CodeSampleX

Sample

memchr 2.8.3: memchr::memchr

Verified sample for cargo memchr 2.8.3: memchr::memchr. The contract ran on rust 1 · linux alpine/x64 · docker and passed: memchr finds the first occurrence…

sha256:f56e894692a04190c93334058e6a08054844d2be0f7c25492f6d4c270e91e689

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment linux · alpine · musl x64 cargo

Verification-run environments

Environment Contract Stages Run
rust 1 · linux alpine/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · cargo@1rust:1-alpine@sha256:a10e64dd139b…
2026-09-14

Case

HOW
Goal
verify memchr::memchr in pkg:cargo/memchr@2.8.3
Packages
Symbols
  • memchr::memchr
Created
2026-09-14T19:57:38Z

Contract

  1. memchr finds the first occurrence of a byte in a haystack
  2. memchr returns Some with the 0-based index when byte is present
  3. memchr returns None when byte is not present in haystack
  4. memchr returns None when searching in an empty haystack
  5. memchr returns the earliest index when byte occurs multiple times

Files

  • Cargo.lock
  • Cargo.toml
  • PROMPT.md
  • csx.json
  • spec.json
  • src/lib.rs
  • test/contract.rs

Download the source artifact (tar.gz)

Source

Cargo.lock
# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
version = 4

[[package]]
name = "memchr"
version = "2.8.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "cf8baf1c55e62ffcace7a9f06f4bd9cd3f0c4beb022d3b367256b91b87513d98"

[[package]]
name = "sample-memchr"
version = "1.0.0"
dependencies = [
 "memchr",
]
Cargo.toml
[package]
name = "sample-memchr"
version = "1.0.0"
edition = "2021"
publish = false

[dependencies]
memchr = "=2.8.3"

[[bin]]
name = "contract"
path = "test/contract.rs"
PROMPT.md
Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify memchr::memchr in pkg:cargo/memchr@2.8.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:cargo/memchr@2.8.3
Demonstrate these symbols/APIs:
  - memchr::memchr

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.
csx.json
{"case":{"caseId":"case:sha256:bac9c992e1e64857497580a51aac790166e0ecce61e171ed97dc449f3eecab64","contract":["memchr finds the first occurrence of a byte in a haystack","memchr returns Some with the 0-based index when byte is present","memchr returns None when byte is not present in haystack","memchr returns None when searching in an empty haystack","memchr returns the earliest index when byte occurs multiple times"],"goal":"verify memchr::memchr in pkg:cargo/memchr@2.8.3","kind":"HOW","packages":["pkg:cargo/memchr@2.8.3"],"schemaVersion":1,"symbols":["memchr::memchr"]},"contractCommand":["cargo","run","--offline"],"environment":{"arch":"x64","distro":"alpine","ecosystem":"cargo","libc":"musl","os":"linux","packageManager":"cargo","schemaVersion":1},"license":"MIT-0","packages":["pkg:cargo/memchr@2.8.3"],"schemaVersion":1,"subject":"pkg:cargo/memchr@2.8.3","symbols":["memchr::memchr"],"verifierAdapter":"cargo@1"}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify memchr::memchr in pkg:cargo/memchr@2.8.3",
  "kind": "HOW",
  "packages": [
    "pkg:cargo/memchr@2.8.3"
  ],
  "symbols": [
    "memchr::memchr"
  ]
}
src/lib.rs
//! Clean-room verification sample for memchr.

pub use memchr::*;
test/contract.rs
use memchr::memchr;

fn main() {
    // 1. memchr finds the first occurrence of a byte in a haystack
    let text = b"hello world";
    assert_eq!(memchr(b'w', text), Some(6));

    // 2. memchr returns Some with the 0-based index when byte is present
    assert_eq!(memchr(b'h', text), Some(0));
    assert_eq!(memchr(b'd', text), Some(10));

    // 3. memchr returns None when byte is not present in haystack
    assert_eq!(memchr(b'z', text), None);

    // 4. memchr returns None when searching in an empty haystack
    assert_eq!(memchr(b'a', b""), None);

    // 5. memchr returns the earliest index when byte occurs multiple times
    let repeated = b"banana";
    assert_eq!(memchr(b'a', repeated), Some(1));

    println!("All memchr::memchr contract assertions passed successfully.");
}

Origin Seeder

anonymous