glibmm: Glib::Checksum Class Reference

glibmm 2.54.0

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Glib::Checksum Class Reference

Computes the checksum for data. More...

`#include <glibmm/checksum.h>`

## Public Types
enum | ChecksumType { CHECKSUM_MD5, CHECKSUM_SHA1, CHECKSUM_SHA256, CHECKSUM_SHA512 }
| The hashing algorithm to be used by Checksum when performing the digest of some data. More...

## Public Member Functions
| Checksum ()
| Constructs an invalid object. More...
| Checksum (GChecksum* castitem, bool make_a_copy=false)
| Checksum (const Checksum& src)
Checksum& | operator= (const Checksum& src)
| Checksum (Checksum&& other) noexcept
Checksum& | operator= (Checksum&& other) noexcept
| ~Checksum () noexcept
void | swap (Checksum& other) noexcept
GChecksum* | gobj ()
const GChecksum* | gobj () const
GChecksum* | gobj_copy () const
| Provides access to the underlying C instance. The caller is responsible for freeing it. Use when directly setting fields in structs. More...
| Checksum (ChecksumType checksum_type)
| Creates a new Checksum, using the checksum algorithm checksum_type. More...
| operator bool () const
| Returns true if the Checksum object is valid. More...
void | reset ()
| Resets the state of the checksum back to its initial state. More...
void | update (const guchar* data, gsize length)
| Feeds data into an existing Checksum. More...
void | update (const std::string& data)
| Feeds data into an existing Checksum. More...
void | get_digest (guint8* buffer, gsize* digest_len) const
| Gets the digest from checksum as a raw binary vector and places it into buffer. More...
std::string | get_string () const
| Gets the digest as an hexadecimal string. More...

## Static Public Member Functions
static std::string | compute_checksum (ChecksumType checksum_type, const guchar* data, gsize length)
| Computes the checksum for a binary data of length. More...
static std::string | compute_checksum (ChecksumType checksum_type, const std::string& str)
| Computes the checksum of a string. More...
static gssize | get_length (ChecksumType checksum_type)
| Gets the length in bytes of digests of type checksum_type. More...

## Protected Attributes
GChecksum* | gobject_

## Related Functions
(Note that these are not member functions.)
void | swap (Checksum& lhs, Checksum& rhs) noexcept
Glib::Checksum | wrap (GChecksum* object, bool take_copy=false)
| A Glib::wrap() method for this object. More...

## Detailed Description

Computes the checksum for data.

This is a generic API for computing checksums (or "digests") for a sequence of arbitrary bytes, using various hashing algorithms like MD5, SHA-1 and SHA-256. Checksums are commonly used in various environments and specifications.

glibmm supports incremental checksums by calling update() as long as there's data available and then using get_string() or get_digest() to compute the checksum and return it either as a string in hexadecimal form, or as a raw sequence of bytes. To compute the checksum for binary blobs and NULL-terminated strings in one go, use the static compute_checksum() convenience functions().

Since glibmm 2.16:

## Constructor & Destructor Documentation

Glib::Checksum::Checksum | ( |  | ) |

Constructs an invalid object.

E.g. for output arguments to methods. There is not much you can do with the object before it has been assigned a valid value.

Glib::Checksum::Checksum | ( | GChecksum * | castitem,
|  | bool | make_a_copy = `false`
| ) |  |
| explicit

Glib::Checksum::Checksum | ( | const Checksum& | src | ) |

Glib::Checksum::Checksum | ( | Checksum&& | other | ) |
| noexcept

Glib::Checksum::~Checksum | ( |  | ) |
| noexcept

Glib::Checksum::Checksum | ( | ChecksumType | checksum_type | ) |
| explicit

Creates a new Checksum, using the checksum algorithm checksum_type.

If the checksum_type is not known, then operator bool() will return false.

Parameters

  checksum_type | Checksum type, one of defined above.

## Member Function Documentation

static std::string Glib::Checksum::compute_checksum | ( | ChecksumType | checksum_type,
|  | const guchar * | data,
|  | gsize | length
| ) |  |
| static

Computes the checksum for a binary data of length.

This is a convenience wrapper for g_checksum_new(), g_checksum_get_string() and g_checksum_free().

The hexadecimal string returned will be in lower case.

Since glibmm 2.16:

Parameters

  checksum_type | A ChecksumType.
  data | Binary blob to compute the digest of.
  length | Length of data.

Returns
  The digest of the binary data as a string in hexadecimal.

static std::string Glib::Checksum::compute_checksum | ( | ChecksumType | checksum_type,
|  | const std::string & | str
| ) |  |
| static

Computes the checksum of a string.

Parameters

  checksum_type | A ChecksumType
  str | The string to compute the checksum of.

Returns
  The checksum as a hexadecimal string.

void Glib::Checksum::get_digest | ( | guint8 * | buffer,
|  | gsize * | digest_len
| ) |  | const

Gets the digest from checksum as a raw binary vector and places it into buffer.

The size of the digest depends on the type of checksum.

Once this function has been called, the Checksum is closed and can no longer be updated with g_checksum_update().

Since glibmm 2.16:

Parameters

  buffer | Output buffer.
  digest_len | An inout parameter. The caller initializes it to the size of buffer. After the call it contains the length of the digest.

static gssize Glib::Checksum::get_length | ( | ChecksumType | checksum_type | ) |
| static

Gets the length in bytes of digests of type checksum_type.

Parameters

  checksum_type | A ChecksumType.

Returns
  The checksum length, or -1 if checksum_type is not supported.

std::string Glib::Checksum::get_string | ( |  | ) | const

Gets the digest as an hexadecimal string.

Once this function has been called the Checksum can no longer be updated with g_checksum_update().

The hexadecimal characters will be lower case.

Since glibmm 2.16:

Returns
  The hexadecimal representation of the checksum. The returned string is owned by the checksum and should not be modified or freed.

GChecksum* Glib::Checksum::gobj | ( |  | ) |
| inline

const GChecksum* Glib::Checksum::gobj | ( |  | ) | const
| inline

GChecksum* Glib::Checksum::gobj_copy | ( |  | ) | const

Provides access to the underlying C instance. The caller is responsible for freeing it. Use when directly setting fields in structs.

Glib::Checksum::operator bool | ( |  | ) | const
| explicit

Returns true if the Checksum object is valid.

This will return false, for instance, if an unsupported checksum type was provided to the constructor.

Checksum& Glib::Checksum::operator= | ( | const Checksum& | src | ) |

Checksum& Glib::Checksum::operator= | ( | Checksum&& | other | ) |
| noexcept

void Glib::Checksum::reset | ( |  | ) |

Resets the state of the checksum back to its initial state.

Since glibmm 2.18:

void Glib::Checksum::swap | ( | Checksum& | other | ) |
| noexcept

void Glib::Checksum::update | ( | const guchar * | data,
|  | gsize | length
| ) |  |

Feeds data into an existing Checksum.

The checksum must still be open, that is g_checksum_get_string() or g_checksum_get_digest() must not have been called on checksum.

Since glibmm 2.16:

Parameters

  data | Buffer used to compute the checksum.
  length | Size of the buffer, or -1 if it is a null-terminated string.

void Glib::Checksum::update | ( | const std::string & | data | ) |

Feeds data into an existing Checksum.

The checksum must still be open, that is get_string() or get_digest() must not have been called on the checksum.

Parameters

  data | Buffer used to compute the checksum

## Friends And Related Function Documentation

void swap | ( | Checksum& | lhs,
|  | Checksum& | rhs
| ) |  |
| related

Parameters

  lhs | The left-hand side
  rhs | The right-hand side

Glib::Checksum wrap | ( | GChecksum * | object,
|  | bool | take_copy = `false`
| ) |  |
| related

A Glib::wrap() method for this object.

Parameters

  object | The C instance.
  take_copy | False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns
  A C++ instance that wraps this C instance.

## Member Data Documentation

GChecksum* Glib::Checksum::gobject_
| protected