CS计算机代考程序代写 #pragma once
#pragma once
#include
/// format.h defines the file format used by the server. Note that the format
/// changes between phase 1 and phase 2 of the assignment, and again between
/// phase 2 and phase 3.
/// In phase 1, there is only one table that needs to be persisted to file: the
/// authentication table. Furthermore, this authentication table is only
/// persisted in response to an explicit SAV command. To persist the table to a
/// file, each entry needs to be written to the file. The format of each entry
/// is as follows:
///
/// Authentication entry format:
/// – 8-byte constant AUTHAUTH
/// – 4-byte binary write of the length of the username
/// – Binary write of the bytes of the username
/// – 4-byte binary write of the length of the salt
/// – Binary write of the bytes of the salt
/// – 4-byte binary write of the length of the hashed password
/// – Binary write of the bytes of the hashed password
/// – 4-byte binary write of the length of the profile file
/// – If the profile file isn’t empty, binary write of the bytes of the profile
/// file
///
/// Note that there are no newline or other delimiters required by the format.
/// The 8-byte constant, coupled with the *binary* writes of the lengths of the
/// fields, suffice to unambiguously represent the file contents. Note that the
/// username, salt, and hashed password must each be at least one byte.
/// A unique 8-byte code to use as a prefix each time an AuthTable Entry is
/// written to disk.
const std::string AUTHENTRY = “AUTHAUTH”;
/// In phase 2, the authentication table does not change, but a key/value store
/// is added to the server. This key/value store needs to be persisted. It is
/// only persisted in response to an explicit SAV command, and it must be
/// persisted in the same consistent, indivisible operation that persists the
/// authentication table. To persist the table to a file, each entry needs to
/// be written to the file. The format of each entry is as follows:
///
/// K/V entry format:
/// – 8-byte constant KVKVKVKV
/// – 4-byte binary write of the length of the key
/// – Binary write of the bytes of the key
/// – 4-byte binary write of the length of the value
/// – Binary write of the bytes of the value
///
/// Note that the constants are always 8 bytes. This makes it much easier to
/// parse the file. This design decision is analogous to the one that resulted
/// in all commands being 3-bytes. Note, too, that keys and values never have a
/// length of zero.
///
/// The server should assume that it is possible for authentication table
/// entries and key/value table entries to be interspersed in any arbitrary
/// order. However, each entry itself should appear in the file without being
/// interleaved with other entries.
/// A unique 8-byte code to use as a prefix each time a KV pair is written to
/// disk.
const std::string KVENTRY = “KVKVKVKV”;
