russell@unturf.com
a86a765544
minetest-0001: mg_ore.cpp c_wherein vector CONTAINS in voxel inner loop O(V*W) HIGH 3.3x minetest-0002: mg_decoration.cpp c_place_on/c_spawnby vector CONTAINS O(S*P) MEDIUM 1.8x minetest-0003: l_env.cpp find_node_near/find_nodes_in_area filter CONTAINS O(V*F) MEDIUM 1.6x minetest-0004: nodedef.cpp nodeboxConnects sorted vector linear scan O(N) MEDIUM 2.1x minetest-0005: blockmodifier.cpp ABM neighbor check sorted vector O(N) LOW-MEDIUM 1.5x MOAD-0002: g_settings global singleton (architectural, not patchable) MOAD-0003: thread_local log streams (properly scoped, not leaked context) MOAD-0004: CLEAN (no credential logging found) MOAD-0005: CLEAN (no unsynchronized cache patterns found)
92 lines
3.2 KiB
C++
92 lines
3.2 KiB
C++
// minetest-0002-test: CWE-407 decoration c_place_on/c_spawnby linear scan
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// Defect: CONTAINS(c_place_on, content) and CONTAINS(c_spawnby, content)
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// use std::find O(N) per decoration placement candidate.
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// Fix: std::unordered_set<content_t> for O(1) lookup.
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//
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// Severity: MEDIUM
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// Location: src/mapgen/mg_decoration.cpp, canPlaceDecoration()
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// Pattern: CONTAINS(c_place_on, ...) and CONTAINS(c_spawnby, ...)
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#include <vector>
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#include <unordered_set>
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#include <algorithm>
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#include <chrono>
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#include <cassert>
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#include <cstdio>
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#include <cstdint>
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using content_t = uint16_t;
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#define CONTAINS(c, v) (std::find((c).begin(), (c).end(), (v)) != (c).end())
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static long long bench_vector(const std::vector<content_t> &place_on,
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const std::vector<content_t> &nodes, int reps) {
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auto start = std::chrono::high_resolution_clock::now();
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int matches = 0;
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for (int r = 0; r < reps; r++) {
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for (content_t c : nodes) {
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if (CONTAINS(place_on, c))
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matches++;
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}
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}
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auto end = std::chrono::high_resolution_clock::now();
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assert(matches >= 0);
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return std::chrono::duration_cast<std::chrono::nanoseconds>(end - start).count();
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}
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static long long bench_set(const std::unordered_set<content_t> &place_on,
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const std::vector<content_t> &nodes, int reps) {
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auto start = std::chrono::high_resolution_clock::now();
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int matches = 0;
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for (int r = 0; r < reps; r++) {
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for (content_t c : nodes) {
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if (place_on.count(c) > 0)
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matches++;
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}
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}
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auto end = std::chrono::high_resolution_clock::now();
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assert(matches >= 0);
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return std::chrono::duration_cast<std::chrono::nanoseconds>(end - start).count();
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}
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int main() {
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// Modded game: 50 place_on node types (group:soil etc.),
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// 6400 surface nodes per mapchunk (80x80), 50 repetitions (50 decos)
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const int PLACE_ON_SIZE = 50;
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const int SURFACE_NODES = 6400;
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const int REPS = 50;
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std::vector<content_t> place_on_vec;
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std::unordered_set<content_t> place_on_set;
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for (int i = 0; i < PLACE_ON_SIZE; i++) {
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content_t id = 50 + i * 5;
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place_on_vec.push_back(id);
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place_on_set.insert(id);
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}
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std::vector<content_t> surface(SURFACE_NODES);
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for (int i = 0; i < SURFACE_NODES; i++) {
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if (i % 5 == 0)
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surface[i] = place_on_vec[i % PLACE_ON_SIZE];
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else
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surface[i] = 1 + (i % 30);
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}
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bench_vector(place_on_vec, surface, 1);
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bench_set(place_on_set, surface, 1);
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long long vec_ns = bench_vector(place_on_vec, surface, REPS);
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long long set_ns = bench_set(place_on_set, surface, REPS);
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double ratio = (double)vec_ns / (double)set_ns;
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printf("=== minetest-0002: decoration c_place_on membership ===\n");
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printf("place_on size: %d, surface nodes: %d\n", PLACE_ON_SIZE, SURFACE_NODES);
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printf("vector (std::find): %lld ns\n", vec_ns);
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printf("unordered_set (count): %lld ns\n", set_ns);
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printf("ratio: %.1fx\n", ratio);
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fflush(stdout);
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assert(ratio >= 1.5 && "FAIL: unordered_set should be at least 1.5x faster");
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printf("PASS\n");
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return 0;
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}
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