DoxigAlpha
std › math › big › int › calcSetStringLimbCount

calcSetStringLimbCount

Assumes string_len doesn't account for minus signs if the number is negative.

Function parameters

Parameters

#
base:u8
string_len:usize

Used to indicate either limit of a 2s-complement integer.

Types

#
TwosCompIntLimit
Used to indicate either limit of a 2s-complement integer.
Mutable
A arbitrary-precision big integer, with a fixed set of mutable limbs.
Const
A arbitrary-precision big integer, with a fixed set of immutable limbs.
Managed
An arbitrary-precision big integer along with an allocator which manages the memory.

Returns the number of limbs needed to store `scalar`, which must be a

Functions

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calcLimbLen
Returns the number of limbs needed to store `scalar`, which must be a
calcSetStringLimbCount
Assumes `string_len` doesn't account for minus signs if the number is negative.
calcNonZeroTwosCompLimbCount
Compute the number of limbs required to store a 2s-complement number of `bit_count` bits.
calcTwosCompLimbCount
Compute the number of limbs required to store a 2s-complement number of `bit_count` bits.
addMulLimbWithCarry
a + b * c + *carry, sets carry to the overflow bits
llcmp
Returns -1, 0, 1 if |a| < |b|, |a| == |b| or |a| > |b| respectively for limbs.

Source

Implementation

#
pub fn calcSetStringLimbCount(base: u8, string_len: usize) usize {
    const base_f: f32 = @floatFromInt(base);
    const string_len_f: f32 = @floatFromInt(string_len);
    return 1 + @as(usize, @intFromFloat(@ceil(string_len_f * std.math.log2(base_f) / limb_bits)));
}