Andrew's git - gitweb.git/blob

   1/*
   2 * name-hash.c
   3 *
   4 * Hashing names in the index state
   5 *
   6 * Copyright (C) 2008 Linus Torvalds
   7 */
   8#define NO_THE_INDEX_COMPATIBILITY_MACROS
   9#include "cache.h"
  10
  11static unsigned int hash_name(const char *name, int namelen)
  12{
  13        unsigned int hash = 0x123;
  14
  15        do {
  16                unsigned char c = *name++;
  17                hash = hash*101 + c;
  18        } while (--namelen);
  19        return hash;
  20}
  21
  22static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
  23{
  24        void **pos;
  25        unsigned int hash;
  26
  27        if (ce->ce_flags & CE_HASHED)
  28                return;
  29        ce->ce_flags |= CE_HASHED;
  30        ce->next = NULL;
  31        hash = hash_name(ce->name, ce_namelen(ce));
  32        pos = insert_hash(hash, ce, &istate->name_hash);
  33        if (pos) {
  34                ce->next = *pos;
  35                *pos = ce;
  36        }
  37}
  38
  39static void lazy_init_name_hash(struct index_state *istate)
  40{
  41        int nr;
  42
  43        if (istate->name_hash_initialized)
  44                return;
  45        for (nr = 0; nr < istate->cache_nr; nr++)
  46                hash_index_entry(istate, istate->cache[nr]);
  47        istate->name_hash_initialized = 1;
  48}
  49
  50void add_name_hash(struct index_state *istate, struct cache_entry *ce)
  51{
  52        ce->ce_flags &= ~CE_UNHASHED;
  53        if (istate->name_hash_initialized)
  54                hash_index_entry(istate, ce);
  55}
  56
  57struct cache_entry *index_name_exists(struct index_state *istate, const char *name, int namelen)
  58{
  59        unsigned int hash = hash_name(name, namelen);
  60        struct cache_entry *ce;
  61
  62        lazy_init_name_hash(istate);
  63        ce = lookup_hash(hash, &istate->name_hash);
  64
  65        while (ce) {
  66                if (!(ce->ce_flags & CE_UNHASHED)) {
  67                        if (!cache_name_compare(name, namelen, ce->name, ce->ce_flags))
  68                                return ce;
  69                }
  70                ce = ce->next;
  71        }
  72        return NULL;
  73}