Byte Array Manipulation - Algorand Specifications

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Algorand Specifications

OPCODE DESCRIPTION
getbit Bth bit of (byte-array or integer) A. If B is greater than or equal to the bit length of the value (8*byte length), the program fails
setbit Copy of (byte-array or integer) A, with the Bth bit set to (0 or 1) C. If B is greater than or equal to the bit length of the value (8*byte length), the program fails
getbyte Bth byte of A, as an integer. If B is greater than or equal to the array length, the program fails
setbyte Copy of A with the Bth byte set to small integer (between 0..255) C. If B is greater than or equal to the array length, the program fails
concat join A and B
len yields length of byte value A
substring s e A range of bytes from A starting at S up to but not including E. If E < S, or either is larger than the array length, the program fails
substring3 A range of bytes from A starting at B up to but not including C. If C < B, or either is larger than the array length, the program fails
extract s l A range of bytes from A starting at S up to but not including S+L. If L is 0, then extract to the end of the string. If S or S+L is larger than the array length, the program fails
extract3 A range of bytes from A starting at B up to but not including B+C. If B+C is larger than the array length, the program fails
extract_uint16 A uint16 formed from a range of big-endian bytes from A starting at B up to but not including B+2. If B+2 is larger than the array length, the program fails
extract_uint32 A uint32 formed from a range of big-endian bytes from A starting at B up to but not including B+4. If B+4 is larger than the array length, the program fails
extract_uint64 A uint64 formed from a range of big-endian bytes from A starting at B up to but not including B+8. If B+8 is larger than the array length, the program fails
replace2 s Copy of A with the bytes starting at S replaced by the bytes of B. Fails if S+len(B) exceeds len(A)
replace3 Copy of A with the bytes starting at B replaced by the bytes of C. Fails if B+len(C) exceeds len(A)
base64_decode e decode A which was base64-encoded using encoding E. Fail if A is not base64 encoded with encoding E
json_ref r key B’s value, of type R, from a valid utf-8 encoded json object A

The following opcodes take byte-array values that are interpreted as big-endian unsigned integers. For mathematical operators, the returned values are the shortest byte-array that can represent the returned value. For example, the zero value is the empty byte-array. For comparison operators, the returned value is a uint64.

Input lengths are limited to a maximum length of 64 bytes, representing a 512 bit unsigned integer. Output lengths are not explicitly restricted, though only b* and b+ can produce a larger output than their inputs, so there is an implicit length limit of 128 bytes on outputs.

OPCODE DESCRIPTION
b+ A plus B. A and B are interpreted as big-endian unsigned integers
b- A minus B. A and B are interpreted as big-endian unsigned integers. Fail on underflow.
b/ A divided by B (truncated division). A and B are interpreted as big-endian unsigned integers. Fail if B is zero.
b* A times B. A and B are interpreted as big-endian unsigned integers.
b< 1 if A is less than B, else 0. A and B are interpreted as big-endian unsigned integers
b> 1 if A is greater than B, else 0. A and B are interpreted as big-endian unsigned integers
b<= 1 if A is less than or equal to B, else 0. A and B are interpreted as big-endian unsigned integers
b>= 1 if A is greater than or equal to B, else 0. A and B are interpreted as big-endian unsigned integers
b== 1 if A is equal to B, else 0. A and B are interpreted as big-endian unsigned integers
b!= 0 if A is equal to B, else 1. A and B are interpreted as big-endian unsigned integers
b% A modulo B. A and B are interpreted as big-endian unsigned integers. Fail if B is zero.
bsqrt The largest integer I such that I^2 <= A. A and I are interpreted as big-endian unsigned integers

These opcodes operate on the bits of byte-array values. The shorter input array is interpreted as though left padded with zeros until it is the same length as the other input. The returned values are the same length as the longer input. Therefore, unlike array arithmetic, these results may contain leading zero bytes.

OPCODE DESCRIPTION
`b `
b& A bitwise-and B. A and B are zero-left extended to the greater of their lengths
b^ A bitwise-xor B. A and B are zero-left extended to the greater of their lengths
b~ A with all bits inverted