diff --git a/src/core/support/string.c b/src/core/support/string.c index 6a80ccc8411..f85f656da43 100644 --- a/src/core/support/string.c +++ b/src/core/support/string.c @@ -153,6 +153,12 @@ int gpr_ltoa(long value, char *string) { } char *gpr_strjoin(const char **strs, size_t nstrs, size_t *final_length) { + return gpr_strjoin_sep(strs, nstrs, "", final_length); +} + +char *gpr_strjoin_sep(const char **strs, size_t nstrs, const char *sep, + size_t *final_length) { + const size_t sep_len = strlen(sep); size_t out_length = 0; size_t i; char *out; @@ -160,12 +166,19 @@ char *gpr_strjoin(const char **strs, size_t nstrs, size_t *final_length) { out_length += strlen(strs[i]); } out_length += 1; /* null terminator */ + if (nstrs > 0) { + out_length += sep_len * (nstrs - 1); /* separators */ + } out = gpr_malloc(out_length); out_length = 0; for (i = 0; i < nstrs; i++) { - size_t slen = strlen(strs[i]); + const size_t slen = strlen(strs[i]); memcpy(out + out_length, strs[i], slen); out_length += slen; + if (sep_len > 0 && nstrs > 0 && i < nstrs - 1) { + memcpy(out + out_length, sep, sep_len); + out_length += sep_len; + } } out[out_length] = 0; if (final_length != NULL) { diff --git a/src/core/support/string.h b/src/core/support/string.h index 31e9fcb5e95..a4da485dce7 100644 --- a/src/core/support/string.h +++ b/src/core/support/string.h @@ -72,6 +72,12 @@ void gpr_reverse_bytes(char *str, int len); if it is non-null. */ char *gpr_strjoin(const char **strs, size_t nstrs, size_t *total_length); +/* Join a set of strings using a separator, returning the resulting string. + Total combined length (excluding null terminator) is returned in total_length + if it is non-null. */ +char *gpr_strjoin_sep(const char **strs, size_t nstrs, const char *sep, + size_t *total_length); + /* A vector of strings... for building up a final string one piece at a time */ typedef struct { char **strs; diff --git a/test/core/support/string_test.c b/test/core/support/string_test.c index b59082eecf1..24e28d68dd6 100644 --- a/test/core/support/string_test.c +++ b/test/core/support/string_test.c @@ -145,11 +145,53 @@ static void test_asprintf(void) { } } +static void test_strjoin(void) { + const char *parts[4] = {"one", "two", "three", "four"}; + size_t joined_len; + char *joined; + + LOG_TEST_NAME("test_strjoin"); + + joined = gpr_strjoin(parts, 4, &joined_len); + GPR_ASSERT(0 == strcmp("onetwothreefour", joined)); + gpr_free(joined); + + joined = gpr_strjoin(parts, 0, &joined_len); + GPR_ASSERT(0 == strcmp("", joined)); + gpr_free(joined); + + joined = gpr_strjoin(parts, 1, &joined_len); + GPR_ASSERT(0 == strcmp("one", joined)); + gpr_free(joined); +} + +static void test_strjoin_sep(void) { + const char *parts[4] = {"one", "two", "three", "four"}; + size_t joined_len; + char *joined; + + LOG_TEST_NAME("test_strjoin_sep"); + + joined = gpr_strjoin_sep(parts, 4, ", ", &joined_len); + GPR_ASSERT(0 == strcmp("one, two, three, four", joined)); + gpr_free(joined); + + joined = gpr_strjoin_sep(parts, 0, ", ", &joined_len); + GPR_ASSERT(0 == strcmp("", joined)); + gpr_free(joined); + + joined = gpr_strjoin_sep(parts, 1, ", ", &joined_len); + GPR_ASSERT(0 == strcmp("one", joined)); + gpr_free(joined); +} + int main(int argc, char **argv) { grpc_test_init(argc, argv); test_strdup(); test_hexdump(); test_parse_uint32(); test_asprintf(); + test_strjoin(); + test_strjoin_sep(); return 0; }