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Bit::Vector::Overload(3) User Contributed Perl Documentation Bit::Vector::Overload(3)
NAME
Bit::Vector::Overload - Overloaded operators add-on for Bit::Vector
USAGE
Note that you do not need to ""use Bit::Vector;"" in addition to this module.
Simply ""use Bit::Vector::Overload;"" INSTEAD of ""use Bit::Vector;"". You can still use all the
methods from the "Bit::Vector" module in addition to the overloaded operators and methods provided
here after that.
SYNOPSIS
Configuration
$config = Bit::Vector->Configuration();
Bit::Vector->Configuration($config);
$oldconfig = Bit::Vector->Configuration($newconfig);
String Conversion
$string = "$vector"; # depending on configuration
print "\$vector = '$vector'\n";
Emptyness
if ($vector) # if not empty (non-zero)
if (! $vector) # if empty (zero)
unless ($vector) # if empty (zero)
Complement (one's complement)
$vector2 = ~$vector1;
$vector = ~$vector;
Negation (two's complement)
$vector2 = -$vector1;
$vector = -$vector;
Norm
$norm = abs($vector); # depending on configuration
Absolute
$vector2 = abs($vector1); # depending on configuration
Concatenation
$vector3 = $vector1 . $vector2;
$vector1 .= $vector2;
$vector1 = $vector2 . $vector1;
$vector2 = $vector1 . $scalar; # depending on configuration
$vector2 = $scalar . $vector1;
$vector .= $scalar;
Duplication
$vector2 = $vector1 x $factor;
$vector x= $factor;
Shift Left
$vector2 = $vector1 << $bits;
$vector <<= $bits;
Shift Right
$vector2 = $vector1 >> $bits;
$vector >>= $bits;
Union
$vector3 = $vector1 | $vector2;
$vector1 |= $vector2;
$vector2 = $vector1 | $scalar;
$vector |= $scalar;
$vector3 = $vector1 + $vector2; # depending on configuration
$vector1 += $vector2;
$vector2 = $vector1 + $scalar;
$vector += $scalar;
Intersection
$vector3 = $vector1 & $vector2;
$vector1 &= $vector2;
$vector2 = $vector1 & $scalar;
$vector &= $scalar;
$vector3 = $vector1 * $vector2; # depending on configuration
$vector1 *= $vector2;
$vector2 = $vector1 * $scalar;
$vector *= $scalar;
ExclusiveOr
$vector3 = $vector1 ^ $vector2;
$vector1 ^= $vector2;
$vector2 = $vector1 ^ $scalar;
$vector ^= $scalar;
Set Difference
$vector3 = $vector1 - $vector2; # depending on configuration
$vector1 -= $vector2;
$vector1 = $vector2 - $vector1;
$vector2 = $vector1 - $scalar;
$vector2 = $scalar - $vector1;
$vector -= $scalar;
Addition
$vector3 = $vector1 + $vector2; # depending on configuration
$vector1 += $vector2;
$vector2 = $vector1 + $scalar;
$vector += $scalar;
Subtraction
$vector3 = $vector1 - $vector2; # depending on configuration
$vector1 -= $vector2;
$vector1 = $vector2 - $vector1;
$vector2 = $vector1 - $scalar;
$vector2 = $scalar - $vector1;
$vector -= $scalar;
Multiplication
$vector3 = $vector1 * $vector2; # depending on configuration
$vector1 *= $vector2;
$vector2 = $vector1 * $scalar;
$vector *= $scalar;
Division
$vector3 = $vector1 / $vector2;
$vector1 /= $vector2;
$vector1 = $vector2 / $vector1;
$vector2 = $vector1 / $scalar;
$vector2 = $scalar / $vector1;
$vector /= $scalar;
Modulo
$vector3 = $vector1 % $vector2;
$vector1 %= $vector2;
$vector1 = $vector2 % $vector1;
$vector2 = $vector1 % $scalar;
$vector2 = $scalar % $vector1;
$vector %= $scalar;
Exponentiation
$vector3 = $vector1 ** $vector2;
$vector1 **= $vector2;
$vector2 = $vector1 ** $scalar;
$vector2 = $scalar ** $vector1;
$vector **= $scalar;
Increment
++$vector;
$vector++;
Decrement
--$vector;
$vector--;
Lexical Comparison (unsigned)
$cmp = $vector1 cmp $vector2;
if ($vector1 lt $vector2)
if ($vector1 le $vector2)
if ($vector1 gt $vector2)
if ($vector1 ge $vector2)
$cmp = $vector cmp $scalar;
if ($vector lt $scalar)
if ($vector le $scalar)
if ($vector gt $scalar)
if ($vector ge $scalar)
Comparison (signed)
$cmp = $vector1 <=> $vector2;
if ($vector1 < $vector2) # depending on configuration
if ($vector1 <= $vector2)
if ($vector1 > $vector2)
if ($vector1 >= $vector2)
$cmp = $vector <=> $scalar;
if ($vector < $scalar) # depending on configuration
if ($vector <= $scalar)
if ($vector > $scalar)
if ($vector >= $scalar)
Equality
if ($vector1 eq $vector2)
if ($vector1 ne $vector2)
if ($vector eq $scalar)
if ($vector ne $scalar)
if ($vector1 == $vector2)
if ($vector1 != $vector2)
if ($vector == $scalar)
if ($vector != $scalar)
Subset Relationship
if ($vector1 <= $vector2) # depending on configuration
True Subset Relationship
if ($vector1 < $vector2) # depending on configuration
Superset Relationship
if ($vector1 >= $vector2) # depending on configuration
True Superset Relationship
if ($vector1 > $vector2) # depending on configuration
IMPORTANT NOTES
• Boolean values
Boolean values in this module are always a numeric zero ("0") for "false" and a numeric one ("1")
for "true".
• Negative numbers
Numeric factors (as needed for the ""<<"", "">>"" and ""x"" operators) and bit numbers are always
regarded as being UNSIGNED.
As a consequence, whenever you pass a negative number for such a factor or bit number, it will be
treated as a (usually very large) positive number due to its internal two's complement binary
representation, usually resulting in malfunctions or an "index out of range" error message and
program abortion.
Note that this does not apply to "big integer" decimal numbers, which are (usually) passed as
strings, and which may of course be negative (see also the section "Big integers" a little further
below).
• Overloaded operators configuration
Note that the behaviour of certain overloaded operators can be changed in various ways by means of
the ""Configuration()"" method (for more details, see the description of this method further
below).
For instance, scalars (i.e., numbers and strings) provided as operands to overloaded operators are
automatically converted to bit vectors, internally.
These scalars are thereby automatically assumed to be indices or to be in hexadecimal, binary,
decimal or enumeration format, depending on the configuration.
Similarly, when converting bit vectors to strings using double quotes (""), the output format will
also depend on the previously chosen configuration.
Finally, some overloaded operators may have different semantics depending on the proper
configuration; for instance, the operator "+" can be the "union" operator from set theory or the
arithmetic "add" operator.
In all cases (input, output and operator semantics), the defaults have been chosen in such a way so
that the behaviour of the module is backward compatible with previous versions.
• "Big integers"
As long as "big integers" (for "big integer" arithmetic) are small enough so that Perl doesn't need
scientific notation (exponents) to be able to represent them internally, you can provide these "big
integer" constants to the overloaded operators of this module (or to the method ""from_Dec()"") in
numeric form (i.e., either as a numeric constant or expression or as a Perl variable containing a
numeric value).
Note that you will get an error message (resulting in program abortion) if your "big integer"
numbers exceed that limit.
Because this limit is machine-dependent and not obvious to find out, it is strongly recommended
that you enclose ALL your "big integer" constants in your programs in (double or single) quotes.
Examples:
$vector /= 10; # ok because number is small
$vector /= -10; # ok for same reason
$vector /= "10"; # always correct
$vector += "1152921504606846976"; # quotes probably required here
All examples assume
Bit::Vector->Configuration("input=decimal");
having been set beforehand.
Note also that this module does not support scientific notation (exponents) for "big integer"
decimal numbers because you can always make the bit vector large enough for the whole number to fit
without loss of precision (as it would occur if scientific notation were used).
Finally, note that the only characters allowed in "big integer" constant strings are the digits
0..9 and an optional leading sign (""+"" or ""-"").
All other characters produce a syntax error.
• Valid operands for overloaded operators
All overloaded operators expect at least one bit vector operand, in order for the operator to
"know" that not the usual operation is to be carried out, but rather the overloaded variant.
This is especially true for all unary operators:
"$vector"
if ($vector)
if (!$vector)
~$vector
-$vector
abs($vector)
++$vector
$vector++
--$vector
$vector--For $vector-For
For obvious reasons the left operand (the "lvalue") of all assignment operators is also required to
be a bit vector:
.=
x=
<<=
>>=
|=
&=
^=
+=
-=
*=
/=
%=
**=
In the case of three special operators, namely ""<<"", "">>"" and ""x"", as well as their related
assignment variants, ""<<="", "">>="" and ""x="", the left operand is ALWAYS a bit vector and the
right operand is ALWAYS a number (which is the factor indicating how many times the operator is to
be applied).
In all truly binary operators, i.e.,
.
|
&
^
+
-* +*
*
/
%
**
<=> cmp
== eq
!= ne
< lt
<= le
> gt
>= ge
one of either operands may be replaced by a Perl scalar, i.e., a number or a string, either as a
Perl constant, a Perl expression or a Perl variable yielding a number or a string.
The same applies to the right side operand (the "rvalue") of the remaining assignment operators,
i.e.,
.=
|=
&=
^=
+=
-=
*=
/=
%=
**=
Note that this Perl scalar should be of the correct type, i.e., numeric or string, for the chosen
configuration, because otherwise a warning message will occur if your program runs under the ""-w""
switch of Perl.
The acceptable scalar types for each possible configuration are the following:
input = bit indices (default) : numeric
input = hexadecimal : string
input = binary : string
input = decimal : string (in general)
input = decimal : numeric (if small enough)
input = enumeration : string
NOTE ALSO THAT THESE SCALAR OPERANDS ARE CONVERTED TO BIT VECTORS OF THE SAME SIZE AS THE BIT
VECTOR WHICH IS THE OTHER OPERAND.
The only exception from this rule is the concatenation operator (""."") and its assignment variant
("".=""):
If one of the two operands of the concatenation operator (""."") is not a bit vector object but a
Perl scalar, the contents of the remaining bit vector operand are converted into a string (the
format of which depends on the configuration set with the ""Configuration()"" method), which is
then concatenated in the proper order (i.e., as indicated by the order of the two operands) with
the Perl scalar (in other words, a string is returned in such a case instead of a bit vector
object!).
If the right side operand (the "rvalue") of the assignment variant ("".="") of the concatenation
operator is a Perl scalar, it is converted internally to a bit vector of the same size as the left
side operand provided that the configuration states that scalars are to be regarded as indices,
decimal strings or enumerations.
If the configuration states that scalars are to be regarded as hexadecimal or boolean strings,
however, these strings are converted to bit vectors of a size matching the length of the input
string, i.e., four times the length for hexadecimal strings (because each hexadecimal digit is
worth 4 bits) and once the length for binary strings.
If a decimal number ("big integer") is too large to be stored in a bit vector of the given size, a
"numeric overflow error" occurs.
If a bit index is out of range for the given bit vector, an "index out of range" error occurs.
If a scalar operand cannot be converted successfully due to invalid syntax, a fatal "input string
syntax error" is issued.
If the two operands of the operator ""<<"", "">>"" or ""x"" are reversed, a fatal "reversed
operands error" occurs.
If an operand is neither a bit vector nor a scalar, then a fatal "illegal operand type error"
occurs.
• Bit order
Note that bit vectors are stored least order bit and least order word first internally.
I.e., bit #0 of any given bit vector corresponds to bit #0 of word #0 in the array of machine words
representing the bit vector.
(Where word #0 comes first in memory, i.e., it is stored at the least memory address in the
allocated block of memory holding the given bit vector.)
Note however that machine words can be stored least order byte first or last, depending on your
system's implementation.
Note further that whenever bit vectors are converted to and from (binary or hexadecimal) strings,
the RIGHTMOST bit is always the LEAST SIGNIFICANT one, and the LEFTMOST bit is always the MOST
SIGNIFICANT bit.
This is because in our western culture, numbers are always represented in this way (least
significant to most significant digits go from right to left).
Of course this requires an internal reversion of order, which the corresponding conversion methods
perform automatically (without any additional overhead, it's just a matter of starting the internal
loop at the bottom or the top end).
• Matching sizes
In general, for methods involving several bit vectors at the same time, all bit vector arguments
must have identical sizes (number of bits), or a fatal "size mismatch" error will occur.
Exceptions from this rule are the methods ""Concat()"", ""Concat_List()"", ""Copy()"",
""Interval_Copy()"" and ""Interval_Substitute()"", where no conditions at all are imposed on the
size of their bit vector arguments.
In method ""Multiply()"", all three bit vector arguments must in principle obey the rule of
matching sizes, but the bit vector in which the result of the multiplication is to be stored may be
larger than the two bit vector arguments containing the factors for the multiplication.
In method ""Power()"", the bit vector for the result must be the same size or greater than the base
of the exponentiation term. The exponent can be any size.
The same applies to the corresponding overloaded operators.
• Index ranges
All indices for any given bits must lie between "0" and ""$vector->Size()-1"", or a fatal "index
out of range" error will occur.
DESCRIPTION
• "$config = Bit::Vector->Configuration();"
• "Bit::Vector->Configuration($config);"
• "$oldconfig = Bit::Vector->Configuration($newconfig);"
This method serves to alter the semantics (i.e., behaviour) of certain overloaded operators (which
are all implemented in Perl, by the way).
It does not have any effect whatsoever on anything else. In particular, it does not affect the
methods implemented in C.
The method accepts an (optional) string as input in which certain keywords are expected, which
influence some or almost all of the overloaded operators in several possible ways.
The method always returns a string (which you do not need to take care of, i.e., to store, in case
you aren't interested in keeping it) which is a complete representation of the current
configuration (i.e., BEFORE any modifications are applied) and which can be fed back to this method
later in order to restore the previous configuration.
There are three aspects of the way certain overloaded operators behave which can be controlled with
this method:
+ the way scalar operands (replacing one of the two
bit vector object operands) are automatically
converted internally into a bit vector object of
their own,
+ the operation certain overloaded operators perform,
i.e., an operation with sets or an arithmetic
operation,
+ the format to which bit vectors are converted
automatically when they are enclosed in double
quotes.
The input string may contain any number of assignments, each of which controls one of these three
aspects.
Each assignment has the form ""<which>=<value>"".
""<which>"" and ""<value>"" thereby consist of letters ("[a-zA-Z]") and white space.
Multiple assignments have to be separated by one or more comma (","), semi-colon (";"), colon
(":"), vertical bar ("|"), slash ("/"), newline ("\n"), ampersand ("&"), plus ("+") or dash ("-").
Empty lines or statements (only white space) are allowed but will be ignored.
""<which>"" has to contain one or more keywords from one of three groups, each group representing
one of the three aspects that the ""Configuration()"" method controls:
+ "^scalar", "^input", "^in$"
+ "^operator", "^semantic", "^ops$"
+ "^string", "^output", "^out$"
The character "^" thereby denotes the beginning of a word, and "$" denotes the end. Case is ignored
(!).
Using these keywords, you can build any phrase you like to select one of the three aspects (see
also examples given below).
The only condition is that no other keyword from any of the other two groups may match - otherwise
a syntax error will occur (i.e., ambiguities are forbidden). A syntax error also occurs if none of
the keywords matches.
This same principle applies to ""<value>"":
Depending on which aspect you specified for ""<which>"", there are different groups of keywords
that determine the value the selected aspect will be set to:
+ "<which>" = "^scalar", "^input", "^in$":
"<value>" =
* "^bit$", "^index", "^indice"
* "^hex"
* "^bin"
* "^dec"
* "^enum"
+ "<which>" = "^operator", "^semantic", "^ops$":
"<value>" =
* "^set$"
* "^arithmetic"
+ "<which>" = "^string", "^output", "^out$":
"<value>" =
* "^hex"
* "^bin"
* "^dec"
* "^enum"
Examples:
"Any scalar input I provide should be considered to be = a bit index"
"I want to have operator semantics suitable for = arithmetics"
"Any bit vector in double quotes is to be output as = an enumeration"
SCALAR INPUT:
In the case of scalar input, ""^bit$"", ""^index"", or ""^indice"" all cause scalar input to be
considered to represent a bit index, i.e., ""$vector ^= 5;"" will flip bit #5 in the given bit
vector (this is essentially the same as ""$vector->bit_flip(5);"").
Note that "bit indices" is the default setting for "scalar input".
The keyword ""^hex"" will cause scalar input to be considered as being in hexadecimal, i.e.,
""$vector ^= 5;"" will flip bit #0 and bit #2 (because hexadecimal "5" is binary "0101").
(Note though that hexadecimal input should always be enclosed in quotes, otherwise it will be
interpreted as a decimal number by Perl! The example relies on the fact that hexadecimal "0-9" and
decimal "0-9" are the same.)
The keyword ""^bin"" will cause scalar input to be considered as being in binary format. All
characters except "0" and "1" are forbidden in this case (i.e., produce a syntax error).
""$vector ^= '0101';"", for instance, will flip bit #0 and bit #2.
The keyword ""^dec"" causes scalar input to be considered as integers in decimal format, i.e.,
""$vector ^= 5;"" will flip bit #0 and bit #2 (because decimal "5" is binary "0101").
(Note though that all decimal input should be enclosed in quotes, because for large numbers, Perl
will use scientific notation internally for representing them, which produces a syntax error
because scientific notation is neither supported by this module nor needed.)
Finally, the keyword ""^enum"" causes scalar input to be considered as being a list ("enumeration")
of indices and ranges of (contiguous) indices, i.e., ""$vector |= '2,3,5,7-13,17-23';"" will cause
bits #2, #3, #5, #7 through #13 and #17 through #23 to be set.
OPERATOR SEMANTICS:
Several overloaded operators can have two distinct functions depending on this setting.
The affected operators are: ""+"", ""-"", ""*"", ""<"", ""<="", "">"" and "">="".
With the default setting, "set operations", these operators perform:
+ set union ( set1 u set2 )
- set difference ( set1 \ set2 )
* set intersection ( set1 n set2 )
< true subset relationship ( set1 < set2 )
<= subset relationship ( set1 <= set2 )
> true superset relationship ( set1 > set2 )
>= superset relationship ( set1 >= set2 )
With the alternative setting, "arithmetic operations", these operators perform:
+ addition ( num1 + num2 )
- subtraction ( num1 - num2 )
* multiplication ( num1 * num2 )
< "less than" comparison ( num1 < num2 )
<= "less than or equal" comparison ( num1 <= num2 )
> "greater than" comparison ( num1 > num2 )
>= "greater than or equal" comparison ( num1 >= num2 )
Note that these latter comparison operators (""<"", ""<="", "">"" and "">="") regard their operands
as being SIGNED.
To perform comparisons with UNSIGNED operands, use the operators ""lt"", ""le"", ""gt"" and ""ge""
instead (in contrast to the operators above, these operators are NOT affected by the "operator
semantics" setting).
STRING OUTPUT:
There are four methods which convert the contents of a given bit vector into a string:
""to_Hex()"", ""to_Bin()"", ""to_Dec()"" and ""to_Enum()"" (not counting ""Block_Read()"", since
this method does not return a human-readable string).
(For conversion to octal, see the description of the method ""Chunk_List_Read()"".)
Therefore, there are four possible formats into which a bit vector can be converted when it is
enclosed in double quotes, for example:
print "\$vector = '$vector'\n";
$string = "$vector";
Hence you can set "string output" to four different values: To "hex" for hexadecimal format (which
is the default), to "bin" for binary format, to "dec" for conversion to decimal numbers and to
"enum" for conversion to enumerations (".newsrc" style sets).
BEWARE that the conversion to decimal numbers is inherently slow; it can easily take up several
seconds for a single large bit vector!
Therefore you should store the decimal strings returned to you rather than converting a given bit
vector again.
EXAMPLES:
The default setting as returned by the method ""Configuration()"" is:
Scalar Input = Bit Index
Operator Semantics = Set Operators
String Output = Hexadecimal
Performing a statement such as:
Bit::Vector->Configuration("in=bin,ops=arithmetic,out=bin");
print Bit::Vector->Configuration(), "\n";
yields the following output:
Scalar Input = Binary
Operator Semantics = Arithmetic Operators
String Output = Binary
Note that you can always feed this output back into the ""Configuration()"" method to restore that
setting later.
This also means that you can enter the same given setting with almost any degree of verbosity you
like (as long as the required keywords appear and no ambiguities arise).
Note further that any aspect you do not specify is not changed, i.e., the statement
Bit::Vector->Configuration("operators = arithmetic");
leaves all other aspects unchanged.
• "$vector"
Remember that variables enclosed in double quotes are always interpolated in Perl.
Whenever a Perl variable containing the reference of a "Bit::Vector" object is enclosed in double
quotes (either alone or together with other text and/or variables), the contents of the
corresponding bit vector are converted into a printable string.
Since there are several conversion methods available in this module (see the description of the
methods ""to_Hex()"", ""to_Bin()"", ""to_Dec()"" and ""to_Enum()""), it is of course desirable to
be able to choose which of these methods should be applied in this case.
This can actually be done by changing the configuration of this module using the method
""Configure()"" (see the previous chapter, immediately above).
The default is conversion to hexadecimal.
• "if ($vector)"
It is possible to use a Perl variable containing the reference of a "Bit::Vector" object as a
boolean expression.
The condition above is true if the corresponding bit vector contains at least one set bit, and it
is false if ALL bits of the corresponding bit vector are cleared.
• "if (!$vector)"
Since it is possible to use a Perl variable containing the reference of a "Bit::Vector" object as a
boolean expression, you can of course also negate this boolean expression.
The condition above is true if ALL bits of the corresponding bit vector are cleared, and it is
false if the corresponding bit vector contains at least one set bit.
Note that this is NOT the same as using the method ""is_full()"", which returns true if ALL bits of
the corresponding bit vector are SET.
• "~$vector"
This term returns a new bit vector object which is the one's complement of the given bit vector.
This is equivalent to inverting all bits.
• "-$vector" (unary minus)
This term returns a new bit vector object which is the two's complement of the given bit vector.
This is equivalent to inverting all bits and incrementing the result by one.
(This is the same as changing the sign of a number in two's complement binary representation.)
• "abs($vector)"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this term either returns the number of set bits in the given bit vector (this is the same
as calculating the number of elements which are contained in the given set) - which is the default
behaviour, or it returns a new bit vector object which contains the absolute value of the number
stored in the given bit vector.
• "$vector1 . $vector2"
This term usually returns a new bit vector object which is the result of the concatenation of the
two bit vector operands.
The left operand becomes the most significant, and the right operand becomes the least significant
part of the new bit vector object.
If one of the two operands is not a bit vector object but a Perl scalar, however, the contents of
the remaining bit vector operand are converted into a string (the format of which depends on the
configuration set with the ""Configuration()"" method), which is then concatenated in the proper
order (i.e., as indicated by the order of the two operands) with the Perl scalar.
In other words, a string is returned in such a case instead of a bit vector object!
• "$vector x $factor"
This term returns a new bit vector object which is the concatenation of as many copies of the given
bit vector operand (the left operand) as the factor (the right operand) specifies.
If the factor is zero, a bit vector object with a length of zero bits is returned.
If the factor is one, just a new copy of the given bit vector is returned.
Note that a fatal "reversed operands error" occurs if the two operands are swapped.
• "$vector << $bits"
This term returns a new bit vector object which is a copy of the given bit vector (the left
operand), which is then shifted left (towards the most significant bit) by as many places as the
right operand, "$bits", specifies.
This means that the "$bits" most significant bits are lost, all other bits move up by "$bits"
positions, and the "$bits" least significant bits that have been left unoccupied by this shift are
all set to zero.
If "$bits" is greater than the number of bits of the given bit vector, this term returns an empty
bit vector (i.e., with all bits cleared) of the same size as the given bit vector.
Note that a fatal "reversed operands error" occurs if the two operands are swapped.
• "$vector >> $bits"
This term returns a new bit vector object which is a copy of the given bit vector (the left
operand), which is then shifted right (towards the least significant bit) by as many places as the
right operand, "$bits", specifies.
This means that the "$bits" least significant bits are lost, all other bits move down by "$bits"
positions, and the "$bits" most significant bits that have been left unoccupied by this shift are
all set to zero.
If "$bits" is greater than the number of bits of the given bit vector, this term returns an empty
bit vector (i.e., with all bits cleared) of the same size as the given bit vector.
Note that a fatal "reversed operands error" occurs if the two operands are swapped.
• "$vector1 | $vector2"
This term returns a new bit vector object which is the result of a bitwise OR operation between the
two bit vector operands.
This is the same as calculating the union of two sets.
• "$vector1 & $vector2"
This term returns a new bit vector object which is the result of a bitwise AND operation between
the two bit vector operands.
This is the same as calculating the intersection of two sets.
• "$vector1 ^ $vector2"
This term returns a new bit vector object which is the result of a bitwise XOR (exclusive-or)
operation between the two bit vector operands.
This is the same as calculating the symmetric difference of two sets.
• "$vector1 + $vector2"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this term either returns a new bit vector object which is the result of a bitwise OR
operation between the two bit vector operands (this is the same as calculating the union of two
sets) - which is the default behaviour, or it returns a new bit vector object which contains the
sum of the two numbers stored in the two bit vector operands.
• "$vector1 - $vector2"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this term either returns a new bit vector object which is the set difference of the two
sets represented in the two bit vector operands - which is the default behaviour, or it returns a
new bit vector object which contains the difference of the two numbers stored in the two bit vector
operands.
• "$vector1 * $vector2"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this term either returns a new bit vector object which is the result of a bitwise AND
operation between the two bit vector operands (this is the same as calculating the intersection of
two sets) - which is the default behaviour, or it returns a new bit vector object which contains
the product of the two numbers stored in the two bit vector operands.
• "$vector1 / $vector2"
This term returns a new bit vector object containing the result of the division of the two numbers
stored in the two bit vector operands.
• "$vector1 % $vector2"
This term returns a new bit vector object containing the remainder of the division of the two
numbers stored in the two bit vector operands.
• "$vector1 ** $vector2"
This term returns a new bit vector object containing the result of the exponentiation of the left
bit vector elevated to the right bit vector's power.
• "$vector1 .= $vector2;"
This statement "appends" the right bit vector operand (the "rvalue") to the left one (the
"lvalue").
The former contents of the left operand become the most significant part of the resulting bit
vector, and the right operand becomes the least significant part.
Since bit vectors are stored in "least order bit first" order, this actually requires the left
operand to be shifted "up" by the length of the right operand, which is then copied to the now
freed least significant part of the left operand.
If the right operand is a Perl scalar, it is first converted to a bit vector of the same size as
the left operand, provided that the configuration states that scalars are to be regarded as
indices, decimal strings or enumerations.
If the configuration states that scalars are to be regarded as hexadecimal or boolean strings,
however, these strings are converted to bit vectors of a size matching the length of the input
string, i.e., four times the length for hexadecimal strings (because each hexadecimal digit is
worth 4 bits) and once the length for binary strings.
• "$vector x= $factor;"
This statement replaces the given bit vector by a concatenation of as many copies of the original
contents of the given bit vector as the factor (the right operand) specifies.
If the factor is zero, the given bit vector is resized to a length of zero bits.
If the factor is one, the given bit vector is not changed at all.
• "$vector <<= $bits;"
This statement moves the contents of the given bit vector left by "$bits" positions (towards the
most significant bit).
This means that the "$bits" most significant bits are lost, all other bits move up by "$bits"
positions, and the "$bits" least significant bits that have been left unoccupied by this shift are
all set to zero.
If "$bits" is greater than the number of bits of the given bit vector, the given bit vector is
erased completely (i.e., all bits are cleared).
• "$vector >>= $bits;"
This statement moves the contents of the given bit vector right by "$bits" positions (towards the
least significant bit).
This means that the "$bits" least significant bits are lost, all other bits move down by "$bits"
positions, and the "$bits" most significant bits that have been left unoccupied by this shift are
all set to zero.
If "$bits" is greater than the number of bits of the given bit vector, the given bit vector is
erased completely (i.e., all bits are cleared).
• "$vector1 |= $vector2;"
This statement performs a bitwise OR operation between the two bit vector operands and stores the
result in the left operand.
This is the same as calculating the union of two sets.
• "$vector1 &= $vector2;"
This statement performs a bitwise AND operation between the two bit vector operands and stores the
result in the left operand.
This is the same as calculating the intersection of two sets.
• "$vector1 ^= $vector2;"
This statement performs a bitwise XOR (exclusive-or) operation between the two bit vector operands
and stores the result in the left operand.
This is the same as calculating the symmetric difference of two sets.
• "$vector1 += $vector2;"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this statement either performs a bitwise OR operation between the two bit vector operands
(this is the same as calculating the union of two sets) - which is the default behaviour, or it
calculates the sum of the two numbers stored in the two bit vector operands.
The result of this operation is stored in the left operand.
• "$vector1 -= $vector2;"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this statement either calculates the set difference of the two sets represented in the
two bit vector operands - which is the default behaviour, or it calculates the difference of the
two numbers stored in the two bit vector operands.
The result of this operation is stored in the left operand.
• "$vector1 *= $vector2;"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this statement either performs a bitwise AND operation between the two bit vector
operands (this is the same as calculating the intersection of two sets) - which is the default
behaviour, or it calculates the product of the two numbers stored in the two bit vector operands.
The result of this operation is stored in the left operand.
• "$vector1 /= $vector2;"
This statement puts the result of the division of the two numbers stored in the two bit vector
operands into the left operand.
• "$vector1 %= $vector2;"
This statement puts the remainder of the division of the two numbers stored in the two bit vector
operands into the left operand.
• "$vector1 **= $vector2;"
This statement puts the result of the exponentiation of the left operand elevated to the right
operand's power into the left operand.
• "++$vector", "$vector++"
This operator performs pre- and post-incrementation of the given bit vector.
The value returned by this term is a reference of the given bit vector object (after or before the
incrementation, respectively).
• "--$vector", "$vector--"
This operator performs pre- and post-decrementation of the given bit vector.
The value returned by this term is a reference of the given bit vector object (after or before the
decrementation, respectively).
• "($vector1 cmp $vector2)"
This term returns ""-1"" if "$vector1" is less than "$vector2", "0" if "$vector1" and "$vector2"
are the same, and "1" if "$vector1" is greater than "$vector2".
This comparison assumes UNSIGNED bit vectors.
• "($vector1 eq $vector2)"
This term returns true ("1") if the contents of the two bit vector operands are the same and false
("0") otherwise.
• "($vector1 ne $vector2)"
This term returns true ("1") if the two bit vector operands differ and false ("0") otherwise.
• "($vector1 lt $vector2)"
This term returns true ("1") if "$vector1" is less than "$vector2", and false ("0") otherwise.
This comparison assumes UNSIGNED bit vectors.
• "($vector1 le $vector2)"
This term returns true ("1") if "$vector1" is less than or equal to "$vector2", and false ("0")
otherwise.
This comparison assumes UNSIGNED bit vectors.
• "($vector1 gt $vector2)"
This term returns true ("1") if "$vector1" is greater than "$vector2", and false ("0") otherwise.
This comparison assumes UNSIGNED bit vectors.
• "($vector1 ge $vector2)"
This term returns true ("1") if "$vector1" is greater than or equal to "$vector2", and false ("0")
otherwise.
This comparison assumes UNSIGNED bit vectors.
• "($vector1 <=> $vector2)"
This term returns ""-1"" if "$vector1" is less than "$vector2", "0" if "$vector1" and "$vector2"
are the same, and "1" if "$vector1" is greater than "$vector2".
This comparison assumes SIGNED bit vectors.
• "($vector1 == $vector2)"
This term returns true ("1") if the contents of the two bit vector operands are the same and false
("0") otherwise.
• "($vector1 != $vector2)"
This term returns true ("1") if the two bit vector operands differ and false ("0") otherwise.
• "($vector1 < $vector2)"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this term either returns true ("1") if "$vector1" is a true subset of "$vector2" (and
false ("0") otherwise) - which is the default behaviour, or it returns true ("1") if "$vector1" is
less than "$vector2" (and false ("0") otherwise).
The latter comparison assumes SIGNED bit vectors.
• "($vector1 <= $vector2)"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this term either returns true ("1") if "$vector1" is a subset of "$vector2" (and false
("0") otherwise) - which is the default behaviour, or it returns true ("1") if "$vector1" is less
than or equal to "$vector2" (and false ("0") otherwise).
The latter comparison assumes SIGNED bit vectors.
• "($vector1 > $vector2)"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this term either returns true ("1") if "$vector1" is a true superset of "$vector2" (and
false ("0") otherwise) - which is the default behaviour, or it returns true ("1") if "$vector1" is
greater than "$vector2" (and false ("0") otherwise).
The latter comparison assumes SIGNED bit vectors.
• "($vector1 >= $vector2)"
Depending on the configuration (see the description of the method ""Configuration()"" for more
details), this term either returns true ("1") if "$vector1" is a superset of "$vector2" (and false
("0") otherwise) - which is the default behaviour, or it returns true ("1") if "$vector1" is
greater than or equal to "$vector2" (and false ("0") otherwise).
The latter comparison assumes SIGNED bit vectors.
SEE ALSO
Bit::Vector(3), Bit::Vector::String(3).
VERSION
This man page documents "Bit::Vector::Overload" version 7.2.
AUTHOR
Steffen Beyer
mailto:STBEY@cpan.org
http://www.engelschall.com/u/sb/download/
COPYRIGHT
Copyright (c) 2000 - 2012 by Steffen Beyer. All rights reserved.
LICENSE
This package is free software; you can redistribute it and/or modify it under the same terms as Perl
itself, i.e., under the terms of the "Artistic License" or the "GNU General Public License".
The C library at the core of this Perl module can additionally be redistributed and/or modified under
the terms of the "GNU Library General Public License".
Please refer to the files "Artistic.txt", "GNU_GPL.txt" and "GNU_LGPL.txt" in this distribution for
details!
DISCLAIMER
This package is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the "GNU General Public License" for more details.
perl v5.16.2 2012-05-17 Bit::Vector::Overload(3)
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