Add test "prod_jumps_to_buffer_start_and_reaches_cons"

.gitignore

@@ -37,4 +37,5 @@
 /examples/raw_receiver
 /examples/raw_sender
 /tests/test_main
+/tests/test_prod_jumps_to_buffer_start_and_reaches_cons
 /tests/test_prod_reaches_buffer_end

Makefile.am

@@ -10,6 +10,7 @@ lib_LIBRARIES = libshmemq.a
 
 TESTS = \
 	tests/test_main \
+	tests/test_prod_jumps_to_buffer_start_and_reaches_cons \
 	tests/test_prod_reaches_buffer_end
 
 noinst_PROGRAMS = \
@@ -31,6 +32,10 @@ tests_test_main_SOURCES = \
 	$(libshmemq_a_SOURCES) \
 	tests/test_main.c
 
+tests_test_prod_jumps_to_buffer_start_and_reaches_cons_SOURCES = \
+	$(libshmemq_a_SOURCES) \
+	tests/test_prod_jumps_to_buffer_start_and_reaches_cons.c
+
 tests_test_prod_reaches_buffer_end_SOURCES = \
 	$(libshmemq_a_SOURCES) \
 	tests/test_prod_reaches_buffer_end.c

src/main.c

@@ -147,6 +147,18 @@ ShmemqFrame shmemq_push_start(const Shmemq shmemq)
     if (
         shmemq->buffer->header.write_frame_index >=
         shmemq->buffer->header.frames_count
+    ) {
+        if (shmemq->buffer->header.read_frame_index > 0) {
+            shmemq->buffer->header.write_frame_index = 0;
+        }
+        else {
+            return NULL;
+        }
+    }
+
+    if (
+        shmemq->buffer->header.write_frame_index ==
+        shmemq->buffer->header.read_frame_index - 1
     ) {
         return NULL;
     }
@@ -182,6 +194,14 @@ void shmemq_push_end(
         return;
     }
 
+    if (
+        shmemq->buffer->header.write_frame_index ==
+        shmemq->buffer->header.read_frame_index - 1
+    ) {
+        if (error_ptr) *error_ptr = SHMEMQ_ERROR_BUG_PUSH_END_ON_FULL_QUEUE;
+        return;
+    }
+
     const ShmemqFrame frame =
         &shmemq->buffer->frames[shmemq->buffer->header.write_frame_index];
 

tests/test_prod_jumps_to_buffer_start_and_reaches_cons.c

@@ -0,0 +1,59 @@
+#include <shmemq.h>
+
+#include <assert.h>
+
+static const char name[] = "/foobar";
+
+int main()
+{
+    ShmemqError error;
+
+    const Shmemq consumer = shmemq_new(name, true, &error);
+    assert(error == SHMEMQ_ERROR_NONE);
+
+    const Shmemq producer = shmemq_new(name, false, &error);
+    assert(error == SHMEMQ_ERROR_NONE);
+
+    for (unsigned i = 0; i < 100; ++i) {
+        const ShmemqFrame frame = shmemq_push_start(producer);
+        assert(frame != NULL);
+
+        *(unsigned*)frame->data = i;
+
+        shmemq_push_end(producer, sizeof(unsigned), &error);
+        assert(error == SHMEMQ_ERROR_NONE);
+    }
+
+    for (unsigned i = 0; i < 10; ++i) {
+        const ShmemqFrame frame = shmemq_pop_start(consumer);
+        assert(frame != NULL);
+
+        assert(*(unsigned*)frame->data == i);
+
+        shmemq_pop_end(consumer, &error);
+        assert(error == SHMEMQ_ERROR_NONE);
+    }
+
+    for (unsigned i = 0; i < 9; ++i) {
+        const ShmemqFrame frame = shmemq_push_start(producer);
+        assert(frame != NULL);
+
+        *(unsigned*)frame->data = i;
+
+        shmemq_push_end(producer, sizeof(unsigned), &error);
+        assert(error == SHMEMQ_ERROR_NONE);
+    }
+
+    assert(shmemq_push_start(producer) == NULL);
+
+    shmemq_push_end(producer, sizeof(unsigned), &error);
+    assert(error == SHMEMQ_ERROR_BUG_PUSH_END_ON_FULL_QUEUE);
+
+    shmemq_delete(consumer, &error);
+    assert(error == SHMEMQ_ERROR_NONE);
+
+    shmemq_delete(producer, &error);
+    assert(error == SHMEMQ_ERROR_NONE);
+
+    return 0;
+}