In-memory binary data terms

Binary data terms (or "blobs")

Sometimes you may need to hold some arbitrary raw, opaque data in memory. The data cannot be directly interpreted (at least not easily), and might contain any sequence of bytes. Such an in-memory block is sometimes called a "blob". The more formal name is a binary data term.

A binary data term is therefore just a block of memory with arbitrary data. Often it is just an in-memory copy of a binary file. This can be useful when your code makes many individual reads from different locations in the file, since it avoids repeated file-open and file-close operations, and accesses everything in memory. Sometimes the in-memory image is a portion of a binary file.

Creating a binary data term in memory

The following are ways in which a binary data term can be created.

• A base64 literal, e.g., base64'uC8AMcjLQA=='
• A base16 literal, e.g., base16'b82f0031c8cb40'
• WriteBinaryFile("<>", ...)
• ReadBinaryFile( filename, typeFlags:7 )
• GetFromBinaryData(..., typeFlags:7)
• WriteImageFile( "<>", ...)

Note that functions that read or write to external sources (files) require Analytica Enterprise or better.

Reading the contents of an in-memory binary data term

• BinaryDataSize(data) -- returns the number of bytes
• GetFromBinaryData(...)

Generally when you are reading a piece of information from the blob, you'll want to interpret the contents in some way. The parameters of GetFromBinaryData enable you to control this interpretation so that you can read as different non-opaque data types.

Conversions

This table summarizes various data transformations to and from binary data formats that you might need.

! From	To	Method	Required release
Binary file (or part of)	binary data term	ReadBinaryFile	Analytica 6.2
binary data term (or part of)	Binary file	WriteBinaryFile	Analytica 6.2
Part of binary data term	another binary data term	GetFromBinaryData(...typeFlags:7)	Analytica 6.2
Image file	binary data term	ReadBinaryFile(filename,typeFlags:7)	Analytica 6.4
In-memory image	binary data term	WriteImageFile("<>", image)	Analytica 6.4
image file	WriteBinaryFile(...,typeflags:7) The binary data must contain the bytes for a valid image. || Analytica 6.2
binary data term	in-memory image	GetFromBinaryData( ..., typeFlags:8 )	Analytica 6.4
base64 literal	binary data term	base64'....	Analytica 6.2
base64 text	binary data term	Evaluate( f"base64'{txt}'") | Analytica 6.2
base64 literal	image	GetFromBinaryData( base64'...', typeFlags:8 )	Analytica 6.4
base64 text	image	GetFromBinaryData( f"base64'{txt}'", typeFlags:8 )	Analytica 6.4
binary data term	base64 literal text	f"{data:b}"	Analytica 6.2
hexadecimal literal	binary data term	base16'....	Analytica 6.4
hexadecimal text	binary data term	Evaluate( f"base16'{txt}'") | Analytica 6.4
hexadecimal literal	image	GetFromBinaryData( base16'...', typeFlags:8 )	Analytica 6.4
hexadecimal text	image	ImageFromHex( text )	Analytica 5.0
binary data term	hexadecimal literal text	f"{data:X}"	Analytica 6.4
binary data term	hexadecimal text (digits only)	f"{data:H}"	Analytica 6.4

See Also

• ReadBinaryFile
• GetFromBinaryData
• WriteBinaryFile
• BinaryDataSize
• Base64-encoded binary term literals
• ReadImageFile, WriteImageFile
• Formatted Text Literals