73 lines
2.1 KiB
Markdown
73 lines
2.1 KiB
Markdown
# py-xbc
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`py-xbc` is a pure-Python library for reading and writing files in the
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eXtra BootConfig (XBC) file format specified by the Linux kernel. This
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is not a strictly-conforming implementation: in particular, this
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implementation does not enforce the 32,767-byte ceiling on XBC files,
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nor does it enforce the 16-level cap on keys and blocks.
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# Requirements
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`py-xbc` currently requires `pyparsing` and Python 3.7+.
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# Usage
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`py-xbc` exports four functions:
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- `loads_xbc` parses a string.
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- `load_xbc` opens a file and then parses a string.
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- `saves_xbc` renders to a string.
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- `save_xbc` renders to a string and writes the string to a file.
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## Format
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XBC files consist of a series of statements, of which there are three
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kinds:
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- A key is a sequence of one or more bytes in the range `a-zA-Z0-9_-`.
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They are namespaced with periods (`.`) and may be followed by an
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equals sign (`=`). Key statements are terminated by a semicolon (`;`),
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a linefeed, or a semicolon followed by a linefeed.
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- A key/value statement is a key followed by an operator, followed in
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turn by one or more values. There are three operators:
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- Assignment (`=`) specifies an initial value.
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- Updates (`:=`) overwrites whatever value was previously there.
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- Appends (`+=`) appends one or more values.
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There are two kinds of values: strings and arrays. Strings can be
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either 'bare' or quoted.
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- Bare strings are a sequence of one or more bytes that are not in the
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range `{}#=+:;,\n'" `.
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- Quoted strings are a sequence of bytes that begins with a single
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quote (`'`) or a double quote (`"`) and ends only with the same
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quote. Quotes cannot be escaped.
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- Arrays are a sequence of one or more values delimited by a comma
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(`,`).
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- A block is a key followed by a pair of curly braces, inside which is
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one or more key or key/value statements.
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Keys are composable. The following examples are equivalent:
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```xbc
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foo {
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bar {
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fluff = 1
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}
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}
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# is equivalent to
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foo.bar.fluff = 1
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# is equivalent to
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foo.bar { fluff = 1 }
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# is equivalent to
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foo { bar.fluff = 1 }
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```
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# Licence
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`py-xbc` is published under the MIT license. See `LICENSE.txt` for more
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information.
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