| /* key-gen.c --- manufacturing sequential keys for some db tables |
| * |
| * ==================================================================== |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| * ==================================================================== |
| */ |
| |
| #ifndef SVN_LIBSVN_FS_KEY_GEN_H |
| #define SVN_LIBSVN_FS_KEY_GEN_H |
| |
| #include <apr.h> |
| |
| #include "svn_types.h" |
| #include "private/svn_skel.h" /* ### for svn_fs_base__{get,put}size() */ |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif /* __cplusplus */ |
| |
| |
| /* The alphanumeric keys passed in and out of svn_fs_base__next_key |
| are guaranteed never to be longer than this many bytes, |
| *including* the trailing null byte. It is therefore safe |
| to declare a key as "char key[MAX_KEY_SIZE]". |
| |
| Note that this limit will be a problem if the number of |
| keys in a table ever exceeds |
| |
| 18217977168218728251394687124089371267338971528174 |
| 76066745969754933395997209053270030282678007662838 |
| 67331479599455916367452421574456059646801054954062 |
| 15017704234999886990788594743994796171248406730973 |
| 80736524850563115569208508785942830080999927310762 |
| 50733948404739350551934565743979678824151197232629 |
| 947748581376, |
| |
| but that's a risk we'll live with for now. */ |
| #define MAX_KEY_SIZE 200 |
| |
| /* In many of the databases, the value at this key is the key to use |
| when storing a new record. */ |
| #define NEXT_KEY_KEY "next-key" |
| |
| |
| /* Generate the next key after a given alphanumeric key. |
| * |
| * The first *LEN bytes of THIS are an ascii representation of a |
| * number in base 36: digits 0-9 have their usual values, and a-z have |
| * values 10-35. |
| * |
| * The new key is stored in NEXT, null-terminated. NEXT must be at |
| * least *LEN + 2 bytes long -- one extra byte to hold a possible |
| * overflow column, and one for null termination. On return, *LEN |
| * will be set to the length of the new key, not counting the null |
| * terminator. In other words, the outgoing *LEN will be either equal |
| * to the incoming, or to the incoming + 1. |
| * |
| * If THIS contains anything other than digits and lower-case |
| * alphabetic characters, or if it starts with `0' but is not the |
| * string "0", then *LEN is set to zero and the effect on NEXT |
| * is undefined. |
| */ |
| void svn_fs_base__next_key(const char *this, apr_size_t *len, char *next); |
| |
| |
| /* Compare two strings A and B as base-36 alphanumber keys. |
| * |
| * Return TRUE iff both keys are NULL or both keys have the same |
| * contents. |
| */ |
| svn_boolean_t svn_fs_base__same_keys(const char *a, const char *b); |
| |
| |
| #ifdef __cplusplus |
| } |
| #endif /* __cplusplus */ |
| |
| #endif /* SVN_LIBSVN_FS_KEY_GEN_H */ |