Werner's Miscellanea
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| 1 | /* |
| 2 | * id.h - Registry of unique and alphabetically sorted identifiers |
| 3 | * |
| 4 | * Written 2010 by Werner Almesberger |
| 5 | * Copyright 2010 Werner Almesberger |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | */ |
| 12 | |
| 13 | #ifndef ID_H |
| 14 | #define ID_H |
| 15 | |
| 16 | #include <sys/types.h> |
| 17 | |
| 18 | #include "jrb.h" |
| 19 | |
| 20 | |
| 21 | /* |
| 22 | * The role of key and value in jrb nodes: |
| 23 | * |
| 24 | * - the key points to a "struct id". This "struct id" is unique for the |
| 25 | * identifier in question and its location can be used to check for equality |
| 26 | * with a simple pointer comparison. |
| 27 | * |
| 28 | * A caller to find_id may therefore be interested in a pointer to the key, |
| 29 | * even if the content of the key is known. |
| 30 | * |
| 31 | * - for the value, we have to distinguish between packages and versions: |
| 32 | * |
| 33 | * - package: pointer to the first package definition. If there are multiple |
| 34 | * packages with the same name, the rest is linked via pkg->more. |
| 35 | * |
| 36 | * The value can be NULL if a reference to the package has been |
| 37 | * encountered, but |
| 38 | * |
| 39 | * - the package definition has not been parsed yet, |
| 40 | * - no corresponding package definition exist (which would be an error), |
| 41 | * - the reference is an item listed in Provides: (this will change once |
| 42 | * we handle Provides: properly) |
| 43 | * |
| 44 | * - version: the value is not used |
| 45 | */ |
| 46 | |
| 47 | |
| 48 | struct id; |
| 49 | |
| 50 | struct tree { |
| 51 | int (*comp)(const void *a, const void *b); |
| 52 | struct jrb *root; |
| 53 | }; |
| 54 | |
| 55 | struct id { |
| 56 | struct jrb *jrb; |
| 57 | const char *s; |
| 58 | size_t len; |
| 59 | }; |
| 60 | |
| 61 | |
| 62 | /* |
| 63 | * Helper macro for printing identifiers. |
| 64 | * Use with "... %.*s ..." |
| 65 | */ |
| 66 | |
| 67 | #define ID2PF(id) (int) (id)->len, (id)->s |
| 68 | |
| 69 | |
| 70 | int comp_id(const void *a, const void *b); |
| 71 | int comp_versions(const struct id *va, const struct id *vb); |
| 72 | |
| 73 | struct tree *make_tree(int (*comp)(const void *a, const void *b)); |
| 74 | struct jrb *make_id(struct tree *tree, const char *s, size_t len); |
| 75 | const struct jrb *find_id(const struct tree *tree, const char *s, size_t len); |
| 76 | |
| 77 | #endif /* !ID_H */ |
| 78 |
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