/*
* Matt McCutchen's Big Integer Library
-* http://mysite.verizon.net/mccutchen/bigint/
*/
#ifndef BIGINTEGERUTILS
BigUnsigned easyStringToBU(const std::string &s);
BigInteger easyStringToBI(const std::string &s);
+// Creates a BigInteger from data such as `char's; read below for details.
+template <class T>
+BigInteger easyDataToBI(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);
// My somewhat arbitrary policy: a negative sign comes before a base indicator (like -0xFF).
std::ostream &operator <<(std::ostream &os, const BigInteger &x);
+/*
+* =================================
+* BELOW THIS POINT are template definitions; above are declarations. See `NumberlikeArray.hh'.
+*/
+
+/*
+* 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 easyDataToBI(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