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

For conciseness, the table says "blob" for in-memory binary data term.

! From	To	Method	Required release
Binary file (or part of)	blob	ReadBinaryFile	Analytica 6.2
blob (or part of)	Binary file	WriteBinaryFile	Analytica 6.2
Part of blob	another blob	GetFromBinaryData(...typeFlags:7)	Analytica 6.2
Image file	blob	ReadBinaryFile(filename,typeFlags:7)	Analytica 6.4
In-memory image	blob	WriteImageFile("<>", image)	Analytica 6.4
blob	in-memory image	GetFromBinaryData( ..., typeFlags:8 )	Analytica 6.4
base64 text	blob	As a literal: [base64'....] From text only: Evaluate( f"base64'{txt}')	Analytica 6.4