Fix circular_buffer growth when _next != 0

2 files changed, 36 insertions, 10 deletions

diff --git a/src/rt/circular_buffer.cpp b/src/rt/circular_buffer.cpp
index c3b068ac..54898fb7 100644
--- a/src/rt/circular_buffer.cpp
+++ b/src/rt/circular_buffer.cpp
@@ -63,7 +63,7 @@ circular_buffer::enqueue(void *src) {
     I(dom, _unread <= _buffer_sz);
 
     // Grow if necessary.
-    if (_unread + unit_sz > _buffer_sz) {
+    if (_next + _unread + unit_sz > _buffer_sz) {
         size_t new_buffer_sz = _buffer_sz << 1;
         I(dom, new_buffer_sz <= MAX_CIRCULAR_BUFFFER_SIZE);
         void *new_buffer = dom->malloc(new_buffer_sz);
@@ -76,15 +76,16 @@ circular_buffer::enqueue(void *src) {
 
     dom->log(rust_log::MEM | rust_log::COMM,
              "circular_buffer enqueue "
-             "unread: %d, buffer_sz: %d, unit_sz: %d",
-             _unread, _buffer_sz, unit_sz);
+             "unread: %d, next: %d, buffer_sz: %d, unit_sz: %d",
+             _unread, _next, _buffer_sz, unit_sz);
 
     I(dom, is_power_of_two(_buffer_sz));
     I(dom, _unread < _buffer_sz);
-    I(dom, _unread + unit_sz <= _buffer_sz);
+    I(dom, _next + _unread + unit_sz <= _buffer_sz);
 
     // Copy data
     size_t i = (_next + _unread) & (_buffer_sz - 1);
+    I(dom, i + unit_sz <= _buffer_sz);
     memcpy(&_buffer[i], src, unit_sz);
     _unread += unit_sz;
 
@@ -106,8 +107,8 @@ circular_buffer::dequeue(void *dst) {
 
     dom->log(rust_log::MEM | rust_log::COMM,
              "circular_buffer dequeue "
-             "unread: %d, buffer_sz: %d, unit_sz: %d",
-             _unread, _buffer_sz, unit_sz);
+             "unread: %d, next: %d, buffer_sz: %d, unit_sz: %d",
+             _unread, _next, _buffer_sz, unit_sz);
 
     if (dst != NULL) {
         memcpy(dst, &_buffer[_next], unit_sz);
diff --git a/src/test/run-pass/chan-poweroftwo.rs b/src/test/run-pass/chan-poweroftwo.rs
index be7c18ad..044d8238 100644
--- a/src/test/run-pass/chan-poweroftwo.rs
+++ b/src/test/run-pass/chan-poweroftwo.rs
@@ -10,7 +10,7 @@ import std._uint;
 import std._vec;
 
 // A 12-byte unit to send over the channel
-type record = rec(i32 val1, i32 val2, i32 val3);
+type record = rec(u32 val1, u32 val2, u32 val3);
 
 // Assuming that the default buffer size needs to hold 8 units,
 // then the minimum buffer size needs to be 96. That's not a
@@ -20,7 +20,7 @@ impure fn test_init() {
     let port[record] myport = port();
     auto mychan = chan(myport);
 
-    let record val = rec(val1=0i32, val2=0i32, val3=0i32);
+    let record val = rec(val1=0u32, val2=0u32, val3=0u32);
 
     mychan <| val;
 }
@@ -31,7 +31,7 @@ impure fn test_grow() {
     let port[record] myport = port();
     auto mychan = chan(myport);
 
-    let record val = rec(val1=0i32, val2=0i32, val3=0i32);
+    let record val = rec(val1=0u32, val2=0u32, val3=0u32);
 
     for each (uint i in _uint.range(0u, 100u)) {
         mychan <| val;
@@ -51,7 +51,7 @@ impure fn test_shrink2() {
     let port[record] myport = port();
     auto mychan = chan(myport);
 
-    let record val = rec(val1=0i32, val2=0i32, val3=0i32);
+    let record val = rec(val1=0u32, val2=0u32, val3=0u32);
 
     for each (uint i in _uint.range(0u, 100u)) {
         mychan <| val;
@@ -62,11 +62,36 @@ impure fn test_shrink2() {
     }
 }
 
+// Test rotating the buffer when the unit size is not a power of two
+impure fn test_rotate() {
+    let port[record] myport = port();
+    auto mychan = chan(myport);
+
+    let record val = rec(val1=0u32, val2=0u32, val3=0u32);
+
+    for each (uint j in _uint.range(0u, 10u)) {
+        for each (uint i in _uint.range(0u, 10u)) {
+            let record val = rec(val1=i as u32,
+                                 val2=i as u32,
+                                 val3=i as u32);
+            mychan <| val;
+        }
+
+        for each (uint i in _uint.range(0u, 10u)) {
+            auto x <- myport;
+            check (x.val1 == i as u32);
+            check (x.val2 == i as u32);
+            check (x.val3 == i as u32);
+        }
+    }
+}
+
 impure fn main() {
     test_init();
     test_grow();
     test_shrink1();
     test_shrink2();
+    test_rotate();
 }
 
 // Local Variables: