jsoncons::csv::basic_csv_encoder

#include <jsoncons_ext/csv/csv_encoder.hpp>

template<
    class CharT,
    class Sink,
    class Allocator=std::allocator<CharT>=std::allocator<CharT>>
> class basic_csv_encoder : public jsoncons::basic_json_visitor<CharT>

basic_csv_encoder and basic_compact_json_encoder are noncopyable and nonmoveable.

Four specializations for common character types and result types are defined:

Type	Definition
csv_stream_encoder	basic_csv_encoder<char,jsoncons::stream_sink>
csv_string_encoder	basic_csv_encoder<char,jsoncons::string_sinkstd::string>
wcsv_stream_encoder	basic_csv_encoder<wchar_t,jsoncons::stream_sink<wchar_t>>
wcsv_string_encoder	basic_csv_encoder<wchar_t,jsoncons::string_sinkstd::wstring>

Member types

Type	Definition
char_type	CharT
sink_type	Sink
string_view_type

Constructors

explicit basic_csv_encoder(Sink&& sink)

Constructs a new csv encoder that is associated with the destination sink.

basic_csv_encoder(Sink&& sink, 
                     const basic_csv_options<CharT>& options)

Constructs a new csv encoder that is associated with the destination sink and uses the specified csv options.

Destructor

virtual ~basic_csv_encoder() noexcept

Member functions

void reset();

Reset encoder to write another value to the same sink

void reset(Sink&& sink)

Reset encoder to write a new value to a new sink

Inherited from basic_json_visitor

void flush(); (1)

bool begin_object(semantic_tag tag=semantic_tag::none,
                  const ser_context& context=ser_context()); (2)

bool begin_object(std::size_t length, 
                  semantic_tag tag=semantic_tag::none, 
                  const ser_context& context = ser_context()); (3)

bool end_object(const ser_context& context = ser_context()); (4)

bool begin_array(semantic_tag tag=semantic_tag::none,
                 const ser_context& context=ser_context()); (5)

bool begin_array(std::size_t length, 
                 semantic_tag tag=semantic_tag::none,
                 const ser_context& context=ser_context()); (6)

bool end_array(const ser_context& context=ser_context()); (7)

bool key(const string_view_type& name, 
          const ser_context& context=ser_context()); (8)

bool null_value(semantic_tag tag = semantic_tag::none,
                const ser_context& context=ser_context()); (9) 

bool bool_value(bool value, 
                semantic_tag tag = semantic_tag::none,
                const ser_context& context=ser_context()); (10) 

bool string_value(const string_view_type& value, 
                  semantic_tag tag = semantic_tag::none, 
                  const ser_context& context=ser_context()); (11) 

bool byte_string_value(const byte_string_view& source, 
                       semantic_tag tag=semantic_tag::none, 
                       const ser_context& context=ser_context()); (12) (until 0.152.0)

template <typename Source>
bool byte_string_value(const Source& souce, 
                       semantic_tag tag=semantic_tag::none, 
                       const ser_context& context=ser_context()); (12) (since 0.152.0)

template <typename Source>
bool byte_string_value(const Source& souce, 
                       uint64_t ext_tag, 
                       const ser_context& context=ser_context()); (13) (since 0.152.0)

bool uint64_value(uint64_t value, 
                  semantic_tag tag = semantic_tag::none, 
                  const ser_context& context=ser_context()); (14)

bool int64_value(int64_t value, 
                 semantic_tag tag = semantic_tag::none, 
                 const ser_context& context=ser_context()); (15)

bool half_value(uint16_t value, 
                semantic_tag tag = semantic_tag::none, 
                const ser_context& context=ser_context()); (16)

bool double_value(double value, 
                  semantic_tag tag = semantic_tag::none, 
                  const ser_context& context=ser_context()); (17)

bool begin_object(semantic_tag tag,
                  const ser_context& context,
                  std::error_code& ec); (18)

bool begin_object(std::size_t length, 
                  semantic_tag tag, 
                  const ser_context& context,
                  std::error_code& ec); (19)

bool end_object(const ser_context& context, 
                std::error_code& ec); (20)

bool begin_array(semantic_tag tag, 
                 const ser_context& context, 
                 std::error_code& ec); (21)

bool begin_array(std::size_t length, 
                 semantic_tag tag, 
                 const ser_context& context, 
                 std::error_code& ec); (22)

bool end_array(const ser_context& context, 
               std::error_code& ec); (23)

bool key(const string_view_type& name, 
          const ser_context& context, 
          std::error_code& ec); (24)

bool null_value(semantic_tag tag,
                const ser_context& context,
                std::error_code& ec); (25) 

bool bool_value(bool value, 
                semantic_tag tag,
                const ser_context& context,
                std::error_code& ec); (26) 

bool string_value(const string_view_type& value, 
                  semantic_tag tag, 
                  const ser_context& context,
                  std::error_code& ec); (27) 

bool byte_string_value(const byte_string_view& source, 
                       semantic_tag tag, 
                       const ser_context& context,
                       std::error_code& ec); (28) (until 0.152.0)

template <typename Source>   
bool byte_string_value(const Source& source, 
                       semantic_tag tag, 
                       const ser_context& context,
                       std::error_code& ec); (28) (since 0.152.0)

template <typename Source>   
bool byte_string_value(const Source& source, 
                       uint64_t ext_tag, 
                       const ser_context& context,
                       std::error_code& ec); (29) (since 0.152.0)

bool uint64_value(uint64_t value, 
                  semantic_tag tag, 
                  const ser_context& context,
                  std::error_code& ec); (30)

bool int64_value(int64_t value, 
                 semantic_tag tag, 
                 const ser_context& context,
                 std::error_code& ec); (31)

bool half_value(uint16_t value, 
                semantic_tag tag, 
                const ser_context& context,
                std::error_code& ec); (32)

bool double_value(double value, 
                  semantic_tag tag, 
                  const ser_context& context,
                  std::error_code& ec); (33)

template <typename T>
bool typed_array(const span<T>& data, 
                 semantic_tag tag=semantic_tag::none,
                 const ser_context& context=ser_context()); (34)

bool typed_array(half_arg_t, const span<const uint16_t>& s,
    semantic_tag tag = semantic_tag::none,
    const ser_context& context = ser_context()); (35)

bool begin_multi_dim(const span<const size_t>& shape,
                     semantic_tag tag,
                     const ser_context& context); (36) 

bool end_multi_dim(const ser_context& context=ser_context()); (37) 

template <typename T>
bool typed_array(const span<T>& data, 
                 semantic_tag tag,
                 const ser_context& context,
                 std::error_code& ec); (38)

bool typed_array(half_arg_t, const span<const uint16_t>& s,
                 semantic_tag tag,
                 const ser_context& context,
                 std::error_code& ec); (39)

bool begin_multi_dim(const span<const size_t>& shape,
                     semantic_tag tag,
                     const ser_context& context, 
                     std::error_code& ec); (40)

bool end_multi_dim(const ser_context& context,
                   std::error_code& ec); (41)

(1) Flushes whatever is buffered to the destination.

(2) Indicates the begining of an object of indefinite length. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(3) Indicates the begining of an object of known length. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(4) Indicates the end of an object. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(5) Indicates the beginning of an indefinite length array. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(6) Indicates the beginning of an array of known length. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(7) Indicates the end of an array. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(8) Writes the name part of an object name-value pair. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(9) Writes a null value. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(10) Writes a boolean value. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(11) Writes a text string value. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(12) Writes a byte string value source with a generic tag. Type Source must be a container that has member functions data() and size(), and member type value_type with size exactly 8 bits (since 0.152.0.) Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(13) Writes a byte string value source with a format specific tag, ext_tag. Type Source must be a container that has member functions data() and size(), and member type value_type with size exactly 8 bits (since 0.152.0.) Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(14) Writes a non-negative integer value. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(15) Writes a signed integer value. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(16) Writes a half precision floating point value. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(17) Writes a double precision floating point value. Returns true if the consumer wishes to receive more events, false otherwise. Throws a ser_error on parse errors.

(18)-(33) Same as (2)-(17), except sets ec and returns false on parse errors.

Examples

Serializing an array of json values to a comma delimted file

JSON input file

[
    ["country_code","name"],
    ["ABW","ARUBA"],
    ["ATF","FRENCH SOUTHERN TERRITORIES, D.R. OF"],
    ["VUT","VANUATU"],
    ["WLF","WALLIS & FUTUNA ISLANDS"]
]

Note

The third array element has a value that contains a comma, in the CSV file this value will be quoted.

Serializing the comma delimited file with csv_stream_encoder

std::string in_file = "input/countries.json";
std::ifstream is(in_file);

json_decoder<json> decoder;
json_stream_reader reader(is,decoder);
reader.read();
json countries = decoder.get_result();

csv_stream_encoder encoder(std::cout);

countries.dump(encoder);

Output

country_code,name
ABW,ARUBA
ATF,"FRENCH SOUTHERN TERRITORIES, D.R. OF"
VUT,VANUATU
WLF,WALLIS & FUTUNA ISLANDS

Serializing an array of json objects to a tab delimted file

JSON input file

[
    {
        "dept":"sales",
        "employee-name":"Smith, Matthew",
        "employee-no":"00000001",
        "note":"",
        "salary":"150,000.00"
    },
    {
        "dept":"sales",
        "employee-name":"Brown, Sarah",
        "employee-no":"00000002",
        "note":"",
        "salary":"89,000.00"
    },
    {
        "dept":"finance",
        "employee-name":"Oberc, Scott",
        "employee-no":"00000003",
        "salary":"110,000.00"
    },
    {
        "dept":"sales",
        "employee-name":"Scott, Colette",
        "employee-no":"00000004",
        "note":"\"Exemplary\" employee\nDependable, trustworthy",
        "comment":"Team player",
        "salary":"75,000.00"
    }
]

Note

The names in the first object in the array will be used for the header row of the CSV file
The fourth object has a note member whose value contains escaped quotes and an escaped new line character, in the CSV file, this value will be quoted, and it will contain a new line character and escaped quotes.

Dump json value to a tab delimited file

std::string in_file = "input/employees.json";
std::ifstream is(in_file);

json_decoder<json> decoder;
auto options = csv_options{}          
    .field_delimiter = '\t';

json_stream_reader reader(is,decoder);
reader.read();
json employees = decoder.get_result();

csv_stream_encoder encoder(std::cout,options);

employees.dump(encoder);

Tab delimited output file

dept    employee-name   employee-no     note    salary
sales   Smith, Matthew  00000001                150,000.00
sales   Brown, Sarah    00000002                89,000.00
finance Oberc, Scott    00000003                110,000.00
sales   Scott, Colette  00000004        ""Exemplary"" employee
Dependable, trustworthy 75,000.00

Dump json value to csv file

#include <jsoncons/json.hpp>
#include <jsoncons_ext/csv/csv_encoder.hpp>

using namespace jsoncons;

int main()
{
    const json books = json::parse(R"(
    [
        {
            "title" : "Kafka on the Shore",
            "author" : "Haruki Murakami",
            "price" : 25.17
        },
        {
            "title" : "Women: A Novel",
            "author" : "Charles Bukowski",
            "price" : 12.00
        },
        {
            "title" : "Cutter's Way",
            "author" : "Ivan Passer"
        }
    ]
    )");

    auto options = csv_options{}          
        .column_names("author,title,price");

    csv_stream_encoder encoder(std::cout, options);

    books.dump(encoder);
}

Output:

author,title,price
Haruki Murakami,Kafka on the Shore,25.17
Charles Bukowski,Women: A Novel,12.0
Ivan Passer,Cutter's Way,

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basic_csv_encoder.md

basic_csv_encoder.md

jsoncons::csv::basic_csv_encoder

Member types

Constructors

Destructor

Member functions

Inherited from basic_json_visitor

Examples

Serializing an array of json values to a comma delimted file

JSON input file

Serializing the comma delimited file with csv_stream_encoder

Output

Serializing an array of json objects to a tab delimted file

JSON input file

Dump json value to a tab delimited file

Tab delimited output file

Dump json value to csv file

See also

Files

basic_csv_encoder.md

Latest commit

History

basic_csv_encoder.md

File metadata and controls

jsoncons::csv::basic_csv_encoder

Member types

Constructors

Destructor

Member functions

Inherited from basic_json_visitor

Examples

Serializing an array of json values to a comma delimted file

JSON input file

Serializing the comma delimited file with csv_stream_encoder

Output

Serializing an array of json objects to a tab delimted file

JSON input file

Dump json value to a tab delimited file

Tab delimited output file

Dump json value to csv file

See also