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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef Forth_DEFINED
#define Forth_DEFINED
#include "SkTypes.h"
class ForthOutput {
public:
virtual void show(const char output[]) = 0;
};
union FloatIntDual {
int32_t fInt;
float fFloat;
};
static inline int32_t f2i_bits(float x) {
FloatIntDual d;
d.fFloat = x;
return d.fInt;
}
static inline float i2f_bits(int32_t x) {
FloatIntDual d;
d.fInt = x;
return d.fFloat;
}
class ForthEngine {
public:
ForthEngine(ForthOutput*);
~ForthEngine();
int depth() const { return fStackStop - fStackCurr; }
void clearStack() { fStackCurr = fStackStop; }
void push(intptr_t value);
intptr_t top() const { return this->peek(0); }
intptr_t peek(size_t index) const;
void setTop(intptr_t value);
intptr_t pop();
void fpush(float value) { this->push(f2i_bits(value)); }
float fpeek(size_t i) const { return i2f_bits(this->fpeek(i)); }
float ftop() const { return i2f_bits(this->top()); }
void fsetTop(float value) { this->setTop(f2i_bits(value)); }
float fpop() { return i2f_bits(this->pop()); }
void sendOutput(const char text[]);
private:
ForthOutput* fOutput;
intptr_t* fStackBase;
intptr_t* fStackCurr;
intptr_t* fStackStop;
void signal_error(const char msg[]) const {
SkDebugf("ForthEngine error: %s\n", msg);
}
};
struct ForthCallBlock {
const intptr_t* in_data;
size_t in_count;
intptr_t* out_data;
size_t out_count;
size_t out_depth;
};
class ForthWord {
public:
virtual ~ForthWord() {}
virtual void exec(ForthEngine*) = 0;
// todo: return error state of the engine
void call(ForthCallBlock*);
};
class ForthEnv {
public:
ForthEnv();
~ForthEnv();
void addWord(const char name[], ForthWord*);
void parse(const char code[]);
ForthWord* findWord(const char name[]);
void run(ForthOutput* = NULL);
private:
class Impl;
Impl* fImpl;
};
#endif
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