java-topology/docs/tickets/raylib-0001-getglyphindex-linear-scan-per-char-draw.md
russell@unturf.com 9934133dcf whitepaper: 312 sites / 151 ecosystems — wave2+3 defect tables and PDF rebuild
Add 88 new defect entries to HIGH and MEDIUM tables:
  HIGH: mysql-0001/0002, mariadb-0001, redis-0001/0002, valkey-0001/0002, openvpn-0001,
        vlc-0001, prometheus-0001, otel-collector-0001, cockroachdb-0001..0004,
        tidb-0001..0008, kubernetes-0001/0002, go-0001, kotlin-0002, scala-0001,
        allegro5-0001, sdl2-0001, grafana-0001, clickhouse-0001, duckdb-0001,
        mongodb-0001, envoy-0001, istio-0001, cilium-0001, linkerd2-0001,
        linux-0001/0002/0003, tor-0002/0003, curl-0001, julia-0001, lua-0001,
        perl5-0001, nats-0001, spring-0003/0004, tomcat-0001, onos-0002, odl-0002

  MEDIUM: helm-0001, mariadb-0002, openssl-0001/0002, memcached-0001,
          cassandra-0001..0004, flink-0001, storm-0001/0002, zookeeper-0001..0003,
          pip-0001, gradle-0001, nginx-0001, haproxy-0001, caddy-0001, varnish-0001,
          ffmpeg-0001, gstreamer-0001, raylib-0001, love2d-0001, php-0001/0002,
          r-source-0001, cpython-0002, ruby-0001, rabbitmq-0003/0004, activemq-0001,
          ovs-0001, onos-0003, odl-0002, jetty-0001

PDF: 976K
2026-03-27 15:23:43 -04:00

2.1 KiB

raylib-0001 — GetGlyphIndex O(n) linear scan per character per DrawText call

Status

PATCHED

Severity

HIGH

Target

raylib src/rtext.c

CWE

CWE-407: Algorithmic Complexity — Insufficient Complexity Reduction Before Algorithmic Intensive Operation

Description

GetGlyphIndex(Font font, int codepoint) performs an O(n) linear scan of font.glyphs[] for every character in every text draw call (DrawText, DrawTextEx, MeasureText, MeasureTextEx, DrawTextCodepoint, etc.). For a font with N glyphs, rendering a string of L characters costs O(L * N) per frame.

In the SUPPORT_UNORDERED_CHARSET branch (enabled by default via #define), every call walks the full glyphs array until it finds the matching codepoint or exhausts the array.

// rtext.c:1453
int GetGlyphIndex(Font font, int codepoint)
{
    int index = 0;
    ...
    for (int i = 0; i < font.glyphCount; i++)  // O(n) every call
    {
        if (font.glyphs[i].value == 63) fallbackIndex = i;
        if (font.glyphs[i].value == codepoint) { index = i; break; }
    }
    ...
}

Call Sites (partial)

  • DrawTextDrawTextEx → inner loop calls GetGlyphIndex per codepoint
  • MeasureTextEx → inner loop calls GetGlyphIndex per codepoint
  • DrawTextCodepoints → inner loop
  • GetGlyphInfoGetGlyphIndex
  • GetGlyphAtlasRecGetGlyphIndex

Fix

Build a codepoint → index hash map (or sorted array + binary search) once at font load time. GetGlyphIndex then becomes O(1) average (hash map) or O(log n) (binary search on sorted glyphs).

Patch: sort glyphs by codepoint value at load time and use binary search. This keeps memory layout unchanged and requires no new heap allocation.

Complexity

  • Before: O(L * N) per DrawText call where L = string length, N = font.glyphCount
  • After: O(L * log N) with binary search; O(L) with hash map

Benchmark

See defects/raylib/unit/RaylibGlyphIndexTest.java — at N=2048 glyphs:

  • slow() (linear scan): ~2048 comparisons per lookup
  • fast() (binary search): ~11 comparisons per lookup
  • Ratio: ~186x

Files

  • defects/raylib/patch/raylib-0001.patch
  • defects/raylib/unit/RaylibGlyphIndexTest.java