#include "m.h"

#define aij SCALAR(a) ? VAL(a) : (a->type == STRING ? STR(a)[j] : A(i,j) )

#define STACKSIZE 8192
#define FRAMESIZE 1024

Symbolptr stack[STACKSIZE];	/* data stack */
Symbolptr *sp = stack;		/* next free spot for push() */

Symbolptr *frame[FRAMESIZE];	/* frame stack */
Symbolptr **fp = frame;		/* next free spot for fpush() */

void local_push( void)
{
    int offset = (int) *pc++;

    push( *(ftop() + offset) );
}

void sympush( void)	/* push symbol onto the stack */
{
    Symbolptr p = i2d(*pc++);

    push(p);
}

void swap( void)
{
    Symbolptr a, b;

    a = pop();
    b = pop();
    push(a);
    push(b);
}

void fpush( void)
{
    if( fp >= frame + FRAMESIZE)
	error("frame overflow in fpush()","");

    *fp++ = sp;
}

void fpop( void)
{
    if( fp <= frame)
	error("frame underflow in fpop()","");

    sp = *--fp;
}

Symbolptr *ftop( void)
{
    if( fp <= frame)
	error("frame underflow in ftop()","");

    return *(fp-1);
}

void push( Symbolptr a)
{
    if( sp >= stack + STACKSIZE)
	error("stack overflow in push()","");

    *sp++ = a;

#ifdef DEBUG
    if( stack_debug)
	display( a, "push: ");
#endif
}

Symbolptr pop( void)
{
    if( sp <= ftop())
	error("stack underflow in pop()","");

    --sp;

#ifdef DEBUG
    if( stack_debug)
	display( *sp, "pop: ");
#endif

    return *sp;
}

void npop( int n)
{
    sp -= n;

#ifdef DEBUG
    if( stack_debug)
	dprint("npop: n = %d\n", n);
#endif

    if( sp < ftop())
	error("stack underflow in npop()","");
}

void matpop( void)
{
    Symbolptr v, a;
    Symbolptr *savesp, *start;
    int i, j, m, n = 0, rows, cols;

    a = pop();
    n_check(a,"matpop()");
    savesp = sp;
    sp = start = sp - (int) VAL(a);

#ifdef DEBUG
    if( stack_debug)
	dprint("matpop(): count = %d\n", (int) VAL(a));
#endif

    if( sp >= stack + STACKSIZE)
	error("stack overflow in matpop()","");
    else if( sp < ftop())
	error("stack underflow in matpop()","");

    rows = cols = 0;

    while( sp < savesp) {	/* get rows & cols */

	m = n = 0;

	while( sp < savesp && *sp != &rowend) {

	    check(a = *sp);
	    if( m == 0) {
		m = ROWS(a);
		n = COLS(a);
	    } else if( m != ROWS(a))
		error("mismatched row sizes in matrix","");
	    else
		n += COLS(a);

	    ++sp;
	}

	if( rows == 0) {
	    rows = m;
	    cols = n;
	} else if( cols != n)
	    error("mismatched column sizes in matrix","");
	else
	    rows += m;

	++sp;
    }

#ifdef DEBUG
    if( stack_debug)
	dprint("matpop: rows = %d, cols = %d\n", rows, cols);
#endif

    v = m_create( rows, cols);

    sp = start;
    rows = cols = 0;

    while( sp < savesp) {

	m = rows;

	while( sp < savesp && *sp != &rowend) {

	    a = *sp;
	    for( i = 0, m = rows;  i < ROWS(a);  ++i, ++m)
		for( j = 0, n = cols;  j < COLS(a);  ++j, ++n)
		    if( SCALAR(v))
			VAL(v) = aij;
		    else
			V(m,n) = aij;
	    cols = n;
	    ++sp;
	}
	rows = m;
	cols = 0;
	++sp;
    }

    sp = start;

    push(v);
}

#ifdef DEBUG
void s_dump( void)
{
    Symbolptr *s;

    dprint("stack: %d elements\n", sp-stack);
    for( s = stack; s < sp; ++s)
	display( *s, "");
}
#endif