#include <stdio.h>
#include <malloc.h>
#include <string.h>
#include "lceb.h"

void print_stack(stack, details)
    STACK *stack;
    int details;
{
    int i;

    if (details) {
        printf("Stack [%s] dump: %d/%d used\n", stack->name, stack->last, stack->size);
        printf("\tValue: %4d\n", stack->eval);
        for (i=0; i<stack->last; ++i)
            printf("\t%02d: Op=%s Val=%4d\n",
                   i, (char *)stack->stack[i].op, stack->stack[i].val);
    } else {
        printf("Stack [%s] : ", stack->name);
        for (i=0; i<stack->last; ++i) {
            printf("%d[%s] ", stack->stack[i].val, (char *)stack->stack[i].op);
        }
        printf("\n");
    }
}

STACK *new_stack(size, name)
    int size;                                     /* 0 if empty */
    char *name;
{
    STACK *stack;
    STACKELT *pelt;
    int i;

    stack=malloc(sizeof (STACK));
    stack->stack=NULL;
    stack->size=0;
    stack->last=0;
    stack->eval=0;
    strncpy(stack->name, name? name: "No name", sizeof(stack->name));
    if (size) {
        pelt=malloc(size*sizeof(STACKELT));
        stack->size=size;
        stack->stack=pelt;
        for (i=0; i<size; ++i) {
            (pelt+i)->nop=0;
            (pelt+i)->curop=0;
            (pelt+i)->op[0]=End;
            (pelt+i)->val=-1;
            (pelt+i)->next=i+1;
            (pelt+i+1)->prev=i;
        }
        (pelt+i-1)->next=-1;
    }
    return stack;
}

STACKELT *push_stack(stack, op, val)
    STACK *stack;
    OPER op;
    int val;
{
    int pos=stack->last;
    int size=stack->size;
    STACKELT *pelt=stack->stack+stack->last;

    if (pos >= size) {
        fprintf(stderr, "stack overflow: size=%d last=%d\n", size, pos);
        return NULL;
    }
    pelt->nop=0;
    pelt->curop=0;
    //pelt->op[0]=op;
    pelt->val=val;
    stack->last++;
    return pelt;
}

STACKELT *pop_stack(stack)
    STACK *stack;
{
    int pos=stack->last+1;
    int size=stack->size;
    STACKELT *pelt=stack->stack+stack->last;

    if (pos==0) {
        fprintf(stderr, "stack empty: size=%d last=%d\n", size, pos);
        return NULL;
    }
    stack->last--;
    return pelt;
}

STACK *dup_stack(stack, name)
    STACK *stack;
    char *name;
{
    STACK *new;
    STACKELT *src=stack->stack, *dst;
    int size=stack->size, last=stack->last, i;

    new=new_stack(size, name);
    dst=new->stack;
    for (i=0; i<last; ++i) {
        dst->nop=src->nop;
        dst->curop=src->curop;
        dst->val=src->val;
        memcpy(dst->op, src->op, sizeof(src->op));
    }
    stack->last++;
    return new;
}

void swap(elts, i, j)
    STACKELT *elts;
    int i, j;
{
    STACKELT tmp=elts[i];
    elts[i] = elts[j];
    elts[j] = tmp;
}

int permute_stack(array, n)
    STACKELT *array;
    int n;
{
    int i, j, start, end;

    for(i=n-2; i>-1; i--) {
        if(array[i+1].val > array[i].val) {
            for(j=n-1; j>i; j--){
                if(array[j].val > array[i].val){
                    // swap
                    swap(array, i, j);
                    // reverse
                    for (start=i+1, end=n-1; start < end; ++start, --end)
                        swap(array, start, end);
                    return 1;
                }
            }
        }
    }
    return 0;
}


void mergesort_stack(array, left, right)
    STACKELT *array;
    int left, right;
{
    int mid = (left+right)/2;
    int pos=0, l=left, r=mid+1, i;
    STACKELT tmp[right-left+1];

    if(left < right) {
        mergesort_stack(array, left, mid);
        mergesort_stack(array, mid+1,right);
        while (l <= mid && r <= right) {
            if (array[l].val < array[r].val) {
                tmp[pos++] = array[l++];
            }
            else {
                tmp[pos++] = array[r++];
            }
        }
        while (l <= mid)
            tmp[pos++] = array[l++];
        while (r <= right)
            tmp[pos++] = array[r++];
        for (i = 0; i < pos; ++i)
            array[i+left] = tmp[i];
    }
}

STACKELT *set_op_stack(stack, pos, op)
    STACK *stack;
    int pos;
    OPER op;
{
    int size=stack->size;
    STACKELT *pelt=stack->stack+pos;

    if (pos >= size) {
        fprintf(stderr, "set_op: stack overflow: size=%d last=%d\n", size, pos);
        return NULL;
    }
    pelt->op[pelt->nop++]=op;
    pelt->op[pelt->nop]=End;
    //pelt->val=val;
    //stack->last++;
    return pelt;
}

STACKELT *set_ops_stack(stack, ops)
    STACK *stack;
    char *ops;
{
    //int size=stack->size;
    int last=stack->last;
    int i, j;                                     /* 1st operator in on second number */
    STACKELT *pelt=stack->stack;

    printf("setting ops [%s]\n", (char *)ops);
    for (i=1, j=0; i<last; ++i, ++j) {
        pelt[i].nop=1;
        pelt[i].curop=0;
        printf("setting op [%c-%x] to pos %d[%d]\n", ops[j], ops[j], i, pelt[i].nop);
        pelt[i].op[0]=ops[j];
        pelt[i].op[1]=End;
    }
    return pelt;
}