Disk ARchive
2.4.2
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this is a partial implementation of the generic_file interface to cypher/decypher data block by block. More...
#include <tronconneuse.hpp>
Inherits libdar::generic_file.
Inherited by libdar::crypto_sym.
Public Member Functions | |
tronconneuse (U_32 block_size, generic_file &encrypted_side, bool no_initial_shift, const archive_version &reading_ver) | |
This is the constructor. | |
tronconneuse (const tronconneuse &ref) | |
copy constructor | |
const tronconneuse & | operator= (const tronconneuse &ref) |
assignment operator | |
virtual | ~tronconneuse () |
destructor | |
bool | skip (const infinint &pos) |
inherited from generic_file | |
bool | skip_to_eof () |
inherited from generic_file | |
bool | skip_relative (S_I x) |
inherited from generic_file | |
infinint | get_position () |
inherited from generic_file | |
void | write_end_of_file () |
in write_only mode indicate that end of file is reached | |
void | set_initial_shift (const infinint &x) |
this method to modify the initial shift. This overrides the constructor "no_initial_shift" of the constructor | |
void | set_callback_trailing_clear_data (infinint(*call_back)(generic_file &below, const archive_version &reading_ver)) |
Protected Member Functions | |
virtual U_32 | encrypted_block_size_for (U_32 clear_block_size)=0 |
defines the size necessary to encrypt a given amount of clear data | |
virtual U_32 | clear_block_allocated_size_for (U_32 clear_block_size)=0 |
it may be necessary by the inherited class have few more bytes allocated after the clear data given for encryption | |
virtual U_32 | encrypt_data (const infinint &block_num, const char *clear_buf, const U_32 clear_size, const U_32 clear_allocated, char *crypt_buf, U_32 crypt_size)=0 |
this method encrypts the clear data given | |
virtual U_32 | decrypt_data (const infinint &block_num, const char *crypt_buf, const U_32 crypt_size, char *clear_buf, U_32 clear_size)=0 |
this method decyphers data |
this is a partial implementation of the generic_file interface to cypher/decypher data block by block.
This class is a pure virtual one, as several calls have to be defined by inherited classes
tronconneuse is either read_only or write_only, read_write is not allowed. The openning mode is defined by encrypted_side's mode. In write_only no skip() is allowed, writing is sequential from the beginning of the file to the end (like writing to a pipe). In read_only all skip() functions are available.
Definition at line 63 of file tronconneuse.hpp.
libdar::tronconneuse::tronconneuse | ( | U_32 | block_size, |
generic_file & | encrypted_side, | ||
bool | no_initial_shift, | ||
const archive_version & | reading_ver | ||
) |
This is the constructor.
[in] | block_size | is the size of block encryption (the size of clear data encrypted toghether). |
[in] | encrypted_side | where encrypted data are read from or written to. |
[in] | no_initial_shift | assume that no unencrypted data is located at the begining of the underlying file, else this is the position of the encrypted_side at the time of this call that is used as initial_shift |
[in] | reading_ver | version of the archive format |
virtual U_32 libdar::tronconneuse::clear_block_allocated_size_for | ( | U_32 | clear_block_size | ) | [protected, pure virtual] |
it may be necessary by the inherited class have few more bytes allocated after the clear data given for encryption
[in] | clear_block_size | is the size in byte of the clear data that will be asked to encrypt. |
Implemented in libdar::crypto_sym.
virtual U_32 libdar::tronconneuse::decrypt_data | ( | const infinint & | block_num, |
const char * | crypt_buf, | ||
const U_32 | crypt_size, | ||
char * | clear_buf, | ||
U_32 | clear_size | ||
) | [protected, pure virtual] |
this method decyphers data
[in] | block_num | block number of the data to decrypt. |
[in] | crypt_buf | pointer to the first byte of encrypted data. |
[in] | crypt_size | size of encrypted data to decrypt. |
[in,out] | clear_buf | pointer where to put clear data. |
[in] | clear_size | allocated size of clear_buf. |
Implemented in libdar::crypto_sym.
virtual U_32 libdar::tronconneuse::encrypt_data | ( | const infinint & | block_num, |
const char * | clear_buf, | ||
const U_32 | clear_size, | ||
const U_32 | clear_allocated, | ||
char * | crypt_buf, | ||
U_32 | crypt_size | ||
) | [protected, pure virtual] |
this method encrypts the clear data given
block_num | is the number of the block to which correspond the given data, This is an informational field for inherited classes. | |
[in] | clear_buf | points to the first byte of clear data to encrypt. |
[in] | clear_size | is the length in byte of data to encrypt. |
[in] | clear_allocated | is the size of the allocated memory (modifiable bytes) in clear_buf: clear_block_allocated_size_for(clear_size) |
[in,out] | crypt_buf | is the area where to put corresponding encrypted data. |
[in] | crypt_size | is the allocated memory size for crypt_buf: encrypted_block_size_for(clear_size) |
Implemented in libdar::crypto_sym.
virtual U_32 libdar::tronconneuse::encrypted_block_size_for | ( | U_32 | clear_block_size | ) | [protected, pure virtual] |
defines the size necessary to encrypt a given amount of clear data
[in] | clear_block_size | is the size of the clear block to encrypt. |
Implemented in libdar::crypto_sym.
void libdar::tronconneuse::set_callback_trailing_clear_data | ( | infinint(*)(generic_file &below, const archive_version &reading_ver) | call_back | ) | [inline] |
let the caller give a callback function that given a generic_file with cyphered data, is able to return the offset of the first clear byte located *after* all the cyphered data, this callback function is used (if defined by the following method), when reaching End of File.
Definition at line 112 of file tronconneuse.hpp.
void libdar::tronconneuse::write_end_of_file | ( | ) | [inline] |
in write_only mode indicate that end of file is reached
this call must be called in write mode to purge the internal cache before deleting the object (else some data may be lost) no further write call is allowed
Definition at line 101 of file tronconneuse.hpp.
References libdar::generic_file::is_terminated().