libkmod-index: keep index and comments in .c
Just like other source files, keep the index and comments in the source file rather than the header. This also removes INDEX_PRIORITY_MIN that was never being used.
This commit is contained in:
Lucas De Marchi
parent
27eceb2e4e
commit
c4cbdf8e17
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@ -34,35 +34,109 @@
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#include "libkmod-internal.h"
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#include "libkmod-index.h"
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/* index.c: module index file shared functions for modprobe and depmod */
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/* libkmod-index.c: module index file implementation
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*
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* Integers are stored as 32 bit unsigned in "network" order, i.e. MSB first.
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* All files start with a magic number.
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*
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* Magic spells "BOOTFAST". Second one used on newer versioned binary files.
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* #define INDEX_MAGIC_OLD 0xB007FA57
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*
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* We use a version string to keep track of changes to the binary format
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* This is stored in the form: INDEX_MAJOR (hi) INDEX_MINOR (lo) just in
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* case we ever decide to have minor changes that are not incompatible.
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*/
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#define INDEX_MAGIC 0xB007F457
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#define INDEX_VERSION_MAJOR 0x0002
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#define INDEX_VERSION_MINOR 0x0001
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#define INDEX_VERSION ((INDEX_VERSION_MAJOR<<16)|INDEX_VERSION_MINOR)
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/* The index file maps keys to values. Both keys and values are ASCII strings.
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* Each key can have multiple values. Values are sorted by an integer priority.
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*
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* The reader also implements a wildcard search (including range expressions)
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* where the keys in the index are treated as patterns.
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* This feature is required for module aliases.
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*/
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#define INDEX_CHILDMAX 128
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/* Disk format:
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uint32_t magic = INDEX_MAGIC;
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uint32_t version = INDEX_VERSION;
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uint32_t root_offset;
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(node_offset & INDEX_NODE_MASK) specifies the file offset of nodes:
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char[] prefix; // nul terminated
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char first;
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char last;
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uint32_t children[last - first + 1];
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uint32_t value_count;
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struct {
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uint32_t priority;
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char[] value; // nul terminated
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} values[value_count];
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(node_offset & INDEX_NODE_FLAGS) indicates which fields are present.
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Empty prefixes are omitted, leaf nodes omit the three child-related fields.
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This could be optimised further by adding a sparse child format
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(indicated using a new flag).
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*
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* uint32_t magic = INDEX_MAGIC;
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* uint32_t version = INDEX_VERSION;
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* uint32_t root_offset;
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*
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* (node_offset & INDEX_NODE_MASK) specifies the file offset of nodes:
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*
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* char[] prefix; // nul terminated
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*
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* char first;
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* char last;
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* uint32_t children[last - first + 1];
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*
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* uint32_t value_count;
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* struct {
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* uint32_t priority;
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* char[] value; // nul terminated
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* } values[value_count];
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*
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* (node_offset & INDEX_NODE_FLAGS) indicates which fields are present.
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* Empty prefixes are omitted, leaf nodes omit the three child-related fields.
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*
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* This could be optimised further by adding a sparse child format
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* (indicated using a new flag).
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*
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*
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* Implementation is based on a radix tree, or "trie".
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* Each arc from parent to child is labelled with a character.
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* Each path from the root represents a string.
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*
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* == Example strings ==
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*
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* ask
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* ate
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* on
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* once
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* one
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*
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* == Key ==
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* + Normal node
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* * Marked node, representing a key and it's values.
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*
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* +
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* |-a-+-s-+-k-*
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* | |
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* | `-t-+-e-*
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* |
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* `-o-+-n-*-c-+-e-*
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* |
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* `-e-*
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*
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* Naive implementations tend to be very space inefficient; child pointers
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* are stored in arrays indexed by character, but most child pointers are null.
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*
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* Our implementation uses a scheme described by Wikipedia as a Patrica trie,
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*
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* "easiest to understand as a space-optimized trie where
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* each node with only one child is merged with its child"
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*
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* +
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* |-a-+-sk-*
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* | |
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* | `-te-*
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* |
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* `-on-*-ce-*
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* |
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* `-e-*
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*
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* We still use arrays of child pointers indexed by a single character;
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* the remaining characters of the label are stored as a "prefix" in the child.
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*
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* The paper describing the original Patrica trie works on individiual bits -
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* each node has a maximum of two children, which increases space efficiency.
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* However for this application it is simpler to use the ASCII character set.
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* Since the index file is read-only, it can be compressed by omitting null
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* child pointers at the start and end of arrays.
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*/
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/* Format of node offsets within index file */
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@ -22,85 +22,6 @@
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#include <inttypes.h>
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/* Integers are stored as 32 bit unsigned in "network" order, i.e. MSB first.
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All files start with a magic number.
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Magic spells "BOOTFAST". Second one used on newer versioned binary files.
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*/
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/* #define INDEX_MAGIC_OLD 0xB007FA57 */
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#define INDEX_MAGIC 0xB007F457
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/* We use a version string to keep track of changes to the binary format
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* This is stored in the form: INDEX_MAJOR (hi) INDEX_MINOR (lo) just in
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* case we ever decide to have minor changes that are not incompatible.
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*/
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#define INDEX_VERSION_MAJOR 0x0002
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#define INDEX_VERSION_MINOR 0x0001
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#define INDEX_VERSION ((INDEX_VERSION_MAJOR<<16)|INDEX_VERSION_MINOR)
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/* The index file maps keys to values. Both keys and values are ASCII strings.
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Each key can have multiple values. Values are sorted by an integer priority.
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The reader also implements a wildcard search (including range expressions)
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where the keys in the index are treated as patterns.
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This feature is required for module aliases.
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*/
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/* Implementation is based on a radix tree, or "trie".
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Each arc from parent to child is labelled with a character.
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Each path from the root represents a string.
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== Example strings ==
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ask
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ate
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on
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once
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one
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== Key ==
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+ Normal node
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* Marked node, representing a key and it's values.
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+
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|-a-+-s-+-k-*
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| |
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| `-t-+-e-*
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|
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`-o-+-n-*-c-+-e-*
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`-e-*
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Naive implementations tend to be very space inefficient; child pointers
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are stored in arrays indexed by character, but most child pointers are null.
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Our implementation uses a scheme described by Wikipedia as a Patrica trie,
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"easiest to understand as a space-optimized trie where
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each node with only one child is merged with its child"
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+
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|-a-+-sk-*
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| |
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| `-te-*
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|
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`-on-*-ce-*
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|
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`-e-*
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We still use arrays of child pointers indexed by a single character;
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the remaining characters of the label are stored as a "prefix" in the child.
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The paper describing the original Patrica trie works on individiual bits -
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each node has a maximum of two children, which increases space efficiency.
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However for this application it is simpler to use the ASCII character set.
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Since the index file is read-only, it can be compressed by omitting null
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child pointers at the start and end of arrays.
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*/
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#define INDEX_PRIORITY_MIN UINT32_MAX
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struct index_value {
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struct index_value *next;
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unsigned int priority;
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