diff options
| -rw-r--r-- | source/tanya/math/mp.d | 55 |
1 files changed, 47 insertions, 8 deletions
diff --git a/source/tanya/math/mp.d b/source/tanya/math/mp.d index cd3be87..057a10d 100644 --- a/source/tanya/math/mp.d +++ b/source/tanya/math/mp.d @@ -161,6 +161,45 @@ struct Integer } /** + * Constructs the integer from a two's complement representation. + * + * Params: + * R = Range type. + * value = Range. + * allocator = Allocator. + * + * Precondition: $(D_INLINECODE allocator !is null) + */ + this(R)(R value, + shared Allocator allocator = defaultAllocator) + if (isBidirectionalRange!R && hasLength!R + && is(Unqual!(ElementType!R) == ubyte)) + { + this(Sign.positive, value, allocator); + + if (!value.empty && ((value.front & 0x80) != 0)) + { + // Negative number. + opOpAssign!"-"(exp2(countBits())); + } + } + + /// + nothrow @safe @nogc unittest + { + { + ubyte[8] range = [ 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xdd, 0xee ]; + auto integer = Integer(range[]); + assert(integer == 7383520307673030126); + } + { + ubyte[8] range = [ 0xe6, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xdd, 0xee ]; + auto integer = Integer(range[]); + assert(integer == -1839851729181745682); + } + } + + /** * Copies the integer. */ this(this) nothrow @trusted @nogc @@ -219,10 +258,10 @@ struct Integer { if (this.sign) { - const bitCount = countBits(); - auto length = bitCount + (8 - (bitCount & 0x07)); + const bc = countBits(); + auto length = bc + (8 - (bc & 0x07)); - if (((countLSBs() + 1) == bitCount) && ((bitCount & 0x07) == 0)) + if (((countLSBs() + 1) == bc) && ((bc & 0x07) == 0)) { --length; } @@ -1418,10 +1457,10 @@ struct Integer { return vector; } - const bitCount = countBits(); - const remainingBits = bitCount & 0x07; + const bc = countBits(); + const remainingBits = bc & 0x07; - vector.reserve(bitCount / 8); + vector.reserve(bc / 8); if (remainingBits == 0) { vector.insertBack(ubyte.init); @@ -1431,9 +1470,9 @@ struct Integer Integer tmp; if (this.sign) { - auto length = bitCount + (8 - remainingBits); + auto length = bc + (8 - remainingBits); - if (((countLSBs() + 1) == bitCount) && (remainingBits == 0)) + if (((countLSBs() + 1) == bc) && (remainingBits == 0)) { length -= 8; } |