py/dynruntime: Add mp_binary_get_size/get_val_array/set_val_array.

These are needed to read/write array.array objects, which is useful in
native code to provide fast extensions that work with big arrays of data.
Signed-off-by: Damien George <damien@micropython.org>

py/dynruntime.h

@@ -29,6 +29,7 @@
 // This header file contains definitions to dynamically implement the static
 // MicroPython runtime API defined in py/obj.h and py/runtime.h.
 
+#include "py/binary.h"
 #include "py/nativeglue.h"
 #include "py/objfun.h"
 #include "py/objstr.h"
@@ -184,6 +185,10 @@ static inline void *mp_obj_malloc_helper_dyn(size_t num_bytes, const mp_obj_type
 /******************************************************************************/
 // General runtime functions
 
+#define mp_binary_get_size(struct_type, val_type, palign) (mp_fun_table.binary_get_size((struct_type), (val_type), (palign)))
+#define mp_binary_get_val_array(typecode, p, index) (mp_fun_table.binary_get_val_array((typecode), (p), (index)))
+#define mp_binary_set_val_array(typecode, p, index, val_in) (mp_fun_table.binary_set_val_array((typecode), (p), (index), (val_in)))
+
 #define mp_load_name(qst)                 (mp_fun_table.load_name((qst)))
 #define mp_load_global(qst)               (mp_fun_table.load_global((qst)))
 #define mp_load_attr(base, attr)          (mp_fun_table.load_attr((base), (attr)))

py/nativeglue.c

@@ -29,6 +29,7 @@
 #include <string.h>
 #include <assert.h>
 
+#include "py/binary.h"
 #include "py/runtime.h"
 #include "py/smallint.h"
 #include "py/nativeglue.h"
@@ -330,6 +331,9 @@ const mp_fun_table_t mp_fun_table = {
     mp_obj_get_float_to_d,
     mp_get_buffer,
     mp_get_stream_raise,
+    mp_binary_get_size,
+    mp_binary_get_val_array,
+    mp_binary_set_val_array,
     &mp_plat_print,
     &mp_type_type,
     &mp_type_str,

py/nativeglue.h

@@ -156,7 +156,12 @@ typedef struct _mp_fun_table_t {
     double (*obj_get_float_to_d)(mp_obj_t o);
     bool (*get_buffer)(mp_obj_t obj, mp_buffer_info_t *bufinfo, mp_uint_t flags);
     const mp_stream_p_t *(*get_stream_raise)(mp_obj_t self_in, int flags);
+    size_t (*binary_get_size)(char struct_type, char val_type, size_t *palign);
+    mp_obj_t (*binary_get_val_array)(char typecode, void *p, size_t index);
+    void (*binary_set_val_array)(char typecode, void *p, size_t index, mp_obj_t val_in);
     const mp_print_t *plat_print;
+    // The following entries start at index 70 and are referenced by tools-mpy_ld.py,
+    // see constant MP_FUN_TABLE_MP_TYPE_TYPE_OFFSET.
     const mp_obj_type_t *type_type;
     const mp_obj_type_t *type_str;
     const mp_obj_type_t *type_list;

tools/mpy_ld.py

@@ -52,6 +52,7 @@ MP_SCOPE_FLAG_VIPERRELOC = 0x10
 MP_SCOPE_FLAG_VIPERRODATA = 0x20
 MP_SCOPE_FLAG_VIPERBSS = 0x40
 MP_SMALL_INT_BITS = 31
+MP_FUN_TABLE_MP_TYPE_TYPE_OFFSET = 70
 
 # ELF constants
 R_386_32 = 1
@@ -754,7 +755,7 @@ def link_objects(env, native_qstr_vals_len):
     # Resolve unknown symbols
     mp_fun_table_sec = Section(".external.mp_fun_table", b"", 0)
     fun_table = {
-        key: 67 + idx
+        key: MP_FUN_TABLE_MP_TYPE_TYPE_OFFSET + idx
         for idx, key in enumerate(
             [
                 "mp_type_type",