Zip64 structure check

zip64-structure-check · version 1.0.0 · Structured formats · free, no key needed

Check ZIP64 EOCD and central-directory structure with exact decimal-string values.

Use when you need to: check ZIP64 directory structure · validate ZIP64 EOCD bounds · inspect ZIP64 record counts.

Decide before calling

Read the versioned contract and the supported scope below. Reuse zip64-structure-check@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use zip64-structure-check@1.0.0 for check ZIP64 directory structure. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• check ZIP64 directory structure
• validate ZIP64 EOCD bounds
• inspect ZIP64 record counts
• read ZIP64 directory extent
• verify ZIP64 EOCD length
• audit ZIP64 directory consistency

Not supported

• extracting file contents
• repairing malformed archives
• multi-disk or encrypted archives

Behavior

• Implements PKWARE APPNOTE 6.3.10 sections 4.3.14, 4.3.15, and 4.5.3.
• ZIP64 sentinel replacements are consumed in APPNOTE order: uncompressed size, compressed size, local-header offset, disk start.
• All 64-bit sizes and offsets are returned as exact base-10 strings; malformed input is rejected without repair.
• Only single-disk, unencrypted archives are accepted.
• Disclaimer: format transform only; provides no confidentiality, integrity, or authenticity.

Input

• archive_base64 (string, required): min length 4; max length 87384; pattern ^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$

Output

• standard_version (constant "PKWARE APPNOTE 6.3.10 sections 4.3.14, 4.3.15, and 4.5.3", required)
• valid (boolean, required)
• central_directory_offset (string, required): pattern ^(0|[1-9][0-9]*)$
• central_directory_size (string, required): pattern ^(0|[1-9][0-9]*)$
• entry_count (string, required): pattern ^(0|[1-9][0-9]*)$
• zip64_eocd_size (string, required): pattern ^(0|[1-9][0-9]*)$

Limits

• max archive bytes: 65536
• max entries: 64
• max name bytes: 256
• max extra bytes: 1024

Example

Request input:

{
  "archive_base64": "UEsGBiwAAAAAAAAALQAtAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABQSwYHAAAAAAAAAAAAAAAAAQAAAFBLBQYAAAAA////////////////AAA="
}

Response:

{
  "result": {
    "standard_version": "PKWARE APPNOTE 6.3.10 sections 4.3.14, 4.3.15, and 4.5.3",
    "valid": true,
    "central_directory_offset": "0",
    "central_directory_size": "0",
    "entry_count": "0",
    "zip64_eocd_size": "44"
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "zip64-structure-check",
  "version": "1.0.0",
  "input": {
    "archive_base64": "UEsGBiwAAAAAAAAALQAtAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABQSwYHAAAAAAAAAAAAAAAAAQAAAFBLBQYAAAAA////////////////AAA="
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/zip64-structure-check/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"archive_base64":"UEsGBiwAAAAAAAAALQAtAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABQSwYHAAAAAAAAAAAAAAAAAQAAAFBLBQYAAAAA////////////////AAA="}'

The machine-readable contract is at /v1/tools/zip64-structure-check/versions/1.0.0.

CLI

node cli.mjs run zip64-structure-check 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Zip64 locator check: Check a ZIP64 locator and report its exact EOCD offset and disk count.
• Fixed width records validate: Validate fixed-width records with explicit offsets, widths, alignment, padding, Unicode units, and bounded diagnostics.
• INI win validate: Check initialization-file text against the pinned Windows profile grammar.
• Asn1 der validate: Check one ASN.1 DER value for canonical TLV structure and return a reason.
• Toml10 validate: Check a TOML 1.0 document and locate the first structural error.
• Zip64 entries list: List ZIP64 central-directory entries with exact decimal-string sizes and offsets.