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| author |  Karsten Blees <karsten.blees@gmail.com> | 2014-07-03 00:22:54 +0200 |
|---|---|---|
| committer |  Junio C Hamano <gitster@pobox.com> | 2014-07-07 13:56:38 -0700 |
| commit | 7b64d42d22206d9995a8f0cb3b515e623cac4702 (patch) | |
| tree | 26895c5fde113b1d84f52409f951feb37f451412 /Documentation/technical/api-hashmap.txt | |
| parent | hashmap: add simplified hashmap_get_from_hash() API (diff) | |
| download | tgif-7b64d42d22206d9995a8f0cb3b515e623cac4702.tar.xz | |
hashmap: add string interning API
Interning short strings with high probability of duplicates can reduce the
memory footprint and speed up comparisons.
Add strintern() and memintern() APIs that use a hashmap to manage the pool
of unique, interned strings.
Note: strintern(getenv()) could be used to sanitize git's use of getenv(),
in case we ever encounter a platform where a call to getenv() invalidates
previous getenv() results (which is allowed by POSIX).
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'Documentation/technical/api-hashmap.txt')
| -rw-r--r-- | Documentation/technical/api-hashmap.txt | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/technical/api-hashmap.txt b/Documentation/technical/api-hashmap.txt index 8ed92a9f85..ad7a5bddd2 100644 --- a/Documentation/technical/api-hashmap.txt +++ b/Documentation/technical/api-hashmap.txt @@ -193,6 +193,21 @@ more entries. `hashmap_iter_first` is a combination of both (i.e. initializes the iterator and returns the first entry, if any). +`const char *strintern(const char *string)`:: +`const void *memintern(const void *data, size_t len)`:: + + Returns the unique, interned version of the specified string or data, + similar to the `String.intern` API in Java and .NET, respectively. + Interned strings remain valid for the entire lifetime of the process. ++ +Can be used as `[x]strdup()` or `xmemdupz` replacement, except that interned +strings / data must not be modified or freed. ++ +Interned strings are best used for short strings with high probability of +duplicates. ++ +Uses a hashmap to store the pool of interned strings. + Usage example ------------- |