gitk: Second try to work around the command line limit on Windows
[git/dscho.git] / name-hash.c
blob0031d78e8c98a32d61cd0dc0f939a033e24ed890
1 /*
2 * name-hash.c
4 * Hashing names in the index state
6 * Copyright (C) 2008 Linus Torvalds
7 */
8 #define NO_THE_INDEX_COMPATIBILITY_MACROS
9 #include "cache.h"
12 * This removes bit 5 if bit 6 is set.
14 * That will make US-ASCII characters hash to their upper-case
15 * equivalent. We could easily do this one whole word at a time,
16 * but that's for future worries.
18 static inline unsigned char icase_hash(unsigned char c)
20 return c & ~((c & 0x40) >> 1);
23 static unsigned int hash_name(const char *name, int namelen)
25 unsigned int hash = 0x123;
27 do {
28 unsigned char c = *name++;
29 c = icase_hash(c);
30 hash = hash*101 + c;
31 } while (--namelen);
32 return hash;
35 static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
37 void **pos;
38 unsigned int hash;
40 if (ce->ce_flags & CE_HASHED)
41 return;
42 ce->ce_flags |= CE_HASHED;
43 ce->next = NULL;
44 hash = hash_name(ce->name, ce_namelen(ce));
45 pos = insert_hash(hash, ce, &istate->name_hash);
46 if (pos) {
47 ce->next = *pos;
48 *pos = ce;
52 static void lazy_init_name_hash(struct index_state *istate)
54 int nr;
56 if (istate->name_hash_initialized)
57 return;
58 for (nr = 0; nr < istate->cache_nr; nr++)
59 hash_index_entry(istate, istate->cache[nr]);
60 istate->name_hash_initialized = 1;
63 void add_name_hash(struct index_state *istate, struct cache_entry *ce)
65 ce->ce_flags &= ~CE_UNHASHED;
66 if (istate->name_hash_initialized)
67 hash_index_entry(istate, ce);
70 static int slow_same_name(const char *name1, int len1, const char *name2, int len2)
72 if (len1 != len2)
73 return 0;
75 while (len1) {
76 unsigned char c1 = *name1++;
77 unsigned char c2 = *name2++;
78 len1--;
79 if (c1 != c2) {
80 c1 = toupper(c1);
81 c2 = toupper(c2);
82 if (c1 != c2)
83 return 0;
86 return 1;
89 static int same_name(const struct cache_entry *ce, const char *name, int namelen, int icase)
91 int len = ce_namelen(ce);
94 * Always do exact compare, even if we want a case-ignoring comparison;
95 * we do the quick exact one first, because it will be the common case.
97 if (len == namelen && !cache_name_compare(name, namelen, ce->name, len))
98 return 1;
100 return icase && slow_same_name(name, namelen, ce->name, len);
103 struct cache_entry *index_name_exists(struct index_state *istate, const char *name, int namelen, int icase)
105 unsigned int hash = hash_name(name, namelen);
106 struct cache_entry *ce;
108 lazy_init_name_hash(istate);
109 ce = lookup_hash(hash, &istate->name_hash);
111 while (ce) {
112 if (!(ce->ce_flags & CE_UNHASHED)) {
113 if (same_name(ce, name, namelen, icase))
114 return ce;
116 ce = ce->next;
118 return NULL;