CSV

CSV API

CSV API provides stream-oriented reading of delimiter-separated value files. The first row defines the column names (headers), and each call to csv_next() reads one data line into the current fields vector.

Example

The following example demonstrates how to use the CSV API.

{{< readfile file="../examples/csv_file.c" code="true" lang="c" >}}

Typedefs

CsvDesc

typedef struct CsvDesc {
  const char* file_name;
  FILE*       file;
  Vector      header;
  Vector      fields;
  size_t      line_maxlen;
  char*       line;
} CsvDesc;

Functions

csv_open

Open and parse a CSV file into a CsvDesc descriptor object.

The first row is consumed as the header row (column names); all subsequent rows are stored as data rows. Fields may be separated by commas or semicolons.

Parameters

path (const char*)

Path to a CSV file. If NULL, the CSV_FILE environment variable is used. If the resolved path cannot be opened an empty CsvDesc is returned without error.

Returns

CsvDesc (struct)

CSV descriptor object. Call csv_close() when finished.

csv_count

Return the number of fields in the current parsed row.

Parameters

csv (CsvDesc*)

CSV descriptor object.

Returns

size_t

Number of fields in CsvDesc.fields.

csv_header

Return the header (column name) for a column index.

Parameters

csv (CsvDesc*)

CSV descriptor object.

col (size_t)

Zero-based column index.

Returns

const char*

Column name, or NULL if the index is out of range.

csv_next

Read and parse the next data line.

Parameters

csv (CsvDesc*)

CSV descriptor object.

Returns

int

0 on success, -ENODATA at end of file, -EINVAL on a parse error (bad token or wrong field count), -EOVERFLOW on truncated lines (line exceeds configured buffer), -ENOMEM on allocation failure.

csv_field

Return a field value from the current parsed row.

Parameters

csv (CsvDesc*)

CSV descriptor object.

col (size_t)

Zero-based column index.

Returns

double

Parsed value, or 0.0 if the index is out of range.

csv_fields

Read multiple field values from the current row.

Parameters

csv (CsvDesc*)

CSV descriptor object.

col (size_t[])

Column index list.

val (double[])

Output value array.

len (size_t)

Number of requested columns.

Returns

void

csv_close

Release all resources owned by a CSV descriptor.

Parameters

csv (CsvDesc*)

CSV descriptor object.