Add a function that finds the longest string from a string_list that
is a prefix of a given string.
Signed-off-by: Michael Haggerty <mhag...@alum.mit.edu>
---
Documentation/technical/api-string-list.txt | 8 ++++++++
string-list.c | 20 +++++++++++++++++++
string-list.h | 8 ++++++++
t/t0063-string-list.sh | 30 +++++++++++++++++++++++++++++
test-string-list.c | 20 +++++++++++++++++++
5 files changed, 86 insertions(+)
diff --git a/Documentation/technical/api-string-list.txt
b/Documentation/technical/api-string-list.txt
index 0f8b7ce..32b35d9 100644
--- a/Documentation/technical/api-string-list.txt
+++ b/Documentation/technical/api-string-list.txt
@@ -75,6 +75,14 @@ Functions
to be deleted. Preserve the order of the items that are
retained.
+`string_list_longest_prefix`::
+
+ Return the longest string within a string_list that is a
+ prefix (in the sense of prefixcmp()) of the specified string,
+ or NULL if no such prefix exists. This function does not
+ require the string_list to be sorted (it does a linear
+ search).
+
`print_string_list`::
Dump a string_list to stdout, useful mainly for debugging purposes. It
diff --git a/string-list.c b/string-list.c
index decfa74..c54b816 100644
--- a/string-list.c
+++ b/string-list.c
@@ -136,6 +136,26 @@ void filter_string_list(struct string_list *list, int
free_util,
list->nr = dst;
}
+char *string_list_longest_prefix(const struct string_list *prefixes,
+ const char *string)
+{
+ int i, max_len = -1;
+ char *retval = NULL;
+
+ for (i = 0; i < prefixes->nr; i++) {
+ char *prefix = prefixes->items[i].string;
+ if (!prefixcmp(string, prefix)) {
+ int len = strlen(prefix);
+ if (len > max_len) {
+ retval = prefix;
+ max_len = len;
+ }
+ }
+ }
+
+ return retval;
+}
+
void string_list_clear(struct string_list *list, int free_util)
{
if (list->items) {
diff --git a/string-list.h b/string-list.h
index 3a6a6dc..5efd07b 100644
--- a/string-list.h
+++ b/string-list.h
@@ -38,6 +38,14 @@ int for_each_string_list(struct string_list *list,
void filter_string_list(struct string_list *list, int free_util,
string_list_each_func_t want, void *cb_data);
+/*
+ * Return the longest string in prefixes that is a prefix (in the
+ * sense of prefixcmp()) of string, or NULL if no such prefix exists.
+ * This function does not require the string_list to be sorted (it
+ * does a linear search).
+ */
+char *string_list_longest_prefix(const struct string_list *prefixes, const
char *string);
+
/* Use these functions only on sorted lists: */
int string_list_has_string(const struct string_list *list, const char *string);
diff --git a/t/t0063-string-list.sh b/t/t0063-string-list.sh
index dbfc05e..41c8826 100755
--- a/t/t0063-string-list.sh
+++ b/t/t0063-string-list.sh
@@ -17,6 +17,14 @@ test_split () {
"
}
+test_longest_prefix () {
+ test "$(test-string-list longest_prefix "$1" "$2")" = "$3"
+}
+
+test_no_longest_prefix () {
+ test_must_fail test-string-list longest_prefix "$1" "$2"
+}
+
test_split "foo:bar:baz" ":" "-1" <<EOF
3
[0]: "foo"
@@ -88,4 +96,26 @@ test_expect_success "test remove_duplicates" '
test a:b:c = "$(test-string-list remove_duplicates a:a:a:b:b:b:c:c:c)"
'
+test_expect_success "test longest_prefix" '
+ test_no_longest_prefix - '' &&
+ test_no_longest_prefix - x &&
+ test_longest_prefix "" x "" &&
+ test_longest_prefix x x x &&
+ test_longest_prefix "" foo "" &&
+ test_longest_prefix : foo "" &&
+ test_longest_prefix f foo f &&
+ test_longest_prefix foo foobar foo &&
+ test_longest_prefix foo foo foo &&
+ test_no_longest_prefix bar foo &&
+ test_no_longest_prefix bar:bar foo &&
+ test_no_longest_prefix foobar foo &&
+ test_longest_prefix foo:bar foo foo &&
+ test_longest_prefix foo:bar bar bar &&
+ test_longest_prefix foo::bar foo foo &&
+ test_longest_prefix foo:foobar foo foo &&
+ test_longest_prefix foobar:foo foo foo &&
+ test_longest_prefix foo: bar "" &&
+ test_longest_prefix :foo bar ""
+'
+
test_done
diff --git a/test-string-list.c b/test-string-list.c
index 2d6eda7..5e9631f 100644
--- a/test-string-list.c
+++ b/test-string-list.c
@@ -97,6 +97,26 @@ int main(int argc, char **argv)
return 0;
}
+ if (argc == 4 && !strcmp(argv[1], "longest_prefix")) {
+ /* arguments: <colon-separated-prefixes>|- <string> */
+ struct string_list prefixes = STRING_LIST_INIT_DUP;
+ int retval;
+ const char *prefix_string = argv[2];
+ const char *string = argv[3];
+ const char *match;
+
+ parse_string_list(&prefixes, prefix_string);
+ match = string_list_longest_prefix(&prefixes, string);
+ if (match) {
+ printf("%s\n", match);
+ retval = 0;
+ }
+ else
+ retval = 1;
+ string_list_clear(&prefixes, 0);
+ return retval;
+ }
+
fprintf(stderr, "%s: unknown function name: %s\n", argv[0],
argv[1] ? argv[1] : "(there was none)");
return 1;
--
1.7.11.3
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