Module complexity 

Cyclomatic Complexity Calculation from Branch Counts

This module calculates cyclomatic complexity using the Z-coordinate (branch_count) from the 3D spatial representation of CFG blocks.

Formula

Cyclomatic Complexity M = E - N + 2P where:

• E = number of edges
• N = number of nodes
• P = number of connected components (usually 1 for a function)

Using spatial coordinates: M = 1 + sum(branch_count) for all blocks

Complexity

• Time: O(n) single pass through blocks
• Space: O(1) constant space

Example

use geographdb_core::algorithms::complexity::{calculate_cyclomatic_complexity, ComplexityBlock};

let blocks = vec![
    ComplexityBlock { id: 0, z: 0.0 },  // Entry (no branches)
    ComplexityBlock { id: 1, z: 1.0 },  // If statement (1 branch)
    ComplexityBlock { id: 2, z: 0.0 },  // Sequential
    ComplexityBlock { id: 3, z: 1.0 },  // Another if (1 branch)
];

let result = calculate_cyclomatic_complexity(&blocks);
assert_eq!(result.cyclomatic_complexity, 3);  // 1 + 1 + 1 = 3

Structs

BlockComplexity

Complexity metrics for a single block

ComplexityBlock

A block for complexity calculation

ComplexityResult

Result of complexity analysis

Enums

ComplexityRating

Complexity rating based on McCabe number

Functions

calculate_cyclomatic_complexity

Calculate cyclomatic complexity from CFG blocks

calculate_per_block_complexity

Calculate complexity for each block individually

find_most_complex_blocks

Identify the most complex blocks (top N by branch count)

get_complexity_trend

Get complexity trend description

is_complexity_acceptable

Check if complexity is within acceptable limits