circuitpython/py/modstruct.c
Damien George 57a4b4f178 py: Add typecode to buffer protocol.
When querying an object that supports the buffer protocol, that object
must now return a typecode (as per binary.[ch]).  This does not have to
be honoured by the caller, but can be useful for determining element
size.
2014-04-18 22:29:21 +01:00

94 lines
2.6 KiB
C

#include <assert.h>
#include <string.h>
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
#include "builtin.h"
#include "objtuple.h"
#include "binary.h"
#if MICROPY_ENABLE_MOD_STRUCT
STATIC char get_fmt_type(const char **fmt) {
char t = **fmt;
switch (t) {
case '!':
t = '>';
break;
case '@':
case '=':
case '<':
case '>':
break;
default:
return '@';
}
// Skip type char
(*fmt)++;
return t;
}
STATIC uint calcsize_items(const char *fmt) {
// TODO
return strlen(fmt);
}
STATIC mp_obj_t struct_calcsize(mp_obj_t fmt_in) {
const char *fmt = mp_obj_str_get_str(fmt_in);
char fmt_type = get_fmt_type(&fmt);
(void)fmt_type;
machine_uint_t size;
for (size = 0; *fmt; fmt++) {
int sz = mp_binary_get_size(*fmt);
// TODO
assert(sz != -1);
size += sz;
}
return MP_OBJ_NEW_SMALL_INT(size);
}
MP_DEFINE_CONST_FUN_OBJ_1(struct_calcsize_obj, struct_calcsize);
STATIC mp_obj_t struct_unpack(mp_obj_t fmt_in, mp_obj_t data_in) {
// TODO: "The buffer must contain exactly the amount of data required by the format (len(bytes) must equal calcsize(fmt))."
const char *fmt = mp_obj_str_get_str(fmt_in);
char fmt_type = get_fmt_type(&fmt);
uint size = calcsize_items(fmt);
mp_obj_tuple_t *res = mp_obj_new_tuple(size, NULL);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(data_in, &bufinfo);
byte *p = bufinfo.buf;
for (uint i = 0; i < size; i++) {
mp_obj_t item = mp_binary_get_val(fmt_type, *fmt++, &p);
res->items[i] = item;
}
return res;
}
MP_DEFINE_CONST_FUN_OBJ_2(struct_unpack_obj, struct_unpack);
STATIC const mp_map_elem_t mp_module_struct_globals_table[] = {
{ MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR_struct) },
{ MP_OBJ_NEW_QSTR(MP_QSTR_calcsize), (mp_obj_t)&struct_calcsize_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_unpack), (mp_obj_t)&struct_unpack_obj },
};
STATIC const mp_obj_dict_t mp_module_struct_globals = {
.base = {&mp_type_dict},
.map = {
.all_keys_are_qstrs = 1,
.table_is_fixed_array = 1,
.used = sizeof(mp_module_struct_globals_table) / sizeof(mp_map_elem_t),
.alloc = sizeof(mp_module_struct_globals_table) / sizeof(mp_map_elem_t),
.table = (mp_map_elem_t*)mp_module_struct_globals_table,
},
};
const mp_obj_module_t mp_module_struct = {
.base = { &mp_type_module },
.name = MP_QSTR_struct,
.globals = (mp_obj_dict_t*)&mp_module_struct_globals,
};
#endif