1 files changed, 70 insertions, 0 deletions
diff --git a/rushs/evalexpr/tinylibstream/stdin_buffering_test.c b/rushs/evalexpr/tinylibstream/stdin_buffering_test.c
new file mode 100644
index 0000000..6d3361b
--- /dev/null
+++ b/rushs/evalexpr/tinylibstream/stdin_buffering_test.c
@@ -0,0 +1,70 @@
+#define _GNU_SOURCE
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+struct slow_cookie
+{
+    int fd;
+};
+
+static ssize_t slow_read(void *vcookie, char *buf, size_t count)
+{
+    struct slow_cookie *cookie = vcookie;
+    usleep(500000); // sleep for half of a second
+
+    ssize_t res;
+
+    while ((res = read(cookie->fd, buf, count)) < 0)
+        if (errno != EINTR && errno != EAGAIN)
+            break;
+
+    return res;
+}
+
+static int slow_close(void *vcookie)
+{
+    struct slow_cookie *cookie = vcookie;
+    return close(cookie->fd);
+}
+
+cookie_io_functions_t slow_stdio = {
+    .read = slow_read,
+    .close = slow_close,
+};
+
+int main(void)
+{
+    /* setup a custom stdin stream with a slow read function */
+    struct slow_cookie cookie = {
+        .fd = STDIN_FILENO,
+    };
+
+    FILE *input_stream = fopencookie(&cookie, "r", slow_stdio);
+
+    /* change the buffer size to the one given by stdbuf.
+    ** it doesn't work out of the box as stdbuf only does
+    ** this for the already existing stdin stream.
+    */
+    char *buffer = NULL;
+    char *buffer_size = getenv("_STDBUF_I");
+    if (buffer_size)
+    {
+        size_t size = atoi(buffer_size);
+        buffer = malloc(size);
+        setvbuf(input_stream, buffer, _IOFBF, size);
+    }
+
+    /* forward all characters from stdin to stdout */
+    int c;
+    while ((c = fgetc(input_stream)) != EOF)
+    {
+        fputc(c, stdout);
+        fflush(stdout);
+    }
+
+    fclose(input_stream);
+    free(buffer);
+    return 0;
+}