1 files changed, 123 insertions, 0 deletions
diff --git a/py/pystack.h b/py/pystack.h
new file mode 100644
index 000000000..82ac3743d
--- /dev/null
+++ b/py/pystack.h
@@ -0,0 +1,123 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#ifndef MICROPY_INCLUDED_PY_PYSTACK_H
+#define MICROPY_INCLUDED_PY_PYSTACK_H
+
+#include "py/mpstate.h"
+
+// Enable this debugging option to check that the amount of memory freed is
+// consistent with amounts that were previously allocated.
+#define MP_PYSTACK_DEBUG (0)
+
+#if MICROPY_ENABLE_PYSTACK
+
+void mp_pystack_init(void *start, void *end);
+void *mp_pystack_alloc(size_t n_bytes);
+
+// This function can free multiple continuous blocks at once: just pass the
+// pointer to the block that was allocated first and it and all subsequently
+// allocated blocks will be freed.
+static inline void mp_pystack_free(void *ptr) {
+    assert((uint8_t*)ptr >= MP_STATE_THREAD(pystack_start));
+    assert((uint8_t*)ptr <= MP_STATE_THREAD(pystack_cur));
+    #if MP_PYSTACK_DEBUG
+    size_t n_bytes_to_free = MP_STATE_THREAD(pystack_cur) - (uint8_t*)ptr;
+    size_t n_bytes = *(size_t*)(MP_STATE_THREAD(pystack_cur) - MICROPY_PYSTACK_ALIGN);
+    while (n_bytes < n_bytes_to_free) {
+        n_bytes += *(size_t*)(MP_STATE_THREAD(pystack_cur) - n_bytes - MICROPY_PYSTACK_ALIGN);
+    }
+    if (n_bytes != n_bytes_to_free) {
+        mp_printf(&mp_plat_print, "mp_pystack_free() failed: %u != %u\n", (uint)n_bytes_to_free,
+            (uint)*(size_t*)(MP_STATE_THREAD(pystack_cur) - MICROPY_PYSTACK_ALIGN));
+        assert(0);
+    }
+    #endif
+    MP_STATE_THREAD(pystack_cur) = (uint8_t*)ptr;
+}
+
+static inline void mp_pystack_realloc(void *ptr, size_t n_bytes) {
+    mp_pystack_free(ptr);
+    mp_pystack_alloc(n_bytes);
+}
+
+static inline size_t mp_pystack_usage(void) {
+    return MP_STATE_THREAD(pystack_cur) - MP_STATE_THREAD(pystack_start);
+}
+
+static inline size_t mp_pystack_limit(void) {
+    return MP_STATE_THREAD(pystack_end) - MP_STATE_THREAD(pystack_start);
+}
+
+#endif
+
+#if !MICROPY_ENABLE_PYSTACK
+
+#define mp_local_alloc(n_bytes) alloca(n_bytes)
+
+static inline void mp_local_free(void *ptr) {
+    (void)ptr;
+}
+
+static inline void *mp_nonlocal_alloc(size_t n_bytes) {
+    return m_new(uint8_t, n_bytes);
+}
+
+static inline void *mp_nonlocal_realloc(void *ptr, size_t old_n_bytes, size_t new_n_bytes) {
+    return m_renew(uint8_t, ptr, old_n_bytes, new_n_bytes);
+}
+
+static inline void mp_nonlocal_free(void *ptr, size_t n_bytes) {
+    m_del(uint8_t, ptr, n_bytes);
+}
+
+#else
+
+static inline void *mp_local_alloc(size_t n_bytes) {
+    return mp_pystack_alloc(n_bytes);
+}
+
+static inline void mp_local_free(void *ptr) {
+    mp_pystack_free(ptr);
+}
+
+static inline void *mp_nonlocal_alloc(size_t n_bytes) {
+    return mp_pystack_alloc(n_bytes);
+}
+
+static inline void *mp_nonlocal_realloc(void *ptr, size_t old_n_bytes, size_t new_n_bytes) {
+    (void)old_n_bytes;
+    mp_pystack_realloc(ptr, new_n_bytes);
+    return ptr;
+}
+
+static inline void mp_nonlocal_free(void *ptr, size_t n_bytes) {
+    (void)n_bytes;
+    mp_pystack_free(ptr);
+}
+
+#endif
+
+#endif // MICROPY_INCLUDED_PY_PYSTACK_H