#include <windows.h>
#include <stdio.h>
#include <signal.h>
#include <float.h>
#include <time.h>
#include <malloc.h>
#include <stdlib.h>
#include <math.h>

static char Name[] = "Ken Reneris. Units ala Unix style";



#define DBL     double
#define MAXTYPE 5

extern  UCHAR *UnitTab[];
UCHAR   token[] = " \t\n";

typedef struct _UNIT {
    struct _UNIT    *Next;

    PSZ             UnitName;
    PSZ             Conversion;
} UNIT, *PUNIT;

PUNIT       UnitList;
BOOLEAN     Muund;

typedef struct _HALFVALUE {
    DBL         Accum;

    ULONG       NoType;
    struct {
        PUNIT       Unit;
        ULONG       Pow;
    } Type [MAXTYPE];

} HALFVALUE, *PHALFVALUE;

typedef struct _FULLVALUE {
    ULONG       Fuzz;
    HALFVALUE   Nom;
    HALFVALUE   Dom;
} FULLVALUE, *PFULLVALUE;

struct {
    PSZ         Prefix;
    ULONG       stringlen;
    DBL         Scaler;
} BuiltInScalers[] = {
    "giga",     4, 1000000000.0,
    "mega",     4,    1000000.0,
    "kilo",     4,       1000.0,
    "centi",    5,          0.01,
    "milli",    5,          0.001,
    "micro",    5,          0.000001,
    "nano",     4,          0.000000001,
    "decinano", 8,          0.0000000001,
    NULL
};

struct {
    PSZ         BaseType;
    PSZ         DefaultDump;
} BuiltInDumps[] = {
    "sec",   "hour second millisec microsec nttime nanosec",
    "bit",   "terabyte gigabyte megabyte kilobyte dword byte bit",
    "meter", "km meter cm mm micron mile feet yard inch",
    "kg",    "kb gram kilokg milligram ton lb ounce dram",
    NULL
};

#define ASSERT(_exp_)   if (_exp_) { AssertFailed (__FILE__, __LINE__); }



PVOID   zalloc (IN ULONG len);
PSZ     StrDup (IN PSZ String);
VOID    ReadUnitTab (VOID);
PUNIT   LookupUnit (PSZ UnitName);
VOID    DumpValue (IN PFULLVALUE Value);
VOID    InitializeValue (IN PFULLVALUE Value);
VOID    ConvertValue (PFULLVALUE, PSZ, PFULLVALUE, PSZ);
BOOLEAN ProcessString (PUNIT, PSZ, PFULLVALUE);
PSZ     CopyUnitName (PSZ Out, PSZ String);
PSZ     CopyWord (PSZ Out, PSZ String);
PSZ     SkipSpace (PSZ String);
BOOLEAN MatchPattern (PUCHAR String, PUCHAR Pattern);
VOID    ReduceTypes (IN OUT PHALFVALUE MValue, IN OUT PHALFVALUE DValue);
VOID    AddTypes (IN OUT PHALFVALUE Dest, IN PHALFVALUE Child);
BOOLEAN DumpMatchingTypes (PSZ Str);
VOID    GetInput (PSZ Desc, PSZ Str);
VOID    AssertFailed (PSZ FileName, ULONG LineNo);


void __cdecl main(int argc, char **argv)
{
    UCHAR       have[80], want[80], want2[200];
    FULLVALUE   hValue, wValue;
    PSZ         p;
    ULONG       i;

    ReadUnitTab ();

    if (argc > 1) {
        //
        // Arguments on the command line.  Argv[1] is "have"
        //

        argv++;
        argc -= 2;
        strcpy (have, *(argv++));

        if (DumpMatchingTypes (have)) {
            exit (0);
        }

        if (!ProcessString (NULL, have, &hValue)) {
            printf ("Usage: Units [have] [want]\n");
            exit   (1);
        }

        //
        // If no Argv[2], then check for default dump
        //

        if (!argc  &&  hValue.Nom.NoType) {
            for (i=0; BuiltInDumps[i].BaseType; i++) {
                if (strcmp (BuiltInDumps[i].BaseType, hValue.Nom.Type[0].Unit->UnitName) == 0) {

                    //
                    // Dump defaults
                    //

                    p = BuiltInDumps[i].DefaultDump;
                    while (*p) {
                        p = CopyWord(want, p);

                        if (ProcessString (NULL, want, &wValue)) {
                            ConvertValue (&hValue, have, &wValue, want);
                        }
                    }
                    break;
                }
            }
        }

        //
        // Dump argv[2..n]
        //

        for ( ; argc; argc--, argv++) {
            if (!ProcessString (NULL, *argv, &wValue)) {
                exit (1);
            }

            ConvertValue (&hValue, have, &wValue, *argv);
        }

        exit (1);
    }

    //
    // Interactive... ask "have" & "want"
    //

    for (; ;) {
        for (; ;) {
            GetInput ("You have: ", have);
            if (ProcessString (NULL, have, &hValue)) {
                break;
            }
        }

        GetInput ("You want: ", want2);
        p = want2;
        do {
            p = CopyWord (want, p);

            if (ProcessString (NULL, want, &wValue)) {
                ConvertValue (&hValue, have, &wValue, want);
            }
        } while (*p);
        printf ("\n");
    }

    return ;
}

VOID
GetInput (
    PSZ     Desc,
    PSZ     Str
    )
{
    for (; ;) {
        printf (Desc);
        if (!gets(Str)) {
            exit(1);
        }
        _strlwr (Str);

        if (strcmp (Str, "q") == 0) {
            exit (1);
        }

        if (!DumpMatchingTypes (Str)) {
            break;
        }
    }
}

BOOLEAN DumpMatchingTypes (PSZ Str)
{
    PSZ         Title, Line;
    ULONG       LineNo;
    UCHAR       UnitName[80];
    BOOLEAN     DumpTitle;

    if (!strchr (Str, '*') && !strchr (Str, '?')  && !strchr(Str, '[')) {
        return FALSE;
    }

    //
    // Dump matching known unitnames
    //

    printf ("\nKnown types/groups matching: %s\n", Str);
    Title = NULL;
    for (LineNo = 0; UnitTab[LineNo]; LineNo++) {
        Line = UnitTab[LineNo];
        if (Line[0] == '/') {
            Title = Line;
            DumpTitle = MatchPattern (Title, Str);
        }

        CopyUnitName (UnitName, Line);
        if (!UnitName[0]) {
            continue;
        }

        if (MatchPattern (UnitName, Str) || DumpTitle) {
            if (Title) {
                printf ("%s\n", Title);
                Title = NULL;
            }
            printf ("    %s\n", Line);

        }
    }
    printf ("\n");
    return TRUE;
}



PSZ SkipSpace (PSZ String)
{
    while (*String && (*String == ' ' ||  *String < ' ' ||  *String == '^')) {
        String ++;
    }

    return String;
}

PSZ CopyNumber (PSZ Out, PSZ String)
{
    while (*String >= '0' && *String <= '9' || *String == '.') {
        *(Out++) = *(String++);
    }

    *Out = 0;
    return String;
}

PSZ CopyWord (PSZ Out, PSZ String)
{
    UCHAR   c;

    while (*String) {
        if (*String <= ' ') {
            break;
        }

        *(Out++) = *(String++);
    }

    *Out = 0;
    return SkipSpace (String);
}



PSZ CopyUnitName (PSZ Out, PSZ String)
{
    UCHAR   c;

    while (c = *String) {
        if (c >= '0'  &&  c <= '9'  ||  c == '.') {
            break;
        }

        if (c == '-'  ||  c == '+'  ||  c == '/'  ||  c == ' ') {
            break;
        }

        if (c == '^'  ||  c < ' ') {
            String++;
            continue;
        }

        *(Out++) = *(String++);
    }

    *Out = 0;
    return String;
}


VOID
AssertFailed (PSZ FileName, ULONG LineNo)
{
    printf ("Assert failed - file %s line %d\n", FileName, LineNo);
    exit (1);
}


PSZ
GetBaseType (
    IN PSZ          Out,
    IN PHALFVALUE   HValue
    )
{
    ULONG       i;

    if (HValue->NoType == 0) {
        Out += sprintf (Out, "constant");
    } else {
        for (i=0; i < HValue->NoType; i++) {
            Out += sprintf (Out, "%s%s", i ? "-" : "", HValue->Type[i].Unit->UnitName);
            if (HValue->Type[i].Pow != 1) {
                Out += sprintf (Out, "^%d", HValue->Type[i].Pow);
            }
        }
    }
    return Out;
}

VOID
GetBaseTypes (
    OUT PSZ     Out,
    IN PFULLVALUE   Value
    )
/**
 *  Returns ascii dump of values data type
 */
{
    PUNIT   Unit;
    ULONG   i;

    Out = GetBaseType (Out, &Value->Nom);

    if (Value->Dom.NoType) {
        Out += sprintf (Out, "/");
        Out  = GetBaseType (Out, &Value->Dom);
    }
}

VOID
DumpValue (
    IN PFULLVALUE   Value
    )
{
    UCHAR   s[80];

    GetBaseTypes (s, Value);
    printf ("%g/%g type %s\n", Value->Nom.Accum, Value->Dom.Accum, s);
}

VOID
SortType (
    IN PHALFVALUE   Value
    )
{
    ULONG   i, j;
    ULONG   hpow;
    PUNIT   hunit;


    //
    // Sort by lowest power, then alphabetical
    //

    for (i=0; i < Value->NoType; i++) {
        for (j=i+1; j < Value->NoType; j++) {
            if (Value->Type[i].Pow > Value->Type[j].Pow ||
               (Value->Type[i].Pow == Value->Type[j].Pow  &&
                strcmp (Value->Type[i].Unit->UnitName, Value->Type[j].Unit->UnitName) > 0)) {

                // swap
                hpow  = Value->Type[i].Pow;
                hunit = Value->Type[i].Unit;
                Value->Type[i].Pow  = Value->Type[j].Pow;
                Value->Type[i].Unit = Value->Type[j].Unit;
                Value->Type[j].Pow  = hpow;
                Value->Type[j].Unit = hunit;
            }
        }
    }
}


VOID
FormatDbl (
    OUT PSZ     s,
    IN  DBL     Value
    )
/**
 * Function to print double "Value" into string "s".  This
 * functions sole purpose is to get a better readable reresentation
 * of the value into ascii
 */
{
    PSZ     p1, p2, dp;
    UCHAR   t[80];
    LONG    i;

    i = 18 - sprintf (t, "%.1f", Value);
    if (i < 0) {
        i = 0;
    }
    sprintf (t, "%.*f", i, Value);

    //
    // strip off trailing zeros
    //

    for (dp=t; *dp; dp++) {
        if (*dp == '.') {
            for (p1=p2=dp+1; *p2; p2++) {
                if (*p2 != '0') {
                    p1 = p2;
                }
            }

            p1[1] = 0;
            if (p1 == dp+1  &&  p1[0] == '0') {
                // it's ".0" remove the whole thing
                *dp = 0;
            }

            break;
        }
    }

    i = (LONG)(dp - t);     // # of digits before decimal point
    i = i % 3;
    if (i == 0) {
        i = 3;
    }

    //
    // Copy to decimal point while adding commas
    //

    for (p1=s, p2=t; *p2 && *p2 != '.'; p2++) {
        if (i-- == 0) {
            *(p1++) = ',';
            i = 2;
        }

        *(p1++) = *p2;
    }

    //
    // Copy remainer
    //

    do {
        *(p1++) = *p2;
    } while (*(p2++));

    //
    // Did result == 0?  Probabily lost precision
    //

    if (strcmp (s, "0") == 0) {
        sprintf (s, "%.18g", Value);
    }
}


VOID
ConvertValue (
    IN PFULLVALUE   hValue,
    IN PSZ      have,
    IN PFULLVALUE   wValue,
    IN PSZ      want
    )
{
    DBL         ans;
    UCHAR       s1[80], s2[80], cf[80];
    FULLVALUE   Junk1, Junk2;
    BOOLEAN     flag;
    DBL         hAccum, wAccum;
    PSZ         p1, p2, p3, p4, p5;

    have   = SkipSpace(have);
    want   = SkipSpace(want);
    hAccum = hValue->Nom.Accum / hValue->Dom.Accum;
    wAccum = wValue->Nom.Accum / wValue->Dom.Accum;
    ans    = hAccum / wAccum;

    p3     = "";
    p5     = NULL;

    //
    // See if types match by checking if they cancle each other out
    //

    Junk1 = *hValue;
    Junk2 = *wValue;
    AddTypes (&Junk1.Nom, &Junk2.Dom);
    AddTypes (&Junk1.Dom, &Junk2.Nom);
    ReduceTypes (&Junk1.Nom, &Junk1.Dom);

    if (Junk1.Nom.NoType + Junk1.Dom.NoType != 0) {

        //
        // See if types are inverse
        //

        Junk1 = *hValue;
        Junk2 = *wValue;
        AddTypes (&Junk1.Nom, &Junk2.Nom);
        AddTypes (&Junk1.Dom, &Junk2.Dom);
        ReduceTypes (&Junk1.Nom, &Junk1.Dom);

        if (Junk1.Nom.NoType + Junk1.Dom.NoType == 0) {

            // inverse result
            ans = 1.0 / (hAccum / (1.0 / wAccum));
            p5  = "Warning";

        } else {

            // types are not conforming
            p5 = "Conformance";
        }
    }

    cf[0] = 0;
    if (p5) {
        SortType (&hValue->Nom);
        SortType (&hValue->Dom);
        SortType (&wValue->Nom);
        SortType (&wValue->Dom);
        GetBaseTypes (s1, hValue);
        GetBaseTypes (s2, wValue);
        sprintf (cf, "    (%s: %s -> %s)", p5, s1, s2);
    }

    FormatDbl (s1, ans);            // fancy
    sprintf (s2, "%.g", ans);       // bland

    p1 = (have[0] >= 'a'  &&  have[0] <= 'z') ? "1" : "";
    p2 = (hValue->Fuzz | wValue->Fuzz) ? "(fuzzy) " : "",
    printf ("    %s%s -> %s %s%s%s%s\n", p1, have, s1, p2, p3, want, cf);

    p4 = strchr (s2, 'e');
    if (p4   &&  !strchr(s1,'e')  &&  atoi(p4+2) > 9) {
        // print bland answer as well
        printf ("    %s%s -> %s %s%s%s%s\n", p1, have, s2, p2, p3, want, cf);
    }
}

BOOLEAN
ProcessString (
    IN PUNIT    Unit,
    IN PSZ      String,
    OUT PFULLVALUE  ReturnValue
    )
{
    UCHAR       s[80], c;
    ULONG       i, j;
    FULLVALUE   ChildValue;
    PHALFVALUE  MValue, DValue, hldvalue;

    ReturnValue->Fuzz = 0;
    MValue = &ReturnValue->Nom;
    DValue = &ReturnValue->Dom;

    MValue->Accum  = 1.0;
    MValue->NoType = 0;

    DValue->Accum  = 1.0;
    DValue->NoType = 0;

    String = SkipSpace(String);
    c = *String;

    if (c == '*') {
        //
        // This is a base value
        //

        MValue->NoType = 1;
        MValue->Type[0].Unit = Unit;
        MValue->Type[0].Pow  = 1;
        return TRUE;
    }

    if (c >= '0' &&  c <= '9'  ||  c == '.') {
        //
        // Constant multiplcation
        //

        String = CopyNumber (s, String);
        String = SkipSpace(String);
        MValue->Accum *= atof(s);
    }

    if (*String == '|') {
        //
        // Constant Division
        //

        String++;
        String = CopyNumber (s, String);
        if (s[0]) {
            DValue->Accum *= atof(s);
        }
    }

    if (*String == '+'  ||  *String == '-') {
        //
        // 10^x
        //

        s[0] = *(String++);
        String = CopyNumber (s+1, String);
        MValue->Accum *= pow (10.0, atof(s));
    }

    for (; ;) {
        String = SkipSpace(String);
        if (!*String) {
            break;
        }

        switch (*String) {
            case '/':
                // flip denominator & numerator
                hldvalue = MValue;
                MValue   = DValue;
                DValue   = hldvalue;
                String++;
                continue;       // get next token

            case '-':
                // skip these
                String++;
                continue;

            default:
                break;
        }

        //
        // Find sub unit type
        //

        String = CopyUnitName (s, String);
        Unit   = LookupUnit (s);
        if (!Unit) {

            //
            // Check for common scaler prefix on keyword
            //

            for (i=0; BuiltInScalers[i].Prefix; i++) {
                if (strncmp (s,
                        BuiltInScalers[i].Prefix,
                        BuiltInScalers[i].stringlen) == 0) {

                    // Scale the value & skip word prefix
                    MValue->Accum *= BuiltInScalers[i].Scaler;
                    Unit = LookupUnit (s + BuiltInScalers[i].stringlen);
                    break;
                }
            }

            if (!Unit) {
                printf ("Unit type '%s' unkown\n", s);
                return FALSE;
            }
        }


        //
        // Get conversion value for this component
        //

        if (!ProcessString (Unit, Unit->Conversion, &ChildValue)) {
            return FALSE;
        }

        if (strcmp (Unit->UnitName, "fuzz") == 0) {
            ReturnValue->Fuzz = 1;
        }

        if (*String >= '1'  &&  *String <= '9') {
            // raise power
            i = *(String++) - '0';

            ChildValue.Nom.Accum = pow (ChildValue.Nom.Accum, i);
            ChildValue.Dom.Accum = pow (ChildValue.Dom.Accum, i);

            for (j=0; j < ChildValue.Nom.NoType; j++) {
                ChildValue.Nom.Type[j].Pow *= i;
            }

            for (j=0; j < ChildValue.Dom.NoType; j++) {
                ChildValue.Dom.Type[i].Pow *= i;
            }
        }

        //
        // Merge values from child
        //

        ReturnValue->Fuzz |= ChildValue.Fuzz;
        MValue->Accum *= ChildValue.Nom.Accum;
        DValue->Accum *= ChildValue.Dom.Accum;

        //
        // Merge data types from child
        //

        AddTypes (MValue, &ChildValue.Nom);
        AddTypes (DValue, &ChildValue.Dom);
        ReduceTypes (MValue, DValue);
    }
    return TRUE;
}


VOID
AddTypes (
    IN OUT PHALFVALUE   Dest,
    IN PHALFVALUE       Child
    )
/**
 *  Add's types from Child to Dest.  If the data type already exist in
 *  dest then it's power is raised; otherwise the new type is added to the list
 *
 */
{
    ULONG   i, j;

    for (i=0; i < Child->NoType; i++) {
        for (j=0; j < Dest->NoType; j++) {
            if (Child->Type[i].Unit == Dest->Type[j].Unit) {
                // unit already is destionation - move it
                Dest->Type[j].Pow  += Child->Type[i].Pow;
                Child->Type[i].Unit = NULL;
                Child->Type[i].Pow  = 0;
            }
        }

        if (Child->Type[i].Unit) {
            // unit not in destionation - add it
            j = (Dest->NoType++);
            ASSERT (j >= MAXTYPE);
            Dest->Type[j].Unit = Child->Type[i].Unit;
            Dest->Type[j].Pow  = Child->Type[i].Pow;
        }
    }
}

VOID
ReduceTypes (
    IN OUT PHALFVALUE   MValue,
    IN OUT PHALFVALUE   DValue
    )
/**
 *  Divides & cancles data types.
 */
{
    ULONG       i, j, k;
    BOOLEAN     Restart;

    Restart = TRUE;
    while (Restart) {
        Restart = FALSE;

        for (i=0; i < MValue->NoType; i++) {
            for (j=0; j < DValue->NoType; j++) {
                if (MValue->Type[i].Unit == DValue->Type[j].Unit) {
                    // matching types - reduce
                    MValue->Type[i].Pow -= DValue->Type[j].Pow;
                    DValue->Type[j].Unit = NULL;
                    DValue->Type[j].Pow  = 0;
                }

                if (DValue->Type[j].Pow == 0) {
                    // pull this type out of the denominator
                    for (k=j+1; k < DValue->NoType; k++) {
                        DValue->Type[k-1] = DValue->Type[k];
                    }
                    DValue->NoType -= 1;
                    Restart = TRUE;
                    continue;
                }
            }

            if (MValue->Type[i].Pow == 0) {
                // pull this type out of the numerator
                for (k=i+1; k < DValue->NoType; k++) {
                    DValue->Type[k-1] = DValue->Type[k];
                }
                MValue->NoType -= 1;
                Restart = TRUE;
                continue;
            }
        }
    }
}



VOID
ReadUnitTab (VOID)
{
    UCHAR       Line[80], s[80];
    ULONG       LineNo;
    PUNIT       Unit;
    PSZ         p, p1;

    for (LineNo = 0; UnitTab[LineNo]; LineNo++) {
        strcpy (Line, UnitTab[LineNo]);

        //
        // Strip off trailing blanks
        //

        for (p=p1=Line; *p; p++) {
            if (*p != ' ') {
                p1 = p;
            }
        }
        p1[1] = 0;

        //
        // First word is type of unit
        //

        p = SkipSpace (Line);
        if (*p == 0  ||  *p == '/') {
            continue;
        }

        p = CopyUnitName (s, p);
        Unit = zalloc (sizeof(UNIT));
        Unit->UnitName = StrDup (s);

        //
        // Rest of line is Conversion string
        //

        p = SkipSpace (p);
        Unit->Conversion = StrDup (p);

        //
        // Add Unit to list of all known units
        //

        Unit->Next = UnitList;
        UnitList = Unit;
    }
}

PUNIT LookupUnit (PSZ UnitName)
{
    PUNIT   Unit;
    UCHAR   Name[40];
    ULONG   i;

    for (i=0; UnitName[i]; i++) {
        Name[i] = UnitName[i];
        if (Name[i] >= '0'  &&  Name[i] <= '9') {
            break;
        }
    }

    Name[i] = 0;
    for (Unit=UnitList; Unit; Unit = Unit->Next) {
        if (strcmp (Unit->UnitName, Name) == 0) {
            break;
        }
    }

    return Unit;
}


PSZ StrDup (IN PSZ String)
{
    ULONG   len;
    PSZ     p;

    // allocate & duplicate string

    len = strlen(String)+1;
    p   = malloc (len);
    if (!p) {
        printf ("Out of memory\n");
        exit (1);
    }

    memcpy (p, String, len);
    return p;
}


PVOID zalloc (IN ULONG len)
{
    PVOID   p;

    // allocate & zero memory

    p = malloc (len);
    if (!p) {
        printf ("Out of memory\n");
        exit (1);
    }

    memset (p, 0, len);
    return p;
}




/*** MatchPattern - check if string matches pattern
 *
 *   Supports:
 *        *      - Matches any number of characters (including zero)
 *        ?      - Matches any 1 character
 *        [set]  - Matches any charater to charater in set
 *                   (set can be a list or range)
 *
 */

BOOLEAN MatchPattern (PUCHAR String, PUCHAR Pattern)
{
    UCHAR   c, p, l;

    for (; ;) {
        switch (p = *Pattern++) {
            case 0:                             // end of pattern
                return *String ? FALSE : TRUE;  // if end of string TRUE

            case '*':
                while (*String) {               // match zero or more char
                    if (MatchPattern (String++, Pattern))
                        return TRUE;
                }
                return MatchPattern (String, Pattern);

            case '?':
                if (*String++ == 0)             // match any one char
                    return FALSE;                   // not end of string
                break;

            case '[':
                if ( (c = *String++) == 0)      // match char set
                    return FALSE;                   // syntax

                c = (UCHAR)tolower(c);
                l = 0;
                while (p = *Pattern++) {
                    if (p == ']')               // if end of char set, then
                        return FALSE;           // no match found

                    if (p == '-') {             // check a range of chars?
                        p = *Pattern;           // get high limit of range
                        if (p == 0  ||  p == ']')
                            return FALSE;           // syntax

                        if (c >= l  &&  c <= p)
                            break;              // if in range, move on
                    }

                    l = p;
                    if (c == p)                 // if char matches this element
                        break;                  // move on
                }

                while (p  &&  p != ']')         // got a match in char set
                    p = *Pattern++;             // skip to end of set

                break;

            default:
                c = *String++;
                if (tolower(c) != p)            // check for exact char
                    return FALSE;                   // not a match

                break;
        }
    }
}