I’m trying to create a shared object with Python to read csv file and be used by a C application.

So I’m having a really hard time doing this.

my code is here:

`from cffi import FFIimport csvimport io

ffi = FFI()

ffi.cdef("""void processCsv(const char[], const char[], const char[]);void processCsvFile(const char[], const char[], const char[]);""")

def process_csv(csv_data, selected_columns, row_filter_definitions):# Parse the CSV datacsv_reader = csv.DictReader(io.StringIO(csv_data.decode('utf-8')))headers = csv_reader.fieldnames

# Parse selected columns
if selected_columns:
    selected_columns = selected_columns.decode('utf-8').split(',')
else:
    selected_columns = headers

# Parse filters
filters = []
if row_filter_definitions:
    for line in row_filter_definitions.decode('utf-8').split('n'):
        if line:
            if '=' in line:
                header, value = line.split('=')
                op = '='
            elif '>' in line:
                header, value = line.split('>')
                op = '>'
            elif '<' in line:
                header, value = line.split('<')
                op = '<'
            filters.append((header, op, value))

# Apply filters and select columns
output = io.StringIO()
csv_writer = csv.DictWriter(output, fieldnames=selected_columns)
csv_writer.writeheader()

for row in csv_reader:
    match = all((op == '=' and row[header] == value) or 
                (op == '>' and row[header] > value) or 
                (op == '<' and row[header] < value) for header, op, value in filters)
    if match:
        csv_writer.writerow({col: row[col] for col in selected_columns})

print(output.getvalue(), end='')

def process_csv_file(csv_file_path, selected_columns, row_filter_definitions):with open(csv_file_path.decode('utf-8'), 'r') as f:process_csv(f.read().encode('utf-8'), selected_columns, row_filter_definitions)your textffi.set_source("_csv_processor","""#include <stdio.h>

void process_csv(const char csv[], const char selectedColumns[], const char rowFilterDefinitions[]);void process_csv_file(const char csvFilePath[], const char selectedColumns[], const char rowFilterDefinitions[]);

void processCsv(const char csv[], const char selectedColumns[], const char rowFilterDefinitions[]) {process_csv(csv, selectedColumns, rowFilterDefinitions);}

void processCsvFile(const char csvFilePath[], const char selectedColumns[], const char rowFilterDefinitions[]) {process_csv_file(csvFilePath, selectedColumns, rowFilterDefinitions);}""")

if name == "main":ffi.compile(verbose=True)`

And i’m generating this code with:

• python3 csv_processor.py

so, when i try:

• gcc -o programa_c programa_c.c -L. -l_csv_processor -lpython3.10

i’m receive it’s error:

• /27818bb096b67c55a7a954c23cec29630e6d644e$ gcc -o programa_c programa_c.c -L. -l_csv_processor -lpython3.10
  /usr/bin/ld: cannot find -l_csv_processor: No such file or directory
  collect2: error: ld returned 1 exit status

the code in c is here:

`#include <stdio.h>

void processCsv(const char[], const char[], const char[]);void processCsvFile(const char[], const char[], const char[]);

int main(){const char csv[] = "header1,header2,header3n1,2,3n4,5,6n7,8,9";processCsv(csv, "header1,header3", "header1>1nheader3<9");

const char csv_file[] = "data.csv";
processCsvFile(csv_file, "header1,header3", "header1>1nheader3<9");

return 0;

}`and i need:

• Implement a library that processes CSV files, applying filters and selecting columns as specified. The solution must be able to integrate with the interface defined in C below.

/**
 * Process the CSV data by applying filters and selecting columns.
 *
 * @param csv The CSV data to be processed.
 * @param selectedColumns The columns to be selected from the CSV data.
 * @param rowFilterDefinitions The filters to be applied to the CSV data.
 *
 * @return void
 */
void processCsv(const char[], const char[], const char[]);

/**
 * Process the CSV file by applying filters and selecting columns.
 *
 * @param csvFilePath The path to the CSV file to be processed.
 * @param selectedColumns The columns to be selected from the CSV data.
 * @param rowFilterDefinitions The filters to be applied to the CSV data.
 *
 * @return void
 */
void processCsvFile(const char[], const char[], const char[]);

processCsv

• csv: String with CSV data, where each line represents a record and the columns are separated by commas.
  • Example: “header1,header2,header3n1,2,3n4,5,6”
• selectedColumns: A string where the names of the columns to be selected are separated by commas.
  • Example: “header1,header3”
• rowFilterDefinitions: A string where each filter is defined on a new line, in the format header(comparador)valor.
  • Example: “header1>1nheader2=2nheader3<6”

processCsvFile

• csvFilePath: String with the CSV file path.
  • Example: “path/to/csv_file.csv”
• selectedColumns: A string where the names of the columns to be selected are separated by commas.
  • Example: “header1,header3”
• rowFilterDefinitions: A string where each filter is defined on a new line, in the format header(comparador)valor.
  • Example: “header1>1nheader2=2nheader3<6”

I don’t know where I could be going wrong, as I’ve never worked with this type of application, it’s the first time