blinky-esp/main/utils.cpp

static const char *TAG = "utils";
#include <esp_log.h>

#include <sys/time.h>
#include <cstring>

#include "utils.hpp"


int64_t time_us() {
    /*struct timeval tv_now;
    gettimeofday(&tv_now, NULL);
    return (int64_t)tv_now.tv_sec * 1000000L + (int64_t)tv_now.tv_usec;*/
    struct timespec ts;
    clock_gettime(CLOCK_MONOTONIC, &ts);
    return (int64_t)ts.tv_sec * 1000000L + (int64_t)ts.tv_nsec / 1000L;
}



std::string read_file(const char *path) {
    std::string data;
    FILE *f = fopen(path, "r");
    if (!f) {
        ESP_LOGE(TAG, "Failed to read %s", path);
        return data;
    }
    constexpr size_t szbuf = 4096;
    char *buf = (char*)malloc(szbuf);
    size_t nread;
    while ((nread = fread(buf, 1, szbuf - 1, f)) > 0) {
        buf[nread] = '\0';
        data += buf;
    }
    fclose(f);
    free(buf);
    return data;
}

void write_file(const char *path, const std::string &data) {
    return write_file(path, data.c_str(), data.length());
}

void write_file(const char *path, const char *data, int len) {
    FILE *f = fopen(path, "w");
    if (!f) {
        ESP_LOGE(TAG, "Failed to open %s", path);
        return;
    }
    const char *ptr = data;
    size_t remain = (len < 0 ? strlen(data) : len);
    size_t nwritten = fwrite(ptr, 1, remain, f);
    if (nwritten != remain) {
        ESP_LOGE(TAG, "Failed to write to %s: %d/%d", path, nwritten, remain);
    }
    fclose(f);
}