#include "calc.h"

/*
    The conversion is made by converting the "from" unit
    into the I.S. unit and then the I.S. unit is converted
    into the "from" one.

    The base units for all categories are:

    ANGLE..........degrees
    AREA...........square meters
    CONSUMPTION....kilometers per liter
    CURRENCY.......Euro
    ENERGY.........joule
    LENGTHS........meters
    POWER..........Watt
    PRESSURE.......Pascal
    TEMPERATURE....kelvin
    TIME...........seconds
    VELOCITY.......meters per second
    VOLUME.........liter
    WEIGHT.........gram

    The '$' character is used as "what you read into the display".
*/
typedef struct {
    DWORD unit;
    const char *formula_from;
    const char *formula_to;
} conv_t;

typedef struct {
    const DWORD   category;
    const conv_t *items;
} conv_category_t;

#define DECLARE_CONV_CAT(_category) \
    { IDS_CONV_##_category, conv_##_category },

#define DECLARE_CONV_UNIT(_category, _unit, _from, _to ) \
    { IDS_##_category##_##_unit, _from, _to },

#define DECLARE_CONV_END \
    { 0, NULL, NULL },

/*
    1 gradian = 0.9 deg
    1 radian = 57.29577951308233 deg
*/
static const conv_t conv_ANGLE[] = {
    DECLARE_CONV_UNIT(ANGLE, DEGREES,  "$", "$")
    DECLARE_CONV_UNIT(ANGLE, GRADIANS, "$*0.9", "$/0.9")
    DECLARE_CONV_UNIT(ANGLE, RADIANS,  "$*180/P", "$*P/180")
    DECLARE_CONV_END
};

/*
    1 acre ................ = 4840 square yd = 4046,8564224 mq
    1 acre brazil ......... = 
    1 acre france ......... = 
    1 acre scots .......... = 5000 mq
    1 acre us ............. = 4840*(36/39.37)^2 m = 6272640/1549.9969 m
    1 are ................. = 100 mq
    1 chou ................ = 108000*(10/33)^2 mq
    1 danbo ............... = 
    1 ha .................. = 10000 mq
    1 jeongbo ............. = 
    1 morgen hungary ...... = 
    1 mu .................. = 
    1 ping ................ = 
    1 pyeong .............. = 
    1 pyeongbangja ........ = 
    1 rai ................. = 
    1 se .................. = 1080*(10/33)^2 mq
    1 square cm ........... = 0.0001 mq
    1 square chr .......... = 
    1 square fathom ....... = 1.8288^2 = 3.34450944 mq
    1 square fathom hungary = 1.8964838^2 = 3.59665080366244 mq
    1 square ft ........... = 0,09290304 mq
    1 square in ........... = 0,00064516 mq
    1 square km ........... = 1000000 mq
    1 square lar .......... = 
    1 square mile ......... = 1609.344^2 = 2589988.110336 mq
    1 square mm ........... = 0,000001 mq
    1 square shaku ........ = (10/33)^2 mq
    1 square tsuen ........ = 
    1 square va ........... = 
    1 square yard ......... = 0,83612736 mq
    1 tan ................. = 10800*(10/33)^2 mq
    1 tsubo ............... = 36*(10/33)^2 mq
*/
static const conv_t conv_AREA[] = {
    DECLARE_CONV_UNIT(AREA, ACRES,                  "$*4046,8564224",    "$/4046,8564224")
//    DECLARE_CONV_UNIT(AREA, ACRES_BRAZIL,           "$", "$")
//    DECLARE_CONV_UNIT(AREA, ACRES_FRANCE,           "$", "$")
    DECLARE_CONV_UNIT(AREA, ACRES_US,               "$*627264/154.99969", "$/627264*154.99969")
    DECLARE_CONV_UNIT(AREA, ACRES_SCOTS,            "$*5000",            "$/5000")
    DECLARE_CONV_UNIT(AREA, ARES,                   "$*100",             "$/100")
    DECLARE_CONV_UNIT(AREA, CHOU,                   "$*10800000/1089",   "$*1089/10800000")
//    DECLARE_CONV_UNIT(AREA, DANBO,                  "$", "$")
    DECLARE_CONV_UNIT(AREA, HECTARES,               "$*10000",           "$/10000")
//    DECLARE_CONV_UNIT(AREA, JEONGBO,                "$", "$")
//    DECLARE_CONV_UNIT(AREA, MORGEN_HUNGARY,         "$", "$")
//    DECLARE_CONV_UNIT(AREA, MU,                     "$", "$")
//    DECLARE_CONV_UNIT(AREA, PING,                   "$", "$")
//    DECLARE_CONV_UNIT(AREA, PYEONG,                 "$", "$")
//    DECLARE_CONV_UNIT(AREA, PYEONGBANGJA,           "$", "$")
//    DECLARE_CONV_UNIT(AREA, RAI,                    "$", "$")
    DECLARE_CONV_UNIT(AREA, SE,                     "$*108000/1089",     "$*1089/108000")
    DECLARE_CONV_UNIT(AREA, SQUARE_CENTIMETERS,     "$*0,0001",          "$/0,0001")
//    DECLARE_CONV_UNIT(AREA, SQUARE_CHR,             "$", "$")
    DECLARE_CONV_UNIT(AREA, SQUARE_FATHOMS,         "$*3.34450944",      "$/3.34450944")
    DECLARE_CONV_UNIT(AREA, SQUARE_FATHOMS_HUNGARY, "$*3.59665080366244", "$/3.59665080366244")
    DECLARE_CONV_UNIT(AREA, SQUARE_FEET,            "$*0,09290304",      "$/0,09290304")
    DECLARE_CONV_UNIT(AREA, SQUARE_INCHES,          "$*0,00064516",      "$/0.00064516")
    DECLARE_CONV_UNIT(AREA, SQUARE_KILOMETERS,      "$*1000000",         "$/1000000")
//    DECLARE_CONV_UNIT(AREA, SQUARE_LAR,             "$", "$")
    DECLARE_CONV_UNIT(AREA, SQUARE_METER,           "$",                 "$")
    DECLARE_CONV_UNIT(AREA, SQUARE_MILES,           "$*2589988.110336",  "$/2589988.110336")
    DECLARE_CONV_UNIT(AREA, SQUARE_MILLIMETERS,     "$*1000000",         "$/1000000")
    DECLARE_CONV_UNIT(AREA, SQUARE_SHAKU,           "$*100/1089",        "$/1089*100")
//    DECLARE_CONV_UNIT(AREA, SQUARE_TSUEN,           "$", "$")
//    DECLARE_CONV_UNIT(AREA, SQUARE_VA,              "$", "$")
    DECLARE_CONV_UNIT(AREA, SQUARE_YARD,            "$*0,83612736",      "$/0,83612736")
    DECLARE_CONV_UNIT(AREA, TAN,                    "$*1080000/1089",    "$*1089/1080000")
    DECLARE_CONV_UNIT(AREA, TSUBO,                  "$*1188/1089",       "$*1089/1188")
    DECLARE_CONV_END
};

/*
    1 l/100Km = 100 km/l -> y = 100/x
    1 miles/gal uk = 1.609344/4.54609 km/l
    1 miles/gal us = 1.609344/3.785411784 km/l
*/
static const conv_t conv_CONSUMPTION[] = {
    DECLARE_CONV_UNIT(CONSUMPTION, KM_PER_L,        "$", "$")
    DECLARE_CONV_UNIT(CONSUMPTION, L_PER_100_KM,    "100/$", "100/$")
    DECLARE_CONV_UNIT(CONSUMPTION, MILES_GALLON_UK, "$*1.609344/4.54609", "$/1.609344*4.54609")
    DECLARE_CONV_UNIT(CONSUMPTION, MILES_GALLON_US, "$*1.609344/3.785411784", "$/1.609344*3.785411784")
    DECLARE_CONV_END
};

static const conv_t conv_CURRENCY[] = {
    DECLARE_CONV_UNIT(CURRENCY, AUSTRIAN_SCHILLING, "$/13,7603", "$*13,7603")
    DECLARE_CONV_UNIT(CURRENCY, BELGIAN_FRANC,      "$/40,3399", "$*40,3399")
    DECLARE_CONV_UNIT(CURRENCY, CYPRIOT_POUND,      "$/0,585274","$*0,585274")
    DECLARE_CONV_UNIT(CURRENCY, CZECH_KORUNA,       "$/27,9766", "$*27,9766")
    DECLARE_CONV_UNIT(CURRENCY, DEUTSCHE_MARK,      "$/1,9558",  "$*1,9558")
    DECLARE_CONV_UNIT(CURRENCY, DUTCH_GUILDER,      "$/2,20371", "$*2,20371")
    DECLARE_CONV_UNIT(CURRENCY, EURO,               "$",         "$")
    DECLARE_CONV_UNIT(CURRENCY, FINNISH_MARKKA,     "$/5,9457",  "$*5,9457")
    DECLARE_CONV_UNIT(CURRENCY, FRENCH_FRANC,       "$/6,5596",  "$*6,5596")
    DECLARE_CONV_UNIT(CURRENCY, GREEK_DRACHMA,      "$/340,75",  "$*340,75")
    DECLARE_CONV_UNIT(CURRENCY, IRISH_POUND,        "$/0,7876",  "$*0,7876")
    DECLARE_CONV_UNIT(CURRENCY, ITALIAN_LIRA,       "$/1936.27", "$*1936.27")
    DECLARE_CONV_UNIT(CURRENCY, LUXEMBOURG_FRANC,   "$/40,3399", "$*40,3399")
    DECLARE_CONV_UNIT(CURRENCY, MALTESE_LIRA,       "$/0.42930", "$*0.42930")
    DECLARE_CONV_UNIT(CURRENCY, PORTOGUESE_ESCUDO,  "$/200,482", "$*200,482")
    DECLARE_CONV_UNIT(CURRENCY, SLOVAK_KORUNA,      "$/30,126",  "$*30,126")
    DECLARE_CONV_UNIT(CURRENCY, SLOVENIAN_TOLAR,    "$/239,640", "$*239,640")
    DECLARE_CONV_UNIT(CURRENCY, SPANISH_PESETA,     "$/166,386", "$*166,386")
    DECLARE_CONV_END
};

/*
    1 cal15 .... = 4.1855 J
    1 BTU ...... = 1055.056 J
    1 ERG ...... = 0.0000001 J
    1 EV ....... = 0.000000000000000000160217653 J
    1 Foot-Pound = 1.3558179483314004 J
    1 IT calorie = 4.1868 J
    1 KCa ...... = 4186.8 J
    1 KJ ....... = 1000 J
    1 KWh ...... = 3600 J
    1 IUNS ..... = 4.182 J
    1 calth .... = 4.184 J
*/
static const conv_t conv_ENERGY[] = {
    DECLARE_CONV_UNIT(ENERGY, 15_C_CALORIES,        "$*4.1855",   "$/4.1855")
    DECLARE_CONV_UNIT(ENERGY, BTUS,                 "$*1055.056", "$/1055.056")
    DECLARE_CONV_UNIT(ENERGY, ERGS,                 "$*.0000001", "$/.0000001")
    DECLARE_CONV_UNIT(ENERGY, EVS,                  "$*.000000000000000000160217653", "$/.000000000000000000160217653")
    DECLARE_CONV_UNIT(ENERGY, FOOT_POUNDS,          "$*1.3558179483314004",   "$/1.3558179483314004")
    DECLARE_CONV_UNIT(ENERGY, IT_CALORIES,          "$*4.1868",   "$/4.1868")
    DECLARE_CONV_UNIT(ENERGY, IT_KILOCALORIES,      "$*4186.8",   "$/4186.8")
    DECLARE_CONV_UNIT(ENERGY, JOULES,               "$",          "$")
    DECLARE_CONV_UNIT(ENERGY, KILOJOULES,           "$*1000",     "$/1000")
    DECLARE_CONV_UNIT(ENERGY, KILOWATT_HOURS,       "$*3600",     "$/3600")
    DECLARE_CONV_UNIT(ENERGY, NUTRITION_CALORIES,   "$*4.182",    "$/4.182")
    DECLARE_CONV_UNIT(ENERGY, TH_CALORIES,          "$*4.184",    "$/4.184")
    DECLARE_CONV_END
};

/*
    1 angstrom ....... = 0.0000000001 m
    1 astronomical unit= 149598000000 m
    1 barleycorn ..... = 1/3 inch = 0.9144/108 m
    1 cm ............. = 1/100 m
    1 chain uk ....... = 22 yards = 22*0.9144 m
    1 chi ............ = 
    1 chou ........... = 3600/33 m
    1 chr ............ = 
    1 fathom ......... = 2 yard = 2*0.9144 m
    1 fathom ungary .. = 1.8964838 m (fixed)
    1 feet ........... = 12 inch = 0.9144/3 m
    1 furlong ........ = 10 chains = 220*0.9144 m
    1 gan ............ = 
    1 hand ........... = 4 inches = 0.9144/9 m
    1 hunh ........... = 
    1 inch ........... = yard/36 = 0.9144/36 m
    1 ja ............. = 
    1 jeong .......... = 
    1 kabiet ......... = 
    1 ken ............ = 60/33 m
    1 keub ........... = 
    1 km ............. = 1000 m
    1 lar ............ = 
    1 light year ..... = 9460730472580800 m
    1 link uk ........ = 0.01 chains = 0.22*0.9144 m
    1 micron ......... = 0.000001 m
    1 mile ........... = 1760 yards = 1609.344 m
    1 millimeter ..... = 1/1000 m
    1 nautical mile .. = 1852 m
    1 nieu ........... = 
    1 parsec ......... = 30856800000000000 m
    1 pica ........... = yard/216 = 0.9144/216 m
    1 ri japan ....... = 
    1 ri korea ....... = 
    1 rod ............ = 5.0292 m
    1 sawk ........... = 
    1 sen ............ = 
    1 shaku .......... = 10/33 m
    1 span ........... = 9 inches = 0.9144/4 m
    1 sun ............ = 10/330 m
    1 tsuen .......... = 
    1 va ............. = 
    1 yard ........... = 0.9144 m
    1 yote ........... = 
    1 zhang .......... = 
*/
static const conv_t conv_LENGTH[] = {
    DECLARE_CONV_UNIT(LENGTH, ANGSTROMS,            "$*0.0000000001",   "$/0.0000000001")
    DECLARE_CONV_UNIT(LENGTH, ASTRONOMICAL_UNITS,   "$*149598000000",   "$/149598000000")
    DECLARE_CONV_UNIT(LENGTH, BARLEYCORNS,          "$*0.9144/108",     "$/0.9144*108")
    DECLARE_CONV_UNIT(LENGTH, CENTIMETERS,          "$/100",            "$*100")
    DECLARE_CONV_UNIT(LENGTH, CHAINS_UK,            "$*20.1168",        "$/20.1168")
//    DECLARE_CONV_UNIT(LENGTH, CHI,                  "$", "$")
    DECLARE_CONV_UNIT(LENGTH, CHOU,                 "$*3600/33",        "$*33/3600")
//    DECLARE_CONV_UNIT(LENGTH, CHR,                  "$", "$")
//    DECLARE_CONV_UNIT(LENGTH, CUN,                  "$", "$")
    DECLARE_CONV_UNIT(LENGTH, FATHOMS,              "$*1.8288",         "$/1.8288")
    DECLARE_CONV_UNIT(LENGTH, FATHOMS_HUNGARY,      "$*1.8964838",      "$/1.8964838")
    DECLARE_CONV_UNIT(LENGTH, FEET,                 "$*0.3048",         "$/0.3048")
    DECLARE_CONV_UNIT(LENGTH, FURLONGS,             "$*201.168",        "$/201.168")
//    DECLARE_CONV_UNIT(LENGTH, GAN,                  "$", "$")
    DECLARE_CONV_UNIT(LENGTH, HANDS,                "$*0,1016",         "$/0,1016")
//    DECLARE_CONV_UNIT(LENGTH, HUNH,                 "$", "$")
    DECLARE_CONV_UNIT(LENGTH, INCHES,               "$*0.0254",         "$/0.0254")
//    DECLARE_CONV_UNIT(LENGTH, JA,                   "$", "$")
//    DECLARE_CONV_UNIT(LENGTH, JEONG,                "$", "$")
//    DECLARE_CONV_UNIT(LENGTH, KABIET,               "$", "$")
    DECLARE_CONV_UNIT(LENGTH, KEN,                  "$*60/33",          "$*33/60")
//    DECLARE_CONV_UNIT(LENGTH, KEUB,                 "$", "$")
    DECLARE_CONV_UNIT(LENGTH, KILOMETERS,           "$*1000",           "$/1000")
//    DECLARE_CONV_UNIT(LENGTH, LAR,                  "$", "$")
    DECLARE_CONV_UNIT(LENGTH, LIGHT_YEARS,          "$*9460730472580800", "$/9460730472580800")
    DECLARE_CONV_UNIT(LENGTH, LINKS_UK,             "$*0.201168",       "$/0.201168")
    DECLARE_CONV_UNIT(LENGTH, METERS,               "$",                "$")
    DECLARE_CONV_UNIT(LENGTH, MICRONS,              "$*0.000001",       "$/0.000001")
    DECLARE_CONV_UNIT(LENGTH, MILES,                "$*1609.344",       "$/1609.344")
    DECLARE_CONV_UNIT(LENGTH, MILLIMETERS,          "$/1000",           "$*1000")
    DECLARE_CONV_UNIT(LENGTH, NAUTICAL_MILES,       "$*1852",           "$/1852")
//    DECLARE_CONV_UNIT(LENGTH, NIEU,                 "$", "$")
    DECLARE_CONV_UNIT(LENGTH, PARSECS,              "$*30856800000000000", "$/30856800000000000")
    DECLARE_CONV_UNIT(LENGTH, PICAS,                "$*0.9144/216",     "$/0.9144*216")
    DECLARE_CONV_UNIT(LENGTH, RODS,                 "$*5.0292",         "$/5.0292")
//    DECLARE_CONV_UNIT(LENGTH, RI_JAPAN,             "$", "$")
//    DECLARE_CONV_UNIT(LENGTH, RI_KOREA,             "$", "$")
//    DECLARE_CONV_UNIT(LENGTH, SAWK,                 "$", "$")
//    DECLARE_CONV_UNIT(LENGTH, SEN,                  "$", "$")
    DECLARE_CONV_UNIT(LENGTH, SHAKU,                "$*10/33",          "$*33/10")
    DECLARE_CONV_UNIT(LENGTH, SPAN,                 "$*0.9144/4",       "$*4/0.9144")
    DECLARE_CONV_UNIT(LENGTH, SUN,                  "$*10/330",         "$*330/10")
//    DECLARE_CONV_UNIT(LENGTH, TSUEN,                "$", "$")
//    DECLARE_CONV_UNIT(LENGTH, VA,                   "$", "$")
    DECLARE_CONV_UNIT(LENGTH, YARDS,                "$*0.9144",         "$/0.9144")
//    DECLARE_CONV_UNIT(LENGTH, YOTE,                 "$", "$")
//    DECLARE_CONV_UNIT(LENGTH, ZHANG,                "$", "$")
    DECLARE_CONV_END
};

/*
    1 BTU/min = 17.5842642 W
    1 Foot-pound/minute = 0.02259696580552333 W
    1 hp = 745.69987158227022 W
    1 KW = 1000 W
    1 MW = 1000000 W
*/
static const conv_t conv_POWER[] = {
    DECLARE_CONV_UNIT(POWER, BTUS_PER_MINUTE, "$*17.5842642", "$/17.5842642")
    DECLARE_CONV_UNIT(POWER, FPS_PER_MINUTE,  "$*0.02259696580552333", "$/0.02259696580552333")
    DECLARE_CONV_UNIT(POWER, HORSEPOWER,      "$*745.69987158227022", "$/745.69987158227022")
    DECLARE_CONV_UNIT(POWER, KILOWATTS,       "$*1000", "$/1000")
    DECLARE_CONV_UNIT(POWER, MEGAWATTS,       "$*1000000", "$/1000000")
    DECLARE_CONV_UNIT(POWER, WATTS,           "$", "$")
    DECLARE_CONV_END
};

/*
    1 ATM   = 101325 Pa
    1 BAR   = 100000 Pa
    1 hPa   = 100 Pa
    1 kPa   = 1000 Pa
    1 mm HG = 133.322 Pa
    1 psi   = 6894.757 Pa 
*/
static const conv_t conv_PRESSURE[] = {
    DECLARE_CONV_UNIT(PRESSURE, ATMOSPHERES,   "$*101325",   "$/101325")
    DECLARE_CONV_UNIT(PRESSURE, BARS,          "$*100000",   "$/100000")
    DECLARE_CONV_UNIT(PRESSURE, HECTOPASCALS,  "$*100",      "$/100")
    DECLARE_CONV_UNIT(PRESSURE, KILOPASCALS,   "$*1000",     "$/1000")
    DECLARE_CONV_UNIT(PRESSURE, MM_OF_MERCURY, "$*133.322",  "$/133.322")
    DECLARE_CONV_UNIT(PRESSURE, PASCALS,       "$",          "$")
    DECLARE_CONV_UNIT(PRESSURE, PSI,           "$*6894.757", "$/6894.757")
    DECLARE_CONV_END
};

/*
    1 day ....... = 86400 s
    1 hour ...... = 3600 s
    1 microsecond = 0.000001 s
    1 millisecond = 0.001 s
    1 minute .... = 60 s
    1 week ...... = 669600 s
*/
static const conv_t conv_TIME[] = {
    DECLARE_CONV_UNIT(TIME, MINUTES,      "$*60",       "$/60")
    DECLARE_CONV_UNIT(TIME, DAYS,         "$*86400",    "$/86400")
    DECLARE_CONV_UNIT(TIME, HOURS,        "$*3600",     "$/3600")
    DECLARE_CONV_UNIT(TIME, MILISECONDS,  "$*0.001",    "$/0.001")
    DECLARE_CONV_UNIT(TIME, MICROSECONDS, "$*0.000001", "$/0.000001")
    DECLARE_CONV_UNIT(TIME, SECONDS,      "$",          "$")
    DECLARE_CONV_UNIT(TIME, WEEKS,        "$*604800",   "$/604800")
    DECLARE_CONV_UNIT(TIME, YEARS,        "$*31556952", "$/31556952")
    DECLARE_CONV_END
};

/*
    C = K - 273.15
    F = K * 9/5 - 459.67
    R = K * 9/5
 */
static const conv_t conv_TEMPERATURE[] = {
    DECLARE_CONV_UNIT(TEMPERATURE, CELSIUS,     "$+273.15",       "$-273.15")
    DECLARE_CONV_UNIT(TEMPERATURE, FAHRENHEIT,  "($-459.67)*5/9", "$*9/5-459.67")
    DECLARE_CONV_UNIT(TEMPERATURE, KELVIN,      "$",              "$")
    DECLARE_CONV_UNIT(TEMPERATURE, RANKINE,     "$*5/9",          "$*9/5")
    DECLARE_CONV_END
};

/*
    1 cm/s = 0.01 m/s
    1 f/h  = 0.0000846666667 m/s
    1 f/s  = 0.3048 m/s
    1 Km/h = 10/36 m/s -> 0.27778 m/s
    1 knot = 18.52/36 m/s -> 0.51444444 m/s
    1 mach = 340.3 m/s
    1 mph  = 0.44704 m/s
*/
static const conv_t conv_VELOCITY[] = {
    DECLARE_CONV_UNIT(VELOCITY, CMS_SECOND,         "$*.01",      "$/.01")
    DECLARE_CONV_UNIT(VELOCITY, FEET_SECOND,        "$*.3048",    "$/.3048")
    DECLARE_CONV_UNIT(VELOCITY, FEET_HOUR,          "$*.0000846666667", "$/.0000846666667")
    DECLARE_CONV_UNIT(VELOCITY, KILOMETERS_HOUR,    "$*10/36",    "$*36/10")
    DECLARE_CONV_UNIT(VELOCITY, KNOTS,              "$*18.52/36", "$*36/18.52")
    DECLARE_CONV_UNIT(VELOCITY, MACH,               "$*340.3",    "$/340.3")
    DECLARE_CONV_UNIT(VELOCITY, METERS_SECOND,      "$",          "$")
    DECLARE_CONV_UNIT(VELOCITY, MILES_HOUR,         "$*.44704",   "$/.44704")
    DECLARE_CONV_END
};

/*
    1 barrel uk ...... = 163.65924 l
    1 barrel oil ..... = 158.987295 l
    1 bun ............ = 
    1 bushel uk ...... = 36.36872 l
    1 bushel us ...... = 35.23907017 l
    1 cubic cm  ...... = 0.001 l
    1 cubic feet ..... = 28.316846 l
    1 cubic inch ..... = 0.016387064 l
    1 cubic meter .... = 1000 l
    1 cubic yard ..... = 764.554857 l
    1 doe ............ = 
    1 fluid ounce uk   = 0.0284130625 l
    1 fluid ounce us   = 0.0295735295625 l
    1 gallon uk ...... = 4.54609 l
    1 gallon dry us .. = 4.40488377086 l
    1 gallon liquid us = 3.785411784 l
    1 gou ............ = 0.1809 l
    1 hop ............ = 
    1 icce ........... = 
    1 kwian .......... = 
    1 mal ............ = 
    1 milliliter ..... = 0.001 l
    1 pint uk ........ = 0.56826125 l
    1 pint dry us .... = 0.5506104713575 l
    1 pint liquid us   = 0.473176473 l
    1 quart uk ....... = 1.1365225 l
    1 quart dry us ... = 1.101220942715 l
    1 quart liquid us  = 0.946352946 l
    1 seki ........... = 
    1 syou ........... = 
    1 tananloung ..... = 
    1 tang ........... = 
    1 to ............. = 18040 l
*/
static const conv_t conv_VOLUME[] = {
    DECLARE_CONV_UNIT(VOLUME, BARRELS_UK,           "$*163.65924",       "$/163.65924")
    DECLARE_CONV_UNIT(VOLUME, BARRELS_OIL,          "$*158.987295",      "$/158.987295")
//    DECLARE_CONV_UNIT(VOLUME, BUN,                  "$", "$")
    DECLARE_CONV_UNIT(VOLUME, BUSHELS_UK,           "$*36.36872",        "$/36.36872")
    DECLARE_CONV_UNIT(VOLUME, BUSHELS_US,           "$*35.23907017",     "$/35.23907017")
    DECLARE_CONV_UNIT(VOLUME, CUBIC_CENTIMETERS,    "$*0.001",           "$/0.001")
    DECLARE_CONV_UNIT(VOLUME, CUBIC_FEET,           "$*28.316846",       "$/28.316846")
    DECLARE_CONV_UNIT(VOLUME, CUBIC_INCHES,         "$*0.016387064",     "$/0.016387064")
    DECLARE_CONV_UNIT(VOLUME, CUBIC_METERS,         "$*1000",            "$/1000")
    DECLARE_CONV_UNIT(VOLUME, CUBIC_YARDS,          "$*764.554857",      "$/764.554857")
//    DECLARE_CONV_UNIT(VOLUME, DOE,                  "$", "$")
    DECLARE_CONV_UNIT(VOLUME, FLUID_OUNCES_UK,      "$*0.0284130625",    "$/0.0284130625")
    DECLARE_CONV_UNIT(VOLUME, FLUID_OUNCES_US,      "$*0.0295735295625", "$/0.0295735295625")
    DECLARE_CONV_UNIT(VOLUME, GALLONS_UK,           "$*4.54609",         "$/4.54609")
    DECLARE_CONV_UNIT(VOLUME, GALLONS_DRY_US,       "$*4.40488377086",   "$/4.40488377086")
    DECLARE_CONV_UNIT(VOLUME, GALLONS_LIQUID_US,    "$*3.785411784",     "$/3.785411784")
    DECLARE_CONV_UNIT(VOLUME, GOU,                  "$*0.1809",          "$/0.1809")
//    DECLARE_CONV_UNIT(VOLUME, HOP,                  "$", "$")
//    DECLARE_CONV_UNIT(VOLUME, ICCE,                 "$", "$")
//    DECLARE_CONV_UNIT(VOLUME, KWIAN,                "$", "$")
    DECLARE_CONV_UNIT(VOLUME, LITERS,               "$",                 "$")
//    DECLARE_CONV_UNIT(VOLUME, MAL,                  "$", "$")
    DECLARE_CONV_UNIT(VOLUME, MILLILITERS,          "$*0.001",           "$/0.001")
    DECLARE_CONV_UNIT(VOLUME, PINTS_UK,             "$*0.56826125",      "$/0.56826125")
    DECLARE_CONV_UNIT(VOLUME, PINTS_DRY_US,         "$*0.5506104713575", "$/0.5506104713575")
    DECLARE_CONV_UNIT(VOLUME, PINTS_LIQUID_US,      "$*0.473176473",     "$/0.473176473")
    DECLARE_CONV_UNIT(VOLUME, QUARTS_UK,            "$*1.1365225",       "$/1.1365225")
    DECLARE_CONV_UNIT(VOLUME, QUARTS_DRY_US,        "$*1.101220942715",  "$/1.101220942715")
    DECLARE_CONV_UNIT(VOLUME, QUARTS_LIQUID_US,     "$*0.946352946",     "$/0.946352946")
//    DECLARE_CONV_UNIT(VOLUME, SEKI,                 "$", "$")
//    DECLARE_CONV_UNIT(VOLUME, SYOU,                 "$", "$")
//    DECLARE_CONV_UNIT(VOLUME, TANANLOUNG,           "$", "$")
//    DECLARE_CONV_UNIT(VOLUME, TANG,                 "$", "$")
    DECLARE_CONV_UNIT(VOLUME, TO,                   "$*18040",           "$/18040")
    DECLARE_CONV_END
};

/*
    1 baht ............ = 12.244 g
    1 carat ........... = 0.2 g
    1 chung ........... = 
    1 don ............. = 
    1 geun ............ = 
    1 gwan ............ = 
    1 harb ............ = 
    1 jin china ....... = 
    1 jin taiwan ...... = 
    1 Kan ............. =
    1 Kilograms ....... = 1000 g
    1 Kin ............. =
    1 Liang China ..... =
    1 Liang Taiwan .... =
    1 monme ........... = 3.75 g
    1 ounce avoirdupois = 28.349523125 g
    1 ounce troy ...... = 31.1034768 g
    1 pound ........... = 453.59237 g
    1 quintal metric .. = 100000 g
    1 saloung ......... = 
    1 stone ........... = 6350.29318 g
    1 tamlung ......... = 
    1 ton ............. = 1000000 g
    1 ton uk .......... = 1016046.9088 g  // long ton
    1 ton us .......... = 907184.74 g     // short ton
*/
static const conv_t conv_WEIGHT[] = {
    DECLARE_CONV_UNIT(WEIGHT, BAHT,                 "$*12.244",       "$/12.244")
    DECLARE_CONV_UNIT(WEIGHT, CARATS,               "$*0.2",          "$/0.2")
//    DECLARE_CONV_UNIT(WEIGHT, CHUNG,                "$", "$")
//    DECLARE_CONV_UNIT(WEIGHT, DON,                  "$", "$")
//    DECLARE_CONV_UNIT(WEIGHT, GEUN,                 "$", "$")
    DECLARE_CONV_UNIT(WEIGHT, GRAMS,                "$",              "$")
//    DECLARE_CONV_UNIT(WEIGHT, GWAN,                 "$", "$")
//    DECLARE_CONV_UNIT(WEIGHT, HARB,                 "$", "$")
//    DECLARE_CONV_UNIT(WEIGHT, JIN_CHINA,            "$", "$")
//    DECLARE_CONV_UNIT(WEIGHT, JIN_TAIWAN,           "$", "$")
//    DECLARE_CONV_UNIT(WEIGHT, KAN,                  "$", "$")
    DECLARE_CONV_UNIT(WEIGHT, KILOGRAMS,            "$*1000",         "$/1000")
//    DECLARE_CONV_UNIT(WEIGHT, KIN,                  "$", "$")
//    DECLARE_CONV_UNIT(WEIGHT, LIANG_CHINA,          "$", "$")
//    DECLARE_CONV_UNIT(WEIGHT, LIANG_TAIWAN,         "$", "$")
    DECLARE_CONV_UNIT(WEIGHT, MONME,                "$*3.75",         "$/3.75")
    DECLARE_CONV_UNIT(WEIGHT, OUNCES_AVOIRDUPOIS,   "$*28.349523125", "$/28.349523125")
    DECLARE_CONV_UNIT(WEIGHT, OUNCES_TROY,          "$*31.1034768",   "$/31.1034768")
    DECLARE_CONV_UNIT(WEIGHT, POUNDS,               "$*453.59237",    "$/453.59237")
    DECLARE_CONV_UNIT(WEIGHT, QUINTAL_METRIC,       "$*100000",       "$/100000")
//    DECLARE_CONV_UNIT(WEIGHT, SALOUNG,              "$", "$")
    DECLARE_CONV_UNIT(WEIGHT, STONES,               "$*6350.29318",    "$/6350.29318")
//    DECLARE_CONV_UNIT(WEIGHT, TAMLUNG,              "$", "$")
    DECLARE_CONV_UNIT(WEIGHT, TONNES,               "$*1000000",       "$/1000000")
    DECLARE_CONV_UNIT(WEIGHT, TONS_UK,              "$*1016046.9088",  "$/1016046.9088")
    DECLARE_CONV_UNIT(WEIGHT, TONS_US,              "$*907184.74",     "$/907184.74")
    DECLARE_CONV_END
};

static const conv_category_t conv_table[] = {
    DECLARE_CONV_CAT(ANGLE)
    DECLARE_CONV_CAT(AREA)
    DECLARE_CONV_CAT(CONSUMPTION)
    DECLARE_CONV_CAT(CURRENCY)
    DECLARE_CONV_CAT(ENERGY)
    DECLARE_CONV_CAT(LENGTH)
    DECLARE_CONV_CAT(POWER)
    DECLARE_CONV_CAT(PRESSURE)
    DECLARE_CONV_CAT(TIME)
    DECLARE_CONV_CAT(TEMPERATURE)
    DECLARE_CONV_CAT(VELOCITY)
    DECLARE_CONV_CAT(VOLUME)
    DECLARE_CONV_CAT(WEIGHT)
};

void ConvExecute(HWND hWnd)
{
    DWORD         c_cat = (DWORD)SendDlgItemMessage(hWnd, IDC_COMBO_CATEGORY, CB_GETCURSEL, 0, 0);
    const conv_t *items = NULL;
    DWORD         from  = SendDlgItemMessage(hWnd, IDC_COMBO_FROM, CB_GETCURSEL, 0, 0);
    DWORD         to    = SendDlgItemMessage(hWnd, IDC_COMBO_TO,   CB_GETCURSEL, 0, 0);
    TCHAR         txt_cb[128];
    TCHAR         txt[128];
    const conv_t *item;

    /* do nothing if the indexes point to the same unit */
    if (from == to)
        return;

    /* Search correct category, since it can be sorted too */
    SendDlgItemMessage(hWnd, IDC_COMBO_CATEGORY, CB_GETLBTEXT, c_cat, (LPARAM)txt_cb);
    for (c_cat=0; c_cat < SIZEOF(conv_table); c_cat++) {
        LoadString(calc.hInstance, conv_table[c_cat].category, txt, SIZEOF(txt));
        if (!_tcscmp(txt_cb, txt)) {
            items = conv_table[c_cat].items;
            break;
        }
    }
    
    /* The units can be sorted, so I must search the exact match */
    item = items;
    SendDlgItemMessage(hWnd, IDC_COMBO_FROM, CB_GETLBTEXT, from, (LPARAM)txt_cb);
    while (item->unit) {
        LoadString(calc.hInstance, item->unit, txt, SIZEOF(txt));
        if (!_tcscmp(txt_cb, txt)) {
            from = item-items;
            break;
        }
        item++;
    }
    SendDlgItemMessage(hWnd, IDC_COMBO_TO, CB_GETLBTEXT, to, (LPARAM)txt_cb);
    item = items;
    while (item->unit) {
        LoadString(calc.hInstance, item->unit, txt, SIZEOF(txt));
        if (!_tcscmp(txt_cb, txt)) {
            to = item-items;
            break;
        }
        item++;
    }

    calc.Convert[0].data = (char *)items[from].formula_from;
    calc.Convert[1].data = (char *)items[to].formula_to;
    calc.Convert[0].wm_msg = WM_HANDLE_FROM;
    calc.Convert[1].wm_msg = WM_HANDLE_TO;
    PostMessage(hWnd, WM_START_CONV, 0, MAKELPARAM(0, WM_HANDLE_FROM));
}

void ConvAdjust(HWND hWnd, int n_cat)
{
    TCHAR         txt[128];
    TCHAR         txt_cat[128];
    HWND          hFromWnd = GetDlgItem(hWnd, IDC_COMBO_FROM);
    HWND          hToWnd   = GetDlgItem(hWnd, IDC_COMBO_TO);
    const conv_t *item;
    unsigned int  n;

    SendDlgItemMessage(hWnd, IDC_COMBO_CATEGORY, CB_GETLBTEXT, n_cat, (LPARAM)txt_cat);
    for (n=0; n<SIZEOF(conv_table); n++) {
        item = conv_table[n].items;
        LoadString(calc.hInstance, conv_table[n].category, txt, SIZEOF(txt));
        if (!_tcscmp(txt_cat, txt))
            break;
    }

    SendMessage(hFromWnd, CB_RESETCONTENT, 0, 0);
    SendMessage(hToWnd,   CB_RESETCONTENT, 0, 0);
    while (item->unit) {
        LoadString(calc.hInstance, item->unit, txt, SIZEOF(txt));
        SendMessage(hFromWnd, CB_ADDSTRING, 0, (LPARAM)txt);
        SendMessage(hToWnd,   CB_ADDSTRING, 0, (LPARAM)txt);
        item++;
    }
    SendMessage(hFromWnd, CB_SETCURSEL, 0, 0);
    SendMessage(hToWnd,   CB_SETCURSEL, 0, 0);
}

void ConvInit(HWND hWnd)
{
    HWND         hCatWnd = GetDlgItem(hWnd, IDC_COMBO_CATEGORY);
    TCHAR        txt[128];
    unsigned int n;

    /* Fill category combo */
    for (n=0; n<SIZEOF(conv_table); n++) {
        LoadString(calc.hInstance, conv_table[n].category, txt, SIZEOF(txt));
        SendMessage(hCatWnd, CB_ADDSTRING, 0, (LPARAM)txt);
    }
    SendMessage(hCatWnd, CB_SETCURSEL, 0, 0);
    ConvAdjust(hWnd, 0);
}