fix parsing of negative numbers, less memory, faster

This commit is contained in:
VaclavT 2021-03-17 23:58:33 +01:00
parent fcb3b4c5c5
commit 29d8eda238
3 changed files with 53 additions and 49 deletions

View File

@ -17,9 +17,12 @@ MlValue CsvParser::parseCSV(const std::string &csvSource) {
bool newLine(false);
std::string field;
// PERF optimize it for memory usage and performance
std::vector<std::vector<std::string>> parsed_data; // TODO some default size here
std::vector<std::string> line;
std::vector<MlValue> parsed_data;
// TODO when csvSource is really big use some bigger nr to prevent reallocations
parsed_data.reserve(128);
std::vector<MlValue> line;
line.reserve(32);
std::string::const_iterator aChar = csvSource.begin();
while (aChar != csvSource.end()) {
@ -31,7 +34,7 @@ MlValue CsvParser::parseCSV(const std::string &csvSource) {
if (inQuote == true) {
field += *aChar;
} else {
line.push_back(field);
line.push_back(ivalualize(field));
field.clear();
}
} else if (*aChar == line_separator || *aChar == line_separator2) {
@ -39,8 +42,8 @@ MlValue CsvParser::parseCSV(const std::string &csvSource) {
field += *aChar;
} else {
if (newLine == false) {
line.push_back(field);
addLine(line, parsed_data);
line.push_back(ivalualize(field));
add_line(line, parsed_data);
field.clear();
line.clear();
newLine = true;
@ -55,41 +58,15 @@ MlValue CsvParser::parseCSV(const std::string &csvSource) {
}
if (field.size())
line.push_back(field);
line.push_back(ivalualize(field));
addLine(line, parsed_data);
add_line(line, parsed_data);
return ivalualize(parsed_data);
return parsed_data;
}
MlValue CsvParser::ivalualize(std::vector<std::vector<std::string> > &parsed_data) const {
int rows = parsed_data.size();
int cols = rows > 0 ? parsed_data[0].size() : 0;
std::vector<MlValue> result;
if (rows > 0 && cols > 0) {
for (int r = 0; r < rows; r++) {
std::vector<MlValue> row;
for (int c = 0; c < cols; c++) {
std::string value = parsed_data[r][c];
if (is_string_int(value)) {
row.push_back(MlValue(stoi(value)));
}
if (is_string_float(value)) {
row.push_back(MlValue(std::stod(value)));
} else {
row.push_back(MlValue::string(value));
}
}
result.push_back(row);
}
}
return result;
}
void CsvParser::addLine(const std::vector<std::string> &line, std::vector<std::vector<std::string> > &lines) {
void CsvParser::add_line(const std::vector<MlValue> &line, std::vector<MlValue> &lines) {
if (skip_header && !header_skiped) {
header_skiped = true;
} else {
@ -98,17 +75,40 @@ void CsvParser::addLine(const std::vector<std::string> &line, std::vector<std::v
}
}
// std::regex int_underscored_regex("[0-9][0-9_]+[0-9]");
std::regex int_regex("[0-9]+");
std::regex double_regex("[0-9]+\\.[0-9]+");
MlValue CsvParser::ivalualize(const std::string &value) const {
long int_val;
double float_val;
if (value.empty() || ((!isdigit(value[0])) && (value[0] != '-') && (value[0] != '+'))) {
return MlValue::string(value);
} else if (is_string_int(value, int_val)) {
return MlValue(int_val);
} else if (is_string_float(value, float_val)) {
return MlValue(float_val);
} else {
return MlValue::string(value);
}
}
// Is string representing int value
bool CsvParser::is_string_int(const std::string &str) const {
return std::regex_match(str, int_regex);
bool CsvParser::is_string_int(const std::string &s, long &val) const {
char *end_ptr;
errno = 0;
if(s.empty() || ((!isdigit(s[0])) && (s[0] != '-') && (s[0] != '+'))) return false;
val = strtol(s.c_str(), &end_ptr, 10);
if ( *end_ptr != '\0' ) return false;
if (errno == ERANGE && (val == LONG_MIN || val == LONG_MAX)) return false;
if (val == 0 && errno != 0) return false;
return true;
}
// Is string representing float value
bool CsvParser::is_string_float(const std::string &str) const {
return std::regex_match(str, double_regex);
bool CsvParser::is_string_float(const std::string &s, double &val) const {
char *end_ptr;
errno = 0;
if(s.empty() || ((!isdigit(s[0])) && (s[0] != '-') && (s[0] != '+'))) return false;
val = strtod(s.c_str(), &end_ptr);
if ( *end_ptr != '\0' ) return false;
if (errno == ERANGE && (val == HUGE_VAL || val == -HUGE_VAL)) return false;
if (val == 0 && errno != 0) return false;
return true;
}

View File

@ -3,6 +3,7 @@
#include "../ml.h"
#include <math.h>
#include <string>
#include <vector>
#include <regex>
@ -25,11 +26,11 @@ public:
MlValue parseCSV(const std::string &csvSource);
private:
void addLine(const std::vector<std::string> &line, std::vector<std::vector<std::string> > &lines);
void add_line(const std::vector<MlValue> &line, std::vector<MlValue> &lines);
MlValue ivalualize(std::vector<std::vector<std::string> > &parsed_data) const;
MlValue ivalualize(const std::string &value) const;
bool is_string_int(const std::string &str) const;
bool is_string_int(const std::string &s, long &val) const;
bool is_string_float(const std::string &str) const;
bool is_string_float(const std::string &s, double &val) const;
};

View File

@ -26,5 +26,8 @@
(benchmark "benchmark range 1000 : " (range 1 1000))
(define fdx_list (parse-csv (read-file "tests/csv_data.csv")))
(print fdx_list)
(sleep 1.5)