Commit 5b15daf6 authored by Paul Sokolovsky's avatar Paul Sokolovsky
Browse files

Add support for stream and buffer protocols.

Stream protocol is abstraction of serial I/O. Buffer protocol is
abstraction of random-access I/O. These protocols are defined down
to C level, to allow generic, while still efficient algorithms
to be coded in C (like, buffered transfer between 2 stream objects,
saving/loading of buffer object to/from stream, etc). (Note that CPython
define buffer protocol on C level, but apparently not stream protocol).
parent ea9e441a
......@@ -76,6 +76,41 @@ typedef struct _mp_method_t {
mp_const_obj_t fun;
} mp_method_t;
// Buffer protocol
typedef struct _buffer_info_t {
// if we'd bother to support various versions of structure
// (with different number of fields), we can distinguish
// them with ver = sizeof(struct). Cons: overkill for *micro*?
//int ver; // ?
void *buf;
machine_int_t len;
// Rationale: have array.array and have SIMD operations on them
// Cons: users can pass item size to processing functions themselves,
// though that's not "plug&play"
// int itemsize;
// Rationale: to load arbitrary-sized sprites directly to LCD
// Cons: a bit adhoc usecase
// int stride;
} buffer_info_t;
#define BUFFER_READ (1)
#define BUFFER_WRITE (2)
#define BUFFER_RW (BUFFER_READ | BUFFER_WRITE)
typedef struct _mp_buffer_p_t {
machine_int_t (*get_buffer)(mp_obj_t obj, buffer_info_t *bufinfo, int flags);
} mp_buffer_p_t;
// Stream protocol
typedef struct _mp_stream_p_t {
// On error, functions should return -1 and fill in *errcode (values are
// implementation-dependent, but will be exposed to user, e.g. via exception).
machine_int_t (*read)(mp_obj_t obj, void *buf, machine_uint_t size, int *errcode);
machine_int_t (*write)(mp_obj_t obj, const void *buf, machine_uint_t size, int *errcode);
// add seek() ?
} mp_stream_p_t;
struct _mp_obj_type_t {
mp_obj_base_t base;
const char *name;
......@@ -90,6 +125,12 @@ struct _mp_obj_type_t {
mp_fun_1_t getiter;
mp_fun_1_t iternext;
// Alternatively, pointer(s) to interfaces to save space
// in mp_obj_type_t at the expense of extra pointer and extra dereference
// when actually used.
mp_buffer_p_t buffer_p;
mp_stream_p_t stream_p;
const mp_method_t *methods;
/*
......
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