jsdtoa.c

java script test programing source code

        z = (*xa++ >> 16) - (*xb++ >> 16) - borrow;
        borrow = (z & 0x10000) >> 16;
        Storeinc(xc, z, y);
        }
        while(xb < xbe);
    while(xa < xae) {
        y = (*xa & 0xffff) - borrow;
        borrow = (y & 0x10000) >> 16;
        z = (*xa++ >> 16) - borrow;
        borrow = (z & 0x10000) >> 16;
        Storeinc(xc, z, y);
        }
#endif
    while(!*--xc)
        wa--;
    c->wds = wa;
    return c;
}

/* Return the absolute difference between x and the adjacent greater-magnitude double number (ignoring exponent overflows). */
static double ulp(double x)
{
    register Long L;
    double a = 0;

    L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1;
#ifndef Sudden_Underflow
    if (L > 0) {
#endif
        set_word0(a, L);
        set_word1(a, 0);
#ifndef Sudden_Underflow
    }
    else {
        L = -L >> Exp_shift;
        if (L < Exp_shift) {
            set_word0(a, 0x80000 >> L);
            set_word1(a, 0);
        }
        else {
            set_word0(a, 0);
            L -= Exp_shift;
            set_word1(a, L >= 31 ? 1 : 1 << (31 - L));
        }
    }
#endif
    return a;
}


static double b2d(Bigint *a, int32 *e)
{
    ULong *xa, *xa0, w, y, z;
    int32 k;
    double d = 0;
#define d0 word0(d)
#define d1 word1(d)
#define set_d0(x) set_word0(d, x)
#define set_d1(x) set_word1(d, x)

    xa0 = a->x;
    xa = xa0 + a->wds;
    y = *--xa;
#ifdef DEBUG
    if (!y) Bug("zero y in b2d");
#endif
    k = hi0bits(y);
    *e = 32 - k;
    if (k < Ebits) {
        set_d0(Exp_1 | y >> (Ebits - k));
        w = xa > xa0 ? *--xa : 0;
        set_d1(y << (32-Ebits + k) | w >> (Ebits - k));
        goto ret_d;
    }
    z = xa > xa0 ? *--xa : 0;
    if (k -= Ebits) {
        set_d0(Exp_1 | y << k | z >> (32 - k));
        y = xa > xa0 ? *--xa : 0;
        set_d1(z << k | y >> (32 - k));
    }
    else {
        set_d0(Exp_1 | y);
        set_d1(z);
    }
  ret_d:
#undef d0
#undef d1
#undef set_d0
#undef set_d1
    return d;
}


/* Convert d into the form b*2^e, where b is an odd integer.  b is the returned
 * Bigint and e is the returned binary exponent.  Return the number of significant
 * bits in b in bits.  d must be finite and nonzero. */
static Bigint *d2b(double d, int32 *e, int32 *bits)
{
    Bigint *b;
    int32 de, i, k;
    ULong *x, y, z;
#define d0 word0(d)
#define d1 word1(d)
#define set_d0(x) set_word0(d, x)
#define set_d1(x) set_word1(d, x)

    b = Balloc(1);
    if (!b)
        return NULL;
    x = b->x;

    z = d0 & Frac_mask;
    set_d0(d0 & 0x7fffffff);  /* clear sign bit, which we ignore */
#ifdef Sudden_Underflow
    de = (int32)(d0 >> Exp_shift);
    z |= Exp_msk11;
#else
    if ((de = (int32)(d0 >> Exp_shift)) != 0)
        z |= Exp_msk1;
#endif
    if ((y = d1) != 0) {
        if ((k = lo0bits(&y)) != 0) {
            x[0] = y | z << (32 - k);
            z >>= k;
        }
        else
            x[0] = y;
        i = b->wds = (x[1] = z) ? 2 : 1;
    }
    else {
        JS_ASSERT(z);
        k = lo0bits(&z);
        x[0] = z;
        i = b->wds = 1;
        k += 32;
    }
#ifndef Sudden_Underflow
    if (de) {
#endif
        *e = de - Bias - (P-1) + k;
        *bits = P - k;
#ifndef Sudden_Underflow
    }
    else {
        *e = de - Bias - (P-1) + 1 + k;
        *bits = 32*i - hi0bits(x[i-1]);
    }
#endif
    return b;
}
#undef d0
#undef d1
#undef set_d0
#undef set_d1


static double ratio(Bigint *a, Bigint *b)
{
    double da, db;
    int32 k, ka, kb;

    da = b2d(a, &ka);
    db = b2d(b, &kb);
    k = ka - kb + 32*(a->wds - b->wds);
    if (k > 0)
        set_word0(da, word0(da) + k*Exp_msk1);
    else {
        k = -k;
        set_word0(db, word0(db) + k*Exp_msk1);
    }
    return da / db;
}

static CONST double
tens[] = {
    1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9,
    1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19,
    1e20, 1e21, 1e22
};

static CONST double bigtens[] = { 1e16, 1e32, 1e64, 1e128, 1e256 };
static CONST double tinytens[] = { 1e-16, 1e-32, 1e-64, 1e-128,
#ifdef Avoid_Underflow
        9007199254740992.e-256
#else
        1e-256
#endif
        };
/* The factor of 2^53 in tinytens[4] helps us avoid setting the underflow */
/* flag unnecessarily.  It leads to a song and dance at the end of strtod. */
#define Scale_Bit 0x10
#define n_bigtens 5


#ifdef INFNAN_CHECK

#ifndef NAN_WORD0
#define NAN_WORD0 0x7ff80000
#endif

#ifndef NAN_WORD1
#define NAN_WORD1 0
#endif

static int match(CONST char **sp, char *t)
{
    int c, d;
    CONST char *s = *sp;

    while(d = *t++) {
        if ((c = *++s) >= 'A' && c <= 'Z')
            c += 'a' - 'A';
        if (c != d)
            return 0;
        }
    *sp = s + 1;
    return 1;
    }
#endif /* INFNAN_CHECK */


#ifdef JS_THREADSAFE
static JSBool initialized = JS_FALSE;

/* hacked replica of nspr _PR_InitDtoa */
static void InitDtoa(void)
{
    freelist_lock = PR_NewLock();
        p5s_lock = PR_NewLock();
    initialized = JS_TRUE;
}
#endif

void js_FinishDtoa(void)
{
    int count;
    Bigint *temp;

#ifdef JS_THREADSAFE
    if (initialized == JS_TRUE) {
        PR_DestroyLock(freelist_lock);
        PR_DestroyLock(p5s_lock);
        initialized = JS_FALSE;
    }
#endif

    /* clear down the freelist array and p5s */

    /* static Bigint *freelist[Kmax+1]; */
    for (count = 0; count <= Kmax; count++) {
        Bigint **listp = &freelist[count];
        while ((temp = *listp) != NULL) {
            *listp = temp->next;
            free(temp);
        }
        freelist[count] = NULL;
    }

    /* static Bigint *p5s; */
    while (p5s) {
        temp = p5s;
        p5s = p5s->next;
        free(temp);
    }
}

/* nspr2 watcom bug ifdef omitted */

JS_FRIEND_API(double)
JS_strtod(CONST char *s00, char **se, int *err)
{
    int32 scale;
    int32 bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, dsign,
        e, e1, esign, i, j, k, nd, nd0, nf, nz, nz0, sign;
    CONST char *s, *s0, *s1;
    double aadj, aadj1, adj, rv, rv0;
    Long L;
    ULong y, z;
    Bigint *bb, *bb1, *bd, *bd0, *bs, *delta;

    *err = 0;

    bb = bd = bs = delta = NULL;
    sign = nz0 = nz = 0;
    rv = 0.;

    /* Locking for Balloc's shared buffers that will be used in this block */
    ACQUIRE_DTOA_LOCK();

    for(s = s00;;s++) switch(*s) {
    case '-':
        sign = 1;
        /* no break */
    case '+':
        if (*++s)
            goto break2;
        /* no break */
    case 0:
        s = s00;
        goto ret;
    case '\t':
    case '\n':
    case '\v':
    case '\f':
    case '\r':
    case ' ':
        continue;
    default:
        goto break2;
    }
break2:

    if (*s == '0') {
        nz0 = 1;
        while(*++s == '0') ;
        if (!*s)
            goto ret;
    }
    s0 = s;
    y = z = 0;
    for(nd = nf = 0; (c = *s) >= '0' && c <= '9'; nd++, s++)
        if (nd < 9)
            y = 10*y + c - '0';
        else if (nd < 16)
            z = 10*z + c - '0';
    nd0 = nd;
    if (c == '.') {
        c = *++s;
        if (!nd) {
            for(; c == '0'; c = *++s)
                nz++;
            if (c > '0' && c <= '9') {
                s0 = s;
                nf += nz;
                nz = 0;
                goto have_dig;
            }
            goto dig_done;
        }
        for(; c >= '0' && c <= '9'; c = *++s) {
        have_dig:
            nz++;
            if (c -= '0') {
                nf += nz;
                for(i = 1; i < nz; i++)
                    if (nd++ < 9)
                        y *= 10;
                    else if (nd <= DBL_DIG + 1)
                        z *= 10;
                if (nd++ < 9)
                    y = 10*y + c;
                else if (nd <= DBL_DIG + 1)
                    z = 10*z + c;
                nz = 0;
            }
        }
    }
dig_done:
    e = 0;
    if (c == 'e' || c == 'E') {
        if (!nd && !nz && !nz0) {
            s = s00;
            goto ret;
        }
        s00 = s;
        esign = 0;
        switch(c = *++s) {
        case '-':
            esign = 1;
        case '+':
            c = *++s;
        }
        if (c >= '0' && c <= '9') {
            while(c == '0')
                c = *++s;
            if (c > '0' && c <= '9') {
                L = c - '0';
                s1 = s;
                while((c = *++s) >= '0' && c <= '9')
                    L = 10*L + c - '0';
                if (s - s1 > 8 || L > 19999)
                    /* Avoid confusion from exponents
                     * so large that e might overflow.
                     */
                    e = 19999; /* safe for 16 bit ints */
                else
                    e = (int32)L;
                if (esign)
                    e = -e;
            }
            else
                e = 0;
        }
        else
            s = s00;
    }
    if (!nd) {
        if (!nz && !nz0) {
#ifdef INFNAN_CHECK
            /* Check for Nan and Infinity */
            switch(c) {
              case 'i':
              case 'I':
                if (match(&s,"nfinity")) {
                    set_word0(rv, 0x7ff00000);
                    set_word1(rv, 0);
                    goto ret;
                    }
                break;
              case 'n':
              case 'N':
                if (match(&s, "an")) {
                    set_word0(rv, NAN_WORD0);
                    set_word1(rv, NAN_WORD1);
                    goto ret;
                    }
              }
#endif /* INFNAN_CHECK */
            s = s00;
            }
        goto ret;
    }
    e1 = e -= nf;

    /* Now we have nd0 digits, starting at s0, followed by a
     * decimal point, followed by nd-nd0 digits.  The number we're
     * after is the integer represented by those digits times
     * 10**e */

    if (!nd0)
        nd0 = nd;
    k = nd < DBL_DIG + 1 ? nd : DBL_DIG + 1;
    rv = y;
    if (k > 9)
        rv = tens[k - 9] * rv + z;
    bd0 = 0;
    if (nd <= DBL_DIG
#ifndef RND_PRODQUOT
        && FLT_ROUNDS == 1
#endif
        ) {
        if (!e)
            goto ret;
        if (e > 0) {
            if (e <= Ten_pmax) {
                /* rv = */ rounded_product(rv, tens[e]);
                goto ret;
            }
            i = DBL_DIG - nd;
            if (e <= Ten_pmax + i) {
                /* A fancier test would sometimes let us do
                 * this for larger i values.
                 */
                e -= i;
                rv *= tens[i];
                /* rv = */ rounded_product(rv, tens[e]);
                goto ret;
            }
        }
#ifndef Inaccurate_Divide
        else if (e >= -Ten_pmax) {
            /* rv = */ rounded_quotient(rv, tens[-e]);
            goto ret;
        }
#endif
    }
    e1 += nd - k;

    scale = 0;

    /* Get starting approximation = rv * 10**e1 */

    if (e1 > 0) {
        if ((i = e1 & 15) != 0)
            rv *= tens[i];
        if (e1 &= ~15) {
            if (e1 > DBL_MAX_10_EXP) {
            ovfl:
                *err = JS_DTOA_ERANGE;