/*****
* array.h
* Tom Prince 2005/06/18
*
* Array type used by virtual machine.
*****/

#ifndef ARRAY_H
#define ARRAY_H

#include "vm.h"
#include "common.h"
#include "item.h"

namespace vm {

extern const char *dereferenceNullArray;

// Arrays are vectors with push and pop functions.
class array : public mem::vector<item> {
 bool cycle;

 void setNonBridgingSlice(size_t l, size_t r, mem::vector<item> *a);
 void setBridgingSlice(size_t l, size_t r, mem::vector<item> *a);
public:
 array() : cycle(false) {}

 array(size_t n)
   : mem::vector<item>(n), cycle(false)
 {}

 array(size_t n, item i, size_t depth);

 void push(item i)
 {
   push_back(i);
 }

 item pop()
 {
   item i=back();
   pop_back();
   return i;
 }

 template <typename T>
 T read(size_t i) const
 {
   return get<T>((*this)[i]);
 }

 array *slice(Int left, Int right);
 void setSlice(Int left, Int right, array *a);

 void cyclic(bool b) {
   cycle=b;
 }

 bool cyclic() const {
   return cycle;
 }

 array *copyToDepth(size_t depth);
};

template <typename T>
inline T read(const array *a, size_t i)
{
 return a->array::read<T>(i);
}

template <typename T>
inline T read(const array &a, size_t i)
{
 return a.array::read<T>(i);
}

inline size_t checkArray(const vm::array *a)
{
 if(a == 0) vm::error(dereferenceNullArray);
 return a->size();
}

inline void checkEqual(size_t i, size_t j) {
 if(i == j) return;
 ostringstream buf;
 buf << "operation attempted on arrays of different lengths: "
     << i << " != " << j;
 vm::error(buf);
}

inline size_t checkArrays(const vm::array *a, const vm::array *b)
{
 size_t asize=checkArray(a);
 size_t bsize=checkArray(b);
 checkEqual(asize,bsize);
 return asize;
}

// Copies an item to a depth d.  If d == 0 then the item is just returned
// without copying, otherwise, the array and its subarrays are copied to
// depth d.
item copyItemToDepth(item i, size_t depth);

} // namespace vm

#endif // ARRAY_H