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#include "icm-pp.h"
/*
int
push_active(int), actual activity request
pop_active(void), returns previous output_active value
negate_active(void); negate the current request
push_active() receives an activity request and combines it with the current
top's d_active value to obtain a new d_active value which is returned as the
new output_active value.
pop_active() removes the current top and returns the popped d_active value
negate_active() changes d_request on top of the stack, and determines and
returns the new d_active value
construct_active() initializes the stack.
*/
typedef struct
{
int d_active; /* output_active of current nesting level */
int d_request; /* requested activity level */
} ACTIVESTACK_;
static int sp = 0;
static ACTIVESTACK_ *stack = NULL;
static int active(void)
{
return stack[sp].d_active = stack[sp - 1].d_active && stack[sp].d_request;
}
void construct_active(void)
{
stack = malloc(sizeof(ACTIVESTACK_));
stack->d_active = 1;
stack->d_request = 0;
}
int negate_active() /* negate the current request */
{
stack[sp].d_request = !stack[sp].d_request;
return active();
}
int pop_active() /* returns previous output_active value */
{
if (!sp--)
error("%s: %d: too many lone #endif directives",
filestack[filesp].n, filestack[filesp].l);
return stack[sp].d_active;
}
int push_active(int request) /* actual activity request */
{
++sp;
stack = xrealloc(stack, (sp + 1) * sizeof(ACTIVESTACK_));
stack[sp].d_request = request;
return active();
}
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