init commitHEADmaster

1 files changed, 37 insertions, 0 deletions

diff --git a/uicc/reader.c b/uicc/reader.c
new file mode 100644
index 0000000..ea21b82
--- /dev/null
+++ b/uicc/reader.c
@@ -0,0 +1,37 @@
+#include <ui_utils.h>
+
+typedef struct {
+  int fd;
+  uint64_t buffer_size;
+  char *buffer;
+} Reader;
+
+Reader *reader_open(Arena *arena, const char *path, uint64_t buffer_size) {
+  Reader *reader = {0};
+  int fd;
+
+  assert_failure(fd = open(path, O_RDONLY, O_NOFOLLOW), -1);
+
+  reader = arena_type(arena, Reader);
+  reader->fd = fd;
+  reader->buffer_size = buffer_size;
+  reader->buffer = arena_array(arena, char, reader->buffer_size);
+
+  return reader;
+}
+
+void reader_advance(Reader *self, uint32_t *start, uint32_t *end) {
+  if (*end > self->buffer_size) {
+    if (*start == 0) {
+      /* TODO(roberto): maybe reallocate the buffer instead of crashing */
+      crash_error("ERROR: token is too long\n");
+    }
+
+    assert_errno(lseek(self->fd, *start * -1, SEEK_CUR));
+    assert_errno(read(self->fd, self->buffer, self->buffer_size));
+    *end -= *start;
+    *start = 0;
+  }
+}
+
+void reader_close(Reader *self) { close(self->fd); }