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)
83 lines
2.8 KiB
C++
83 lines
2.8 KiB
C++
// minetest-0004-test: CWE-407 nodeboxConnects sorted vector linear scan
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// Defect: CONTAINS() on SORT_AND_UNIQUE'd connects_to_ids uses std::find O(N)
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// instead of std::binary_search O(log N). Called 6x per connected
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// nodebox node during mesh generation.
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// Fix: std::binary_search on the already-sorted vector.
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//
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// Severity: MEDIUM
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// Location: src/nodedef.cpp:1288,1295
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#include <vector>
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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_linear(const std::vector<content_t> &ids,
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const std::vector<content_t> &queries) {
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auto start = std::chrono::high_resolution_clock::now();
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int found = 0;
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for (content_t q : queries) {
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if (CONTAINS(ids, q))
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found++;
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}
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auto end = std::chrono::high_resolution_clock::now();
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assert(found >= 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_binary(const std::vector<content_t> &ids,
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const std::vector<content_t> &queries) {
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auto start = std::chrono::high_resolution_clock::now();
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int found = 0;
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for (content_t q : queries) {
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if (std::binary_search(ids.begin(), ids.end(), q))
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found++;
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}
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auto end = std::chrono::high_resolution_clock::now();
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assert(found >= 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: connected nodebox with 30 connection targets
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// Mesh generation: 6 faces * ~1000 connected nodes per mapblock = 6000 lookups
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const int IDS_SIZE = 30;
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const int LOOKUPS = 6000;
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std::vector<content_t> ids;
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for (int i = 0; i < IDS_SIZE; i++)
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ids.push_back(10 + i * 4);
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std::sort(ids.begin(), ids.end()); // SORT_AND_UNIQUE already applied
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std::vector<content_t> queries(LOOKUPS);
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for (int i = 0; i < LOOKUPS; i++) {
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if (i % 3 == 0)
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queries[i] = ids[i % IDS_SIZE]; // hit
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else
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queries[i] = 5 + (i % 200); // likely miss
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}
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// Warmup
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bench_linear(ids, queries);
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bench_binary(ids, queries);
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long long lin_ns = bench_linear(ids, queries);
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long long bin_ns = bench_binary(ids, queries);
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double ratio = (double)lin_ns / (double)bin_ns;
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printf("=== minetest-0004: nodeboxConnects sorted vector scan ===\n");
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printf("connects_to_ids size: %d, lookups: %d\n", IDS_SIZE, LOOKUPS);
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printf("linear (std::find): %lld ns\n", lin_ns);
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printf("binary (binary_search): %lld ns\n", bin_ns);
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printf("ratio: %.1fx\n", ratio);
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assert(ratio >= 1.5 && "FAIL: binary_search should be faster on sorted data");
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printf("PASS\n");
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return 0;
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}
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