#include <stdio.h> #include <stdlib.h> #include <darwintest.h> #include <darwintest_perf.h> static void perf_fixed_size(size_t size_per_write) { dt_stat_time_t latency = dt_stat_time_create("write_latency", "adding %zu bytes to a memstream", size_per_write); dt_stat_set_variable_d(latency, "bytes", (double)size_per_write); char *src = calloc(1, size_per_write); T_QUIET; T_ASSERT_NOTNULL(src, "allocated source buffer"); while (!dt_stat_stable(latency)) { char *buf = NULL; size_t size = 0; FILE *victim = open_memstream(&buf, &size); T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(victim, "opened memstream"); T_STAT_MEASURE_BATCH(latency) { (void)fwrite(src, size_per_write, 1, victim); } fclose(victim); T_QUIET; T_ASSERT_NOTNULL(buf, "buffer was set by open_memstream"); T_QUIET; T_ASSERT_GE(size, size_per_write, "memstream added non-zero bytes"); free(buf); } free(src); dt_stat_finalize(latency); } T_DECL(perf_open_memstream, "measure the performance of open_memstream") { size_t sizes[] = { 1, 8, 16, 64, 1024, 2048, 4096, 16 * 1024 }; for (size_t i = 0; i < sizeof(sizes) / sizeof(sizes[0]); i++) { perf_fixed_size(sizes[i]); } }