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engines/ultima/ultima8/usecode/uc_stack.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef ULTIMA8_USECODE_UCSTACK_H
+#define ULTIMA8_USECODE_UCSTACK_H
+
+#include "common/scummsys.h"
+
+namespace Ultima {
+namespace Ultima8 {
+
+// A little-endian stack for use with usecode
+class BaseUCStack {
+protected:
+	uint8 *_buf;
+	uint8 *_bufPtr;
+	uint32 _size;
+public:
+
+	BaseUCStack(uint32 len, uint8 *b) : _buf(b), _size(len) {
+		// stack grows downward, so start at the end of the buffer
+		_bufPtr = _buf + _size;
+	}
+	virtual ~BaseUCStack() { }
+
+	inline uint32 getSize() const {
+		return _size;
+	}
+
+	inline uint32 stacksize() const {
+		return _size - (_bufPtr - _buf);
+	}
+
+	inline void addSP(const int32 offset) {
+		_bufPtr += offset;
+	}
+
+	inline unsigned int getSP() const {
+		return static_cast<unsigned int>(_bufPtr - _buf);
+	}
+
+	inline void setSP(unsigned int pos) {
+		_bufPtr = _buf + pos;
+	}
+
+	//
+	// Push values to the stack
+	//
+
+	inline void push1(uint8 val) {
+		_bufPtr--;
+		_bufPtr[0] = val;
+	}
+
+	inline void push2(uint16 val) {
+		_bufPtr -= 2;
+		_bufPtr[0] = static_cast<uint8>(val     & 0xFF);
+		_bufPtr[1] = static_cast<uint8>((val >> 8) & 0xFF);
+	}
+	inline void push4(uint32 val) {
+		_bufPtr -= 4;
+		_bufPtr[0] = static_cast<uint8>(val      & 0xFF);
+		_bufPtr[1] = static_cast<uint8>((val >> 8)  & 0xFF);
+		_bufPtr[2] = static_cast<uint8>((val >> 16) & 0xFF);
+		_bufPtr[3] = static_cast<uint8>((val >> 24) & 0xFF);
+	}
+	// Push an arbitrary number of bytes of 0
+	inline void push0(const uint32 count) {
+		_bufPtr -= count;
+		memset(_bufPtr, 0, count);
+	}
+	// Push an arbitrary number of bytes
+	inline void push(const uint8 *in, const uint32 count) {
+		_bufPtr -= count;
+		memcpy(_bufPtr, in, count);
+	}
+
+	//
+	// Pop values from the stack
+	//
+
+	inline uint16 pop2() {
+		uint8 b0, b1;
+		b0 = *_bufPtr++;
+		b1 = *_bufPtr++;
+		return (b0 | (b1 << 8));
+	}
+	inline uint32 pop4() {
+		uint8 b0, b1, b2, b3;
+		b0 = *_bufPtr++;
+		b1 = *_bufPtr++;
+		b2 = *_bufPtr++;
+		b3 = *_bufPtr++;
+		return (b0 | (b1 << 8) | (b2 << 16) | (b3 << 24));
+	}
+	inline void pop(uint8 *out, const uint32 count) {
+		memcpy(out, _bufPtr, count);
+		_bufPtr += count;
+	}
+
+	//
+	// Access a value from a location in the stack
+	//
+
+	inline uint8 access1(const uint32 offset) const {
+		return _buf[offset];
+	}
+	inline uint16 access2(const uint32 offset) const {
+		return (_buf[offset] | (_buf[offset + 1] << 8));
+	}
+	inline uint32 access4(const uint32 offset) const {
+		return _buf[offset] | (_buf[offset + 1] << 8) |
+		       (_buf[offset + 2] << 16) | (_buf[offset + 3] << 24);
+	}
+	inline uint8 *access(const uint32 offset) {
+		return _buf + offset;
+	}
+	inline uint8 *access() {
+		return _bufPtr;
+	}
+
+	//
+	// Assign a value to a location in the stack
+	//
+
+	inline void assign1(const uint32 offset, const uint8 val) {
+		const_cast<uint8 *>(_buf)[offset]   = static_cast<uint8>(val     & 0xFF);
+	}
+	inline void assign2(const uint32 offset, const uint16 val) {
+		const_cast<uint8 *>(_buf)[offset]   = static_cast<uint8>(val     & 0xFF);
+		const_cast<uint8 *>(_buf)[offset + 1] = static_cast<uint8>((val >> 8) & 0xFF);
+	}
+	inline void assign4(const uint32 offset, const uint32 val) {
+		const_cast<uint8 *>(_buf)[offset]   = static_cast<uint8>(val      & 0xFF);
+		const_cast<uint8 *>(_buf)[offset + 1] = static_cast<uint8>((val >> 8)  & 0xFF);
+		const_cast<uint8 *>(_buf)[offset + 2] = static_cast<uint8>((val >> 16) & 0xFF);
+		const_cast<uint8 *>(_buf)[offset + 3] = static_cast<uint8>((val >> 24) & 0xFF);
+	}
+	inline void assign(const uint32 offset, const uint8 *in, const uint32 len) {
+		memcpy(const_cast<uint8 *>(_buf) + offset, in, len);
+	}
+};
+
+class DynamicUCStack : public BaseUCStack {
+public:
+	DynamicUCStack(uint32 len = 0x1000) : BaseUCStack(len, new uint8[len]) { }
+	~DynamicUCStack() override {
+		delete [] _buf;
+	}
+
+#ifdef USE_DYNAMIC_UCSTACK
+#define UCStack DynamicUCStack
+	void save(Common::WriteStream *ws);
+	bool load(Common::ReadStream *rs, uint32 version);
+#endif
+};
+
+#ifndef USE_DYNAMIC_UCSTACK
+class UCStack : public BaseUCStack {
+	uint8   _bufArray[0x1000];
+public:
+	UCStack() : BaseUCStack(0x1000, _bufArray) { }
+	~UCStack() override { }
+
+	void save(Common::WriteStream *ws);
+	bool load(Common::ReadStream *rs, uint32 version);
+};
+#endif
+
+} // End of namespace Ultima8
+} // End of namespace Ultima
+
+#endif