circuitpython/py/binary.c

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#include <stdint.h>
#include <stdlib.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 struct_type, char val_type, uint *palign) {
int size = 0;
int align = 1;
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;
case 'q': case 'Q':
size = 8; 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.
switch (val_type) {
case BYTEARRAY_TYPECODE:
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;
case 'q': case 'Q':
// TODO: This is for x86
align = sizeof(int); size = sizeof(long long); break;
case 'P': case 'O':
align = size = sizeof(void*); break;
}
}
}
if (palign != NULL) {
*palign = align;
}
return size;
}
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 align;
int size = mp_binary_get_size(struct_type, val_type, &align);
if (struct_type == '@') {
// Make pointer aligned
p = (byte*)(((machine_uint_t)p + align - 1) & ~(align - 1));
#if MP_ENDIANNESS_LITTLE
struct_type = '<';
#else
struct_type = '>';
#endif
}
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 (val_type == 'O') {
return (mp_obj_t)val;
} else 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(char struct_type, char val_type, mp_obj_t val_in, byte **ptr) {
byte *p = *ptr;
uint align;
int size = mp_binary_get_size(struct_type, val_type, &align);
if (struct_type == '@') {
// Make pointer aligned
p = (byte*)(((machine_uint_t)p + align - 1) & ~(align - 1));
#if MP_ENDIANNESS_LITTLE
struct_type = '<';
#else
struct_type = '>';
#endif
}
#if MP_ENDIANNESS_BIG
#error Not implemented
#endif
machine_int_t val;
byte *in = (byte*)&val;
switch (val_type) {
case 'O':
in = (byte*)&val_in;
break;
default:
val = mp_obj_get_int(val_in);
}
int in_delta, out_delta;
uint val_sz = MIN(size, sizeof(val));
if (struct_type == '>') {
in_delta = -1;
out_delta = 1;
in += val_sz - 1;
} else {
in_delta = out_delta = 1;
}
for (uint i = val_sz; i > 0; i--) {
*p = *in;
p += out_delta;
in += in_delta;
}
*ptr += size;
}
void mp_binary_set_val_array(char typecode, void *p, int index, mp_obj_t val_in) {
switch (typecode) {
#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
default:
mp_binary_set_val_array_from_int(typecode, p, index, mp_obj_get_int(val_in));
}
}
void mp_binary_set_val_array_from_int(char typecode, void *p, int index, machine_int_t val) {
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] = val;
break;
case 'd':
((double*)p)[index] = val;
break;
#endif
}
}