/************************************************

  range.c -

  $Author$
  $Date$
  created at: Thu Aug 19 17:46:47 JST 1993

  Copyright (C) 1993-2000 Yukihiro Matsumoto

************************************************/

#include "ruby.h"

VALUE rb_cRange;
static ID id_cmp, id_beg, id_end;

#define EXCL(r) FL_TEST((r), FL_USER1)
#define SET_EXCL(r) FL_SET((r), FL_USER1)

static VALUE
range_check(args)
    VALUE *args;
{
    rb_funcall(args[0], id_cmp, 1, args[1]);
    return Qnil;
}

static VALUE
range_failed()
{
    rb_raise(rb_eArgError, "bad value for range");
    return Qnil;		/* dummy */
}

static void
range_init(obj, beg, end, exclude_end)
    VALUE obj, beg, end;
    int exclude_end;
{
    VALUE args[2];

    args[0] = beg; args[1] = end;
    if (!FIXNUM_P(beg) || !FIXNUM_P(end)) {
	rb_rescue(range_check, (VALUE)args, range_failed, 0);
    }

    if (exclude_end) {
	SET_EXCL(obj);
    }

    rb_ivar_set(obj, id_beg, beg);
    rb_ivar_set(obj, id_end, end);
}

VALUE
rb_range_new(beg, end, exclude_end)
    VALUE beg, end;
    int exclude_end;
{
    VALUE obj = rb_obj_alloc(rb_cRange);

    range_init(obj, beg, end, exclude_end);
    return obj;
}

static VALUE
range_initialize(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    VALUE beg, end, flag;
    
    rb_scan_args(argc, argv, "21", &beg, &end, &flag);
    /* Ranges are immutable, so that they should be initialized only once. */
    if (rb_ivar_defined(obj, id_beg)) {
	rb_raise(rb_eNameError, "`initialize' called twice");
    }
    range_init(obj, beg, end, RTEST(flag));
    return Qnil;
}

static VALUE
range_exclude_end_p(range)
    VALUE range;
{
    return EXCL(range)?Qtrue:Qfalse;
}

static VALUE
range_eqq(range, obj)
    VALUE range, obj;
{
    VALUE beg, end;

    beg = rb_ivar_get(range, id_beg);
    end = rb_ivar_get(range, id_end);

    if (FIXNUM_P(beg) && FIXNUM_P(obj) && FIXNUM_P(end)) {
	if (NUM2LONG(beg) <= NUM2LONG(obj)) {
	    if (EXCL(range)) {
		if (NUM2LONG(obj) < NUM2LONG(end)) return Qtrue;
	    }
	    else {
		if (NUM2LONG(obj) <= NUM2LONG(end)) return Qtrue;
	    }
	}
	return Qfalse;
    }
    else if (RTEST(rb_funcall(beg, rb_intern("<="), 1, obj))) {
	if (EXCL(range)) {
	    if (RTEST(rb_funcall(end, rb_intern(">"), 1, obj)))
		return Qtrue;
	}
	else {
	    if (RTEST(rb_funcall(end, rb_intern(">="), 1, obj)))
		return Qtrue;
	}
    }
    return Qfalse;
}

static VALUE
range_each(range)
    VALUE range;
{
    VALUE b, e;

    b = rb_ivar_get(range, id_beg);
    e = rb_ivar_get(range, id_end);

    if (FIXNUM_P(b) && FIXNUM_P(e)) { /* fixnums are special */
	long end = FIX2LONG(e);
	long i;

	if (!EXCL(range)) end += 1;
	for (i=FIX2LONG(b); i<end; i++) {
	    rb_yield(INT2NUM(i));
	}
    }
    else if (TYPE(b) == T_STRING) {
	rb_str_upto(b, e, EXCL(range));
    }
    else if (rb_obj_is_kind_of(b, rb_cNumeric)) {
	b = rb_Integer(b);
	e = rb_Integer(e);

	if (!EXCL(range)) e = rb_funcall(e, '+', 1, INT2FIX(1));
	while (RTEST(rb_funcall(b, '<', 1, e))) {
	    rb_yield(b);
	    b = rb_funcall(b, '+', 1, INT2FIX(1));
	}
    }
    else {			/* generic each */
	VALUE v = b;
	ID succ = rb_intern("succ");

	if (EXCL(range)) {
	    while (RTEST(rb_funcall(v, '<', 1, e))) {
		if (rb_equal(v, e)) break;
		rb_yield(v);
		v = rb_funcall(v, succ, 0, 0);
	    }
	}
	else {
	    ID le = rb_intern("<=");

	    while (RTEST(rb_funcall(v, le, 1, e))) {
		rb_yield(v);
		if (rb_equal(v, e)) break;
		v = rb_funcall(v, succ, 0, 0);
	    }
	}
    }

    return range;
}

static VALUE
range_first(obj)
    VALUE obj;
{
    VALUE b;

    b = rb_ivar_get(obj, id_beg);
    return b;
}

static VALUE
range_last(obj)
    VALUE obj;
{
    VALUE e;

    e = rb_ivar_get(obj, id_end);
    return e;
}

VALUE
rb_range_beg_len(range, begp, lenp, len, err)
    VALUE range;
    long *begp, *lenp;
    long len;
    int err;
{
    long beg, end, b, e;

    if (!rb_obj_is_kind_of(range, rb_cRange)) return Qfalse;

    beg = b = NUM2LONG(rb_ivar_get(range, id_beg));
    end = e = NUM2LONG(rb_ivar_get(range, id_end));

    if (beg < 0) {
	beg += len;
	if (beg < 0) goto out_of_range;
    }
    if (err == 0 || err == 2) {
	if (beg > len) goto out_of_range;
	if (end > len || (!EXCL(range) && end == len))
	    end = len;
    }
    if (end < 0) {
	end += len;
	if (end < 0) {
	    if (beg == 0 && end == -1 && !EXCL(range)) {
		len = 0;
		goto length_set;
	    }
	    goto out_of_range;
	}
    }
    len = end - beg;
    if (!EXCL(range)) len++;	/* include end point */
    if (len < 0) goto out_of_range;

  length_set:
    *begp = beg;
    *lenp = len;

    return Qtrue;

  out_of_range:
    if (err) {
	rb_raise(rb_eRangeError, "%d..%s%d out of range",
		 b, EXCL(range)?".":"", e);
    }
    return Qnil;
}

static VALUE
range_to_s(range)
    VALUE range;
{
    VALUE str, str2;

    str = rb_obj_as_string(rb_ivar_get(range, id_beg));
    str2 = rb_obj_as_string(rb_ivar_get(range, id_end));
    str = rb_str_dup(str);
    rb_str_cat(str, "...", EXCL(range)?3:2);
    rb_str_append(str, str2);
    OBJ_INFECT(str, str2);

    return str;
}

static VALUE
range_inspect(range)
    VALUE range;
{
    VALUE str, str2;

    str = rb_inspect(rb_ivar_get(range, id_beg));
    str2 = rb_inspect(rb_ivar_get(range, id_end));
    str = rb_str_dup(str);
    rb_str_cat(str, "...", EXCL(range)?3:2);
    rb_str_append(str, str2);
    OBJ_INFECT(str, str2);

    return str;
}

static VALUE
length_i(i, length)
    VALUE i;
    int *length;
{
    (*length)++;
    return Qnil;
}

VALUE
rb_length_by_each(obj)
    VALUE obj;
{
    int length = 0;

    rb_iterate(rb_each, obj, length_i, (VALUE)&length);
    return INT2FIX(length);
}

static VALUE
range_length(range)
    VALUE range;
{
    VALUE beg, end;
    long size;

    beg = rb_ivar_get(range, id_beg);
    end = rb_ivar_get(range, id_end);

    if (RTEST(rb_funcall(beg, '>', 1, end))) {
	return INT2FIX(0);
    }
    if (FIXNUM_P(beg) && FIXNUM_P(end)) {
	if (EXCL(range)) {
	    return INT2NUM(NUM2LONG(end) - NUM2LONG(beg));
	}
	else {
	    return INT2NUM(NUM2LONG(end) - NUM2LONG(beg) + 1);
	}
    }
    if (!rb_obj_is_kind_of(beg, rb_cInteger)) {
	return rb_length_by_each(range);
    }
    size = rb_funcall(end, '-', 1, beg);
    if (!EXCL(range)) {
	size = rb_funcall(size, '+', 1, INT2FIX(1));
    }

    return size;
}

void
Init_Range()
{
    rb_cRange = rb_define_class("Range", rb_cObject);
    rb_include_module(rb_cRange, rb_mEnumerable);
    rb_define_method(rb_cRange, "initialize", range_initialize, -1);
    rb_define_method(rb_cRange, "===", range_eqq, 1);
    rb_define_method(rb_cRange, "each", range_each, 0);
    rb_define_method(rb_cRange, "first", range_first, 0);
    rb_define_method(rb_cRange, "last", range_last, 0);
    rb_define_method(rb_cRange, "begin", range_first, 0);
    rb_define_method(rb_cRange, "end", range_last, 0);
    rb_define_method(rb_cRange, "to_s", range_to_s, 0);
    rb_define_method(rb_cRange, "inspect", range_inspect, 0);

    rb_define_method(rb_cRange, "exclude_end?", range_exclude_end_p, 0);

    rb_define_method(rb_cRange, "length", range_length, 0);
    rb_define_method(rb_cRange, "size", range_length, 0);

    id_cmp = rb_intern("<=>");
    id_beg = rb_intern("begin");
    id_end = rb_intern("end");
}