github.com/ashaduri/csv-parser

Csv::Parser (csv-parser)

Compile-time and runtime CSV parser written in C++17.

Features

• Header-only.
• Requires only standard C++ (C++17).
• Supports reading CSV data from std::string_view during compilation (using constexpr).
• Fully supports RFC 4180, including quoted values, escaped quotes, and newlines in field values.
• Liberal in terms of accepting not-quite-standard CSV files, but detects errors when needed.
• Supports Excel CSV variations.
• Supports reading data as different types (string, double, empty field) (runtime only).
• Extensively tested using Catch2.

Usage Examples

Runtime Parsing into 2D std::vector

Example:

#include "csv_parser.h"

// ...

using namespace std::string_view_literals;


// Data to parse
std::string_view data = "abc,def\n5,6"sv;

// Let "cell_refs" be a vector of columns.
// After parsing, each element will contain a std::string_view referencing
// a part of the original data.
std::vector<std::vector<Csv::CellReference>> cell_refs;

Csv::Parser parser;

try {
    // parseTo() throws Csv::ParseError on error.
    parser.parseTo(data, cell_refs);
}
catch(Csv::ParseError& ex) {
    std::cerr << "CSV parse error: " << ex.what() << std::endl;
    return EXIT_FAILURE;
}

assert(cell_refs.size() == 2);
assert(cell_refs[0].size() == 2);
assert(cell_refs[1].size() == 2);

assert(cell_refs[0][0].getType() == Csv::CellType::String);
assert(cell_refs[1][0].getType() == Csv::CellType::String);
assert(cell_refs[0][1].getType() == Csv::CellType::Double);
assert(cell_refs[1][1].getType() == Csv::CellType::Double);

std::cout << "Column 0, row 0: " << cell_refs[0][0].getCleanString().value() << std::endl;  // abc
std::cout << "Column 1, row 0: " << cell_refs[1][0].getCleanString().value() << std::endl;  // def
std::cout << "Column 0, row 1: " << cell_refs[0][1].getDouble().value() << std::endl;  // 5
std::cout << "Column 1, row 1: " << cell_refs[1][1].getDouble().value() << std::endl;  // 6

Compile-Time Parsing

Currently, parsing at compile-time has some restrictions:

• Only string_views are supported for output (no doubles).
• Consecutive double-quotes are not collapsed in strings.

One (possibly useful) consequence of compile-time parsing is that a parse error causes compilation error.

Example:

#include "csv_parser.h"

// ...

using namespace std::string_view_literals;

constexpr std::string_view data = "\"abc\",def\n5,6"sv;
constexpr std::size_t columns = 2, rows = 2;

constexpr Csv::Parser parser;

// parse into std::array<std::array<CellStringReference, rows>, columns>
constexpr auto matrix = parser.parseTo2DArray<columns, rows>(data);

// Verify the data at compile time.
static_assert(matrix[0][0].getOriginalStringView() == "abc"sv);
static_assert(matrix[1][0].getOriginalStringView() == "def"sv);
static_assert(matrix[0][1].getOriginalStringView() == "5"sv);
static_assert(matrix[1][1].getOriginalStringView() == "6"sv);

Copyright

Copyright: Alexander Shaduri [e-mail]
License: Zlib