add an example program

CMakeLists.txt

@@ -43,3 +43,9 @@ if (BUILD_TESTING)
   target_link_libraries(allcing_test PRIVATE allcing)
   add_test(NAME allcing_test COMMAND $<TARGET_FILE:allcing_test>)
 endif()
+
+
+# ---- example binary
+add_executable(allcing_example EXCLUDE_FROM_ALL)
+target_sources(allcing_example PRIVATE example.c)
+target_link_libraries(allcing_example PRIVATE allcing)

example.c

@@ -0,0 +1,69 @@
+// No copyright
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+
+// ----
+
+#include "allcing.h"
+
+static inline bool acg_flush(struct acg_stream* s) {
+  assert(NULL != s);
+  if (s->cursor_bits < 8U) {
+    return false;
+  }
+  FILE** fp = (void*) &s->udata;
+  if (NULL == *fp) {
+    *fp = fopen("log.acg", "wb");
+    if (NULL == *fp) {
+      abort();
+    }
+  }
+  if (1U != fwrite(s->buffer, s->cursor_bits/8U, 1U, *fp)) {
+    return false;
+  }
+  if (0U != fflush(*fp)) {
+    return false;
+  }
+  return true;
+}
+#undef  ACG_LOC_FULL
+#define ACG_LOC_FULL ACG_LOC_SHORT
+#undef  ACG_FLUSH
+#define ACG_FLUSH(s) acg_flush((s))
+
+struct acg_stream logstream = {
+  .buffer     = (uint8_t[1024U]) {0U},
+  .size_bytes = 1024U,
+};
+
+// ----
+
+int collatz(int n) {
+  ACG_BEGIN(&logstream);
+  ACG_BLOB(&logstream, sizeof(n), &n);
+
+  if (n == 1U) {
+    ACG_CHECK(&logstream);
+    ACG_BLOB_LITERAL(&logstream, "it's finished!");
+
+  } else if (n%2U) {
+    ACG_CHECK(&logstream);
+    n = collatz(3U*n + 1U);
+
+  } else {
+    ACG_CHECK(&logstream);
+    n = collatz(n / 2U);
+  }
+
+  ACG_END(&logstream);
+  ACG_BLOB(&logstream, sizeof(n), &n);
+  return n;
+}
+
+int main(int, char**) {
+  ACG_BEGIN(&logstream);
+  collatz(100);
+  ACG_END(&logstream);
+}