Cosmo/src/cstate.h

#ifndef CSTATE_H
#define CSTATE_H

#include "cosmo.h"
#include "cvalue.h"
#include "cobj.h"
#include "ctable.h"

typedef struct CCallFrame {
    CObjClosure *closure;
    INSTRUCTION *pc;
    CValue* base;
} CCallFrame;

typedef enum {
    INTERNALSTRING_INIT, // __init
    INTERNALSTRING_EQUAL, // __equal
    INTERNALSTRING_MAX
} InternalStringEnum;

typedef struct CState {
    bool panic;
    int freezeGC; // when > 0, GC events will be ignored (for internal use)
    CObj *objects; // tracks all of our allocated objects
    CObj **grayStack; // keeps track of which objects *haven't yet* been traversed in our GC, but *have been* found
    int grayCount;
    int grayCapacity;
    size_t allocatedBytes;
    size_t nextGC; // when allocatedBytes reaches this threshhold, trigger a GC event

    CObjUpval *openUpvalues; // tracks all of our still open (meaning still on the stack) upvalues
    CTable strings;
    CTable globals;

    CValue *top; // top of the stack
    CValue stack[STACK_MAX]; // stack
    CCallFrame callFrame[FRAME_MAX]; // call frames
    int frameCount;

    CObjString *internalStrings[INTERNALSTRING_MAX]; // strings used internally by the VM, eg. __init
    CObjObject *metaObj; // start met obj for all objects (NULL by default)
} CState;

COSMO_API CState *cosmoV_newState();
COSMO_API void cosmoV_register(CState *state, const char *identifier, CValue val);
COSMO_API void cosmoV_freeState(CState *state);
COSMO_API void cosmoV_printStack(CState *state);

// pushes value to the stack
static inline void cosmoV_pushValue(CState *state, CValue val) {
    *(state->top++) = val;
}

// sets stack->top to stack->top - indx
static inline StkPtr cosmoV_setTop(CState *state, int indx) {
    state->top -= indx;
    return state->top;
}

// returns stack->top - indx - 1
static inline StkPtr cosmoV_getTop(CState *state, int indx) {
    return &state->top[-(indx + 1)];
}

// pops 1 value off the stack
static inline StkPtr cosmoV_pop(CState *state) {
    return cosmoV_setTop(state, 1);
}

#endif