| 1 | /* |
| 2 | * Matt McCutchen's Big Integer Library |
| 3 | */ |
| 4 | |
| 5 | #ifndef BIGINTEGERUTILS |
| 6 | #define BIGINTEGERUTILS |
| 7 | |
| 8 | #include "BigInteger.hh" |
| 9 | #include <string> |
| 10 | #include <iostream> |
| 11 | |
| 12 | /* |
| 13 | * This file includes: |
| 14 | * (1) `std::string <=> BigUnsigned/BigInteger' conversion routines easier than `BigUnsignedInABase' |
| 15 | * (2) << and >> operators for BigUnsigned/BigInteger, std::istream/std::ostream |
| 16 | */ |
| 17 | |
| 18 | // Conversion routines. Base 10 only. |
| 19 | std::string easyBUtoString(const BigUnsigned &x); |
| 20 | std::string easyBItoString(const BigInteger &x); |
| 21 | BigUnsigned easyStringToBU(const std::string &s); |
| 22 | BigInteger easyStringToBI(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 easyDataToBI(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 | /* |
| 36 | * ================================= |
| 37 | * BELOW THIS POINT are template definitions; above are declarations. See `NumberlikeArray.hh'. |
| 38 | */ |
| 39 | |
| 40 | /* |
| 41 | * Converts binary data to a BigInteger. |
| 42 | * Pass an array `data', its length, and the desired sign. |
| 43 | * |
| 44 | * Elements of `data' may be of any type `T' that has the following |
| 45 | * two properties (this includes almost all integral types): |
| 46 | * |
| 47 | * (1) `sizeof(T)' correctly gives the amount of binary data in one |
| 48 | * value of `T' and is a factor of `sizeof(Blk)'. |
| 49 | * |
| 50 | * (2) When a value of `T' is casted to a `Blk', the low bytes of |
| 51 | * the result contain the desired binary data. |
| 52 | */ |
| 53 | template <class T> |
| 54 | BigInteger easyDataToBI(const T* data, BigInteger::Index length, BigInteger::Sign sign) { |
| 55 | // really ceiling(numBytes / sizeof(BigInteger::Blk)) |
| 56 | unsigned int pieceSizeInBits = 8 * sizeof(T); |
| 57 | unsigned int piecesPerBlock = sizeof(BigInteger::Blk) / sizeof(T); |
| 58 | unsigned int numBlocks = (length + piecesPerBlock - 1) / piecesPerBlock; |
| 59 | |
| 60 | // Allocate our block array |
| 61 | BigInteger::Blk *blocks = new BigInteger::Blk[numBlocks]; |
| 62 | |
| 63 | BigInteger::Index blockNum, pieceNum, pieceNumHere; |
| 64 | |
| 65 | // Convert |
| 66 | for (blockNum = 0, pieceNum = 0; blockNum < numBlocks; blockNum++) { |
| 67 | BigInteger::Blk curBlock = 0; |
| 68 | for (pieceNumHere = 0; pieceNumHere < piecesPerBlock && pieceNum < length; |
| 69 | pieceNumHere++, pieceNum++) |
| 70 | curBlock |= (BigInteger::Blk(data[pieceNum]) << (pieceSizeInBits * pieceNumHere)); |
| 71 | blocks[blockNum] = curBlock; |
| 72 | } |
| 73 | |
| 74 | // Create the BigInteger. |
| 75 | BigInteger x(blocks, numBlocks, sign); |
| 76 | |
| 77 | delete blocks; |
| 78 | return x; |
| 79 | } |
| 80 | |
| 81 | #endif |