Svet Ganov | e6986e1 | 2015-06-04 14:52:15 -0700 | [diff] [blame] | 1 | // Copyright 2014 PDFium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | // Original code by Matt McCutchen, see the LICENSE file. |
| 6 | |
| 7 | #ifndef BIGINTEGERUTILS_H |
| 8 | #define BIGINTEGERUTILS_H |
| 9 | |
| 10 | #include "BigInteger.hh" |
| 11 | #include <string> |
Philip P. Moltmann | ac3d58c | 2016-03-04 15:19:21 -0800 | [diff] [blame] | 12 | #include <ostream> |
Svet Ganov | e6986e1 | 2015-06-04 14:52:15 -0700 | [diff] [blame] | 13 | |
| 14 | /* This file provides: |
| 15 | * - Convenient std::string <-> BigUnsigned/BigInteger conversion routines |
| 16 | * - std::ostream << operators for BigUnsigned/BigInteger */ |
| 17 | |
| 18 | // std::string conversion routines. Base 10 only. |
| 19 | std::string bigUnsignedToString(const BigUnsigned &x); |
| 20 | std::string bigIntegerToString(const BigInteger &x); |
| 21 | BigUnsigned stringToBigUnsigned(const std::string &s); |
| 22 | BigInteger stringToBigInteger(const std::string &s); |
| 23 | |
| 24 | // Creates a BigInteger from data such as `char's; read below for details. |
| 25 | template <class T> |
| 26 | BigInteger dataToBigInteger(const T* data, BigInteger::Index length, BigInteger::Sign sign); |
| 27 | |
| 28 | // Outputs x to os, obeying the flags `dec', `hex', `bin', and `showbase'. |
| 29 | std::ostream &operator <<(std::ostream &os, const BigUnsigned &x); |
| 30 | |
| 31 | // Outputs x to os, obeying the flags `dec', `hex', `bin', and `showbase'. |
| 32 | // My somewhat arbitrary policy: a negative sign comes before a base indicator (like -0xFF). |
| 33 | std::ostream &operator <<(std::ostream &os, const BigInteger &x); |
| 34 | |
| 35 | // BEGIN TEMPLATE DEFINITIONS. |
| 36 | |
| 37 | /* |
| 38 | * Converts binary data to a BigInteger. |
| 39 | * Pass an array `data', its length, and the desired sign. |
| 40 | * |
| 41 | * Elements of `data' may be of any type `T' that has the following |
| 42 | * two properties (this includes almost all integral types): |
| 43 | * |
| 44 | * (1) `sizeof(T)' correctly gives the amount of binary data in one |
| 45 | * value of `T' and is a factor of `sizeof(Blk)'. |
| 46 | * |
| 47 | * (2) When a value of `T' is casted to a `Blk', the low bytes of |
| 48 | * the result contain the desired binary data. |
| 49 | */ |
| 50 | template <class T> |
| 51 | BigInteger dataToBigInteger(const T* data, BigInteger::Index length, BigInteger::Sign sign) { |
| 52 | // really ceiling(numBytes / sizeof(BigInteger::Blk)) |
| 53 | unsigned int pieceSizeInBits = 8 * sizeof(T); |
| 54 | unsigned int piecesPerBlock = sizeof(BigInteger::Blk) / sizeof(T); |
| 55 | unsigned int numBlocks = (length + piecesPerBlock - 1) / piecesPerBlock; |
| 56 | |
| 57 | // Allocate our block array |
| 58 | BigInteger::Blk *blocks = new BigInteger::Blk[numBlocks]; |
| 59 | |
| 60 | BigInteger::Index blockNum, pieceNum, pieceNumHere; |
| 61 | |
| 62 | // Convert |
| 63 | for (blockNum = 0, pieceNum = 0; blockNum < numBlocks; blockNum++) { |
| 64 | BigInteger::Blk curBlock = 0; |
| 65 | for (pieceNumHere = 0; pieceNumHere < piecesPerBlock && pieceNum < length; |
| 66 | pieceNumHere++, pieceNum++) |
| 67 | curBlock |= (BigInteger::Blk(data[pieceNum]) << (pieceSizeInBits * pieceNumHere)); |
| 68 | blocks[blockNum] = curBlock; |
| 69 | } |
| 70 | |
| 71 | // Create the BigInteger. |
| 72 | BigInteger x(blocks, numBlocks, sign); |
| 73 | |
| 74 | delete [] blocks; |
| 75 | return x; |
| 76 | } |
| 77 | |
| 78 | #endif |