Class: Array

Inherits:
Object
  • Object
show all
Defined in:
(unknown)

Instance Method Summary collapse

Instance Method Details

#mask(*args) ⇒ Object 



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# File 'ext/string_bits/string_bits.c', line 1986

static VALUE
rb_ary_mask(int argc, VALUE *argv, VALUE self)
{
    VALUE bitmap;
    int lsb_first, invert, is_integer;
    parse_mask_kwargs(argc, argv, &bitmap, &lsb_first, &invert, &is_integer);

    ssize_t ary_len = RARRAY_LEN(self);
    const VALUE *src = RARRAY_CONST_PTR(self);
    VALUE result = rb_ary_new_capa(ary_len);

    if (is_integer) {
        for (ssize_t i = 0; i < ary_len; i++) {
            int bit = integer_get_bit(bitmap, i);
            if (invert) bit = !bit;
            rb_ary_push(result, bit ? src[i] : Qnil);
        }
    }
    else {
        const unsigned char *bmp = (const unsigned char *)RSTRING_PTR(bitmap);
        ssize_t bmp_len    = RSTRING_LEN(bitmap);
        ssize_t needed     = (ary_len + 7) >> 3;
        if (needed > bmp_len)
            rb_raise(rb_eArgError,
                     "bitmap too short: need %" PRIdPTR " bytes for %" PRIdPTR
                     " elements, got %" PRIdPTR,
                     (intptr_t)needed, (intptr_t)ary_len, (intptr_t)bmp_len);

        if (!lsb_first) {
            for (ssize_t i = 0; i < ary_len; i++) {
                int bit = (bmp[i >> 3] >> (7 - (i & 7))) & 1;
                if (invert) bit = !bit;
                rb_ary_push(result, bit ? src[i] : Qnil);
            }
        }
        else {
            for (ssize_t i = 0; i < ary_len; i++) {
                int bit = (bmp[i >> 3] >> (i & 7)) & 1;
                if (invert) bit = !bit;
                rb_ary_push(result, bit ? src[i] : Qnil);
            }
        }
    }

    return result;
}

#mask!(*args) ⇒ Object 



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# File 'ext/string_bits/string_bits.c', line 2033

static VALUE
rb_ary_mask_bang(int argc, VALUE *argv, VALUE self)
{
    VALUE bitmap;
    int lsb_first, invert, is_integer;
    parse_mask_kwargs(argc, argv, &bitmap, &lsb_first, &invert, &is_integer);

    ssize_t ary_len = RARRAY_LEN(self);
    rb_ary_modify(self);

    if (is_integer) {
        for (ssize_t i = 0; i < ary_len; i++) {
            int bit = integer_get_bit(bitmap, i);
            if (invert) bit = !bit;
            if (!bit) rb_ary_store(self, i, Qnil);
        }
    }
    else {
        const unsigned char *bmp = (const unsigned char *)RSTRING_PTR(bitmap);
        ssize_t bmp_len    = RSTRING_LEN(bitmap);
        ssize_t needed     = (ary_len + 7) >> 3;
        if (needed > bmp_len)
            rb_raise(rb_eArgError,
                     "bitmap too short: need %" PRIdPTR " bytes for %" PRIdPTR
                     " elements, got %" PRIdPTR,
                     (intptr_t)needed, (intptr_t)ary_len, (intptr_t)bmp_len);

        if (!lsb_first) {
            for (ssize_t i = 0; i < ary_len; i++) {
                int bit = (bmp[i >> 3] >> (7 - (i & 7))) & 1;
                if (invert) bit = !bit;
                if (!bit) rb_ary_store(self, i, Qnil);
            }
        }
        else {
            for (ssize_t i = 0; i < ary_len; i++) {
                int bit = (bmp[i >> 3] >> (i & 7)) & 1;
                if (invert) bit = !bit;
                if (!bit) rb_ary_store(self, i, Qnil);
            }
        }
    }

    return self;
}