{"id":20033095,"url":"https://github.com/ocsmit/bitter","last_synced_at":"2026-07-22T11:03:54.540Z","repository":{"id":180520073,"uuid":"665246257","full_name":"ocsmit/bitter","owner":"ocsmit","description":"Compact/succinct representations for vectors and arrays","archived":false,"fork":false,"pushed_at":"2023-07-31T20:51:48.000Z","size":58,"stargazers_count":2,"open_issues_count":0,"forks_count":1,"subscribers_count":1,"default_branch":"main","last_synced_at":"2025-10-30T10:43:52.516Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":"","language":"C","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"mit","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/ocsmit.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2023-07-11T19:13:52.000Z","updated_at":"2025-03-27T01:24:58.000Z","dependencies_parsed_at":null,"dependency_job_id":"3183d03e-5e08-4419-9183-2f87a3eb3037","html_url":"https://github.com/ocsmit/bitter","commit_stats":null,"previous_names":["ocsmit/bitter"],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/ocsmit/bitter","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ocsmit%2Fbitter","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ocsmit%2Fbitter/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ocsmit%2Fbitter/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ocsmit%2Fbitter/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/ocsmit","download_url":"https://codeload.github.com/ocsmit/bitter/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ocsmit%2Fbitter/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":35759168,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-07-20T02:08:10.276Z","status":"online","status_checked_at":"2026-07-22T02:00:06.236Z","response_time":124,"last_error":null,"robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":true,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2024-11-13T09:44:30.872Z","updated_at":"2026-07-22T11:03:54.515Z","avatar_url":"https://github.com/ocsmit.png","language":"C","funding_links":[],"categories":[],"sub_categories":[],"readme":"# bitter\nCompact/succinct representations for vectors and arrays\n\n## BitArray\n\nCompact bit arrays are space effecient representation of the classical array\nas described in \"[Compact Data Structures, a practical approach](https://doi.org/10.1017/CBO9781316588284)\" and its extensive bibliography.\n\nArrays are stored in a compact form by using only the bits needed for each\nelement. E.g. below the array A is shown to be stored using only two uint32\nelements (W). From the compact representation, the values from the original\narray (A) can be read, written, and operated on.\n \n```\n ┌──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┐\n A │ 20 │ 18 │ 22 │ 22 │ 16 │ 21 │ 11 │ 22 │ 21 │ 21 │\n └──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┘\n │ │ │ │ │ │ │ │ │ │\n │ │ │ │ │ │ │ │ │ │\n ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼\n ┌──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┐\n B │10100 │10010 │10110 │10110 │10000 │10101 │01011 │10110 │10101 │10101 │ \n └──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┘\n │ │ │ │ │ │ │ │ │ │\n │ │ │ B is a virtual bit array │ │ │ │\n │ │ │ │ │ │ │ │ │ │\n ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼\n ┌─────────────────────────────────────────────────────────────────────┐\n B │10100 10010 10110 10110 10000 10101 01011 10110 10101 10101 │\n └─────────────────────────────────────────────────────────────────────┘\n │ ┌────────────────────────┐\n │ The bits are reordered to provide │ │\n │ 0 based indexing from W ┌─────┬─────┐ │\n │ MSB │ 010 │ 11 │ LSB │\n │ └─────┴─────┘ │\n │ A[6] │ │\n │ ┌───────────────────────────────────────────────┘ │\n ▼ ┌ ┼ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┬ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─│─ ┐\n ▼ ▼\n W │11 10101 10000 10110 10110 10010 10100 │10101 10101 10110 010 │\n ^^ ^^^\n └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┴ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘\n A[6] │ A[0] A[9] │ A[6]\n ┌───────────────┘ │\n │ ┌──────────────────────────────────────┘\n ▼ ▼\n ┌────────────┬────────────┐\n W │ 3943389780 │ 177586 │\n └────────────┴────────────┘\n``` \nIt is key to note that the values of A are stored lowest significant first.\nThe same is true for entries which span multiple words. E.g. A[6] in the\nabove visual is split with the 2 lowest sig bits in word 1, and the three\nhighest sig bits in word 2. In word 1 the lowest sig bits of A[6] will be\nthe last bits accessed, while in word 2 the highest sig bits of A[6] will\nbe accessed first.\n\nfor implementation and operation details see:\n - [bitarr.h](src/bitarr.h)\n - [bitops.h](src/bitops.h)\n - [bitarr_io.h](src/bitarr_io.h)\n\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Focsmit%2Fbitter","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Focsmit%2Fbitter","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Focsmit%2Fbitter/lists"}