greg7mdp/sparsepp

Health v2 · maintenance only

Flags: no_license

Adoption not part of the score

1312 stars · 127 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

Sparsepp is a fast, memory-efficient hash map and hash set library for C++, derived from Google's sparsehash. It serves as a drop-in replacement for std::unordered_map/unordered_set with very low memory overhead and minimal memory spikes during resizing.

Use cases

• replace std::unordered_map with a faster, lower-memory hash map in C++
• store large hash maps with minimal memory overhead per entry
• avoid large memory spikes when a hash table resizes
• use a sparsehash-style container with C++11 support
• speed up lookups and insertions compared to the standard unordered_map

When to choose

• you need extremely low memory usage (about one byte overhead per entry)
• your workload resizes hash tables frequently and memory high-water marks matter
• you are stuck with a pre-C++11 compiler
• you want a drop-in replacement for unordered_map/unordered_set

When to avoid

• you can use C++11 or later - the author recommends parallel-hashmap instead for better speed
• slightly higher memory usage is acceptable and you want maximum performance
• you need a consistently faster option and can afford dense_hash_map's memory usage

Facets

library · maturity maintenance

caching developer-tools performance developer-tools cpp cross-platform windows hash-map hash-set sparsehash unordered-map open-addressing memory-efficiency header-only algorithms linux macos

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