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// Copyright 2014 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code by Matt McCutchen, see the LICENSE file.
#ifndef BIGINTEGERUTILS_H
#define BIGINTEGERUTILS_H
#include "BigInteger.hh"
#include <string>
#include <ostream>
/* This file provides:
* - Convenient std::string <-> BigUnsigned/BigInteger conversion routines
* - std::ostream << operators for BigUnsigned/BigInteger */
// std::string conversion routines. Base 10 only.
std::string bigUnsignedToString(const BigUnsigned &x);
std::string bigIntegerToString(const BigInteger &x);
BigUnsigned stringToBigUnsigned(const std::string &s);
BigInteger stringToBigInteger(const std::string &s);
// Creates a BigInteger from data such as `char's; read below for details.
template <class T>
BigInteger dataToBigInteger(const T* data, BigInteger::Index length, BigInteger::Sign sign);
// Outputs x to os, obeying the flags `dec', `hex', `bin', and `showbase'.
std::ostream &operator <<(std::ostream &os, const BigUnsigned &x);
// Outputs x to os, obeying the flags `dec', `hex', `bin', and `showbase'.
// My somewhat arbitrary policy: a negative sign comes before a base indicator (like -0xFF).
std::ostream &operator <<(std::ostream &os, const BigInteger &x);
// BEGIN TEMPLATE DEFINITIONS.
/*
* Converts binary data to a BigInteger.
* Pass an array `data', its length, and the desired sign.
*
* Elements of `data' may be of any type `T' that has the following
* two properties (this includes almost all integral types):
*
* (1) `sizeof(T)' correctly gives the amount of binary data in one
* value of `T' and is a factor of `sizeof(Blk)'.
*
* (2) When a value of `T' is casted to a `Blk', the low bytes of
* the result contain the desired binary data.
*/
template <class T>
BigInteger dataToBigInteger(const T* data, BigInteger::Index length, BigInteger::Sign sign) {
// really ceiling(numBytes / sizeof(BigInteger::Blk))
unsigned int pieceSizeInBits = 8 * sizeof(T);
unsigned int piecesPerBlock = sizeof(BigInteger::Blk) / sizeof(T);
unsigned int numBlocks = (length + piecesPerBlock - 1) / piecesPerBlock;
// Allocate our block array
BigInteger::Blk *blocks = new BigInteger::Blk[numBlocks];
BigInteger::Index blockNum, pieceNum, pieceNumHere;
// Convert
for (blockNum = 0, pieceNum = 0; blockNum < numBlocks; blockNum++) {
BigInteger::Blk curBlock = 0;
for (pieceNumHere = 0; pieceNumHere < piecesPerBlock && pieceNum < length;
pieceNumHere++, pieceNum++)
curBlock |= (BigInteger::Blk(data[pieceNum]) << (pieceSizeInBits * pieceNumHere));
blocks[blockNum] = curBlock;
}
// Create the BigInteger.
BigInteger x(blocks, numBlocks, sign);
delete [] blocks;
return x;
}
#endif
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