char * construct_next_attribute( char * (*get_attribute)(char *, unsigned int ) )
{
unsigned int start_position = eat_whitespaces( current_position );
if ( start_position == strlen( attributes_line ) ) return NULL;
current_position = eat_not_whitespaces( start_position );
return get_attribute( attributes_line + start_position, current_position - start_position );
}
// Try to consume characters from the input stream and match the
// pattern string. Leading whitespaces from the input are ignored if
// ignore_ws is true.
bool match(const std::string& pattern, std::istream& input,
bool ignore_ws) {
if (ignore_ws) {
eat_whitespaces(input);
}
std::string::const_iterator cur(pattern.begin());
char ch(0);
while(input && !input.eof() && cur != pattern.end()) {
input.get(ch);
if (ch != *cur) {
input.putback(ch);
return false;
} else {
cur++;
}
}
return cur == pattern.end();
}
bool parse_number(std::istream& input, long* value) {
eat_whitespaces(input);
char ch;
std::string value_str;
std::string exp_str; // whole exp part
std::string exp_value_str; // value of exp part
int sign = 1;
int e_sign = 1;
bool correct = true;
long e_value;
enum {
p_number,
p_e,
p_enumber
} p_state = p_number;
if (match("-", input)) {
sign = -1;
} else {
match("+", input);
}
while(input && !input.eof()) {
input.get(ch);
switch (p_state) {
case p_number: {
// DBG("st = p_number, ch=%c\n",ch);
if (ch == 'E' || ch == 'e') {
exp_str.push_back(ch);
p_state = p_e;
continue;
}
if (!isdigit(ch)) {
input.putback(ch);
correct = false;
break;
}
value_str.push_back(ch);
} break;
case p_e: {
// DBG("st = p_e, ch=%c\n",ch);
if (ch == '+') {
exp_str.push_back(ch);
p_state = p_enumber;
} else if (ch == '-') {
e_sign = -1;
exp_str.push_back(ch);
p_state = p_enumber;
} else if (isdigit(ch)) {
exp_value_str.push_back(ch);
exp_str.push_back(ch);
p_state = p_enumber;
} else {
input.putback(ch);
correct = false;
}
} break;
case p_enumber: {
// DBG("st = p_enumber, ch=%c\n",ch);
if (isdigit(ch)) {
exp_value_str.push_back(ch);
exp_str.push_back(ch);
} else {
input.putback(ch);
correct = false;
}
} break;
}
if (!correct)
break;
}
if (p_state == p_e) {
// todo: check also some other error states
for (std::string::reverse_iterator r_it=
exp_str.rbegin(); r_it != exp_str.rend(); r_it++)
input.putback(*r_it);
for (std::string::reverse_iterator r_it=
value_str.rbegin(); r_it != value_str.rend(); r_it++)
input.putback(*r_it);
return false;
}
if (value_str.size() > 0) {
std::istringstream(value_str) >> *value;
*value*=sign;
if (exp_value_str.size()) {
std::istringstream(exp_value_str) >> e_value;
if (e_value && e_sign==-1) {
// should have been catched by parse_float
for (std::string::reverse_iterator r_it=
exp_str.rbegin(); r_it != exp_str.rend(); r_it++)
input.putback(*r_it);
for (std::string::reverse_iterator r_it=
value_str.rbegin(); r_it != value_str.rend(); r_it++)
input.putback(*r_it);
return false;
}
*value *= pow(10, e_value);
}
