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authorJunio C Hamano <gitster@pobox.com>2011-10-26 23:13:31 (GMT)
committerJunio C Hamano <gitster@pobox.com>2011-10-26 23:13:31 (GMT)
commit60f60b49629b6693ce5b8ce9201b2f6dd3989354 (patch)
tree6207a4c3e49edccf3da2627135b55373b693a7d3 /Documentation
parent7bb07f6fbfeca68a71580a7d8b2228f19b4a9820 (diff)
parent5d40a179855a39ae9e8ac22e1874720f2b98a91c (diff)
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Merge branch 'jk/argv-array' into maint
* jk/argv-array: run_hook: use argv_array API checkout: use argv_array API bisect: use argv_array API quote: provide sq_dequote_to_argv_array refactor argv_array into generic code quote.h: fix bogus comment add sha1_array API docs
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/technical/api-argv-array.txt46
-rw-r--r--Documentation/technical/api-sha1-array.txt79
2 files changed, 125 insertions, 0 deletions
diff --git a/Documentation/technical/api-argv-array.txt b/Documentation/technical/api-argv-array.txt
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+++ b/Documentation/technical/api-argv-array.txt
@@ -0,0 +1,46 @@
+argv-array API
+==============
+
+The argv-array API allows one to dynamically build and store
+NULL-terminated lists. An argv-array maintains the invariant that the
+`argv` member always points to a non-NULL array, and that the array is
+always NULL-terminated at the element pointed to by `argv[argc]`. This
+makes the result suitable for passing to functions expecting to receive
+argv from main(), or the link:api-run-command.html[run-command API].
+
+The link:api-string-list.html[string-list API] is similar, but cannot be
+used for these purposes; instead of storing a straight string pointer,
+it contains an item structure with a `util` field that is not compatible
+with the traditional argv interface.
+
+Each `argv_array` manages its own memory. Any strings pushed into the
+array are duplicated, and all memory is freed by argv_array_clear().
+
+Data Structures
+---------------
+
+`struct argv_array`::
+
+ A single array. This should be initialized by assignment from
+ `ARGV_ARRAY_INIT`, or by calling `argv_array_init`. The `argv`
+ member contains the actual array; the `argc` member contains the
+ number of elements in the array, not including the terminating
+ NULL.
+
+Functions
+---------
+
+`argv_array_init`::
+ Initialize an array. This is no different than assigning from
+ `ARGV_ARRAY_INIT`.
+
+`argv_array_push`::
+ Push a copy of a string onto the end of the array.
+
+`argv_array_pushf`::
+ Format a string and push it onto the end of the array. This is a
+ convenience wrapper combining `strbuf_addf` and `argv_array_push`.
+
+`argv_array_clear`::
+ Free all memory associated with the array and return it to the
+ initial, empty state.
diff --git a/Documentation/technical/api-sha1-array.txt b/Documentation/technical/api-sha1-array.txt
new file mode 100644
index 0000000..4a4bae8
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+++ b/Documentation/technical/api-sha1-array.txt
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+sha1-array API
+==============
+
+The sha1-array API provides storage and manipulation of sets of SHA1
+identifiers. The emphasis is on storage and processing efficiency,
+making them suitable for large lists. Note that the ordering of items is
+not preserved over some operations.
+
+Data Structures
+---------------
+
+`struct sha1_array`::
+
+ A single array of SHA1 hashes. This should be initialized by
+ assignment from `SHA1_ARRAY_INIT`. The `sha1` member contains
+ the actual data. The `nr` member contains the number of items in
+ the set. The `alloc` and `sorted` members are used internally,
+ and should not be needed by API callers.
+
+Functions
+---------
+
+`sha1_array_append`::
+ Add an item to the set. The sha1 will be placed at the end of
+ the array (but note that some operations below may lose this
+ ordering).
+
+`sha1_array_sort`::
+ Sort the elements in the array.
+
+`sha1_array_lookup`::
+ Perform a binary search of the array for a specific sha1.
+ If found, returns the offset (in number of elements) of the
+ sha1. If not found, returns a negative integer. If the array is
+ not sorted, this function has the side effect of sorting it.
+
+`sha1_array_clear`::
+ Free all memory associated with the array and return it to the
+ initial, empty state.
+
+`sha1_array_for_each_unique`::
+ Efficiently iterate over each unique element of the list,
+ executing the callback function for each one. If the array is
+ not sorted, this function has the side effect of sorting it.
+
+Examples
+--------
+
+-----------------------------------------
+void print_callback(const unsigned char sha1[20],
+ void *data)
+{
+ printf("%s\n", sha1_to_hex(sha1));
+}
+
+void some_func(void)
+{
+ struct sha1_array hashes = SHA1_ARRAY_INIT;
+ unsigned char sha1[20];
+
+ /* Read objects into our set */
+ while (read_object_from_stdin(sha1))
+ sha1_array_append(&hashes, sha1);
+
+ /* Check if some objects are in our set */
+ while (read_object_from_stdin(sha1)) {
+ if (sha1_array_lookup(&hashes, sha1) >= 0)
+ printf("it's in there!\n");
+
+ /*
+ * Print the unique set of objects. We could also have
+ * avoided adding duplicate objects in the first place,
+ * but we would end up re-sorting the array repeatedly.
+ * Instead, this will sort once and then skip duplicates
+ * in linear time.
+ */
+ sha1_array_for_each_unique(&hashes, print_callback, NULL);
+}
+-----------------------------------------