/*
 * snprintf.c
 */

#include "snprintf.h"

static size_t dopr(char *buffer, size_t maxlen, const char *format, va_list args);
static void fmtstr(char *buffer, size_t *currlen, size_t maxlen, char *value, int flags, int min, int max);
static void fmtint(char *buffer, size_t *currlen, size_t maxlen, long value, int base, int min, int max, int flags);
static void fmtfp(char *buffer, size_t *currlen, size_t maxlen, LDOUBLE fvalue, int min, int max, int flags);
static void dopr_outch(char *buffer, size_t *currlen, size_t maxlen, char c);

static int temp_isdigit(char ch) {
    if (ch >= '0' && ch <= '9') {
        return 1;
    }
    return 0;
}

static size_t dopr(char *buffer, size_t maxlen, const char *format, va_list args)
{
    char ch;
    LLONG value;
    LDOUBLE fvalue;
    char *strvalue;
    int min;
    int max;
    int state;
    int flags;
    int cflags;
    size_t currlen;

    state = DP_S_DEFAULT;
    currlen = flags = cflags = min = 0;
    max = -1;
    ch = *format++;
    while (state != DP_S_DONE) {
        if (ch == '\0') 
            state = DP_S_DONE;

        switch (state) {
            case DP_S_DEFAULT:
                if (ch == '%') 
                    state = DP_S_FLAGS;
                else 
                    dopr_outch(buffer, &currlen, maxlen, ch);
                ch = *format++;
                break;
            case DP_S_FLAGS:
                switch (ch) {
                case '-':
                    flags |= DP_F_MINUS;
                    ch = *format++;
                    break;
                case '+':
                    flags |= DP_F_PLUS;
                    ch = *format++;
                    break;
                case ' ':
                    flags |= DP_F_SPACE;
                    ch = *format++;
                    break;
                case '#':
                    flags |= DP_F_NUM;
                    ch = *format++;
                    break;
                case '0':
                    flags |= DP_F_ZERO;
                    ch = *format++;
                    break;
                default:
                    state = DP_S_MIN;
                    break;
                }
                break;
            case DP_S_MIN:
                if (temp_isdigit((unsigned char)ch)) {
                    min = 10*min + char_to_int (ch);
                    ch = *format++;
                } else if (ch == '*') {
                    min = va_arg (args, int);
                    ch = *format++;
                    state = DP_S_DOT;
                } else {
                    state = DP_S_DOT;
                }
                break;
            case DP_S_DOT:
                if (ch == '.') {
                    state = DP_S_MAX;
                    ch = *format++;
                } else { 
                    state = DP_S_MOD;
                }
                break;
            case DP_S_MAX:
                if (temp_isdigit((unsigned char)ch)) {
                    if (max < 0)
                        max = 0;
                    max = 10*max + char_to_int (ch);
                    ch = *format++;
                } else if (ch == '*') {
                    max = va_arg (args, int);
                    ch = *format++;
                    state = DP_S_MOD;
                } else {
                    state = DP_S_MOD;
                }
                break;
            case DP_S_MOD:
                switch (ch) {
                    case 'h':
                        cflags = DP_C_SHORT;
                        ch = *format++;
                        break;
                    case 'l':
                        cflags = DP_C_LONG;
                        ch = *format++;
                        if (ch == 'l') { /* It's a long long */
                            cflags = DP_C_LLONG;
                            ch = *format++;
                        }
                        break;
                    case 'L':
                        cflags = DP_C_LDOUBLE;
                        ch = *format++;
                        break;
                    default:
                        break;
                }
                state = DP_S_CONV;
                break;
            case DP_S_CONV:
                switch (ch) {
                    case 'd':
                    case 'i':
                        if (cflags == DP_C_SHORT) 
                            value = va_arg (args, int);
                        else if (cflags == DP_C_LONG)
                            value = va_arg (args, long int);
                        else if (cflags == DP_C_LLONG)
                            value = va_arg (args, LLONG);
                        else
                            value = va_arg (args, int);
                        fmtint (buffer, &currlen, maxlen, value, 10, min, max, flags);
                        break;
                    case 'o':
                        flags |= DP_F_UNSIGNED;
                        if (cflags == DP_C_SHORT)
                            value = va_arg (args, unsigned int);
                        else if (cflags == DP_C_LONG)
                            value = (long)va_arg (args, unsigned long int);
                        else if (cflags == DP_C_LLONG)
                            value = (long)va_arg (args, unsigned LLONG);
                        else
                            value = (long)va_arg (args, unsigned int);
                        fmtint (buffer, &currlen, maxlen, value, 8, min, max, flags);
                        break;
                    case 'u':
                        flags |= DP_F_UNSIGNED;
                        if (cflags == DP_C_SHORT)
                            value = va_arg (args, unsigned int);
                        else if (cflags == DP_C_LONG)
                            value = (long)va_arg (args, unsigned long int);
                        else if (cflags == DP_C_LLONG)
                            value = (LLONG)va_arg (args, unsigned LLONG);
                        else
                            value = (long)va_arg (args, unsigned int);
                        fmtint (buffer, &currlen, maxlen, value, 10, min, max, flags);
                        break;
                    case 'X':
                        flags |= DP_F_UP;
                    case 'x':
                        flags |= DP_F_UNSIGNED;
                        if (cflags == DP_C_SHORT)
                            value = va_arg (args, unsigned int);
                        else if (cflags == DP_C_LONG)
                            value = (long)va_arg (args, unsigned long int);
                        else if (cflags == DP_C_LLONG)
                            value = (LLONG)va_arg (args, unsigned LLONG);
                        else
                            value = (long)va_arg (args, unsigned int);
                        fmtint (buffer, &currlen, maxlen, value, 16, min, max, flags);
                        break;
                    case 'f':
                        if (cflags == DP_C_LDOUBLE)
                            fvalue = va_arg (args, LDOUBLE);
                        else
                            fvalue = va_arg (args, double);
                        /* um, floating point? */
                        fmtfp (buffer, &currlen, maxlen, fvalue, min, max, flags);
                        break;
                    case 'E':
                        flags |= DP_F_UP;
                    case 'e':
                        if (cflags == DP_C_LDOUBLE)
                            fvalue = va_arg (args, LDOUBLE);
                        else
                            fvalue = va_arg (args, double);
                        break;
                    case 'G':
                        flags |= DP_F_UP;
                    case 'g':
                        if (cflags == DP_C_LDOUBLE)
                            fvalue = va_arg (args, LDOUBLE);
                        else
                            fvalue = va_arg (args, double);
                        break;
                    case 'c':
                        dopr_outch(buffer, &currlen, maxlen, va_arg (args, int));
                        break;
                    case 's':
                        strvalue = va_arg (args, char *);
                        if (max == -1) {
                            max = strlen(strvalue);
                        }
                        if (min > 0 && max >= 0 && min > max) max = min;
                        fmtstr (buffer, &currlen, maxlen, strvalue, flags, min, max);
                        break;
                    case 'p':
                        strvalue = va_arg (args, void *);
                        fmtint (buffer, &currlen, maxlen, (long) strvalue, 16, min, max, flags);
                        break;
                    case 'n':
                        if (cflags == DP_C_SHORT) {
                            short int *num;
                            num = va_arg (args, short int *);
                            *num = currlen;
                        } else if (cflags == DP_C_LONG) {
                            long int *num;
                            num = va_arg (args, long int *);
                            *num = (long int)currlen;
                        } else if (cflags == DP_C_LLONG) {
                            LLONG *num;
                            num = va_arg (args, LLONG *);
                            *num = (LLONG)currlen;
                        } else {
                            int *num;
                            num = va_arg (args, int *);
                            *num = currlen;
                        }
                        break;
                    case '%':
                        dopr_outch(buffer, &currlen, maxlen, ch);
                        break;
                    case 'w':
                        /* not supported yet, treat as next char */
                        ch = *format++;
                        break;
                    default:
                        /* Unknown, skip */
                        break;
                    }
                    ch = *format++;
                    state = DP_S_DEFAULT;
                    flags = cflags = min = 0;
                    max = -1;
                    break;
            case DP_S_DONE:
                break;
            default:
                /* hmm? */
                break; /* some picky compilers need this */
        }
    }
    if (maxlen != 0) {
        if (currlen < maxlen - 1) 
            buffer[currlen] = '\0';
        else if (maxlen > 0) 
            buffer[maxlen - 1] = '\0';
    }

    return currlen;
}

static void fmtstr(char *buffer, size_t *currlen, size_t maxlen,
                   char *value, int flags, int min, int max)
{
    int padlen, strln; /* amount to pad */
    int cnt = 0;
    if (value == 0) {
        value = "<NULL>";
    }

    for (strln = 0; value[strln]; ++strln); /* strlen */
    padlen = min - strln;
    if (padlen < 0) 
        padlen = 0;
    if (flags & DP_F_MINUS) 
        padlen = -padlen; /* Left Justify */
        
    while ((padlen > 0) && (cnt < max)) {
        dopr_outch(buffer, currlen, maxlen, ' ');
        --padlen;
        ++cnt;
    }
    while (*value && (cnt < max)) {
        dopr_outch(buffer, currlen, maxlen, *value++);
        ++cnt;
    }
    while ((padlen < 0) && (cnt < max)) {
        dopr_outch(buffer, currlen, maxlen, ' ');
        ++padlen;
        ++cnt;
    }
}

/* Have to handle DP_F_NUM (ie 0x and 0 alternates) */

static void fmtint(char *buffer, size_t *currlen, size_t maxlen,
                   long value, int base, int min, int max, int flags)
{
    int signvalue = 0;
    unsigned long uvalue;
    char convert[20];
    int place = 0;
    int spadlen = 0; /* amount to space pad */
    int zpadlen = 0; /* amount to zero pad */
    int caps = 0;
    if (max < 0)
        max = 0;

    uvalue = value;
        
    if (!(flags & DP_F_UNSIGNED)) {
        if (value < 0) {
            signvalue = '-';
            uvalue = -value;
        } else {
            if (flags & DP_F_PLUS)  /* Do a sign (+/i) */
                signvalue = '+';
            else if (flags & DP_F_SPACE)
                signvalue = ' ';
        }
    }

    if (flags & DP_F_UP) caps = 1; /* Should characters be upper case? */

    do {
        convert[place++] =
            (caps? "0123456789ABCDEF":"0123456789abcdef")
            [uvalue % (unsigned)base  ];
        uvalue = (uvalue / (unsigned)base);
    } while (uvalue && (place < 20));
    if (place == 20) place--;
    convert[place] = 0;

    zpadlen = max - place;
    spadlen = min - MAX (max, place) - (signvalue ? 1 : 0);
    if (zpadlen < 0) zpadlen = 0;
    if (spadlen < 0) spadlen = 0;
    if (flags & DP_F_ZERO) {
        zpadlen = MAX(zpadlen, spadlen);
        spadlen = 0;
    }
    if (flags & DP_F_MINUS) 
        spadlen = -spadlen; /* Left Justifty */

    /* Spaces */
    while (spadlen > 0) {
        dopr_outch(buffer, currlen, maxlen, ' ');
        --spadlen;
    }

    /* Sign */
    if (signvalue) 
        dopr_outch(buffer, currlen, maxlen, signvalue);

    /* Zeros */
    if (zpadlen > 0) {
        while (zpadlen > 0) {
            dopr_outch(buffer, currlen, maxlen, '0');
            --zpadlen;
        }
    }

    /* Digits */
    while (place > 0) 
        dopr_outch(buffer, currlen, maxlen, convert[--place]);

    /* Left Justified spaces */
    while (spadlen < 0) {
        dopr_outch(buffer, currlen, maxlen, ' ');
        ++spadlen;
    }
}

static LDOUBLE abs_val(LDOUBLE value)
{
    LDOUBLE result = value;

    if (value < 0)
        result = -value;

    return result;
}

static LDOUBLE POW10(int exp)
{
    LDOUBLE result = 1;

    while (exp) {
        result *= 10;
        exp--;
    }

    return result;
}

static LLONG ROUND(LDOUBLE value)
{
    LLONG intpart;

    intpart = (LLONG)value;
    value = value - intpart;
    if (value >= 0.5) intpart++;

    return intpart;
}

static void fmtfp (char *buffer, size_t *currlen, size_t maxlen,
                   LDOUBLE fvalue, int min, int max, int flags)
{
    int signvalue = 0;
    double ufvalue;
    char iconvert[311];
    char fconvert[311];
    int iplace = 0;
    int fplace = 0;
    int padlen = 0; /* amount to pad */
    int zpadlen = 0; 
    int caps = 0;
    int index;
    double intpart;
    double fracpart;
    double temp;
    /* 
     * AIX manpage says the default is 0, but Solaris says the default
     * is 6, and sprintf on AIX defaults to 6
     */
    if (max < 0)
        max = 6;

    ufvalue = abs_val (fvalue);

    if (fvalue < 0) {
        signvalue = '-';
    } else {
        if (flags & DP_F_PLUS) { /* Do a sign (+/i) */
            signvalue = '+';
        } else {
            if (flags & DP_F_SPACE)
                signvalue = ' ';
        }
    }

#if 0
    if (flags & DP_F_UP) caps = 1; /* Should characters be upper case? */
#endif

#if 0
    if (max == 0) ufvalue += 0.5; /* if max = 0 we must round */
#endif

    /* 
     * Sorry, we only support 16 digits past the decimal because of our 
     * conversion method
     */
    if (max > 16)
        max = 16;

    /* We "cheat" by converting the fractional part to integer by
     * multiplying by a factor of 10
     */

    temp = ufvalue;
    modf(temp, &intpart);

    fracpart = ROUND((POW10(max)) * (ufvalue - intpart));

    if (fracpart >= POW10(max)) {
        intpart++;
        fracpart -= POW10(max);
    }

    /* Convert integer part */
    do {
        temp = intpart;
        modf(intpart*0.1, &intpart);
        temp = temp*0.1;
        index = (int) ((temp -intpart +0.05)* 10.0);
        /* index = (int) (((double)(temp*0.1) -intpart +0.05) *10.0); */
        /* printf ("%llf, %f, %x\n", temp, intpart, index); */
        iconvert[iplace++] =
                    (caps? "0123456789ABCDEF":"0123456789abcdef")[index];
    } while (intpart && (iplace < 311));
    if (iplace == 311) iplace--;
    iconvert[iplace] = 0;

    /* Convert fractional part */
    if (fracpart)
    {
        do {
            temp = fracpart;
            modf(fracpart*0.1, &fracpart);
            temp = temp*0.1;
            index = (int) ((temp -fracpart +0.05)* 10.0);
            /* index = (int) ((((temp/10) -fracpart) +0.05) *10); */
            /* printf ("%lf, %lf, %ld\n", temp, fracpart, index); */
            fconvert[fplace++] =
                    (caps? "0123456789ABCDEF":"0123456789abcdef")[index];
        } while(fracpart && (fplace < 311));
        if (fplace == 311) fplace--;
    }
    fconvert[fplace] = 0;

    /* -1 for decimal point, another -1 if we are printing a sign */
    padlen = min - iplace - max - 1 - ((signvalue) ? 1 : 0); 
    zpadlen = max - fplace;
    if (zpadlen < 0) zpadlen = 0;
    if (padlen < 0) 
        padlen = 0;
    if (flags & DP_F_MINUS) 
        padlen = -padlen; /* Left Justifty */
        
    if ((flags & DP_F_ZERO) && (padlen > 0)) {
        if (signvalue) {
            dopr_outch(buffer, currlen, maxlen, signvalue);
            --padlen;
            signvalue = 0;
        }
        while (padlen > 0) {
            dopr_outch(buffer, currlen, maxlen, '0');
            --padlen;
        }
    }
    while (padlen > 0) {
        dopr_outch(buffer, currlen, maxlen, ' ');
        --padlen;
    }
    if (signvalue) 
        dopr_outch(buffer, currlen, maxlen, signvalue);
        
    while (iplace > 0) 
        dopr_outch(buffer, currlen, maxlen, iconvert[--iplace]);


    /*
     * Decimal point.  This should probably use locale to find the correct
     * char to print out.
     */
    if (max > 0) {
        dopr_outch(buffer, currlen, maxlen, '.');

        while (fplace > 0) 
            dopr_outch(buffer, currlen, maxlen, fconvert[--fplace]);
    }

    while (zpadlen > 0) {
        dopr_outch(buffer, currlen, maxlen, '0');
        --zpadlen;
    }

    while (padlen < 0) {
        dopr_outch(buffer, currlen, maxlen, ' ');
        ++padlen;
    }
}

static void dopr_outch(char *buffer, size_t *currlen, size_t maxlen, char c) //maxlen is count(length passed in snprintf)-1
{
    if (*currlen < maxlen) {
        buffer[(*currlen)] = c;
    }
    (*currlen)++;
}

int vsnprintf (char *str, size_t count, const char *fmt, va_list args)
{
    return dopr(str, count, fmt, args);
}

int iccc_snprintf(char *str, size_t count, const char *fmt,...)
{
    size_t ret;
    va_list ap;

    va_start(ap, fmt);
    ret = vsnprintf(str, count, fmt, ap);
    va_end(ap);
    return ret;
}