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authorClifford Wolf <clifford@clifford.at>2013-02-27 09:32:19 +0100
committerClifford Wolf <clifford@clifford.at>2013-02-27 09:32:19 +0100
commita321a5c412090d04dfaea4b4876c4901c42cfe44 (patch)
treeb08d286e0aea76be9aab7a543df0b51e76b6ede4 /libs/bigint/BigIntegerUtils.hh
parent4f0c2862a0d7e1ca247e0a4d54301c7f8cc92fd8 (diff)
Moved stand-alone libs to libs/ directory and added libs/subcircuit
Diffstat (limited to 'libs/bigint/BigIntegerUtils.hh')
-rw-r--r--libs/bigint/BigIntegerUtils.hh72
1 files changed, 72 insertions, 0 deletions
diff --git a/libs/bigint/BigIntegerUtils.hh b/libs/bigint/BigIntegerUtils.hh
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+#ifndef BIGINTEGERUTILS_H
+#define BIGINTEGERUTILS_H
+
+#include "BigInteger.hh"
+#include <string>
+#include <iostream>
+
+/* 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