uint64
ExpressionParser::_ParseDereference(void** _address, uint32* _size)
{
int32 starPosition = fTokenizer.CurrentToken().position;
// optional "{ ... }" specifying the size to read
uint64 size = 4;
if (fTokenizer.NextToken().type == TOKEN_OPENING_BRACE) {
int32 position = fTokenizer.CurrentToken().position;
size = _ParseExpression();
if (size != 1 && size != 2 && size != 4 && size != 8) {
snprintf(sTempBuffer, sizeof(sTempBuffer),
"invalid size (%" B_PRIu64 ") for unary * operator", size);
parse_exception(sTempBuffer, position);
}
_EatToken(TOKEN_CLOSING_BRACE);
} else
fTokenizer.RewindToken();
const void* address = (const void*)(addr_t)_ParseUnary();
// read bytes from address into a tempory buffer
uint64 buffer;
if (debug_memcpy(B_CURRENT_TEAM, &buffer, address, size) != B_OK) {
snprintf(sTempBuffer, sizeof(sTempBuffer),
"failed to dereference address %p", address);
parse_exception(sTempBuffer, starPosition);
}
// convert the value to uint64
uint64 value = 0;
switch (size) {
case 1:
value = *(uint8*)&buffer;
break;
case 2:
value = *(uint16*)&buffer;
break;
case 4:
value = *(uint32*)&buffer;
break;
case 8:
value = buffer;
break;
}
if (_address != NULL)
*_address = (void*)address;
if (_size != NULL)
*_size = size;
return value;
}
void
ExpressionParser::_GetUnparsedArgument(int& argc, char** argv)
{
int32 startPosition = fTokenizer.NextToken().position;
fTokenizer.RewindToken();
// match parentheses and brackets, but otherwise skip all tokens
int32 parentheses = 0;
int32 brackets = 0;
bool done = false;
while (!done) {
const Token& token = fTokenizer.NextToken();
switch (token.type) {
case TOKEN_OPENING_PARENTHESIS:
parentheses++;
break;
case TOKEN_OPENING_BRACKET:
brackets++;
break;
case TOKEN_CLOSING_PARENTHESIS:
if (parentheses > 0)
parentheses--;
else
done = true;
break;
case TOKEN_CLOSING_BRACKET:
if (brackets > 0)
brackets--;
else
done = true;
break;
case TOKEN_PIPE:
case TOKEN_SEMICOLON:
if (parentheses == 0 && brackets == 0)
done = true;
break;
case TOKEN_END_OF_LINE:
done = true;
break;
}
}
int32 endPosition = fTokenizer.CurrentToken().position;
fTokenizer.RewindToken();
// add the argument only, if it's not just all spaces
const char* arg = fTokenizer.String() + startPosition;
int32 argLen = endPosition - startPosition;
bool allSpaces = true;
for (int32 i = 0; allSpaces && i < argLen; i++)
allSpaces = isspace(arg[i]);
if (!allSpaces)
_AddArgument(argc, argv, arg, argLen);
}
uint64
ExpressionParser::_ParseExpression(bool expectAssignment)
{
const Token& token = fTokenizer.NextToken();
int32 position = token.position;
if (token.type == TOKEN_IDENTIFIER) {
char variable[MAX_DEBUG_VARIABLE_NAME_LEN];
strlcpy(variable, token.string, sizeof(variable));
int32 assignmentType = fTokenizer.NextToken().type;
if (assignmentType & TOKEN_ASSIGN_FLAG) {
// an assignment
uint64 rhs = _ParseExpression();
// handle the standard assignment separately -- the other kinds
// need the variable to be defined
if (assignmentType == TOKEN_ASSIGN) {
if (!set_debug_variable(variable, rhs)) {
snprintf(sTempBuffer, sizeof(sTempBuffer),
"failed to set value for variable \"%s\"",
variable);
parse_exception(sTempBuffer, position);
}
return rhs;
}
// variable must be defined
if (!is_debug_variable_defined(variable)) {
snprintf(sTempBuffer, sizeof(sTempBuffer),
"variable \"%s\" not defined in modifying assignment",
variable);
parse_exception(sTempBuffer, position);
}
uint64 variableValue = get_debug_variable(variable, 0);
// check for division by zero for the respective assignment types
if ((assignmentType == TOKEN_SLASH_ASSIGN
|| assignmentType == TOKEN_MODULO_ASSIGN)
&& rhs == 0) {
parse_exception("division by zero", position);
}
// compute the new variable value
switch (assignmentType) {
case TOKEN_PLUS_ASSIGN:
variableValue += rhs;
break;
case TOKEN_MINUS_ASSIGN:
variableValue -= rhs;
break;
case TOKEN_STAR_ASSIGN:
variableValue *= rhs;
break;
case TOKEN_SLASH_ASSIGN:
variableValue /= rhs;
break;
case TOKEN_MODULO_ASSIGN:
variableValue %= rhs;
break;
default:
parse_exception("internal error: unknown assignment token",
position);
break;
}
set_debug_variable(variable, variableValue);
return variableValue;
}
} else if (token.type == TOKEN_STAR) {
void* address;
uint32 size;
uint64 value = _ParseDereference(&address, &size);
int32 assignmentType = fTokenizer.NextToken().type;
if (assignmentType & TOKEN_ASSIGN_FLAG) {
// an assignment
uint64 rhs = _ParseExpression();
// check for division by zero for the respective assignment types
if ((assignmentType == TOKEN_SLASH_ASSIGN
|| assignmentType == TOKEN_MODULO_ASSIGN)
&& rhs == 0) {
parse_exception("division by zero", position);
}
// compute the new value
switch (assignmentType) {
case TOKEN_ASSIGN:
value = rhs;
break;
case TOKEN_PLUS_ASSIGN:
value += rhs;
break;
case TOKEN_MINUS_ASSIGN:
value -= rhs;
break;
case TOKEN_STAR_ASSIGN:
value *= rhs;
break;
case TOKEN_SLASH_ASSIGN:
value /= rhs;
break;
case TOKEN_MODULO_ASSIGN:
value %= rhs;
break;
default:
parse_exception("internal error: unknown assignment token",
position);
break;
}
// convert the value for writing to the address
uint64 buffer = 0;
switch (size) {
case 1:
*(uint8*)&buffer = value;
break;
case 2:
*(uint16*)&buffer = value;
break;
case 4:
*(uint32*)&buffer = value;
break;
case 8:
value = buffer;
break;
}
if (debug_memcpy(B_CURRENT_TEAM, address, &buffer, size) != B_OK) {
snprintf(sTempBuffer, sizeof(sTempBuffer),
"failed to write to address %p", address);
parse_exception(sTempBuffer, position);
}
return value;
}
}
if (expectAssignment) {
parse_exception("expected assignment",
fTokenizer.CurrentToken().position);
}
// no assignment -- reset to the identifier position and parse a sum
fTokenizer.SetPosition(position);
return _ParseSum(false, 0);
}
