/*
 * Copyright 2008-2009, Axel Dörfler, axeld@pinc-software.de.
 * This file may be used under the terms of the MIT License.
 */


#include <ctype.h>
#include <stdlib.h>
#include <string.h>

#include <TypeConstants.h>

#ifdef _KERNEL_MODE
#	include <debug.h>
#endif

#include "demangle.h"


//#define TRACE_GCC2_DEMANGLER
#ifdef TRACE_GCC2_DEMANGLER
#	include <stdio.h>
#	define TRACE(x...) printf(x)
#else
#	define TRACE(x...) ;
#endif


class Input {
public:
	Input(const char* string, size_t length)
		:
		fString(string),
		fLength(length)
	{
	}

	const char* String() const
	{
		return fString;
	}

	int CharsRemaining() const
	{
		return fLength;
	}

	void Skip(size_t count)
	{
		if (count > fLength) {
			TRACE("Input::Skip(): fOffset > fLength\n");
			fString += fLength;
			fLength = 0;
			return;
		}

		fString += count;
		fLength -= count;
	}

	Input& operator++()
	{
		Skip(1);
		return *this;
	}
	Input operator++(int)
	{
		Input result(*this);
		++(*this);
		return result;
	}

	char operator[](size_t index) const
	{
		if (index >= fLength) {
			TRACE("Input::operator[](): fOffset + index >= fLength\n");
			return '\0';
		}

		return fString[index];
	}

private:
	const char*	fString;
	size_t		fLength;
};


enum {
	TYPE_FUNCTION,
	TYPE_METHOD,
};


static void
ignore_qualifiers(Input& _arg)
{
	while (isupper(_arg[0])) {
		if (_arg[0] == 'Q') {
			// argument has namespaces
			break;
		}
		if (_arg[0] == 'F') {
			// skip function declaration
			while (_arg.CharsRemaining() && _arg[0] != '_')
				_arg++;

			if (!_arg.CharsRemaining())
				break;
		}

		_arg++;
	}
}


static uint32
argument_type(Input arg, size_t& length)
{
	length = sizeof(int);

	switch (char type = arg[0]) {
		case 'P':	// pointer
		case 'R':	// reference
			length = sizeof(void*);
			ignore_qualifiers(arg);
			if (arg[0] == 'c')
				return B_STRING_TYPE;
			if (arg[0] == 't') {
				// TODO: templates are not yet supported
				return 0;
			}

			return type == 'P' ? B_POINTER_TYPE : B_REF_TYPE;
		case 'x':
			length = sizeof(long long);
			return B_INT64_TYPE;
		case 'l':
			if (sizeof(long) == 4)
				return B_INT32_TYPE;
			return B_INT64_TYPE;
		case 'i':
			return B_INT32_TYPE;
		case 's':
			return B_INT16_TYPE;
		case 'c':
			return B_INT8_TYPE;
		case 'b':
			return B_BOOL_TYPE;
		case 'U':
			switch (arg[1]) {
				case 'x':
					length = sizeof(long long);
					return B_UINT64_TYPE;
				case 'l':
					if (sizeof(long) == 4)
						return B_UINT32_TYPE;
					return B_UINT64_TYPE;
				case 'i':
					return B_UINT32_TYPE;
				case 's':
					return B_UINT16_TYPE;
				case 'c':
					return B_UINT8_TYPE;
				default:
					return B_UINT32_TYPE;
			}
			break;

		case 'f':
			return B_FLOAT_TYPE;
		case 'd':
			length = sizeof(double);
			return B_DOUBLE_TYPE;
		case 'r':
			// TODO: is "long double" supported under Haiku at all?
			return 0;

		case 't':
			// TODO: templates are not yet supported
			return 0;

		default:
			return B_ANY_TYPE;
	}
}


static uint32
parse_number(Input& _arg, bool numberLeft)
{
	Input arg = _arg;

	while (isdigit(arg[0]))
		arg++;

	uint32 value;

	if (arg[0] == '_' && (!numberLeft || isdigit(arg[1]))) {
		// long value
		const char* tmp_arg = _arg.String();
		value = strtoul(tmp_arg, (char**)&tmp_arg, 10);
		_arg.Skip(tmp_arg - _arg.String());
		if (_arg[0] == '_')
			_arg++;
	} else {
		value = _arg[0] - '0';
		_arg++;
	}

	return value;
}


static uint32
parse_repeats(Input& _arg, uint32& index)
{
	if (_arg[0] != 'N')
		return 0;

	_arg++;

	uint32 count = parse_number(_arg, true);
	index = parse_number(_arg, false);

	return count;
}


static void
skip_numbers(Input& _arg, int32 count)
{
	// skip leading character
	_arg++;

	while (count-- > 0) {
		parse_number(_arg, count != 0);
	}
}


static uint32
count_namespaces(Input& _mangled)
{
	Input mangled = _mangled;

	int32 namespaces = 0;
	if (mangled[0] == 'Q') {
		// more than one namespace
		if (mangled[1] == '_') {
			// more than 9 namespaces
			const char* mangled_str = mangled.String();
			namespaces = strtoul(mangled_str + 2, (char**)&mangled_str, 10);
			mangled.Skip(mangled_str - mangled.String());
			if (mangled[0] != '_')
				namespaces = 0;

			mangled++;
		} else {
			namespaces = mangled[1] - '0';
			mangled.Skip(2);
		}
	} else if (isdigit(mangled[0]))
		namespaces = 1;

	_mangled = mangled;
	return namespaces;
}


static void
skip_namespaces(Input& mangled)
{
	int32 namespaces = count_namespaces(mangled);

	while (namespaces-- > 0) {
		if (!isdigit(mangled[0]))
			break;

		const char* mangled_str = mangled.String();
		mangled_str += strtoul(mangled_str, (char**)&mangled_str, 10);
		mangled.Skip(mangled_str - mangled.String());
	}
}


static bool
has_named_argument(Input& arg)
{
	ignore_qualifiers(arg);

	// See if it's a built-in type
	return arg[0] == 'Q' || isdigit(arg[0]);
}


static uint32
argument_length(Input& _arg)
{
	if (_arg[0] == 'N') {
		// skip repeats
		skip_numbers(_arg, 2);
		return 0;
	} else if (_arg[0] == 'T') {
		// skip reference
		skip_numbers(_arg, 1);
		return 0;
	}

	ignore_qualifiers(_arg);

	if (!_arg.CharsRemaining())
		return 0;

	// See if it's a built-in type
	if (_arg[0] != 'Q' && !isdigit(_arg[0]))
		return 1;

	Input mangled = _arg;
	skip_namespaces(mangled);

	return mangled.String() - _arg.String();
}


static Input
next_argument(Input arg)
{
	if (!arg.CharsRemaining() || !arg[0])
		return arg;

	uint32 length = argument_length(arg);
	arg.Skip(length);

	return arg;
}


static Input
first_argument(Input mangled)
{
	skip_namespaces(mangled);

	return mangled;
}


static bool
mangled_start(Input& name, size_t* _symbolLength, int32* _symbolType)
{
	// search '__' starting from the end, don't accept them at the start
	size_t pos = name.CharsRemaining() - 1;
	bool foundStart = false;

	while (pos > 1) {
		if (name[pos] == '_') {
			if (name[pos - 1] == '_') {
				foundStart = true;
				name.Skip(pos + 1);
				break;
			} else
				pos--;
		}
		pos--;
	}

	if (!foundStart)
		return false;

	if (name[0] == 'H') {
		// TODO: we don't support templates yet
		return false;
	}

	if (_symbolLength != NULL)
		*_symbolLength = pos - 1;

	if (name[0] == 'F') {
		if (_symbolType != NULL)
			*_symbolType = TYPE_FUNCTION;
		name.Skip(1);
		return true;
	}

	if (_symbolType != NULL)
		*_symbolType = TYPE_METHOD;
	return true;
}


static status_t
get_next_argument_internal(uint32* _cookie, const char* symbol, char* name,
	size_t nameSize, int32* _type, size_t* _argumentLength, bool repeating)
{
	Input mangled(symbol, strlen(symbol));
	if (!mangled_start(mangled, NULL, NULL))
		return B_BAD_VALUE;

	Input arg = first_argument(mangled);

	// (void) is not an argument
	if (arg[0] == 'v')
		return B_ENTRY_NOT_FOUND;

	uint32 current = *_cookie;
	if (current > 32)
		return B_TOO_MANY_ARGS;

	for (uint32 i = 0; i < current; i++) {
		arg = next_argument(arg);
		if (arg.CharsRemaining() && arg[0] == 'N') {
			// repeat argument 'count' times
			uint32 index;
			uint32 count = parse_repeats(arg, index);
			if (current <= i + count) {
				if (repeating)
					return B_LINK_LIMIT;

				// it's a repeat case
				status_t status = get_next_argument_internal(&index, symbol,
					name, nameSize, _type, _argumentLength, true);
				if (status == B_OK)
					(*_cookie)++;
				return status;
			}

			i += count - 1;
		}
	}

	if (arg[0] == '\0' || !arg.CharsRemaining())
		return B_ENTRY_NOT_FOUND;

	TRACE("\n\targ %ld: %s\n", current, arg.String());

	if (arg[0] == 'T') {
		// duplicate argument
		if (repeating)
			return B_LINK_LIMIT;

		arg++;
		uint32 index = parse_number(arg, false);
		status_t status = get_next_argument_internal(&index, symbol, name,
			nameSize, _type, _argumentLength, true);
		if (status == B_OK)
			(*_cookie)++;
		return status;
	}

	(*_cookie)++;

	size_t argumentLength;
	int32 type = argument_type(arg, argumentLength);
	if (type == 0)
		return B_NOT_SUPPORTED;

	if (_type != NULL)
		*_type = type;
	if (_argumentLength != NULL)
		*_argumentLength = argumentLength;

	name[0] = '\0';
	if (!has_named_argument(arg))
		return B_OK;

	Input namespaceStart = arg;
	int32 namespaces = count_namespaces(namespaceStart);

	while (namespaces-- > 0) {
		if (namespaceStart[0] == 't') {
			// It's a template class after all
			return B_BAD_TYPE;
		}
		if (!isdigit(namespaceStart[0]))
			break;

		const char* ns_str = namespaceStart.String();
		uint32 length = strtoul(ns_str, (char**)&ns_str, 10);
		namespaceStart.Skip(ns_str - namespaceStart.String());

		uint32 max = strlen(name) + length + 1;
		strlcat(name, namespaceStart.String(), min_c(max, nameSize));
		if (namespaces > 0)
			strlcat(name, "::", nameSize);
		namespaceStart.Skip(length);
	}

	return B_OK;
}


//	#pragma mark -


const char*
demangle_symbol_gcc2(const char* name, char* buffer, size_t bufferSize,
	bool* _isObjectMethod)
{
	if (name == NULL)
		return NULL;

	size_t nameLength;
	int32 type;
	Input mangled(name, strlen(name));
	if (!mangled_start(mangled, &nameLength, &type))
		return NULL;

	if (mangled[0] == 'C') {
		// ignore const method
		type = TYPE_METHOD;
		mangled++;
	}

	if (_isObjectMethod != NULL) {
		// we can only guess with GCC2 mangling
		*_isObjectMethod = type == TYPE_METHOD;
	}

	Input namespaceStart = mangled;
	int32 namespaces = count_namespaces(namespaceStart);

	buffer[0] = '\0';

	while (namespaces-- > 0) {
		if (namespaceStart[0] == 't') {
			// It's a template class after all
			return NULL;
		}
		if (!isdigit(namespaceStart[0]))
			break;

		const char* ns_str = namespaceStart.String();
		uint32 length = strtoul(ns_str, (char**)&ns_str, 10);
		namespaceStart.Skip(ns_str - namespaceStart.String());

		uint32 max = strlen(buffer) + length + 1;
		strlcat(buffer, namespaceStart.String(), min_c(max, bufferSize));
		strlcat(buffer, "::", bufferSize);
		namespaceStart.Skip(length);
	}

	size_t max = strlen(buffer) + nameLength + 1;
	strlcat(buffer, name, min_c(max, bufferSize));
	return buffer;
}


status_t
get_next_argument_gcc2(uint32* _cookie, const char* symbol, char* name,
	size_t nameSize, int32* _type, size_t* _argumentLength)
{
	status_t error = get_next_argument_internal(_cookie, symbol, name, nameSize,
		_type, _argumentLength, false);
	if (error != B_OK)
		return error;

	// append the missing '*'/'&' for pointer/ref types
	if (name[0] != '\0' && (*_type == B_POINTER_TYPE || *_type == B_REF_TYPE))
		strlcat(name, *_type == B_POINTER_TYPE ? "*" : "&", nameSize);

	return B_OK;
}