duktape-1.5.2/src-separate/duk_bi_number.c

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/*
 *  Number built-ins
 */
 
#include "duk_internal.h"
 
DUK_LOCAL duk_double_t duk__push_this_number_plain(duk_context *ctx) {
    duk_hobject *h;
 
    /* Number built-in accepts a plain number or a Number object (whose
     * internal value is operated on).  Other types cause TypeError.
     */
 
    duk_push_this(ctx);
    if (duk_is_number(ctx, -1)) {
        DUK_DDD(DUK_DDDPRINT("plain number value: %!T", (duk_tval *) duk_get_tval(ctx, -1)));
        goto done;
    }
    h = duk_get_hobject(ctx, -1);
    if (!h ||
        (DUK_HOBJECT_GET_CLASS_NUMBER(h) != DUK_HOBJECT_CLASS_NUMBER)) {
        DUK_DDD(DUK_DDDPRINT("unacceptable this value: %!T", (duk_tval *) duk_get_tval(ctx, -1)));
        DUK_ERROR_TYPE((duk_hthread *) ctx, "number expected");
    }
    duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_VALUE);
    DUK_ASSERT(duk_is_number(ctx, -1));
    DUK_DDD(DUK_DDDPRINT("number object: %!T, internal value: %!T",
                         (duk_tval *) duk_get_tval(ctx, -2), (duk_tval *) duk_get_tval(ctx, -1)));
    duk_remove(ctx, -2);
 
 done:
    return duk_get_number(ctx, -1);
}
 
DUK_INTERNAL duk_ret_t duk_bi_number_constructor(duk_context *ctx) {
    duk_hthread *thr = (duk_hthread *) ctx;
    duk_idx_t nargs;
    duk_hobject *h_this;
 
    DUK_UNREF(thr);
 
    /*
     *  The Number constructor uses ToNumber(arg) for number coercion
     *  (coercing an undefined argument to NaN).  However, if the
     *  argument is not given at all, +0 must be used instead.  To do
     *  this, a vararg function is used.
     */
 
    nargs = duk_get_top(ctx);
    if (nargs == 0) {
        duk_push_int(ctx, 0);
    }
    duk_to_number(ctx, 0);
    duk_set_top(ctx, 1);
    DUK_ASSERT_TOP(ctx, 1);
 
    if (!duk_is_constructor_call(ctx)) {
        return 1;
    }
 
    /*
     *  E5 Section 15.7.2.1 requires that the constructed object
     *  must have the original Number.prototype as its internal
     *  prototype.  However, since Number.prototype is non-writable
     *  and non-configurable, this doesn't have to be enforced here:
     *  The default object (bound to 'this') is OK, though we have
     *  to change its class.
     *
     *  Internal value set to ToNumber(arg) or +0; if no arg given,
     *  ToNumber(undefined) = NaN, so special treatment is needed
     *  (above).  String internal value is immutable.
     */
 
    /* XXX: helper */
    duk_push_this(ctx);
    h_this = duk_get_hobject(ctx, -1);
    DUK_ASSERT(h_this != NULL);
    DUK_HOBJECT_SET_CLASS_NUMBER(h_this, DUK_HOBJECT_CLASS_NUMBER);
 
    DUK_ASSERT(DUK_HOBJECT_GET_PROTOTYPE(thr->heap, h_this) == thr->builtins[DUK_BIDX_NUMBER_PROTOTYPE]);
    DUK_ASSERT(DUK_HOBJECT_GET_CLASS_NUMBER(h_this) == DUK_HOBJECT_CLASS_NUMBER);
    DUK_ASSERT(DUK_HOBJECT_HAS_EXTENSIBLE(h_this));
 
    duk_dup(ctx, 0);  /* -> [ val obj val ] */
    duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_VALUE, DUK_PROPDESC_FLAGS_NONE);
    return 0;  /* no return value -> don't replace created value */
}
 
DUK_INTERNAL duk_ret_t duk_bi_number_prototype_value_of(duk_context *ctx) {
    (void) duk__push_this_number_plain(ctx);
    return 1;
}
 
DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_string(duk_context *ctx) {
    duk_small_int_t radix;
    duk_small_uint_t n2s_flags;
 
    (void) duk__push_this_number_plain(ctx);
    if (duk_is_undefined(ctx, 0)) {
        radix = 10;
    } else {
        radix = (duk_small_int_t) duk_to_int_check_range(ctx, 0, 2, 36);
    }
    DUK_DDD(DUK_DDDPRINT("radix=%ld", (long) radix));
 
    n2s_flags = 0;
 
    duk_numconv_stringify(ctx,
                          radix /*radix*/,
                          0 /*digits*/,
                          n2s_flags /*flags*/);
    return 1;
}
 
DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_locale_string(duk_context *ctx) {
    /* XXX: just use toString() for now; permitted although not recommended.
     * nargs==1, so radix is passed to toString().
     */
    return duk_bi_number_prototype_to_string(ctx);
}
 
/*
 *  toFixed(), toExponential(), toPrecision()
 */
 
/* XXX: shared helper for toFixed(), toExponential(), toPrecision()? */
 
DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_fixed(duk_context *ctx) {
    duk_small_int_t frac_digits;
    duk_double_t d;
    duk_small_int_t c;
    duk_small_uint_t n2s_flags;
 
    frac_digits = (duk_small_int_t) duk_to_int_check_range(ctx, 0, 0, 20);
    d = duk__push_this_number_plain(ctx);
 
    c = (duk_small_int_t) DUK_FPCLASSIFY(d);
    if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
        goto use_to_string;
    }
 
    if (d >= 1.0e21 || d <= -1.0e21) {
        goto use_to_string;
    }
 
    n2s_flags = DUK_N2S_FLAG_FIXED_FORMAT |
                DUK_N2S_FLAG_FRACTION_DIGITS;
 
    duk_numconv_stringify(ctx,
                          10 /*radix*/,
                          frac_digits /*digits*/,
                          n2s_flags /*flags*/);
    return 1;
 
 use_to_string:
    DUK_ASSERT_TOP(ctx, 2);
    duk_to_string(ctx, -1);
    return 1;
}
 
DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_exponential(duk_context *ctx) {
    duk_bool_t frac_undefined;
    duk_small_int_t frac_digits;
    duk_double_t d;
    duk_small_int_t c;
    duk_small_uint_t n2s_flags;
 
    d = duk__push_this_number_plain(ctx);
 
    frac_undefined = duk_is_undefined(ctx, 0);
    duk_to_int(ctx, 0);  /* for side effects */
 
    c = (duk_small_int_t) DUK_FPCLASSIFY(d);
    if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
        goto use_to_string;
    }
 
    frac_digits = (duk_small_int_t) duk_to_int_check_range(ctx, 0, 0, 20);
 
    n2s_flags = DUK_N2S_FLAG_FORCE_EXP |
               (frac_undefined ? 0 : DUK_N2S_FLAG_FIXED_FORMAT);
 
    duk_numconv_stringify(ctx,
                          10 /*radix*/,
                          frac_digits + 1 /*leading digit + fractions*/,
                          n2s_flags /*flags*/);
    return 1;
 
 use_to_string:
    DUK_ASSERT_TOP(ctx, 2);
    duk_to_string(ctx, -1);
    return 1;
}
 
DUK_INTERNAL duk_ret_t duk_bi_number_prototype_to_precision(duk_context *ctx) {
    /* The specification has quite awkward order of coercion and
     * checks for toPrecision().  The operations below are a bit
     * reordered, within constraints of observable side effects.
     */
 
    duk_double_t d;
    duk_small_int_t prec;
    duk_small_int_t c;
    duk_small_uint_t n2s_flags;
 
    DUK_ASSERT_TOP(ctx, 1);
 
    d = duk__push_this_number_plain(ctx);
    if (duk_is_undefined(ctx, 0)) {
        goto use_to_string;
    }
    DUK_ASSERT_TOP(ctx, 2);
 
    duk_to_int(ctx, 0);  /* for side effects */
 
    c = (duk_small_int_t) DUK_FPCLASSIFY(d);
    if (c == DUK_FP_NAN || c == DUK_FP_INFINITE) {
        goto use_to_string;
    }
 
    prec = (duk_small_int_t) duk_to_int_check_range(ctx, 0, 1, 21);
 
    n2s_flags = DUK_N2S_FLAG_FIXED_FORMAT |
                DUK_N2S_FLAG_NO_ZERO_PAD;
 
    duk_numconv_stringify(ctx,
                          10 /*radix*/,
                          prec /*digits*/,
                          n2s_flags /*flags*/);
    return 1;
 
 use_to_string:
    /* Used when precision is undefined; also used for NaN (-> "NaN"),
     * and +/- infinity (-> "Infinity", "-Infinity").
     */
 
    DUK_ASSERT_TOP(ctx, 2);
    duk_to_string(ctx, -1);
    return 1;
}