mirror of
https://github.com/git/git.git
synced 2024-11-25 19:04:18 +08:00
cd2fef59ed
Right now nobody uses it, but "index_name_exists()" gets a flag so you can enable it on a case-by-case basis. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
120 lines
2.5 KiB
C
120 lines
2.5 KiB
C
/*
|
|
* name-hash.c
|
|
*
|
|
* Hashing names in the index state
|
|
*
|
|
* Copyright (C) 2008 Linus Torvalds
|
|
*/
|
|
#define NO_THE_INDEX_COMPATIBILITY_MACROS
|
|
#include "cache.h"
|
|
|
|
/*
|
|
* This removes bit 5 if bit 6 is set.
|
|
*
|
|
* That will make US-ASCII characters hash to their upper-case
|
|
* equivalent. We could easily do this one whole word at a time,
|
|
* but that's for future worries.
|
|
*/
|
|
static inline unsigned char icase_hash(unsigned char c)
|
|
{
|
|
return c & ~((c & 0x40) >> 1);
|
|
}
|
|
|
|
static unsigned int hash_name(const char *name, int namelen)
|
|
{
|
|
unsigned int hash = 0x123;
|
|
|
|
do {
|
|
unsigned char c = *name++;
|
|
c = icase_hash(c);
|
|
hash = hash*101 + c;
|
|
} while (--namelen);
|
|
return hash;
|
|
}
|
|
|
|
static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
|
|
{
|
|
void **pos;
|
|
unsigned int hash;
|
|
|
|
if (ce->ce_flags & CE_HASHED)
|
|
return;
|
|
ce->ce_flags |= CE_HASHED;
|
|
ce->next = NULL;
|
|
hash = hash_name(ce->name, ce_namelen(ce));
|
|
pos = insert_hash(hash, ce, &istate->name_hash);
|
|
if (pos) {
|
|
ce->next = *pos;
|
|
*pos = ce;
|
|
}
|
|
}
|
|
|
|
static void lazy_init_name_hash(struct index_state *istate)
|
|
{
|
|
int nr;
|
|
|
|
if (istate->name_hash_initialized)
|
|
return;
|
|
for (nr = 0; nr < istate->cache_nr; nr++)
|
|
hash_index_entry(istate, istate->cache[nr]);
|
|
istate->name_hash_initialized = 1;
|
|
}
|
|
|
|
void add_name_hash(struct index_state *istate, struct cache_entry *ce)
|
|
{
|
|
ce->ce_flags &= ~CE_UNHASHED;
|
|
if (istate->name_hash_initialized)
|
|
hash_index_entry(istate, ce);
|
|
}
|
|
|
|
static int slow_same_name(const char *name1, int len1, const char *name2, int len2)
|
|
{
|
|
if (len1 != len2)
|
|
return 0;
|
|
|
|
while (len1) {
|
|
unsigned char c1 = *name1++;
|
|
unsigned char c2 = *name2++;
|
|
len1--;
|
|
if (c1 != c2) {
|
|
c1 = toupper(c1);
|
|
c2 = toupper(c2);
|
|
if (c1 != c2)
|
|
return 0;
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static int same_name(const struct cache_entry *ce, const char *name, int namelen, int icase)
|
|
{
|
|
int len = ce_namelen(ce);
|
|
|
|
/*
|
|
* Always do exact compare, even if we want a case-ignoring comparison;
|
|
* we do the quick exact one first, because it will be the common case.
|
|
*/
|
|
if (len == namelen && !cache_name_compare(name, namelen, ce->name, len))
|
|
return 1;
|
|
|
|
return icase && slow_same_name(name, namelen, ce->name, len);
|
|
}
|
|
|
|
struct cache_entry *index_name_exists(struct index_state *istate, const char *name, int namelen, int icase)
|
|
{
|
|
unsigned int hash = hash_name(name, namelen);
|
|
struct cache_entry *ce;
|
|
|
|
lazy_init_name_hash(istate);
|
|
ce = lookup_hash(hash, &istate->name_hash);
|
|
|
|
while (ce) {
|
|
if (!(ce->ce_flags & CE_UNHASHED)) {
|
|
if (same_name(ce, name, namelen, icase))
|
|
return ce;
|
|
}
|
|
ce = ce->next;
|
|
}
|
|
return NULL;
|
|
}
|