first commit.

1 files changed, 177 insertions, 0 deletions

diff --git a/stopwatch.c b/stopwatch.c
new file mode 100644
index 0000000..bb7a90e
--- /dev/null
+++ b/stopwatch.c
@@ -0,0 +1,177 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <termios.h>
+#include <time.h>
+#include <unistd.h>
+
+#define NB_EOF   -1
+#define NB_AGAIN -2
+
+static char   buffer[ BUFSIZ ];
+static size_t buf_pos  = 0;
+static size_t buf_fill = 0;
+
+#define fold inline __attribute__((always_inline)) static
+
+fold void set_stdin_nonblocking(void) {
+    static int done = 0;
+    if (!done) {
+        int flags = fcntl(STDIN_FILENO, F_GETFL);
+        if (flags != -1) { fcntl(STDIN_FILENO, F_SETFL, flags | O_NONBLOCK); }
+        done = 1;
+    }
+}
+
+fold int nb_getchar(void) {
+    set_stdin_nonblocking();
+
+    if (buf_pos < buf_fill) { return (unsigned char) buffer[ buf_pos++ ]; }
+
+    ssize_t n;
+    do { n = read(STDIN_FILENO, buffer, sizeof(buffer)); } while (n == -1 && errno == EINTR);
+
+    if (n == -1) {
+        if (errno == EAGAIN || errno == EWOULDBLOCK) { return NB_AGAIN; }
+        return NB_EOF;
+    }
+
+    if (n == 0) { return NB_EOF; }
+
+    buf_pos  = 0;
+    buf_fill = n;
+
+    return (unsigned char) buffer[ buf_pos++ ];
+}
+
+fold uint64_t time_ms(void) {
+    struct timespec ts;
+    clock_gettime(CLOCK_REALTIME, &ts);
+    return (uint64_t) ts.tv_sec * 1000 + (uint64_t) ts.tv_nsec / 1000000;
+}
+
+#define clear() printf("\033[2J\033[H")
+
+static struct termios original_tio;
+static int            tio_saved = 0;
+
+void enter_state(void) {
+    if (!isatty(STDIN_FILENO)) return;
+    if (!tio_saved) {
+        if (tcgetattr(STDIN_FILENO, &original_tio) == -1) {
+            perror("tcgetattr");
+            exit(1);
+        }
+        tio_saved = 1;
+    }
+    struct termios raw = original_tio;
+    raw.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
+    raw.c_oflag &= ~OPOST;
+    raw.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
+    raw.c_cflag &= ~(CSIZE | PARENB);
+    raw.c_cflag |= CS8;
+    raw.c_cc[ VMIN ]  = 1;
+    raw.c_cc[ VTIME ] = 0;
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) {
+        perror("tcsetattr (raw)");
+        exit(1);
+    }
+}
+
+void exit_state(void) {
+    if (tio_saved && isatty(STDIN_FILENO)) {
+        if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &original_tio) == -1) {
+            perror("tcsetattr (restore)");
+            exit(1);
+        }
+    }
+}
+
+void bye() {
+    printf("\r\n\ngoodbye.\r\n");
+    exit(0);
+}
+
+fold void print_dur(uint64_t duration) {
+    uint64_t hours = 0, minutes = 0, seconds = 0, ms = 0;
+
+    ms = duration % 1000;
+    duration /= 1000;
+    seconds = duration % 60;
+    duration /= 60;
+    minutes = duration % 60;
+    duration /= 60;
+    hours = duration;
+
+    printf("%2" PRIu64 "h ", hours);
+    printf("%2" PRIu64 "m ", minutes);
+    printf("%2" PRIu64 "s ", seconds);
+    printf("%4" PRIu64 "ms", ms);
+    fflush(stdout);
+}
+
+fold void yield(void) {
+    struct timespec ts = { .tv_sec = 0, .tv_nsec = 999000 };
+    nanosleep(&ts, NULL);
+}
+
+#define unlikely(a) __builtin_expect(!!(a), 0)
+
+int main() {
+    enter_state();
+    atexit(exit_state);
+
+    printf(
+        "\r\nstopwatch\r\n\n"
+        "instructions:\r\n"
+        "  space => pause/resume\r\n"
+        "  ctrl+c / ctrl+d / eof => exit\r\n"
+        "  press space to start.\r\n"
+        "\r\n");
+    int c;
+    while ((c = nb_getchar()) != ' ') {
+        if (unlikely(c == 3 || c == 4 || c == NB_EOF)) bye();
+        yield();
+    }
+
+    uint64_t tally = 0;
+    uint64_t start;
+
+    while (1) {
+        uint64_t cur;
+        start = time_ms();
+
+        char parity = 1;
+        while ((c = nb_getchar()) != ' ') {
+            // clear();
+            cur = time_ms();
+
+            if (parity) {
+                printf("\r");
+                printf("[ ] ");
+                print_dur(cur - start + tally);
+            }
+
+            parity = !parity;
+
+            if (unlikely(c == 3 || c == 4 || c == NB_EOF)) bye();
+            yield();
+        }
+
+        tally += time_ms() - start;
+
+        printf("\r");
+        printf("[x] ");
+        print_dur(tally);
+
+        while ((c = nb_getchar()) != ' ') {
+            if (unlikely(c == 3 || c == 4 || c == NB_EOF)) bye();
+            yield();
+        }
+    }
+
+    bye();
+}