circuitpython/py/binary.c

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#include <stdint.h>
#include <assert.h>
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
#include "binary.h"
// Helpers to work with binary-encoded data
int mp_binary_get_size(char typecode) {
// This assumes that unsigned and signed types are of the same type,
// which is invariant for [u]intN_t.
switch (typecode) {
case BYTEARRAY_TYPECODE:
case 'b':
case 'B':
return sizeof(int8_t);
case 'h':
case 'H':
return sizeof(int16_t);
case 'i':
case 'I':
return sizeof(int32_t);
case 'l':
case 'L':
return sizeof(int32_t);
case 'q':
case 'Q':
return sizeof(long long);
#if MICROPY_ENABLE_FLOAT
case 'f':
return sizeof(float);
case 'd':
return sizeof(double);
#endif
}
return -1;
}
mp_obj_t mp_binary_get_val_array(char typecode, void *p, int index) {
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machine_int_t val = 0;
switch (typecode) {
case 'b':
val = ((int8_t*)p)[index];
break;
case BYTEARRAY_TYPECODE:
case 'B':
val = ((uint8_t*)p)[index];
break;
case 'h':
val = ((int16_t*)p)[index];
break;
case 'H':
val = ((uint16_t*)p)[index];
break;
case 'i':
case 'l':
return mp_obj_new_int(((int32_t*)p)[index]);
case 'I':
case 'L':
return mp_obj_new_int_from_uint(((uint32_t*)p)[index]);
#if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
case 'q':
case 'Q':
// TODO: Explode API more to cover signedness
return mp_obj_new_int_from_ll(((long long*)p)[index]);
#endif
#if MICROPY_ENABLE_FLOAT
case 'f':
return mp_obj_new_float(((float*)p)[index]);
case 'd':
return mp_obj_new_float(((double*)p)[index]);
#endif
}
return MP_OBJ_NEW_SMALL_INT(val);
}
#define is_signed(typecode) (typecode > 'Z')
mp_obj_t mp_binary_get_val(char struct_type, char val_type, byte **ptr) {
byte *p = *ptr;
uint size = 0;
switch (struct_type) {
case '<': case '>':
switch (val_type) {
case 'b': case 'B':
size = 1; break;
case 'h': case 'H':
size = 2; break;
case 'i': case 'I':
size = 4; break;
case 'l': case 'L':
size = 4; break;
}
break;
case '@': {
// TODO:
// The simplest heuristic for alignment is to align by value
// size, but that doesn't work for "bigger than int" types,
// for example, long long may very well have long alignment
// So, we introduce separate alignment handling, but having
// formal support for that is different from actually supporting
// particular (or any) ABI.
uint align = 0;
switch (val_type) {
case 'b': case 'B':
align = size = 1; break;
case 'h': case 'H':
align = size = sizeof(short); break;
case 'i': case 'I':
align = size = sizeof(int); break;
case 'l': case 'L':
align = size = sizeof(long); break;
}
// Make pointer aligned
p = (byte*)(((machine_uint_t)p + align - 1) & ~(align - 1));
#if MP_ENDIANNESS_LITTLE
struct_type = '<';
#else
struct_type = '>';
#endif
break;
}
}
int delta;
if (struct_type == '<') {
delta = -1;
p += size - 1;
} else {
delta = 1;
}
machine_int_t val = 0;
if (is_signed(val_type) && *p & 0x80) {
val = -1;
}
for (uint i = 0; i < size; i++) {
val <<= 8;
val |= *p;
p += delta;
}
*ptr += size;
if (is_signed(val_type)) {
return mp_obj_new_int(val);
} else {
return mp_obj_new_int_from_uint(val);
}
}
void mp_binary_set_val_array(char typecode, void *p, int index, mp_obj_t val_in) {
machine_int_t val = 0;
if (MP_OBJ_IS_INT(val_in)) {
val = mp_obj_int_get(val_in);
}
switch (typecode) {
case 'b':
((int8_t*)p)[index] = val;
break;
case BYTEARRAY_TYPECODE:
case 'B':
val = ((uint8_t*)p)[index] = val;
break;
case 'h':
val = ((int16_t*)p)[index] = val;
break;
case 'H':
val = ((uint16_t*)p)[index] = val;
break;
case 'i':
case 'l':
((int32_t*)p)[index] = val;
break;
case 'I':
case 'L':
((uint32_t*)p)[index] = val;
break;
#if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
case 'q':
case 'Q':
assert(0);
((long long*)p)[index] = val;
break;
#endif
#if MICROPY_ENABLE_FLOAT
case 'f':
((float*)p)[index] = mp_obj_float_get(val_in);
break;
case 'd':
((double*)p)[index] = mp_obj_float_get(val_in);
break;
#endif
}
}