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// file : libbutl/sha1.mxx -*- C++ -*-
// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#ifndef __cpp_modules
#pragma once
#endif
// C includes.
#ifndef __cpp_lib_modules
#include <string>
#include <cstddef> // size_t
#include <cstdint>
#include <cstring> // strlen()
#endif
// Other includes.
#ifdef __cpp_modules
export module butl.sha1;
#ifdef __cpp_lib_modules
import std.core;
#endif
#endif
#include <libbutl/export.hxx>
LIBBUTL_MODEXPORT namespace butl
{
// SHA1 checksum calculator.
//
// For a single chunk of data a sum can be obtained in one line, for
// example:
//
// cerr << sha1 ("123").string () << endl;
//
class LIBBUTL_SYMEXPORT sha1
{
public:
sha1 ();
// Append binary data.
//
void
append (const void*, std::size_t);
sha1 (const void* b, std::size_t n): sha1 () {append (b, n);}
// Append string.
//
// Note that the hash includes the '\0' terminator. Failed that, a call
// with an empty string will be indistinguishable from no call at all.
//
void
append (const std::string& s) {append (s.c_str (), s.size () + 1);}
void
append (const char* s) {append (s, std::strlen (s) + 1);}
explicit
sha1 (const std::string& s): sha1 () {append (s);}
explicit
sha1 (const char* s): sha1 () {append (s);}
// Extract result.
//
// It can be obtained as either a 20-byte binary digest or as a 40-
// character hex-encoded C-string.
//
using digest_type = std::uint8_t[20];
const digest_type&
binary () const;
const char*
string () const;
std::string
abbreviated_string (std::size_t n) const
{
return std::string (string (), n < 40 ? n : 40);
}
private:
struct context // Note: identical to SHA1_CTX.
{
union {
std::uint8_t b8[20];
std::uint32_t b32[5];
} h;
union {
std::uint8_t b8[8];
std::uint64_t b64[1];
} c;
union {
std::uint8_t b8[64];
std::uint32_t b32[16];
} m;
std::uint8_t count;
};
union
{
mutable context ctx_;
mutable char buf_[sizeof (context)]; // Also used to store string rep.
};
mutable digest_type bin_;
mutable bool done_;
};
}
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