Add util function to locate a column in a string

This will help to parse the result of "adb shell ip route" to find the
device IP address.

PR #2827 <https://github.com/Genymobile/scrcpy/pull/2827>
This commit is contained in:
Romain Vimont 2021-11-18 09:32:21 +01:00
parent 3bf6fd2894
commit b52f87a892
3 changed files with 67 additions and 0 deletions

View file

@ -304,3 +304,29 @@ sc_str_truncate(char *data, size_t len, const char *endchars) {
data[idx] = '\0'; data[idx] = '\0';
return idx; return idx;
} }
ssize_t
sc_str_index_of_column(const char *s, unsigned col, const char *seps) {
size_t colidx = 0;
size_t idx = 0;
while (s[idx] != '\0' && colidx != col) {
size_t r = strcspn(&s[idx], seps);
idx += r;
if (s[idx] == '\0') {
// Not found
return -1;
}
size_t consecutive_seps = strspn(&s[idx], seps);
assert(consecutive_seps); // At least one
idx += consecutive_seps;
if (s[idx] != '\0') {
++colidx;
}
}
return col == colidx ? (ssize_t) idx : -1;
}

View file

@ -114,4 +114,24 @@ sc_str_wrap_lines(const char *input, unsigned columns, unsigned indent);
size_t size_t
sc_str_truncate(char *data, size_t len, const char *endchars); sc_str_truncate(char *data, size_t len, const char *endchars);
/**
* Find the start of a column in a string
*
* A string may represent several columns, separated by some "spaces"
* (separators). This function aims to find the start of the column number
* `col`.
*
* For example, to find the 4th column (column number 3):
*
* // here
* // v
* const char *s = "abc def ghi jk";
* ssize_t index = sc_str_index_of_column(s, 3, " ");
* assert(index == 16); // points to "jk"
*
* Return -1 if no such column exists.
*/
ssize_t
sc_str_index_of_column(const char *s, unsigned col, const char *seps);
#endif #endif

View file

@ -364,6 +364,26 @@ static void test_truncate(void) {
assert(!strcmp("hello", s4)); assert(!strcmp("hello", s4));
} }
static void test_index_of_column(void) {
assert(sc_str_index_of_column("a bc d", 0, " ") == 0);
assert(sc_str_index_of_column("a bc d", 1, " ") == 2);
assert(sc_str_index_of_column("a bc d", 2, " ") == 6);
assert(sc_str_index_of_column("a bc d", 3, " ") == -1);
assert(sc_str_index_of_column("a ", 0, " ") == 0);
assert(sc_str_index_of_column("a ", 1, " ") == -1);
assert(sc_str_index_of_column("", 0, " ") == 0);
assert(sc_str_index_of_column("", 1, " ") == -1);
assert(sc_str_index_of_column("a \t \t bc \t d\t", 0, " \t") == 0);
assert(sc_str_index_of_column("a \t \t bc \t d\t", 1, " \t") == 8);
assert(sc_str_index_of_column("a \t \t bc \t d\t", 2, " \t") == 15);
assert(sc_str_index_of_column("a \t \t bc \t d\t", 3, " \t") == -1);
assert(sc_str_index_of_column(" a bc d", 1, " ") == 2);
}
int main(int argc, char *argv[]) { int main(int argc, char *argv[]) {
(void) argc; (void) argc;
(void) argv; (void) argv;
@ -384,5 +404,6 @@ int main(int argc, char *argv[]) {
test_strlist_contains(); test_strlist_contains();
test_wrap_lines(); test_wrap_lines();
test_truncate(); test_truncate();
test_index_of_column();
return 0; return 0;
} }