[PATCH v2 06/10] strmap: add more utility functions
From: Elijah Newren <newren@gmail.com>
This adds a number of additional convienence functions I want/need:
* strmap_empty()
* strmap_get_size()
* strmap_remove()
* strmap_for_each_entry()
* strmap_get_entry()
I suspect the first four are self-explanatory.
strmap_get_entry() is similar to strmap_get() except that instead of just
returning the void* value that the string maps to, it returns the
strmap_entry that contains both the string and the void* value (or
NULL if the string isn't in the map). This is helpful because it avoids
multiple lookups, e.g. in some cases a caller would need to call:
* strmap_contains() to check that the map has an entry for the string
* strmap_get() to get the void* value
* <do some work to update the value>
* strmap_put() to update/overwrite the value
If the void* pointer returned really is a pointer, then the last step is
unnecessary, but if the void* pointer is just cast to an integer then
strmap_put() will be needed. In contrast, one can call strmap_get_entry()
and then:
* check if the string was in the map by whether the pointer is NULL
* access the value via entry->value
* directly update entry->value
meaning that we can replace two or three hash table lookups with one.
Signed-off-by: Elijah Newren <newren@gmail.com>
---
strmap.c | 20 ++++++++++++++++++++
strmap.h | 38 ++++++++++++++++++++++++++++++++++++++
2 files changed, 58 insertions(+)
diff --git a/strmap.c b/strmap.c
index 4b48d64274..909b9fbedf 100644
--- a/strmap.c
+++ b/strmap.c
@@ -90,6 +90,11 @@ void *strmap_put(struct strmap *map, const char *str, void *data)
return old;
}
+struct strmap_entry *strmap_get_entry(struct strmap *map, const char *str)
+{
+ return find_strmap_entry(map, str);
+}
+
void *strmap_get(struct strmap *map, const char *str)
{
struct strmap_entry *entry = find_strmap_entry(map, str);
@@ -100,3 +105,18 @@ int strmap_contains(struct strmap *map, const char *str)
{
return find_strmap_entry(map, str) != NULL;
}
+
+void strmap_remove(struct strmap *map, const char *str, int free_util)
+{
+ struct strmap_entry entry, *ret;
+ hashmap_entry_init(&entry.ent, strhash(str));
+ entry.key = str;
+ ret = hashmap_remove_entry(&map->map, &entry, ent, NULL);
+ if (!ret)
+ return;
+ if (free_util)
+ free(ret->value);
+ if (map->strdup_strings)
+ free((char*)ret->key);
+ free(ret);
+}
diff --git a/strmap.h b/strmap.h
index 493d19cbc0..e49d020970 100644
--- a/strmap.h
+++ b/strmap.h
@@ -42,6 +42,12 @@ void strmap_clear(struct strmap *map, int free_values);
*/
void *strmap_put(struct strmap *map, const char *str, void *data);
+/*
+ * Return the strmap_entry mapped by "str", or NULL if there is not such
+ * an item in map.
+ */
+struct strmap_entry *strmap_get_entry(struct strmap *map, const char *str);
+
/*
* Return the data pointer mapped by "str", or NULL if the entry does not
* exist.
@@ -54,4 +60,36 @@ void *strmap_get(struct strmap *map, const char *str);
*/
int strmap_contains(struct strmap *map, const char *str);
+/*
+ * Remove the given entry from the strmap. If the string isn't in the
+ * strmap, the map is not altered.
+ */
+void strmap_remove(struct strmap *map, const char *str, int free_value);
+
+/*
+ * Return whether the strmap is empty.
+ */
+static inline int strmap_empty(struct strmap *map)
+{
+ return hashmap_get_size(&map->map) == 0;
+}
+
+/*
+ * Return how many entries the strmap has.
+ */
+static inline unsigned int strmap_get_size(struct strmap *map)
+{
+ return hashmap_get_size(&map->map);
+}
+
+/*
+ * iterate through @map using @iter, @var is a pointer to a type strmap_entry
+ */
+#define strmap_for_each_entry(mystrmap, iter, var) \
+ for (var = hashmap_iter_first_entry_offset(&(mystrmap)->map, iter, \
+ OFFSETOF_VAR(var, ent)); \
+ var; \
+ var = hashmap_iter_next_entry_offset(iter, \
+ OFFSETOF_VAR(var, ent)))
+
#endif /* STRMAP_H */
--
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Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>