(str+ofs, len_max-ofs, str_tmp, scale_pref, unit, unit->name_alt);
	ofs += unit_scale_str(str+ofs, len_max-ofs, str_tmp, scale_pref, unit, unit->name);
	return ofs;
}

static int unit_find(const char *str, bUnitDef *unit)
{
	if (unit_find_str(str, unit->name_short))	return 1;
	if (unit_find_str(str, unit->name_plural))	return 1;
	if (unit_find_str(str, unit->name_alt))		return 1;
	if (unit_find_str(str, unit->name))			return 1;

	return 0;
}

/* make a copy of the string that replaces the units with numbers
 * this is used before parsing
 * This is only used when evaluating user input and can afford to be a bit slower
 * 
 * This is to be used before python evaluation so..
 * 10.1km -> 10.1*1000.0
 * ...will be resolved by python.
 * 
 * values will be split by a comma's
 * 5'2" -> 5'0.0254, 2*0.3048
 *
 * str_prev is optional, when valid it is used to get a base unit when none is set.
 *
 * return true of a change was made.
 */
int bUnit_ReplaceString(char *str, int len_max, const char *str_prev, double scale_pref, int system, int type)
{
	bUnitCollection *usys = unit_get_system(system, type);

	bUnitDef *unit;
	char str_tmp[TEMP_STR_SIZE];
	int change= 0;

	if(usys==NULL || usys->units[0].name==NULL) {
		return 0;
	}
	

	{	/* make lowercase */
		int i;
		char *ch= str;

		for(i=0; (i>=len_max || *ch=='\0'); i++, ch++)
			if((*ch>='A') && (*ch<='Z'))
				*ch += ('a'-'A');
	}


	for(unit= usys->units; unit->name; unit++) {
		/* incase there are multiple instances */
		while(unit_replace(str, len_max, str_tmp, scale_pref, unit))
			change= 1;
	}
	unit= NULL;

	{
		/* try other unit systems now, so we can evaluate imperial when metric is set for eg. */
		bUnitCollection *usys_iter;
		int system_iter;

		for(system_iter= 0; system_iter<UNIT_SYSTEM_TOT; system_iter++) {
			if (system_iter != system) {
				usys_iter= unit_get_system(system_iter, type);
				if (usys_iter) {
					for(unit= usys_iter->units; unit->name; unit++) {
						int ofs = 0;
						/* incase there are multiple instances */
						while((ofs=unit_replace(str+ofs, len_max-ofs, str_tmp, scale_pref, unit)))
							change= 1;
					}
				}
			}
		}
	}
	unit= NULL;
	
	if(change==0) {
		/* no units given so infer a unit from the previous string or default */
		if(str_prev) {
			/* see which units the original value had */
			for(unit= usys->units; unit->name; unit++) {
				if (unit_find(str_prev, unit))
					break;
			}
		}

		if(unit==NULL || unit->name == NULL)
			unit= unit_default(usys);


		/* add the unit prefix and re-run, use brackets incase there was an expression given */
		if(BLI_snprintf(str_tmp, sizeof(str_tmp), "(%s)%s", str, unit->name) < sizeof(str_tmp)) {
			strncpy(str, str_tmp, len_max);
			return bUnit_ReplaceString(str, len_max, NULL, scale_pref, system, type);
		}
		else {
			/* BLI_snprintf would not fit into str_tmp, cant do much in this case
			 * check for this because otherwise bUnit_ReplaceString could call its self forever */
			return 0;
		}

	}

	/* replace # with commas when there is no operator between it and the next number
	 *
	 * "1*1# 3*100# * 3"  ->  "1 *1, 3 *100  * 3"
	 *
	 * */
	{
		char *str_found= str;
		char *ch= str;

		while((str_found= strchr(str_found, SEP_CHR))) {

			int op_found= 0;
			/* any operators after this?*/
			for(ch= str_found+1; *ch!='\0'; ch++) {

				if(*ch==' ' || *ch=='\t') {
					/* do nothing */
				}
				else if (ch_is_op(*ch) || *ch==',') { /* found an op, no need to insert a ,*/
					op_found= 1;
					break;
				}
				else { /* found a non-op character */
					op_found= 0;
					break;
				}
			}

			*str_found++ = op_found ? ' ':',';
		}
	}

	return change;
}

/* 45µm --> 45um */
void bUnit_ToUnitAltName(char *str, int len_max, const char *orig_str, int system, int type)
{
	bUnitCollection *usys = unit_get_system(system, type);

	bUnitDef *unit;
	bUnitDef *unit_def= unit_default(usys);

	/* find and substitute all units */
	for(unit= usys->units; unit->name; unit++) {
		if(len_max > 0 && (unit->name_alt || unit == unit_def))
		{
			const char *found= unit_find_str(orig_str, unit->name_short);
			if(found) {
				int offset= (int)(found - orig_str);
				int len_name= 0;

				/* copy everything before the unit */
				offset= (offset<len_max? offset: len_max);
				strncpy(str, orig_str, offset);

				str+= offset;
				orig_str+= offset + strlen(unit->name_short);
				len_max-= offset;

				/* print the alt_name */
				if(unit->name_alt)
					len_name= BLI_snprintf(str, len_max, "%s", unit->name_alt);
				else
					len_name= 0;

				len_name= (len_name<len_max? len_name: len_max);
				str+= len_name;
				len_max-= len_name;
			}
		}
	}

	/* finally copy the rest of the string */
	strncpy(str, orig_str, len_max);
}

double bUnit_ClosestScalar(double value, int system, int type)
{
	bUnitCollection *usys = unit_get_system(system, type);
	bUnitDef *unit;

	if(usys==NULL)
		return -1;

	unit= unit_best_fit(value, usys, NULL, 1);
	if(unit==NULL)
		return -1;

	return unit->scalar;
}

double bUnit_BaseScalar(int system, int type)
{
	bUnitCollection *usys = unit_get_system(system, type);
	return unit_default(usys)->scalar;
}

/* external access */
int bUnit_IsValid(int system, int type)
{
	return !(system < 0 || system > UNIT_SYSTEM_TOT || type < 0 || type > B_UNIT_TYPE_TOT);
}


void bUnit_GetSystem(void **usys_pt, int *len, int system, int type)
{
	bUnitCollection *usys = unit_get_system(system, type);
	*usys_pt= usys;

	if(usys==NULL) {
		*len= 0;
		return;
	}

	*len= usys->length;
}

int bUnit_GetBaseUnit(void *usys_pt)
{
	return ((bUnitCollection *)usys_pt)->base_unit;
}

const char *bUnit_GetName(void *usys_pt, int index)
{
	return ((bUnitCollection *)usys_pt)->units[index].name;
}
const char *bUnit_GetNameDisplay(void *usys_pt, int index)
{
	return ((bUnitCollection *)usys_pt)->units[index].name_display;
}

double bUnit_GetScaler(void *usys_pt, int index)
{
	return ((bUnitCollection *)usys_pt)->units[index].scalar;
}