ACFM (.acfm)
.acfm file signature | application/x-font-adobe-metric
Adobe Composite Font Metrics (ACFM) is a font metric file format created and maintained by Adobe for describing the properties of composite fonts. It is used by Adobe and compatible publishing, typesetting, and print workflows to support font substitution, character mapping, and text layout. The format is legacy and primarily associated with older PostScript and Adobe Font development tools; files are generally safe, though they should be handled cautiously if received from untrusted sources.
Magic Bytes
Offset 0
53 74 61 72 74 46 6F 6E 74 4D 65 74 72 69 63 73
Sources: Apache Tika
Extension
.acfm
MIME Type
application/x-font-adobe-metric
Byte Offset
0
Risk Level
Safe
Validation Code
How to validate .acfm files in Python
def is_acfm(file_path: str) -> bool:
"""Check if file is a valid ACFM by magic bytes."""
signature = bytes([0x53, 0x74, 0x61, 0x72, 0x74, 0x46, 0x6F, 0x6E, 0x74, 0x4D, 0x65, 0x74, 0x72, 0x69, 0x63, 0x73])
with open(file_path, "rb") as f:
return f.read(16) == signatureHow to validate .acfm files in Node.js
function isACFM(buffer: Buffer): boolean {
const signature = Buffer.from([0x53, 0x74, 0x61, 0x72, 0x74, 0x46, 0x6F, 0x6E, 0x74, 0x4D, 0x65, 0x74, 0x72, 0x69, 0x63, 0x73]);
return buffer.subarray(0, 16).equals(signature);
}How to validate .acfm files in Go
func IsACFM(data []byte) bool {
signature := []byte{0x53, 0x74, 0x61, 0x72, 0x74, 0x46, 0x6F, 0x6E, 0x74, 0x4D, 0x65, 0x74, 0x72, 0x69, 0x63, 0x73}
if len(data) < 16 {
return false
}
return bytes.Equal(data[:16], signature)
}API Endpoint
/api/v1/acfm
curl https://filesignature.org/api/v1/acfm
See the full API documentation for all endpoints and parameters.
Related Formats
Frequently Asked Questions
What is a .acfm file?
A .acfm file is identified by the magic bytes 53 74 61 72 74 46 6F 6E 74 4D 65 74 72 69 63 73 at byte offset 0. Adobe Composite Font Metrics (ACFM) is a font metric file format created and maintained by Adobe for describing the properties of composite fonts. It is used by Adobe and compatible publishing, typesetting, and print workflows to support font substitution, character mapping, and text layout. The format is legacy and primarily associated with older PostScript and Adobe Font development tools; files are generally safe, though they should be handled cautiously if received from untrusted sources.
What are the magic bytes for .acfm files?
The magic bytes for ACFM files are 53 74 61 72 74 46 6F 6E 74 4D 65 74 72 69 63 73 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .acfm file?
To validate a .acfm file, read the first bytes of the file and compare them against the known magic bytes (53 74 61 72 74 46 6F 6E 74 4D 65 74 72 69 63 73) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .acfm files?
The primary MIME type for .acfm files is application/x-font-adobe-metric.
Is it safe to open .acfm files?
ACFM (.acfm) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.