diff options
author | Junio C Hamano <gitster@pobox.com> | 2008-05-11 23:08:20 +0400 |
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committer | Junio C Hamano <gitster@pobox.com> | 2008-05-11 23:08:20 +0400 |
commit | dccb3a6acbb2e7c6a405fe67b6487aaee0cf1977 (patch) | |
tree | 936ed4d96eea5d08923a333560e53144c2f9d468 /name-hash.c | |
parent | dfd1b749befcb581d84722caa6a3af56ce6526a5 (diff) | |
parent | c40641b77b0274186fd1b327d5dc3246f814aaaf (diff) |
Merge branch 'lt/core-optim'
* lt/core-optim:
Optimize symlink/directory detection
Avoid some unnecessary lstat() calls
is_racy_timestamp(): do not check timestamp for gitlinks
diff-lib.c: rename check_work_tree_entity()
diff: a submodule not checked out is not modified
Add t7506 to test submodule related functions for git-status
t4027: test diff for submodule with empty directory
Make git-add behave more sensibly in a case-insensitive environment
When adding files to the index, add support for case-independent matches
Make unpack-tree update removed files before any updated files
Make branch merging aware of underlying case-insensitive filsystems
Add 'core.ignorecase' option
Make hash_name_lookup able to do case-independent lookups
Make "index_name_exists()" return the cache_entry it found
Move name hashing functions into a file of its own
Make unpack_trees_options bit flags actual bitfields
Diffstat (limited to 'name-hash.c')
-rw-r--r-- | name-hash.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/name-hash.c b/name-hash.c new file mode 100644 index 0000000000..0031d78e8c --- /dev/null +++ b/name-hash.c @@ -0,0 +1,119 @@ +/* + * 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; +} |