Class: MmapScanner::Mmap

Inherits:
Object
  • Object
show all
Defined in:
ext/mmapscanner.c

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Object 



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# File 'ext/mmapscanner.c', line 43

static VALUE mmap_initialize(int argc, VALUE *argv, VALUE obj)
{
    mmap_data_t *data;
    Data_Get_Struct(obj, mmap_data_t, data);
    if (data->ptr)
        rb_raise(rb_eRuntimeError, "already mapped");
    VALUE file, voffset, vlength;
    off_t offset = 0;
    size_t length = 0;
    rb_scan_args(argc, argv, "12", &file, &voffset, &vlength);
    if (TYPE(file) != T_FILE)
        rb_raise(rb_eTypeError, "File object required");
    if (voffset != Qnil && NUM2LL(voffset) < 0)
        rb_raise(rb_eRangeError, "offset out of range: %lld", NUM2LL(voffset));
    if (vlength != Qnil && NUM2LL(vlength) < 0)
        rb_raise(rb_eRangeError, "length out of range: %lld", NUM2LL(vlength));
    int fd = RFILE(file)->fptr->fd;
    struct stat st;
    if (fstat(fd, &st) < 0)
        rb_sys_fail("fstat");
    offset = voffset == Qnil ? 0 : NUM2SIZET(voffset);
    length = vlength == Qnil ? st.st_size : NUM2SIZET(vlength);
    if (offset + length > st.st_size)
        length = st.st_size - offset;
    void *ptr;
    if ((ptr = mmap(NULL, length, PROT_READ, MAP_SHARED, fd, offset)) == MAP_FAILED)
        rb_sys_fail("mmap");

    data->ptr = ptr;
    data->size = length;
    return Qnil;
}

Instance Method Details

#size ⇒ Object 



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# File 'ext/mmapscanner.c', line 76

static VALUE mmap_size(VALUE obj)
{
    mmap_data_t *data;
    Data_Get_Struct(obj, mmap_data_t, data);
    return SIZET2NUM(data->size);
}

#unmap ⇒ Object 



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# File 'ext/mmapscanner.c', line 83

static VALUE mmap_unmap(VALUE obj)
{
    mmap_data_t *data;
    Data_Get_Struct(obj, mmap_data_t, data);
    if (data->ptr == NULL)
        rb_raise(rb_eRuntimeError, "already unmapped");
    if (munmap(data->ptr, data->size) < 0)
        rb_sys_fail("munmap");
    data->ptr = NULL;
    return Qnil;
}