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 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.
|
ToBinary
|
Converts Base64 encoded data to binary data.
The BinaryDecode function provides a superset
of the ToBase64 functionality.
|
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.) Adobe
recommends that you use the CharsetEncode function to convert
binary data to a string in new applications.
|
