Data

Binary data base class for handling raw byte data

Overview

The NFIQ2::Data class provides a foundation for binary data handling in NFIQ 2. It extends std::basic_string<uint8_t> and provides convenient methods for reading, writing, and converting binary data.

This class serves as the base class for NFIQ2::FingerprintImageData and other data-handling classes in the library.

Class Definition

namespace NFIQ2 {
    class Data : public std::basic_string<uint8_t> {
        // Public interface
    };
}

Constructors

Default Constructor

Data();

Creates an empty Data object.

Constructor with Data Pointer

Data(const uint8_t *pData, uint32_t dataSize);

pData · const uint8_t* · required

Pointer to binary data

dataSize · uint32_t · required

Size of data at the pointer in bytes

Creates a Data object from an existing data buffer.

Copy Constructor

Data(const Data &otherData);

otherData · const Data& · required

Data object to copy from

String Constructor

explicit Data(const std::basic_string<uint8_t> &otherData);

otherData · const std::basic_string<uint8_t>& · required

Binary data in string format

Methods

readFromFile

void readFromFile(const std::string &filename);

Reads the content from a file into this object.

filename · const std::string& · required

Path to the file to read

Throws: NFIQ2::Exception if the file cannot be opened.

Example:

NFIQ2::Data data;
data.readFromFile("/path/to/file.dat");

writeToFile

void writeToFile(const std::string &filename) const;

Writes the content to a file.

filename · const std::string& · required

Path to the file to write

Throws: NFIQ2::Exception if the file cannot be opened.

Example:

data.writeToFile("/path/to/output.dat");

toHexString

std::string toHexString() const;

Generates a hexadecimal string representation of the buffer.

Returns: The content of the buffer as a hexadecimal string.

Throws: NFIQ2::Exception if no data is available in the buffer.

Example:

std::string hexStr = data.toHexString();
std::cout << "Hex: " << hexStr << std::endl;

fromBase64String

void fromBase64String(const std::string &base64String);

Imports data from a Base64 encoded string.

base64String · const std::string& · required

Base64 encoded string to decode

Throws: NFIQ2::Exception if an invalid character is detected in the string.

Example:

NFIQ2::Data data;
data.fromBase64String("SGVsbG8gV29ybGQh");

toBase64String

std::string toBase64String() const;

Generates a Base64 encoded string of the buffer.

Returns: The content of the buffer as a Base64 encoded string.

Example:

std::string base64 = data.toBase64String();
std::cout << "Base64: " << base64 << std::endl;

Usage Example

#include <nfiq2.hpp>

// Reading binary data from file
NFIQ2::Data imageData;
imageData.readFromFile("fingerprint.raw");

// Convert to base64 for transmission
std::string encoded = imageData.toBase64String();

// Later, decode back
NFIQ2::Data decodedData;
decodedData.fromBase64String(encoded);

// Write to new file
decodedData.writeToFile("fingerprint_copy.raw");

Inherited Methods

Since Data extends std::basic_string<uint8_t>, all standard string methods are available:

• size() - Get the size of the data
• empty() - Check if data is empty
• clear() - Clear the data
• data() - Get raw pointer to data
• Standard iterators and operators

See Also

FingerprintImageData

Extends Data for fingerprint images

Exception

Error handling in NFIQ 2