Binary data type and binary encoding

Binary data (also referred to as a binary object) is raw data, such as the contents of a GIF file or an executable program file. You do not normally use binary data directly, but you can use the cffile tag to read a binary file into a variable, typically for conversion to a string binary encoding before transmitting the file using e-mail.

A string binary encoding represents a binary value in a string format that can be transmitted over the web. ColdFusion MX supports three binary encoding formats:

Encoding Format

Base64

Encodes the binary data in the lowest six bits of each byte. It ensures that binary data and non-ANSI character data can be transmitted using e-mail without corruption. The Base64 algorithm is specified by IETF RFC 2045, at www.ietf.org/rfc/rfc2045.txt.

Hex

Uses two characters in the range 0-9 and A-F represent the hexadecimal value of each byte; for example, 3A.

UU

Uses the UNIX UUencode algorithm to convert the data.

ColdFusion provides the following functions that convert among string data, binary data, and string encoded binary data:

Function Description

BinaryDecode

Converts a string that contains encoded binary data to a binary object.

BinaryEncode

Converts binary data to an encoded string.

CharsetDecode

Converts a string to binary data in a specified character encoding.

CharsetEncode

Converts a binary object to a string in a specified character encoding.

ToBase64

Converts string and binary data to Base64 encoded data Macromedia recommends using the BinaryEncode function, instead of this function, to convert binary data to Base64 in new applications.

ToBinary

Converts Base64 encoded data to binary data. Macromedia recommends using the BinaryDecode function, instead of this function, in new applications.

ToString

Converts most simple data types to string data. It can convert numbers, date-time objects, and boolean values. (It converts date-time objects to ODBC timestamp strings.) Macromedia recommends that you use the CharsetEncode function to convert binary data to a string in new applications.


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