Bitwise functions
You can use the following bitwise functions to manipulate fields within searches at the bit level.
 bit_and(<values>)
 bit_or(<values>)
 bit_not(<value>, <bitmask>)
 bit_xor(<values>)
 bit_shift_left(<value>, <shift_offset>)
 bit_shift_right(<value>, <shift_offset>)
These functions add bitwise functionality directly to the Splunk Search Processing Language (SPL), so you can perform operations such as capture a flag or apply masks on values without having to use Python workarounds.
Only nonnegative integers in the range of 0 to 2^{53} 1 are accepted as input to bitwise functions. This means that numbers that are negative or greater than 53 bits return null.
To convert a string representation of a binary number to a decimal number, see tonumber(NUMSTR,BASE). To convert a number to a string version of its binary representation, see tostring(X,Y).
bit_and(<values>)
Description
This function takes two or more nonnegative integers as arguments and sequentially performs logical bitwise AND operations on them. Each argument must be in the range of 0 to 2^{53} 1.
Usage
This function takes an arbitrary number of commaseparated arguments and returns the result of a logical AND operation on each pair of corresponding bits. For example, the result of the following search is 8
.
 makeresults  eval result = bit_and(12, 9)
This is because the result of the bitwise AND operation is 1000, which is the number 8. See the following table for more information about the sequence of operations in this bitwise function.
Operation  Binary string  Result 

12  1100  
9  1001  
bit_and(12, 9)  1000  8 
bit_or(<values>)
Description
This function takes two or more nonnegative integers as arguments and sequentially performs bitwise OR operations on them. Each argument must be in the range of 0 to 2^{53} 1.
Usage
This function takes an arbitrary number of commaseparated arguments and returns the result of a logical OR operation on each pair of corresponding bits. For example, the result of the following search is 6
.
 makeresults  eval result = bit_or(4, 2)
This is because the result of the bitwise OR operation is 0110, which is the number 6. See the following table for more information about the sequence of operations in this bitwise function.
Operation  Binary string  Result 

4  0100  
2  0010  
bit_or(4, 2)  0110  6 
bit_not(<value>, <bitmask>)
Description
This function takes a nonnegative integer as an argument and inverts every bit in the binary representation of that number. This function also takes an optional second argument with a default value of 2^{53} 1 that acts as a bitmask that is used in an AND operation with the result of the first operation. You can think of the bitmask as the value up to which you want to print the result.
Both arguments must be in the range of 0 to 2^{53} 1 or the operation returns null.
Usage
You might want to use an optional integer bitmask as the second argument in a bit_not
function to limit the number of leading 1s in the result. The bitmask truncates the result by performing a silent bitwise AND on the result of a bitwise NOT operation. The number of bits specified as the bitmask indicates the number of bits you want to see in the results. For example, if the bitmask argument is "1111"
, the first four bits of the binary results are displayed. Consider the following search, which specifies a fourbit bitmask:
 makeresults  eval long_result = bit_not(9), short_result = bit_not(9, tonumber("1111", 2))  eval long_binary = tostring(long_result, "binary"), short_binary = tostring(short_result, "binary")
The results look something like this:
_time  long_binary  long_result  short_binary  short_result 

20220905 11:12:53  11111111111111111111111111111111111111111111111110110  9007199254740982  110  6 
The short_binary
result is 110
instead of a long string of bits like the long_binary
results. You might wonder why the result is only three bits, and not four bits, since you specified "1111"
in the bitmask. The binary result is actually 0110
, but the leading 0 is not displayed.
You can take a closer look at what is happening in the sequence of bitwise operations using the following table as a guide. First, the bitmask is set to the bitwise NOT of 0, by default. Then, the result of bit_not(9)
is "bitwise ANDed" with 15, which is the bitmask resulting from tonumber("1111", 2)
. The result of bit_not(9,15)
is 110
in binary and 6
in decimal.
Operation  Binary string  Result 

0  00000 00000000 00000000 00000000 00000000 00000000 00000000


bit_not(0)  11111 11111111 11111111 11111111 11111111 11111111 11111111


9  00000 00000000 00000000 00000000 00000000 00000000 00001001


bit_not(9)  11111 11111111 11111111 11111111 11111111 11111111 11110110


15  00000 00000000 00000000 00000000 00000000 00000000 00001111


bit_not(9, 15)  00000 00000000 00000000 00000000 00000000 00000000 00000110

110 in binary
6 in decimal 
bit_xor(<values>)
Description
This function takes two or more nonnegative integers as arguments and sequentially performs bitwise XOR operations on each of the given arguments. Each argument must be in the range of 0 to 2^{53} 1.
Usage
This function takes an arbitrary number of commaseparated arguments and returns the result of a logical XOR operation on each pair of corresponding bits. For example, the result of the following function is 1
.
 makeresults  eval result = bit_xor(3, 2)
This is because the result of the bitwise XOR operation is 0001, which is the number 1. See the following table for more information about the sequence of operations in this bitwise function.
Operation  Binary string  Result 

3  0011  
2  0010  
bit_xor(3, 2)  0001  1 
bit_shift_left(<value>, <shift_offset>)
Description
This logical left shift function takes two valid nonnegative integers as arguments and shifts the binary representation of the first integer over to the left by the specified shift offset amount. Shifting left drops the 53rd bit and appends a 0 to the binary representation of the input.
Both arguments must be in the range of 0 to 2^{53} 1 or the operation returns null. All results are masked to stay below the 2^{53} 1 limit in case of overflows.
Usage
The shift offset is an integer that specifies the number of times the given integer is shifted to the left. When the bits in a binary digit are shifted to the left, the mostsignificant bit on the left side is lost and a 0 bit is inserted on the right side of the value. For example, the result of the following search is 4
.
 makeresults  eval result = bit_shift_left(2, 1)
This is because the decimal value of 0100 is 4. See the following table for more information about the sequence of operations in this bitwise function.
Operation  Binary string  Result 

2  0010  
bit_shift_left(2, 1)  0100  4 
Because only nonnegative integers in the range of 0 to 2^{53} 1 are supported, if values in bitshift functions are negative or greater than 2^{53}1, such as 2^{53}, the function returns null. Also, if the shift offset is greater than 53 bits, the function returns 0. For example, consider the following search.
 makeresults  eval result = bit_shift_left(1, 53)
The search results look something like this:
_time  result 

20220822 13:39:24  0 
Since the operation results in 54 bits, the 1 on the left drops off and is replaced with 53 zeros, and the value is truncated to 0 when displayed as a search result. After the most significant bit is lost, it is not possible to reverse the operation and recover that bit.
The following table provides examples of leftshift functions to help you understand the results. For the bit_shift_left(3, 52)
function, notice that the result is truncated because the bit on the left that is in bold in the binary string is dropped.
Operation  Binary string  Result 

3  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000011


bit_shift_left(3, 1)  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000110

6 
bit_shift_left(3, 52)  110000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

4503599627370496 
bit_shift_left(3, 57)  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

0 
bit_shift_left(3, 2^{53}1)  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

0 
bit_shift_left(3, 2^{53})  null  
67  00000000 00000000 00000000 00000000 00000000 00000000 00000000 01000011


bit_shift_left(67, 1)  00000000 00000000 00000000 00000000 00000000 00000000 00000000 10000110

134 
bit_shift_left(2^{53}, 1)  null  
bit_shift_left(3, 2)  null  
bit_shift_right(3, 1)  null 
bit_shift_right(<value>, <shift_offset>)
Description
This logical right shift function takes two valid nonnegative integers as arguments and shifts the binary representation of the first integer over to the right by the specified shift offset amount. Shifting right drops the rightmost bit and prepends a 0 to the binary representation of the input.
Both arguments must be in the range of 0 to 2^{53} 1 or the operation returns null. All results are masked to stay below the 2^{53} 1 limit in case of overflows.
Usage
The shift offset is an integer that specifies the number of times the given integer is shifted to the right. For example, the result of the following function is 2
.
 makeresults  eval result = bit_shift_right(4, 1)
This is because the binary representation of the decimal number 4 is 0100, which is 0010 when shifted left by 1. The decimal value of 0010 is 2.
Like the bit_shift_left
function, the bit_shift_right
function supports only nonnegative integers in the range of 0 to 2^{53} 1. As a result, values in bitshift operations that are negative or greater than 53 bits or 2^{53} return null.
Examples
1. Compare the results of bitwise functions
Consider the following search, which includes sequential bitwise AND, bitwise OR, and bitwise XOR functions.
 makeresults
 eval AND_result = bit_and(4, 6), OR_result = bit_or(4, 6), XOR_result = bit_xor(4, 6)
The results look something like this:
_time  AND_result  OR_result  XOR_result 

20220902 13:44:21  4  6  2 
2. Compare the results of bit shift functions
Consider the following search, which includes sequential logical left shift and logical right shift functions.
 makeresults
 eval LEFT_result = bit_shift_left(2,1), RIGHT_result = bit_shift_right(2,1)
The results look something like this:
_time  LEFT_result  RIGHT_result 

20220902 13:44:21  4  1 
3. Get the binary representation of a value from another function
If you want to see your results in binary, you can use the tostring
function to convert an argument to a binary string. See tostring(X,Y).
The following search converts the result of the bit_shift_left(2,1)
to its binary representation, which is 100
.
 makeresults
 eval LEFT_result = bit_shift_left(2,1)
 eval string = tostring(LEFT_result, "binary")
The results look something like this:
_time  LEFT_result  string 

20220902 11:23:43  4  100 
4. Apply a bitmask to limit the binary output
Consider this search, which uses the bit_not
function to invert the bits in the result.
 makeresults
 eval NOT_result = bit_not(9)
 eval string = tostring(NOT_result, "binary")
The results look something like this:
_time  NOT_result  string 

20220902 09:52:12  9007199254740982  11111111111111111111111111111111111111111111111110110 
The binary result in the string
field has a lot of leading 1's that are in the way. To limit the output, add a bitmask that specifies that you want to see only three bits in the final result, like this:
 makeresults
 eval NOT_result = bit_not(9, tonumber("111",2))
 eval string = tostring(NOT_result, "binary")
The results look something like this:
_time  NOT_result  string 

20220902 09:52:12  6  110 
The result is the threebit binary string 110
instead of a lot of 1s and 0s.
5. Using values that are outside the range of supported values
Look at what happens when you use a value as input in a function that falls outside of the range of supported values, which is 0 to 2^{53} 1. In the following search, the input to the function is 2^{53} 1, the max_supported_value
, plus one.
 makeresults
 eval max_supported_val = pow(2, 53)1
 eval result = bit_and(max_supported_val + 1, 1)
The results look something like this:
_time  max_supported_val 

20220904 11:15:19  9007199254740991 
The search returns only the value for max_supported_val
and the value for the result
field is not displayed. This is because result
is outside of the supported range of values, so the function returns null. The function also returns null if you use negative values as input.
6. Update a binary string to set flags
You can run the following search to set multiple flags using a variable called flags
.
 makeresults
 eval flags = "00010", result = tonumber(flags, 2)
 eval result = bit_or(result, tonumber("11001", 2))
 eval result = tostring(result, "binary")
The results look something like this:
_time  flags  result 

20220905 12:19:03  00010  11011 
You can see that the first, fourth, and fifth bits in 11011
are set.
7. Check whether a specific flag in a binary string is set
You can run the following search to check whether the third flag in a variable called flags
is set.
 makeresults
 eval flags = "00010", result = tonumber(flags, 2)
 eval result = bit_and(result, 4)
 eval result = if(result==0, "false", "true")
The results look something like this:
_time  flags  result 

20220905 09:13:22  00010  0 
You can see that the third bit in the flag 00010
is set to 0.
8. Determine the matching bits in two binary strings
This search gives you the matching bits in two binary strings. Every bit that matches is displayed as 1 in the search results.
 makeresults
 eval bin_number1 = "10011", bin_number2 = "10001", number1 = tonumber(bin_number1, 2), number2 = tonumber(bin_number2, 2)
 eval matching_bits = bit_xor(number1, number2)
 eval matching_bits = bit_not(matching_bits, tonumber("11111",2))
 eval matching_bits = tostring(matching_bits, "binary")
The results look something like this:
_time  bin_number1  bin_number2  matching_bits  number1  number2 

20220905 10:15:26  10011  10001  11101  19  17 
You can see that the matching bits in 10011
and 10001
are the first, third, fourth, and last bits.
9. Append a bit flag to a binary string
The following search uses bit_shift_left
and bit_or
to add a bit flag of 1 to the binary string 10001
.
 makeresults
 eval flags = "10001", result = tonumber(flags, 2), flag_bool = 1
 eval result = bit_shift_left(result, 1)
 eval result = bit_or(result, flag_bool)
 eval result = tostring(result, "binary")
The results look something like this:
_time  flags  flag_bool  result 

20220905 12:19:20  10001  1  100011 
You appended 10001
, so now the result is 100011
.
10. Use nested bitwise operations
You can nest multiple bitwise operations in a single search. For example, say you have a field called StreamId=0x12da3b7514f19ce7
. If you want to perform StreamId >> 8 & 0xFFFFFFFF
, which rightshifts the StreamID by 8 and then performs a bitwise AND operation with 0xFFFFFFFF, you can run the following search:
 makeresults
 eval streamId = tonumber("0xa3b7514f19ce7", 16), result = bit_and(bit_shift_right(streamId,8), tonumber("0xFFFFFFFF",16))
The results look something like this:
_time  result  StreamId 

20220905 11:21:02  1964306844  2880123815697639 
PREVIOUS Evaluation functions 
NEXT Comparison and Conditional functions 
This documentation applies to the following versions of Splunk^{®} Enterprise: 9.2.0, 9.2.1
Feedback submitted, thanks!