github.com/klauspost/cpuid/v2 v2.2.10

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 pkg:golang/github.com/klauspost/cpuid/v2@v2.2.10
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/klauspost/cpuid/v2@v2.2.10
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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.

{"case":{"caseId":"case:sha256:97a4e9342480622f88dbd46d9b7389c16f73026e6717715715e08b00f28bb276","contract":["cpuid.CPU provides CPU architecture, vendor information, cache line size, and core topology","cpuid.ParseFeature parses string feature names and returns UNKNOWN for unrecognized names","cpuid.CombineFeatures combines multiple FeatureID values into a flag set checked with cpuid.CPU.HasAll","cpuid.CPUInfo instances support Enable, Disable, and Has for modifying and testing individual features","cpuid.CPUInfo.Supports and cpuid.CPUInfo.AnyOf evaluate presence of multiple hardware feature flags","cpuid.CPUInfo.FeatureSet returns a slice of string names for all enabled CPU features"],"goal":"verify pkg:golang/github.com/klauspost/cpuid/v2@v2.2.10","kind":"HOW","packages":["pkg:golang/github.com/klauspost/cpuid/v2@v2.2.10"],"schemaVersion":1},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/klauspost/cpuid/v2@v2.2.10"],"schemaVersion":1,"subject":"pkg:golang/github.com/klauspost/cpuid/v2@v2.2.10","verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require github.com/klauspost/cpuid/v2 v2.2.10

github.com/klauspost/cpuid/v2 v2.2.10 h1:tBs3QSyvjDyFTq3uoc/9xFpCuOsJQFNPiAhYdw2skhE=
github.com/klauspost/cpuid/v2 v2.2.10/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

package main

import (
	"fmt"

	"github.com/klauspost/cpuid/v2"
)

func main() {
	// Query CPU brand and basic topology
	fmt.Printf("CPU: %s\n", cpuid.CPU.BrandName)
	fmt.Printf("Vendor: %s\n", cpuid.CPU.VendorString)
	fmt.Printf("Physical Cores: %d\n", cpuid.CPU.PhysicalCores)
	fmt.Printf("Logical Cores: %d\n", cpuid.CPU.LogicalCores)
	fmt.Printf("Cache Line: %d bytes\n", cpuid.CPU.CacheLine)

	// Check hardware feature support
	fmt.Printf("SSE2 supported: %v\n", cpuid.CPU.Supports(cpuid.SSE2))
	fmt.Printf("AVX supported: %v\n", cpuid.CPU.Supports(cpuid.AVX))

	// Parse feature name dynamically
	parsed := cpuid.ParseFeature("SSE2")
	fmt.Printf("Parsed SSE2 feature ID: %d\n", parsed)

	// Combine feature flags for compound checks
	flags := cpuid.CombineFeatures(cpuid.SSE, cpuid.SSE2)
	fmt.Printf("Has SSE & SSE2: %v\n", cpuid.CPU.HasAll(flags))

	// Work with independent CPUInfo instance
	var custom cpuid.CPUInfo
	custom.Enable(cpuid.AVX2, cpuid.FMA3)
	fmt.Printf("Custom features: %v\n", custom.FeatureSet())
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/klauspost/cpuid/v2@v2.2.10",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/klauspost/cpuid/v2@v2.2.10"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

package main

import (
	"fmt"
	"os"

	"github.com/klauspost/cpuid/v2"
)

func main() {
	// Contract 1: cpuid.CPU provides CPU architecture, vendor information, cache line size, and core topology
	if cpuid.CPU.CacheLine < 0 {
		fmt.Fprintf(os.Stderr, "FAIL: CacheLine size cannot be negative: %d\n", cpuid.CPU.CacheLine)
		os.Exit(1)
	}
	if cpuid.CPU.ThreadsPerCore < 1 {
		fmt.Fprintf(os.Stderr, "FAIL: ThreadsPerCore must be at least 1: %d\n", cpuid.CPU.ThreadsPerCore)
		os.Exit(1)
	}
	if cpuid.CPU.PhysicalCores < 0 || cpuid.CPU.LogicalCores < 0 {
		fmt.Fprintf(os.Stderr, "FAIL: core count cannot be negative\n")
		os.Exit(1)
	}

	// Contract 2: cpuid.ParseFeature parses string feature names and returns UNKNOWN for unrecognized names
	sse2 := cpuid.ParseFeature("SSE2")
	if sse2 == cpuid.UNKNOWN || sse2 != cpuid.SSE2 {
		fmt.Fprintf(os.Stderr, "FAIL: ParseFeature(\"SSE2\") did not return cpuid.SSE2\n")
		os.Exit(1)
	}
	unknown := cpuid.ParseFeature("NON_EXISTENT_FEATURE_NAME")
	if unknown != cpuid.UNKNOWN {
		fmt.Fprintf(os.Stderr, "FAIL: ParseFeature with invalid name must return UNKNOWN, got %d\n", unknown)
		os.Exit(1)
	}

	// Contract 3: cpuid.CombineFeatures combines multiple FeatureID values into a flag set checked with cpuid.CPU.HasAll
	features := cpuid.CombineFeatures(cpuid.SSE, cpuid.SSE2)
	hasAll := cpuid.CPU.HasAll(features)
	hasBoth := cpuid.CPU.Has(cpuid.SSE) && cpuid.CPU.Has(cpuid.SSE2)
	if hasAll != hasBoth {
		fmt.Fprintf(os.Stderr, "FAIL: HasAll result (%v) does not match individual Has checks (%v)\n", hasAll, hasBoth)
		os.Exit(1)
	}

	// Contract 4: cpuid.CPUInfo instances support Enable, Disable, and Has for modifying and testing individual features
	var custom cpuid.CPUInfo
	if custom.Has(cpuid.AVX2) {
		fmt.Fprintf(os.Stderr, "FAIL: default zero CPUInfo should not have AVX2\n")
		os.Exit(1)
	}
	custom.Enable(cpuid.AVX2, cpuid.FMA3)
	if !custom.Has(cpuid.AVX2) || !custom.Has(cpuid.FMA3) {
		fmt.Fprintf(os.Stderr, "FAIL: custom CPUInfo missing enabled features after Enable\n")
		os.Exit(1)
	}
	custom.Disable(cpuid.AVX2)
	if custom.Has(cpuid.AVX2) {
		fmt.Fprintf(os.Stderr, "FAIL: Disable(AVX2) failed to clear AVX2 flag\n")
		os.Exit(1)
	}
	if !custom.Has(cpuid.FMA3) {
		fmt.Fprintf(os.Stderr, "FAIL: FMA3 should remain enabled after disabling AVX2\n")
		os.Exit(1)
	}

	// Contract 5: cpuid.CPUInfo.Supports and cpuid.CPUInfo.AnyOf evaluate presence of multiple hardware feature flags
	if !custom.Supports(cpuid.FMA3) {
		fmt.Fprintf(os.Stderr, "FAIL: Supports should return true for enabled feature FMA3\n")
		os.Exit(1)
	}
	if custom.Supports(cpuid.FMA3, cpuid.AVX2) {
		fmt.Fprintf(os.Stderr, "FAIL: Supports should return false when AVX2 is not enabled\n")
		os.Exit(1)
	}
	if !custom.AnyOf(cpuid.AVX2, cpuid.FMA3) {
		fmt.Fprintf(os.Stderr, "FAIL: AnyOf should return true when FMA3 is enabled\n")
		os.Exit(1)
	}
	if custom.AnyOf(cpuid.AVX2, cpuid.AVX512F) {
		fmt.Fprintf(os.Stderr, "FAIL: AnyOf should return false when none of the features are enabled\n")
		os.Exit(1)
	}

	// Contract 6: cpuid.CPUInfo.FeatureSet returns a slice of string names for all enabled CPU features
	featList := custom.FeatureSet()
	if len(featList) != 1 || featList[0] != "FMA3" {
		fmt.Fprintf(os.Stderr, "FAIL: FeatureSet returned unexpected features: %v\n", featList)
		os.Exit(1)
	}

	fmt.Println("All contract assertions passed.")
}