Merge branch 'kb/hashmap-v5-minimal' into kb/fscache-v4-t1.8.5

Documentation/technical/api-hashmap.txt

@@ -0,0 +1,235 @@
+hashmap API
+===========
+
+The hashmap API is a generic implementation of hash-based key-value mappings.
+
+Data Structures
+---------------
+
+`struct hashmap`::
+
+	The hash table structure.
++
+The `size` member keeps track of the total number of entries. The `cmpfn`
+member is a function used to compare two entries for equality. The `table` and
+`tablesize` members store the hash table and its size, respectively.
+
+`struct hashmap_entry`::
+
+	An opaque structure representing an entry in the hash table, which must
+	be used as first member of user data structures. Ideally it should be
+	followed by an int-sized member to prevent unused memory on 64-bit
+	systems due to alignment.
++
+The `hash` member is the entry's hash code and the `next` member points to the
+next entry in case of collisions (i.e. if multiple entries map to the same
+bucket).
+
+`struct hashmap_iter`::
+
+	An iterator structure, to be used with hashmap_iter_* functions.
+
+Types
+-----
+
+`int (*hashmap_cmp_fn)(const void *entry, const void *entry_or_key, const void *keydata)`::
+
+	User-supplied function to test two hashmap entries for equality. Shall
+	return 0 if the entries are equal.
++
+This function is always called with non-NULL `entry` / `entry_or_key`
+parameters that have the same hash code. When looking up an entry, the `key`
+and `keydata` parameters to hashmap_get and hashmap_remove are always passed
+as second and third argument, respectively. Otherwise, `keydata` is NULL.
+
+Functions
+---------
+
+`unsigned int strhash(const char *buf)`::
+`unsigned int strihash(const char *buf)`::
+`unsigned int memhash(const void *buf, size_t len)`::
+`unsigned int memihash(const void *buf, size_t len)`::
+
+	Ready-to-use hash functions for strings, using the FNV-1 algorithm (see
+	http://www.isthe.com/chongo/tech/comp/fnv).
++
+`strhash` and `strihash` take 0-terminated strings, while `memhash` and
+`memihash` operate on arbitrary-length memory.
++
+`strihash` and `memihash` are case insensitive versions.
+
+`void hashmap_init(struct hashmap *map, hashmap_cmp_fn equals_function, size_t initial_size)`::
+
+	Initializes a hashmap structure.
++
+`map` is the hashmap to initialize.
++
+The `equals_function` can be specified to compare two entries for equality.
+If NULL, entries are considered equal if their hash codes are equal.
++
+If the total number of entries is known in advance, the `initial_size`
+parameter may be used to preallocate a sufficiently large table and thus
+prevent expensive resizing. If 0, the table is dynamically resized.
+
+`void hashmap_free(struct hashmap *map, int free_entries)`::
+
+	Frees a hashmap structure and allocated memory.
++
+`map` is the hashmap to free.
++
+If `free_entries` is true, each hashmap_entry in the map is freed as well
+(using stdlib's free()).
+
+`void hashmap_entry_init(void *entry, int hash)`::
+
+	Initializes a hashmap_entry structure.
++
+`entry` points to the entry to initialize.
++
+`hash` is the hash code of the entry.
+
+`void *hashmap_get(const struct hashmap *map, const void *key, const void *keydata)`::
+
+	Returns the hashmap entry for the specified key, or NULL if not found.
++
+`map` is the hashmap structure.
++
+`key` is a hashmap_entry structure (or user data structure that starts with
+hashmap_entry) that has at least been initialized with the proper hash code
+(via `hashmap_entry_init`).
++
+If an entry with matching hash code is found, `key` and `keydata` are passed
+to `hashmap_cmp_fn` to decide whether the entry matches the key.
+
+`void *hashmap_get_next(const struct hashmap *map, const void *entry)`::
+
+	Returns the next equal hashmap entry, or NULL if not found. This can be
+	used to iterate over duplicate entries (see `hashmap_add`).
++
+`map` is the hashmap structure.
++
+`entry` is the hashmap_entry to start the search from, obtained via a previous
+call to `hashmap_get` or `hashmap_get_next`.
+
+`void hashmap_add(struct hashmap *map, void *entry)`::
+
+	Adds a hashmap entry. This allows to add duplicate entries (i.e.
+	separate values with the same key according to hashmap_cmp_fn).
++
+`map` is the hashmap structure.
++
+`entry` is the entry to add.
+
+`void *hashmap_put(struct hashmap *map, void *entry)`::
+
+	Adds or replaces a hashmap entry. If the hashmap contains duplicate
+	entries equal to the specified entry, only one of them will be replaced.
++
+`map` is the hashmap structure.
++
+`entry` is the entry to add or replace.
++
+Returns the replaced entry, or NULL if not found (i.e. the entry was added).
+
+`void *hashmap_remove(struct hashmap *map, const void *key, const void *keydata)`::
+
+	Removes a hashmap entry matching the specified key. If the hashmap
+	contains duplicate entries equal to the specified key, only one of
+	them will be removed.
++
+`map` is the hashmap structure.
++
+`key` is a hashmap_entry structure (or user data structure that starts with
+hashmap_entry) that has at least been initialized with the proper hash code
+(via `hashmap_entry_init`).
++
+If an entry with matching hash code is found, `key` and `keydata` are
+passed to `hashmap_cmp_fn` to decide whether the entry matches the key.
++
+Returns the removed entry, or NULL if not found.
+
+`void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter)`::
+`void *hashmap_iter_next(struct hashmap_iter *iter)`::
+`void *hashmap_iter_first(struct hashmap *map, struct hashmap_iter *iter)`::
+
+	Used to iterate over all entries of a hashmap.
++
+`hashmap_iter_init` initializes a `hashmap_iter` structure.
++
+`hashmap_iter_next` returns the next hashmap_entry, or NULL if there are no
+more entries.
++
+`hashmap_iter_first` is a combination of both (i.e. initializes the iterator
+and returns the first entry, if any).
+
+Usage example
+-------------
+
+Here's a simple usage example that maps long keys to double values.
+[source,c]
+------------
+struct hashmap map;
+
+struct long2double {
+	struct hashmap_entry ent; /* must be the first member! */
+	long key;
+	double value;
+};
+
+static int long2double_cmp(const struct long2double *e1, const struct long2double *e2, const void *unused)
+{
+	return !(e1->key == e2->key);
+}
+
+void long2double_init(void)
+{
+	hashmap_init(&map, (hashmap_cmp_fn) long2double_cmp, 0);
+}
+
+void long2double_free(void)
+{
+	hashmap_free(&map, 1);
+}
+
+static struct long2double *find_entry(long key)
+{
+	struct long2double k;
+	hashmap_entry_init(&k, memhash(&key, sizeof(long)));
+	k.key = key;
+	return hashmap_get(&map, &k, NULL);
+}
+
+double get_value(long key)
+{
+	struct long2double *e = find_entry(key);
+	return e ? e->value : 0;
+}
+
+void set_value(long key, double value)
+{
+	struct long2double *e = find_entry(key);
+	if (!e) {
+		e = malloc(sizeof(struct long2double));
+		hashmap_entry_init(e, memhash(&key, sizeof(long)));
+		e->key = key;
+		hashmap_add(&map, e);
+	}
+	e->value = value;
+}
+------------
+
+Using variable-sized keys
+-------------------------
+
+The `hashmap_entry_get` and `hashmap_entry_remove` functions expect an ordinary
+`hashmap_entry` structure as key to find the correct entry. If the key data is
+variable-sized (e.g. a FLEX_ARRAY string) or quite large, it is undesirable
+to create a full-fledged entry structure on the heap and copy all the key data
+into the structure.
+
+In this case, the `keydata` parameter can be used to pass
+variable-sized key data directly to the comparison function, and the `key`
+parameter can be a stripped-down, fixed size entry structure allocated on the
+stack.
+
+See test-hashmap.c for an example using arbitrary-length strings as keys.

Makefile

@@ -556,6 +556,7 @@ TEST_PROGRAMS_NEED_X += test-date
 TEST_PROGRAMS_NEED_X += test-delta
 TEST_PROGRAMS_NEED_X += test-dump-cache-tree
 TEST_PROGRAMS_NEED_X += test-genrandom
+TEST_PROGRAMS_NEED_X += test-hashmap
 TEST_PROGRAMS_NEED_X += test-index-version
 TEST_PROGRAMS_NEED_X += test-line-buffer
 TEST_PROGRAMS_NEED_X += test-match-trees
@@ -676,6 +677,7 @@ LIB_H += gpg-interface.h
 LIB_H += graph.h
 LIB_H += grep.h
 LIB_H += hash.h
+LIB_H += hashmap.h
 LIB_H += help.h
 LIB_H += http.h
 LIB_H += kwset.h
@@ -807,6 +809,7 @@ LIB_OBJS += gpg-interface.o
 LIB_OBJS += graph.o
 LIB_OBJS += grep.o
 LIB_OBJS += hash.o
+LIB_OBJS += hashmap.o
 LIB_OBJS += help.o
 LIB_OBJS += hex.o
 LIB_OBJS += ident.o

hashmap.c

@@ -0,0 +1,228 @@
+/*
+ * Generic implementation of hash-based key value mappings.
+ */
+#include "cache.h"
+#include "hashmap.h"
+
+#define FNV32_BASE ((unsigned int) 0x811c9dc5)
+#define FNV32_PRIME ((unsigned int) 0x01000193)
+
+unsigned int strhash(const char *str)
+{
+	unsigned int c, hash = FNV32_BASE;
+	while ((c = (unsigned char) *str++))
+		hash = (hash * FNV32_PRIME) ^ c;
+	return hash;
+}
+
+unsigned int strihash(const char *str)
+{
+	unsigned int c, hash = FNV32_BASE;
+	while ((c = (unsigned char) *str++)) {
+		if (c >= 'a' && c <= 'z')
+			c -= 'a' - 'A';
+		hash = (hash * FNV32_PRIME) ^ c;
+	}
+	return hash;
+}
+
+unsigned int memhash(const void *buf, size_t len)
+{
+	unsigned int hash = FNV32_BASE;
+	unsigned char *ucbuf = (unsigned char *) buf;
+	while (len--) {
+		unsigned int c = *ucbuf++;
+		hash = (hash * FNV32_PRIME) ^ c;
+	}
+	return hash;
+}
+
+unsigned int memihash(const void *buf, size_t len)
+{
+	unsigned int hash = FNV32_BASE;
+	unsigned char *ucbuf = (unsigned char *) buf;
+	while (len--) {
+		unsigned int c = *ucbuf++;
+		if (c >= 'a' && c <= 'z')
+			c -= 'a' - 'A';
+		hash = (hash * FNV32_PRIME) ^ c;
+	}
+	return hash;
+}
+
+#define HASHMAP_INITIAL_SIZE 64
+/* grow / shrink by 2^2 */
+#define HASHMAP_RESIZE_BITS 2
+/* load factor in percent */
+#define HASHMAP_LOAD_FACTOR 80
+
+static void alloc_table(struct hashmap *map, unsigned int size)
+{
+	map->tablesize = size;
+	map->table = xcalloc(size, sizeof(struct hashmap_entry *));
+
+	/* calculate resize thresholds for new size */
+	map->grow_at = (unsigned int) ((uint64_t) size * HASHMAP_LOAD_FACTOR / 100);
+	if (size <= HASHMAP_INITIAL_SIZE)
+		map->shrink_at = 0;
+	else
+		/*
+		 * The shrink-threshold must be slightly smaller than
+		 * (grow-threshold / resize-factor) to prevent erratic resizing,
+		 * thus we divide by (resize-factor + 1).
+		 */
+		map->shrink_at = map->grow_at / ((1 << HASHMAP_RESIZE_BITS) + 1);
+}
+
+static inline int entry_equals(const struct hashmap *map,
+		const struct hashmap_entry *e1, const struct hashmap_entry *e2,
+		const void *keydata)
+{
+	return (e1 == e2) || (e1->hash == e2->hash && !map->cmpfn(e1, e2, keydata));
+}
+
+static inline unsigned int bucket(const struct hashmap *map,
+		const struct hashmap_entry *key)
+{
+	return key->hash & (map->tablesize - 1);
+}
+
+static void rehash(struct hashmap *map, unsigned int newsize)
+{
+	unsigned int i, oldsize = map->tablesize;
+	struct hashmap_entry **oldtable = map->table;
+
+	alloc_table(map, newsize);
+	for (i = 0; i < oldsize; i++) {
+		struct hashmap_entry *e = oldtable[i];
+		while (e) {
+			struct hashmap_entry *next = e->next;
+			unsigned int b = bucket(map, e);
+			e->next = map->table[b];
+			map->table[b] = e;
+			e = next;
+		}
+	}
+	free(oldtable);
+}
+
+static inline struct hashmap_entry **find_entry_ptr(const struct hashmap *map,
+		const struct hashmap_entry *key, const void *keydata)
+{
+	struct hashmap_entry **e = &map->table[bucket(map, key)];
+	while (*e && !entry_equals(map, *e, key, keydata))
+		e = &(*e)->next;
+	return e;
+}
+
+static int always_equal(const void *unused1, const void *unused2, const void *unused3)
+{
+	return 0;
+}
+
+void hashmap_init(struct hashmap *map, hashmap_cmp_fn equals_function,
+		size_t initial_size)
+{
+	unsigned int size = HASHMAP_INITIAL_SIZE;
+	map->size = 0;
+	map->cmpfn = equals_function ? equals_function : always_equal;
+
+	/* calculate initial table size and allocate the table */
+	initial_size = (unsigned int) ((uint64_t) initial_size * 100
+			/ HASHMAP_LOAD_FACTOR);
+	while (initial_size > size)
+		size <<= HASHMAP_RESIZE_BITS;
+	alloc_table(map, size);
+}
+
+void hashmap_free(struct hashmap *map, int free_entries)
+{
+	if (!map || !map->table)
+		return;
+	if (free_entries) {
+		struct hashmap_iter iter;
+		struct hashmap_entry *e;
+		hashmap_iter_init(map, &iter);
+		while ((e = hashmap_iter_next(&iter)))
+			free(e);
+	}
+	free(map->table);
+	memset(map, 0, sizeof(*map));
+}
+
+void *hashmap_get(const struct hashmap *map, const void *key, const void *keydata)
+{
+	return *find_entry_ptr(map, key, keydata);
+}
+
+void *hashmap_get_next(const struct hashmap *map, const void *entry)
+{
+	struct hashmap_entry *e = ((struct hashmap_entry *) entry)->next;
+	for (; e; e = e->next)
+		if (entry_equals(map, entry, e, NULL))
+			return e;
+	return NULL;
+}
+
+void hashmap_add(struct hashmap *map, void *entry)
+{
+	unsigned int b = bucket(map, entry);
+
+	/* add entry */
+	((struct hashmap_entry *) entry)->next = map->table[b];
+	map->table[b] = entry;
+
+	/* fix size and rehash if appropriate */
+	map->size++;
+	if (map->size > map->grow_at)
+		rehash(map, map->tablesize << HASHMAP_RESIZE_BITS);
+}
+
+void *hashmap_remove(struct hashmap *map, const void *key, const void *keydata)
+{
+	struct hashmap_entry *old;
+	struct hashmap_entry **e = find_entry_ptr(map, key, keydata);
+	if (!*e)
+		return NULL;
+
+	/* remove existing entry */
+	old = *e;
+	*e = old->next;
+	old->next = NULL;
+
+	/* fix size and rehash if appropriate */
+	map->size--;
+	if (map->size < map->shrink_at)
+		rehash(map, map->tablesize >> HASHMAP_RESIZE_BITS);
+	return old;
+}
+
+void *hashmap_put(struct hashmap *map, void *entry)
+{
+	struct hashmap_entry *old = hashmap_remove(map, entry, NULL);
+	hashmap_add(map, entry);
+	return old;
+}
+
+void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter)
+{
+	iter->map = map;
+	iter->tablepos = 0;
+	iter->next = NULL;
+}
+
+void *hashmap_iter_next(struct hashmap_iter *iter)
+{
+	struct hashmap_entry *current = iter->next;
+	for (;;) {
+		if (current) {
+			iter->next = current->next;
+			return current;
+		}
+
+		if (iter->tablepos >= iter->map->tablesize)
+			return NULL;
+
+		current = iter->map->table[iter->tablepos++];
+	}
+}

hashmap.h

@@ -0,0 +1,71 @@
+#ifndef HASHMAP_H
+#define HASHMAP_H
+
+/*
+ * Generic implementation of hash-based key-value mappings.
+ * See Documentation/technical/api-hashmap.txt.
+ */
+
+/* FNV-1 functions */
+
+extern unsigned int strhash(const char *buf);
+extern unsigned int strihash(const char *buf);
+extern unsigned int memhash(const void *buf, size_t len);
+extern unsigned int memihash(const void *buf, size_t len);
+
+/* data structures */
+
+struct hashmap_entry {
+	struct hashmap_entry *next;
+	unsigned int hash;
+};
+
+typedef int (*hashmap_cmp_fn)(const void *entry, const void *entry_or_key,
+		const void *keydata);
+
+struct hashmap {
+	struct hashmap_entry **table;
+	hashmap_cmp_fn cmpfn;
+	unsigned int size, tablesize, grow_at, shrink_at;
+};
+
+struct hashmap_iter {
+	struct hashmap *map;
+	struct hashmap_entry *next;
+	unsigned int tablepos;
+};
+
+/* hashmap functions */
+
+extern void hashmap_init(struct hashmap *map, hashmap_cmp_fn equals_function,
+		size_t initial_size);
+extern void hashmap_free(struct hashmap *map, int free_entries);
+
+/* hashmap_entry functions */
+
+static inline void hashmap_entry_init(void *entry, int hash)
+{
+	struct hashmap_entry *e = entry;
+	e->hash = hash;
+	e->next = NULL;
+}
+extern void *hashmap_get(const struct hashmap *map, const void *key,
+		const void *keydata);
+extern void *hashmap_get_next(const struct hashmap *map, const void *entry);
+extern void hashmap_add(struct hashmap *map, void *entry);
+extern void *hashmap_put(struct hashmap *map, void *entry);
+extern void *hashmap_remove(struct hashmap *map, const void *key,
+		const void *keydata);
+
+/* hashmap_iter functions */
+
+extern void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter);
+extern void *hashmap_iter_next(struct hashmap_iter *iter);
+static inline void *hashmap_iter_first(struct hashmap *map,
+		struct hashmap_iter *iter)
+{
+	hashmap_iter_init(map, iter);
+	return hashmap_iter_next(iter);
+}
+
+#endif

submodule.c

@@ -116,30 +116,7 @@ int remove_path_from_gitmodules(const char *path)
 
 void stage_updated_gitmodules(void)
 {
-	struct strbuf buf = STRBUF_INIT;
-	struct stat st;
-	int pos;
-	struct cache_entry *ce;
-	int namelen = strlen(".gitmodules");
-
-	pos = cache_name_pos(".gitmodules", namelen);
-	if (pos < 0) {
-		warning(_("could not find .gitmodules in index"));
-		return;
-	}
-	ce = active_cache[pos];
-	ce->ce_flags = namelen;
-	if (strbuf_read_file(&buf, ".gitmodules", 0) < 0)
-		die(_("reading updated .gitmodules failed"));
-	if (lstat(".gitmodules", &st) < 0)
-		die_errno(_("unable to stat updated .gitmodules"));
-	fill_stat_cache_info(ce, &st);
-	ce->ce_mode = ce_mode_from_stat(ce, st.st_mode);
-	if (remove_cache_entry_at(pos) < 0)
-		die(_("unable to remove .gitmodules from index"));
-	if (write_sha1_file(buf.buf, buf.len, blob_type, ce->sha1))
-		die(_("adding updated .gitmodules failed"));
-	if (add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE))
+	if (add_file_to_cache(".gitmodules", 0))
 		die(_("staging updated .gitmodules failed"));
 }
 

t/t0011-hashmap.sh

@@ -0,0 +1,240 @@
+#!/bin/sh
+
+test_description='test hashmap and string hash functions'
+. ./test-lib.sh
+
+test_hashmap() {
+	echo "$1" | test-hashmap $3 > actual &&
+	echo "$2" > expect &&
+	test_cmp expect actual
+}
+
+test_expect_success 'hash functions' '
+
+test_hashmap "hash key1" "2215982743 2215982743 116372151 116372151" &&
+test_hashmap "hash key2" "2215982740 2215982740 116372148 116372148" &&
+test_hashmap "hash fooBarFrotz" "1383912807 1383912807 3189766727 3189766727" &&
+test_hashmap "hash foobarfrotz" "2862305959 2862305959 3189766727 3189766727"
+
+'
+
+test_expect_success 'put' '
+
+test_hashmap "put key1 value1
+put key2 value2
+put fooBarFrotz value3
+put foobarfrotz value4
+size" "NULL
+NULL
+NULL
+NULL
+64 4"
+
+'
+
+test_expect_success 'put (case insensitive)' '
+
+test_hashmap "put key1 value1
+put key2 value2
+put fooBarFrotz value3
+size" "NULL
+NULL
+NULL
+64 3" ignorecase
+
+'
+
+test_expect_success 'replace' '
+
+test_hashmap "put key1 value1
+put key1 value2
+put fooBarFrotz value3
+put fooBarFrotz value4
+size" "NULL
+value1
+NULL
+value3
+64 2"
+
+'
+
+test_expect_success 'replace (case insensitive)' '
+
+test_hashmap "put key1 value1
+put Key1 value2
+put fooBarFrotz value3
+put foobarfrotz value4
+size" "NULL
+value1
+NULL
+value3
+64 2" ignorecase
+
+'
+
+test_expect_success 'get' '
+
+test_hashmap "put key1 value1
+put key2 value2
+put fooBarFrotz value3
+put foobarfrotz value4
+get key1
+get key2
+get fooBarFrotz
+get notInMap" "NULL
+NULL
+NULL
+NULL
+value1
+value2
+value3
+NULL"
+
+'
+
+test_expect_success 'get (case insensitive)' '
+
+test_hashmap "put key1 value1
+put key2 value2
+put fooBarFrotz value3
+get Key1
+get keY2
+get foobarfrotz
+get notInMap" "NULL
+NULL
+NULL
+value1
+value2
+value3
+NULL" ignorecase
+
+'
+
+test_expect_success 'add' '
+
+test_hashmap "add key1 value1
+add key1 value2
+add fooBarFrotz value3
+add fooBarFrotz value4
+get key1
+get fooBarFrotz
+get notInMap" "value2
+value1
+value4
+value3
+NULL"
+
+'
+
+test_expect_success 'add (case insensitive)' '
+
+test_hashmap "add key1 value1
+add Key1 value2
+add fooBarFrotz value3
+add foobarfrotz value4
+get key1
+get Foobarfrotz
+get notInMap" "value2
+value1
+value4
+value3
+NULL" ignorecase
+
+'
+
+test_expect_success 'remove' '
+
+test_hashmap "put key1 value1
+put key2 value2
+put fooBarFrotz value3
+remove key1
+remove key2
+remove notInMap
+size" "NULL
+NULL
+NULL
+value1
+value2
+NULL
+64 1"
+
+'
+
+test_expect_success 'remove (case insensitive)' '
+
+test_hashmap "put key1 value1
+put key2 value2
+put fooBarFrotz value3
+remove Key1
+remove keY2
+remove notInMap
+size" "NULL
+NULL
+NULL
+value1
+value2
+NULL
+64 1" ignorecase
+
+'
+
+test_expect_success 'iterate' '
+
+test_hashmap "put key1 value1
+put key2 value2
+put fooBarFrotz value3
+iterate" "NULL
+NULL
+NULL
+key2 value2
+key1 value1
+fooBarFrotz value3"
+
+'
+
+test_expect_success 'iterate (case insensitive)' '
+
+test_hashmap "put key1 value1
+put key2 value2
+put fooBarFrotz value3
+iterate" "NULL
+NULL
+NULL
+fooBarFrotz value3
+key2 value2
+key1 value1" ignorecase
+
+'
+
+test_expect_success 'grow / shrink' '
+
+	rm -f in &&
+	rm -f expect &&
+	for n in $(test_seq 51)
+	do
+		echo put key$n value$n >> in &&
+		echo NULL >> expect
+	done &&
+	echo size >> in &&
+	echo 64 51 >> expect &&
+	echo put key52 value52 >> in &&
+	echo NULL >> expect
+	echo size >> in &&
+	echo 256 52 >> expect &&
+	for n in $(test_seq 12)
+	do
+		echo remove key$n >> in &&
+		echo value$n >> expect
+	done &&
+	echo size >> in &&
+	echo 256 40 >> expect &&
+	echo remove key40 >> in &&
+	echo value40 >> expect &&
+	echo size >> in &&
+	echo 64 39 >> expect &&
+	cat in | test-hashmap > out &&
+	test_cmp expect out
+
+'
+
+test_done

test-hashmap.c

@@ -0,0 +1,340 @@
+#include "cache.h"
+#include "hashmap.h"
+#include <stdio.h>
+
+struct test_entry
+{
+	struct hashmap_entry ent;
+	/* key and value as two \0-terminated strings */
+	char key[FLEX_ARRAY];
+};
+
+static const char *get_value(const struct test_entry *e)
+{
+	return e->key + strlen(e->key) + 1;
+}
+
+static int test_entry_cmp(const struct test_entry *e1,
+		const struct test_entry *e2, const char* key)
+{
+	return strcmp(e1->key, key ? key : e2->key);
+}
+
+static int test_entry_cmp_icase(const struct test_entry *e1,
+		const struct test_entry *e2, const char* key)
+{
+	return strcasecmp(e1->key, key ? key : e2->key);
+}
+
+static struct test_entry *alloc_test_entry(int hash, char *key, int klen,
+		char *value, int vlen)
+{
+	struct test_entry *entry = malloc(sizeof(struct test_entry) + klen
+			+ vlen + 2);
+	hashmap_entry_init(entry, hash);
+	memcpy(entry->key, key, klen + 1);
+	memcpy(entry->key + klen + 1, value, vlen + 1);
+	return entry;
+}
+
+#define HASH_METHOD_FNV 0
+#define HASH_METHOD_I 1
+#define HASH_METHOD_IDIV10 2
+#define HASH_METHOD_0 3
+#define HASH_METHOD_X2 4
+#define TEST_SPARSE 8
+#define TEST_ADD 16
+#define TEST_SIZE 100000
+
+static unsigned int hash(unsigned int method, unsigned int i, const char *key)
+{
+	unsigned int hash;
+	switch (method & 3)
+	{
+	case HASH_METHOD_FNV:
+		hash = strhash(key);
+		break;
+	case HASH_METHOD_I:
+		hash = i;
+		break;
+	case HASH_METHOD_IDIV10:
+		hash = i / 10;
+		break;
+	case HASH_METHOD_0:
+		hash = 0;
+		break;
+	}
+
+	if (method & HASH_METHOD_X2)
+		hash = 2 * hash;
+	return hash;
+}
+
+/*
+ * Test performance of hashmap.[ch]
+ * Usage: time echo "perfhashmap method rounds" | test-hashmap
+ */
+static void perf_hashmap(unsigned int method, unsigned int rounds)
+{
+	struct hashmap map;
+	char buf[16];
+	struct test_entry **entries;
+	unsigned int *hashes;
+	unsigned int i, j;
+
+	entries = malloc(TEST_SIZE * sizeof(struct test_entry *));
+	hashes = malloc(TEST_SIZE * sizeof(int));
+	for (i = 0; i < TEST_SIZE; i++) {
+		snprintf(buf, sizeof(buf), "%i", i);
+		entries[i] = alloc_test_entry(0, buf, strlen(buf), "", 0);
+		hashes[i] = hash(method, i, entries[i]->key);
+	}
+
+	if (method & TEST_ADD) {
+		/* test adding to the map */
+		for (j = 0; j < rounds; j++) {
+			hashmap_init(&map, (hashmap_cmp_fn) test_entry_cmp, 0);
+
+			/* add entries */
+			for (i = 0; i < TEST_SIZE; i++) {
+				hashmap_entry_init(entries[i], hashes[i]);
+				hashmap_add(&map, entries[i]);
+			}
+
+			hashmap_free(&map, 0);
+		}
+	} else {
+		/* test map lookups */
+		hashmap_init(&map, (hashmap_cmp_fn) test_entry_cmp, 0);
+
+		/* fill the map (sparsely if specified) */
+		j = (method & TEST_SPARSE) ? TEST_SIZE / 10 : TEST_SIZE;
+		for (i = 0; i < j; i++) {
+			hashmap_entry_init(entries[i], hashes[i]);
+			hashmap_add(&map, entries[i]);
+		}
+
+		for (j = 0; j < rounds; j++) {
+			for (i = 0; i < TEST_SIZE; i++) {
+				struct hashmap_entry key;
+				hashmap_entry_init(&key, hashes[i]);
+				hashmap_get(&map, &key, entries[i]->key);
+			}
+		}
+
+		hashmap_free(&map, 0);
+	}
+}
+
+struct hash_entry
+{
+	struct hash_entry *next;
+	char key[FLEX_ARRAY];
+};
+
+/*
+ * Test performance of hash.[ch]
+ * Usage: time echo "perfhash method rounds" | test-hashmap
+ */
+static void perf_hash(unsigned int method, unsigned int rounds)
+{
+	struct hash_table map;
+	char buf[16];
+	struct hash_entry **entries, **res, *entry;
+	unsigned int *hashes;
+	unsigned int i, j;
+
+	entries = malloc(TEST_SIZE * sizeof(struct hash_entry *));
+	hashes = malloc(TEST_SIZE * sizeof(int));
+	for (i = 0; i < TEST_SIZE; i++) {
+		snprintf(buf, sizeof(buf), "%i", i);
+		entries[i] = malloc(sizeof(struct hash_entry) + strlen(buf) + 1);
+		strcpy(entries[i]->key, buf);
+		hashes[i] = hash(method, i, entries[i]->key);
+	}
+
+	if (method & TEST_ADD) {
+		/* test adding to the map */
+		for (j = 0; j < rounds; j++) {
+			init_hash(&map);
+
+			/* add entries */
+			for (i = 0; i < TEST_SIZE; i++) {
+				res = (struct hash_entry **) insert_hash(
+						hashes[i], entries[i], &map);
+				if (res) {
+					entries[i]->next = *res;
+					*res = entries[i];
+				} else {
+					entries[i]->next = NULL;
+				}
+			}
+
+			free_hash(&map);
+		}
+	} else {
+		/* test map lookups */
+		init_hash(&map);
+
+		/* fill the map (sparsely if specified) */
+		j = (method & TEST_SPARSE) ? TEST_SIZE / 10 : TEST_SIZE;
+		for (i = 0; i < j; i++) {
+			res = (struct hash_entry **) insert_hash(hashes[i],
+					entries[i], &map);
+			if (res) {
+				entries[i]->next = *res;
+				*res = entries[i];
+			} else {
+				entries[i]->next = NULL;
+			}
+		}
+
+		for (j = 0; j < rounds; j++) {
+			for (i = 0; i < TEST_SIZE; i++) {
+				entry = lookup_hash(hashes[i], &map);
+				while (entry) {
+					if (!strcmp(entries[i]->key, entry->key))
+						break;
+					entry = entry->next;
+				}
+			}
+		}
+
+		free_hash(&map);
+
+	}
+}
+
+#define DELIM " \t\r\n"
+
+/*
+ * Read stdin line by line and print result of commands to stdout:
+ *
+ * hash key -> strhash(key) memhash(key) strihash(key) memihash(key)
+ * put key value -> NULL / old value
+ * get key -> NULL / value
+ * remove key -> NULL / old value
+ * iterate -> key1 value1\nkey2 value2\n...
+ * size -> tablesize numentries
+ *
+ * perfhashmap method rounds -> test hashmap.[ch] performance
+ * perfhash method rounds -> test hash.[ch] performance
+ */
+int main(int argc, char *argv[])
+{
+	char line[1024];
+	struct hashmap map;
+	int icase;
+
+	/* init hash map */
+	icase = argc > 1 && !strcmp("ignorecase", argv[1]);
+	hashmap_init(&map, (hashmap_cmp_fn) (icase ? test_entry_cmp_icase
+			: test_entry_cmp), 0);
+
+	/* process commands from stdin */
+	while (fgets(line, sizeof(line), stdin)) {
+		char *cmd, *p1 = NULL, *p2 = NULL;
+		int l1 = 0, l2 = 0, hash = 0;
+		struct test_entry *entry;
+
+		/* break line into command and up to two parameters */
+		cmd = strtok(line, DELIM);
+		/* ignore empty lines */
+		if (!cmd || *cmd == '#')
+			continue;
+
+		p1 = strtok(NULL, DELIM);
+		if (p1) {
+			l1 = strlen(p1);
+			hash = icase ? strihash(p1) : strhash(p1);
+			p2 = strtok(NULL, DELIM);
+			if (p2)
+				l2 = strlen(p2);
+		}
+
+		if (!strcmp("hash", cmd) && l1) {
+
+			/* print results of different hash functions */
+			printf("%u %u %u %u\n", strhash(p1), memhash(p1, l1),
+					strihash(p1), memihash(p1, l1));
+
+		} else if (!strcmp("add", cmd) && l1 && l2) {
+
+			/* create entry with key = p1, value = p2 */
+			entry = alloc_test_entry(hash, p1, l1, p2, l2);
+
+			/* add to hashmap */
+			hashmap_add(&map, entry);
+
+		} else if (!strcmp("put", cmd) && l1 && l2) {
+
+			/* create entry with key = p1, value = p2 */
+			entry = alloc_test_entry(hash, p1, l1, p2, l2);
+
+			/* add / replace entry */
+			entry = hashmap_put(&map, entry);
+
+			/* print and free replaced entry, if any */
+			puts(entry ? get_value(entry) : "NULL");
+			free(entry);
+
+		} else if (!strcmp("get", cmd) && l1) {
+
+			/* setup static key */
+			struct hashmap_entry key;
+			hashmap_entry_init(&key, hash);
+
+			/* lookup entry in hashmap */
+			entry = hashmap_get(&map, &key, p1);
+
+			/* print result */
+			if (!entry)
+				puts("NULL");
+			while (entry) {
+				puts(get_value(entry));
+				entry = hashmap_get_next(&map, entry);
+			}
+
+		} else if (!strcmp("remove", cmd) && l1) {
+
+			/* setup static key */
+			struct hashmap_entry key;
+			hashmap_entry_init(&key, hash);
+
+			/* remove entry from hashmap */
+			entry = hashmap_remove(&map, &key, p1);
+
+			/* print result and free entry*/
+			puts(entry ? get_value(entry) : "NULL");
+			free(entry);
+
+		} else if (!strcmp("iterate", cmd)) {
+
+			struct hashmap_iter iter;
+			hashmap_iter_init(&map, &iter);
+			while ((entry = hashmap_iter_next(&iter)))
+				printf("%s %s\n", entry->key, get_value(entry));
+
+		} else if (!strcmp("size", cmd)) {
+
+			/* print table sizes */
+			printf("%u %u\n", map.tablesize, map.size);
+
+		} else if (!strcmp("perfhashmap", cmd) && l1 && l2) {
+
+			perf_hashmap(atoi(p1), atoi(p2));
+
+		} else if (!strcmp("perfhash", cmd) && l1 && l2) {
+
+			perf_hash(atoi(p1), atoi(p2));
+
+		} else {
+
+			printf("Unknown command %s\n", cmd);
+
+		}
+	}
+
+	hashmap_free(&map, 1);
+	return 0;
+}