expr.c

/*
 * expr.c: Expression evaluation in Gnumeriuc
 *
 * Author:
 *   Miguel de Icaza (miguel@gnu.org).
 */
#include <config.h>
#include <gnome.h>
#include <math.h>
#include <string.h>
#include "gnumeric.h"
#include "expr.h"
#include "eval.h"
#include "format.h"
#include "func.h"
#include "utils.h"

Value *value_zero = NULL;

ExprTree *
expr_parse_string (const char *expr, Sheet *sheet, int col, int row,
		   const char **desired_format, char **error_msg)
{
	ExprTree *tree;
	g_return_val_if_fail (expr != NULL, NULL);

	switch (gnumeric_expr_parser (expr, sheet, col, row, desired_format, &tree)) {
	case PARSE_OK:
		*error_msg = NULL;
		tree->ref_count = 1;
		return tree;

	case PARSE_ERR_SYNTAX:
		*error_msg = _("Syntax error");
		break;

	case PARSE_ERR_NO_QUOTE:
		*error_msg = _("Missing quote");
		break;
	default:
		g_assert_not_reached ();
		*error_msg = _("Impossible!");
		break;
	}
	return NULL;
}


ExprTree *
expr_tree_new (void)
{
	ExprTree *ans;

	ans = g_new (ExprTree, 1);
	if (!ans)
		return NULL;
	
	ans->ref_count = 1;
	ans->oper = OPER_CONSTANT;
	ans->u.constant = NULL;
	return ans;
}

/*
 * expr_tree_ref:
 * Increments the ref_count for part of a tree
 */
void
expr_tree_ref (ExprTree *tree)
{
	g_return_if_fail (tree != NULL);
	g_return_if_fail (tree->ref_count > 0);

	tree->ref_count++;
}

static void
do_expr_tree_unref (ExprTree *tree)
{
	if (--tree->ref_count > 0)
		return;

	switch (tree->oper){
	case OPER_VAR:
		break;

	case OPER_CONSTANT:
		value_release (tree->u.constant);
		break;

	case OPER_FUNCALL: {
		GList *l;

		for (l = tree->u.function.arg_list; l; l = l->next)
			do_expr_tree_unref (l->data);
		g_list_free (tree->u.function.arg_list);
		symbol_unref (tree->u.function.symbol);
		break;
	}

	case OPER_ANY_BINARY:
		do_expr_tree_unref (tree->u.binary.value_a);
		do_expr_tree_unref (tree->u.binary.value_b);
		break;

	case OPER_ANY_UNARY:
		do_expr_tree_unref (tree->u.value);
		break;
	default:
		g_warning ("do_expr_tree_unref error\n");
		break;
	}

	g_free (tree);
}

/*
 * expr_tree_unref:
 * Decrements the ref_count for part of a tree.  (All trees are expected
 * to have been created with a ref-count of one, so when we hit zero, we
 * go down over the tree and unref the tree and its leaves stuff.)
 */
void
expr_tree_unref (ExprTree *tree)
{
	g_return_if_fail (tree != NULL);
	g_return_if_fail (tree->ref_count > 0);

	do_expr_tree_unref (tree);
}

/*
 * simplistic value rendering
 */
char *
value_get_as_string (const Value *value)
{
	switch (value->type){
	case VALUE_STRING:
		return g_strdup (value->v.str->str);

	case VALUE_INTEGER:
		return g_strdup_printf ("%d", value->v.v_int);

	case VALUE_FLOAT:
		return g_strdup_printf ("%g", value->v.v_float);

	case VALUE_ARRAY: {
		GString *str = g_string_new ("{");
		guint lpx, lpy;
		char *ans;

		for (lpy=0;lpy<value->v.array.y;lpy++) {
			for (lpx=0;lpx<value->v.array.x;lpx++) {
				const Value *v = value->v.array.vals[lpx][lpy];
				g_return_val_if_fail (v->type == VALUE_STRING ||
						      v->type == VALUE_FLOAT ||
						      v->type == VALUE_INTEGER,
						      "Duff Array contents");
				if (lpx)
					g_string_sprintfa (str, ",");
				if (v->type == VALUE_STRING)
					g_string_sprintfa (str, "\"%s\"",
							   v->v.str->str);
				else
					g_string_sprintfa (str, "%g",
							   value_get_as_float (v));
			}
			if (lpy<value->v.array.y-1)
				g_string_sprintfa (str, ";");
		}
		g_string_sprintfa (str, "}");
		ans = str->str;
		g_string_free (str, FALSE);
		return ans;
	}

	case VALUE_CELLRANGE:
		break;
	default:
		g_warning ("value_string problem\n");
		break;
	}

	return g_strdup ("Internal problem");
}

void
value_release (Value *value)
{
	g_return_if_fail (value != NULL);

	switch (value->type){
	case VALUE_STRING:
		string_unref (value->v.str);
		break;

	case VALUE_INTEGER:
		mpz_clear (value->v.v_int);
		break;

	case VALUE_FLOAT:
		mpf_clear (value->v.v_float);
		break;

	case VALUE_ARRAY:{
		guint lpx, lpy;

		for (lpx = 0; lpx < value->v.array.x; lpx++) {
			for (lpy = 0; lpy < value->v.array.y; lpy++)
				value_release (value->v.array.vals[lpx][lpy]);
			g_free (value->v.array.vals [lpx]);
		}

		g_free (value->v.array.vals);
		break;
	}

	case VALUE_CELLRANGE:
		break;

	default:
		g_warning ("value_release problem\n");
		break;
	}
	g_free (value);
}

/*
 * Copies a Value.
 */
void
value_copy_to (Value *dest, const Value *source)
{
	g_return_if_fail (dest != NULL);
	g_return_if_fail (source != NULL);

	dest->type = source->type;

	switch (source->type){
	case VALUE_STRING:
		dest->v.str = source->v.str;
		string_ref (dest->v.str);
		break;

	case VALUE_INTEGER:
		dest->v.v_int = source->v.v_int;
		break;

	case VALUE_FLOAT:
		dest->v.v_float = source->v.v_float;
		break;

	case VALUE_ARRAY: {
		value_array_copy_to (dest, source);
		break;
	}
	case VALUE_CELLRANGE:
		dest->v.cell_range = source->v.cell_range;
		break;
	default:
		g_warning ("value_copy_to problem\n");
		break;
	}
}

/*
 * Makes a copy of a Value
 */
Value *
value_duplicate (const Value *value)
{
	Value *new_value;

	g_return_val_if_fail (value != NULL, NULL);
	new_value = g_new (Value, 1);
	value_copy_to (new_value, value);

	return new_value;
}

Value *
value_new_float (float_t f)
{
	Value *v = g_new (Value, 1);

	v->type = VALUE_FLOAT;
	v->v.v_float = f;

	return v;
}

Value *
value_new_int (int i)
{
	Value *v = g_new (Value, 1);

	v->type = VALUE_INTEGER;
	v->v.v_int = i;

	return v;
}

Value *
value_new_string (const char *str)
{
	Value *v = g_new (Value, 1);

	v->type = VALUE_STRING;
	v->v.str = string_get (str);

	return v;
}

Value *
value_new_cellrange (const CellRef *a, const CellRef *b)
{
	Value *v = g_new (Value, 1);

	v->type = VALUE_CELLRANGE;
	v->v.cell_range.cell_a = *a;
	v->v.cell_range.cell_b = *b;

	return v;
}

/*
 * Casts a value to float if it is integer, and returns
 * a new Value * if required
 */
Value *
value_cast_to_float (Value *v)
{
	Value *newv;

	g_return_val_if_fail (VALUE_IS_NUMBER (v), NULL);

	if (v->type == VALUE_FLOAT)
		return v;

	newv = g_new (Value, 1);
	newv->type = VALUE_FLOAT;
	mpf_set_z (newv->v.v_float, v->v.v_int);
	value_release (v);

	return newv;
}

int
value_get_as_bool (const Value *v, int *err)
{
	*err = 0;

	switch (v->type) {
	case VALUE_STRING:
		return atoi (v->v.str->str);

	case VALUE_CELLRANGE:
		*err = 1;
		return 0;
		
	case VALUE_INTEGER:
		return v->v.v_int != 0;

	case VALUE_FLOAT:
		return v->v.v_float != 0.0;

	case VALUE_ARRAY:
		return 0;
	default:
		g_warning ("Unhandled value in value_get_boolean");
		break;
	}
	return 0;
}

float_t
value_get_as_float (const Value *v)
{
	switch (v->type)
	{
	case VALUE_STRING:
		return atof (v->v.str->str);

	case VALUE_CELLRANGE:
		g_warning ("Getting range as a double: what to do?");
		return 0.0;

	case VALUE_INTEGER:
		return (float_t) v->v.v_int;
		
	case VALUE_ARRAY:
		return 0.0;

	case VALUE_FLOAT:
		return (float_t) v->v.v_float;
	default:
		g_warning ("value_get_as_float type error\n");
		break;
	}
	return 0.0;
}

int
value_get_as_int (const Value *v)
{
	switch (v->type)
	{
	case VALUE_STRING:
		return atoi (v->v.str->str);

	case VALUE_CELLRANGE:
		g_warning ("Getting range as a double: what to do?");
		return 0.0;

	case VALUE_INTEGER:
		return v->v.v_int;

	case VALUE_ARRAY:
		return 0.0;

	case VALUE_FLOAT:
		return (int) v->v.v_float;
	default:
		g_warning ("value_get_as_int unknown type\n");
		break;
	}
	return 0.0;
}

Value *
value_array_new (guint width, guint height)
{
	int x, y;

	Value *v = g_new (Value, 1);
	v->type = VALUE_ARRAY;
	v->v.array.x = width;
	v->v.array.y = height;
	v->v.array.vals = g_new (Value **, width);

	for (x = 0; x < width; x++){
		v->v.array.vals [x] = g_new (Value *, height);
		for (y = 0; y < height; y++)
			v->v.array.vals[x][y] = value_new_int (0);
	}
	return v;
}

void
value_array_set (Value *array, guint col, guint row, Value *v)
{
	g_return_if_fail (v);
	g_return_if_fail (array->type == VALUE_ARRAY);
	g_return_if_fail (col>=0);
	g_return_if_fail (row>=0);
	g_return_if_fail (array->v.array.y > row);
	g_return_if_fail (array->v.array.x > col);

	if (array->v.array.vals[col][row])
		value_release (array->v.array.vals[col][row]);
	array->v.array.vals[col][row] = v;
}

void
value_array_resize (Value *v, guint width, guint height)
{
	int x, y, xcpy, ycpy;
	Value *newval;
	Value ***tmp;

	g_warning ("Totally untested");
	g_return_if_fail (v);
	g_return_if_fail (v->type == VALUE_ARRAY);

	newval = value_array_new (width, height);

	if (width>v->v.array.x)
		xcpy = v->v.array.x;
	else
		xcpy = width;

	if (height>v->v.array.y)
		ycpy = v->v.array.y;
	else
		ycpy = height;

	for (x = 0; x < xcpy; x++)
		for (y = 0; y < ycpy; y++)
			value_array_set (newval, x, y, v->v.array.vals[x][y]);

	tmp = v->v.array.vals;
	v->v.array.vals = newval->v.array.vals;
	newval->v.array.vals = tmp ;
	value_release (newval);

	v->v.array.x = width;
	v->v.array.y = height;
}

void
value_array_copy_to (Value *v, const Value *src)
{
	int x, y;

	g_return_if_fail (src->type == VALUE_ARRAY);
	v->type = VALUE_ARRAY;
	v->v.array.x = src->v.array.x;
	v->v.array.y = src->v.array.y;
	v->v.array.vals = g_new (Value **, v->v.array.x);

	for (x = 0; x < v->v.array.x; x++) {
		v->v.array.vals [x] = g_new (Value *, v->v.array.y);
		for (y = 0; y < v->v.array.y; y++)
			v->v.array.vals [x][y] = value_duplicate (src->v.array.vals [x][y]);
	}
}

guint
value_area_get_width (Value *v)
{
	g_return_val_if_fail (v, 0);
	g_return_val_if_fail (v->type == VALUE_ARRAY ||
			      v->type == VALUE_CELLRANGE, 1);

	if (v->type == VALUE_ARRAY)
		return v->v.array.x;
	else {
		guint ans = v->v.cell_range.cell_b.col -
			    v->v.cell_range.cell_a.col + 1;
		if (v->v.cell_range.cell_a.sheet && 
		    v->v.cell_range.cell_a.sheet->max_col_used < ans)
			ans = v->v.cell_range.cell_a.sheet->max_col_used+1;
		return ans;
	}
}

guint
value_area_get_height (Value *v)
{
	g_return_val_if_fail (v, 0);
	g_return_val_if_fail (v->type == VALUE_ARRAY ||
			      v->type == VALUE_CELLRANGE, 1);

	if (v->type == VALUE_ARRAY)
		return v->v.array.y;
	else {
		guint ans = v->v.cell_range.cell_b.row -
		            v->v.cell_range.cell_a.row + 1;
		if (v->v.cell_range.cell_a.sheet && 
		    v->v.cell_range.cell_a.sheet->max_row_used < ans)
			ans = v->v.cell_range.cell_a.sheet->max_row_used+1;
		return ans;
	}
}

const Value *
value_area_get_at_x_y (Value *v, guint x, guint y)
{
	g_return_val_if_fail (v, 0);
	g_return_val_if_fail (v->type == VALUE_ARRAY ||
			      v->type == VALUE_CELLRANGE,
			     value_new_int (0));

	if (v->type == VALUE_ARRAY){
		g_return_val_if_fail (v->v.array.x < x &&
				      v->v.array.y < y,
				     value_new_int (0));
		return v->v.array.vals [x][y];
	} else {
		CellRef *a, *b;
		Cell *cell;

		a = &v->v.cell_range.cell_a;
		b = &v->v.cell_range.cell_b;
		g_return_val_if_fail (!a->col_relative, value_zero);
		g_return_val_if_fail (!b->col_relative, value_zero);
		g_return_val_if_fail (!a->row_relative, value_zero);
		g_return_val_if_fail (!b->row_relative, value_zero);
		g_return_val_if_fail (a->col<=b->col, value_zero);
		g_return_val_if_fail (a->row<=b->row, value_zero);

		/* Speedup */
		if (a->sheet->max_col_used < a->col+x ||
		    a->sheet->max_row_used < a->row+y)
			return value_zero;

		cell = sheet_cell_get (a->sheet, a->col+x, a->row+y);

		if (cell && cell->value)
			return cell->value;
	}
	
	return value_zero;
}

static void
cell_ref_make_absolute (CellRef *cell_ref, int eval_col, int eval_row)
{
	g_return_if_fail (cell_ref != NULL);

	if (cell_ref->col_relative)
		cell_ref->col = eval_col + cell_ref->col;

	if (cell_ref->row_relative)
		cell_ref->row = eval_row + cell_ref->row;

	cell_ref->row_relative = 0;
	cell_ref->col_relative = 0;
}

static void
cell_ref_restore_absolute (CellRef *cell_ref, const CellRef *orig, int eval_col, int eval_row)
{
	if (orig->col_relative) {
		cell_ref->col -= eval_col;
		cell_ref->col_relative = 1;
	}

	if (orig->row_relative) {
		cell_ref->row -= eval_row;
		cell_ref->row_relative = 1;
	}
}

static Value *
eval_cell_value (Sheet *sheet, Value *value)
{
	Value *res;

	res = g_new (Value, 1);
	res->type = value->type;

	switch (res->type){
	case VALUE_STRING:
		res->v.str = value->v.str;
		string_ref (res->v.str);
		break;

	case VALUE_INTEGER:
		res->v.v_int = value->v.v_int;
		break;

	case VALUE_FLOAT:
		res->v.v_float = value->v.v_float;
		break;

	case VALUE_ARRAY:
		res = value_duplicate (value);
		break;

	case VALUE_CELLRANGE:
		res->v.cell_range = value->v.cell_range;
		break;
	default:
		g_warning ("eval_cell_value error\n");
		break;
	}
	return res;
}

static void
free_values (Value **values, int top)
{
	int i;

	for (i = 0; i < top; i++)
		value_release (values [i]);
	g_free (values);
}

static Value *
eval_funcall (Sheet *sheet, ExprTree *tree, int eval_col, int eval_row, char **error_string)
{
	FunctionDefinition *fd;
	GList *l;
	int argc, arg, i;
	Value *v;

	fd = (FunctionDefinition *) tree->u.function.symbol->data;

	l = tree->u.function.arg_list;
	argc = g_list_length (l);

	if (fd->expr_fn)
	{
		/* Functions that deal with ExprNodes */
		v = fd->expr_fn (sheet, l, eval_col, eval_row, error_string);
	}
	else
	{
		/* Functions that take pre-computed Values */
		Value **values;
		int fn_argc_min = 0, fn_argc_max = 0, var_len = 0;
		char *arg_type = fd->args;
		char *argptr = fd->args;

		/* Get variable limits */
		while (*argptr){
			if (*argptr++ == '|'){
				var_len = 1;
				continue;
			}
			if (!var_len)
				fn_argc_min++;
			fn_argc_max++;
		}

		if (argc > fn_argc_max || argc < fn_argc_min){
			*error_string = _("Invalid number of arguments");
			return NULL;
		}

		values = g_new (Value *, fn_argc_max);

		for (arg = 0; l; l = l->next, arg++, arg_type++){
			ExprTree *t = (ExprTree *) l->data;
			int type_mismatch = 0;

			if (*arg_type=='|')
				arg_type++;

			if ((*arg_type != 'A' &&          /* This is so a cell reference */
			     *arg_type != 'r') ||         /* can be converted to a cell range */
			    !t || (t->oper != OPER_VAR)) { /* without being evaluated */
				if ((v = eval_expr (sheet, t, eval_col,
						    eval_row, error_string))==NULL)
					goto free_list;
			} else {
				g_assert (t->oper == OPER_VAR);
				v =value_new_cellrange (&t->u.ref,
							 &t->u.ref);
				if (!v->v.cell_range.cell_a.sheet)
					v->v.cell_range.cell_a.sheet = sheet;
				if (!v->v.cell_range.cell_b.sheet)
					v->v.cell_range.cell_b.sheet = sheet;
			}

			switch (*arg_type){
			case 'f':

				if (v->type != VALUE_INTEGER &&
				    v->type != VALUE_FLOAT)
					type_mismatch = 1;
				break;
			case 's':
				if (v->type != VALUE_STRING)
					type_mismatch = 1;
				break;
			case 'r':
				if (v->type != VALUE_CELLRANGE)
					type_mismatch = 1;
				else {
					cell_ref_make_absolute (&v->v.cell_range.cell_a, eval_col, eval_row);
					cell_ref_make_absolute (&v->v.cell_range.cell_b, eval_col, eval_row);
				}
				break;
			case 'a':
				if (v->type != VALUE_ARRAY)
					type_mismatch = 1;
				break;
			case 'A':
				if (v->type != VALUE_ARRAY &&
				    v->type != VALUE_CELLRANGE)
					type_mismatch = 1;

				if (v->type == VALUE_CELLRANGE) {
					cell_ref_make_absolute (&v->v.cell_range.cell_a, eval_col, eval_row);
					cell_ref_make_absolute (&v->v.cell_range.cell_b, eval_col, eval_row);
				}
				break;
			}
			if (type_mismatch){
				free_values (values, arg);
				*error_string = _("Type mismatch");
				return NULL;
			}
			values [arg] = v;
		}
		while (arg < fn_argc_max)
			values [arg++] = NULL;
		v = fd->fn (fd, values, error_string);

	free_list:
		for (i = 0; i < arg; i++){
			if (values [i] != NULL)
				value_release (values [i]);
		}
		g_free (values);
		return v;
	}
	return v;
}

Value *
function_def_call_with_values (Sheet *sheet, FunctionDefinition *fd, int argc,
			       Value *values [], char **error_string)
{
	Value *retval;

	if (fd->expr_fn){
		/*
		 * If function deals with ExprNodes, create some
		 * temporary ExprNodes with constants.
		 */
		ExprTree *tree = NULL;
		GList *l = NULL;
		int i;

		if (argc){
			tree = g_new (ExprTree, argc);

			for (i = 0; i < argc; i++){
				tree [i].oper = OPER_CONSTANT;
				tree [i].ref_count = 1;
				tree [i].u.constant = values [i];

				l = g_list_append (l, &(tree[i]));
			}
		}

		retval = fd->expr_fn (sheet, l, 0, 0, error_string);

		if (tree){
			g_free (tree);
			g_list_free (l);
		}

	} else
		retval = fd->fn (fd, values, error_string);

	return retval;
}

/*
 * Use this to invoke a register function: the only drawback is that
 * you have to compute/expand all of the values to use this
 */
Value *
function_call_with_values (Sheet *sheet, const char *name, int argc, Value *values[], char **error_string)
{
	FunctionDefinition *fd;
	Value *retval;
	Symbol *sym;

	g_return_val_if_fail (sheet != NULL, NULL);
	g_return_val_if_fail (IS_SHEET (sheet), NULL);
	g_return_val_if_fail (name != NULL, NULL);

	sym = symbol_lookup (global_symbol_table, name);
	if (sym == NULL){
		*error_string = _("Function does not exist");
		return NULL;
	}
	if (sym->type != SYMBOL_FUNCTION){
		*error_string = _("Calling non-function");
		return NULL;
	}

	fd = sym->data;

	symbol_ref (sym);
	retval = function_def_call_with_values (sheet, fd, argc, values, error_string);

	symbol_unref (sym);

	return retval;
}

typedef enum {
	IS_EQUAL,
	IS_LESS,
	IS_GREATER,
	TYPE_ERROR
} compare_t;

static compare_t
compare_int_int (int a, int b)
{
	if (a == b)
		return IS_EQUAL;
	else if (a < b)
		return IS_LESS;
	else
		return IS_GREATER;
}

static compare_t
compare_float_float (float_t a, float_t b)
{
	if (a == b)
		return IS_EQUAL;
	else if (a < b)
		return IS_LESS;
	else
		return IS_GREATER;
}

/*
 * Compares two (Value *) and returns one of compare_t
 */
static compare_t
compare (Value *a, Value *b)
{
	if (a->type == VALUE_INTEGER){
		int f;

		switch (b->type){
		case VALUE_INTEGER:
			return compare_int_int (a->v.v_int, b->v.v_int);

		case VALUE_FLOAT:
			return compare_float_float (a->v.v_int, b->v.v_float);

		case VALUE_STRING:
			f =value_get_as_float (b);
			return compare_float_float (a->v.v_int, f);

		default:
			return TYPE_ERROR;
		}
	}

	if (a->type == VALUE_FLOAT){
		float_t f;

		switch (b->type){
		case VALUE_INTEGER:
			return compare_float_float (a->v.v_float, b->v.v_int);

		case VALUE_FLOAT:
			return compare_float_float (a->v.v_float, b->v.v_float);

		case VALUE_STRING:
			f =value_get_as_float (b);
			return compare_float_float (a->v.v_float, f);

		default:
			return TYPE_ERROR;
		}
	}

	if (a->type == VALUE_STRING && b->type == VALUE_STRING){
		int t;

		t = strcasecmp (a->v.str->str, b->v.str->str);
		if (t == 0)
			return IS_EQUAL;
		else if (t > 0)
			return IS_GREATER;
		else
			return IS_LESS;
	}

	return TYPE_ERROR;
}

Value *
eval_expr (Sheet *sheet, ExprTree *tree, int eval_col, int eval_row, char **error_string)
{
	Value *a, *b, *res;

	g_return_val_if_fail (tree != NULL, NULL);
	g_return_val_if_fail (sheet != NULL, NULL);
	g_return_val_if_fail (error_string != NULL, NULL);
	g_return_val_if_fail (IS_SHEET (sheet), NULL);

	switch (tree->oper){
	case OPER_EQUAL:
	case OPER_NOT_EQUAL:
	case OPER_GT:
	case OPER_GTE:
	case OPER_LT:
	case OPER_LTE: {
		int comp;

		a = eval_expr (sheet, tree->u.binary.value_a,
			       eval_col, eval_row, error_string);
		b = eval_expr (sheet, tree->u.binary.value_b,
			       eval_col, eval_row, error_string);
		if (!(a && b)){
			if (a)
				value_release (a);
			if (b)
				value_release (b);
			return NULL;
		}
		res = g_new (Value, 1);
		res->type = VALUE_INTEGER;

		comp = compare (a, b);

		if (comp == TYPE_ERROR){
			value_release (a);
			value_release (b);
			*error_string = _("Type error");
			return NULL;
		}

		switch (tree->oper){