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micropython/py/binary.c

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/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <assert.h>
#include "py/binary.h"
#include "py/smallint.h"
// Helpers to work with binary-encoded data
#ifndef alignof
#define alignof(type) offsetof(struct { char c; type t; }, t)
#endif
int mp_binary_get_size(char struct_type, char val_type, mp_uint_t *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;
case 'P': case 'O': case 'S':
size = sizeof(void*); break;
case 'f':
size = sizeof(float); break;
case 'd':
size = sizeof(double); 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 = alignof(short);
size = sizeof(short); break;
case 'i': case 'I':
align = alignof(int);
size = sizeof(int); break;
case 'l': case 'L':
align = alignof(long);
size = sizeof(long); break;
case 'q': case 'Q':
align = alignof(long long);
size = sizeof(long long); break;
case 'P': case 'O': case 'S':
align = alignof(void*);
size = sizeof(void*); break;
case 'f':
align = alignof(float);
size = sizeof(float); break;
case 'd':
align = alignof(double);
size = sizeof(double); break;
}
}
}
if (palign != NULL) {
*palign = align;
}
return size;
}
mp_obj_t mp_binary_get_val_array(char typecode, void *p, mp_uint_t index) {
mp_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_PY_BUILTINS_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);
}
// The long long type is guaranteed to hold at least 64 bits, and size is at
// most 8 (for q and Q), so we will always be able to parse the given data
// and fit it into a long long.
long long mp_binary_get_int(mp_uint_t size, bool is_signed, bool big_endian, const byte *src) {
int delta;
if (!big_endian) {
delta = -1;
src += size - 1;
} else {
delta = 1;
}
long long val = 0;
if (is_signed && *src & 0x80) {
val = -1;
}
for (uint i = 0; i < size; i++) {
val <<= 8;
val |= *src;
src += delta;
}
return 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;
mp_uint_t align;
int size = mp_binary_get_size(struct_type, val_type, &align);
if (struct_type == '@') {
// Make pointer aligned
p = (byte*)(((mp_uint_t)p + align - 1) & ~((mp_uint_t)align - 1));
#if MP_ENDIANNESS_LITTLE
struct_type = '<';
#else
struct_type = '>';
#endif
}
*ptr = p + size;
long long val = mp_binary_get_int(size, is_signed(val_type), (struct_type == '>'), p);
if (val_type == 'O') {
return (mp_obj_t)(mp_uint_t)val;
} else if (val_type == 'S') {
const char *s_val = (const char*)(mp_uint_t)val;
return mp_obj_new_str(s_val, strlen(s_val), false);
} else if (is_signed(val_type)) {
if ((long long)MP_SMALL_INT_MIN <= val && val <= (long long)MP_SMALL_INT_MAX) {
return mp_obj_new_int((mp_int_t)val);
} else {
return mp_obj_new_int_from_ll(val);
}
} else {
if ((unsigned long long)val <= (unsigned long long)MP_SMALL_INT_MAX) {
return mp_obj_new_int_from_uint((mp_uint_t)val);
} else {
return mp_obj_new_int_from_ull(val);
}
}
}
void mp_binary_set_int(mp_uint_t val_sz, bool big_endian, byte *dest, mp_uint_t val) {
if (MP_ENDIANNESS_LITTLE && !big_endian) {
memcpy(dest, &val, val_sz);
} else if (MP_ENDIANNESS_BIG && big_endian) {
// only copy the least-significant val_sz bytes
memcpy(dest, (byte*)&val + sizeof(mp_uint_t) - val_sz, val_sz);
} else {
const byte *src;
if (MP_ENDIANNESS_LITTLE) {
src = (const byte*)&val + val_sz;
} else {
src = (const byte*)&val + sizeof(mp_uint_t);
}
while (val_sz--) {
*dest++ = *--src;
}
}
}
void mp_binary_set_val(char struct_type, char val_type, mp_obj_t val_in, byte **ptr) {
byte *p = *ptr;
mp_uint_t align;
int size = mp_binary_get_size(struct_type, val_type, &align);
if (struct_type == '@') {
// Make pointer aligned
p = (byte*)(((mp_uint_t)p + align - 1) & ~((mp_uint_t)align - 1));
if (MP_ENDIANNESS_LITTLE) {
struct_type = '<';
} else {
struct_type = '>';
}
}
*ptr = p + size;
mp_uint_t val;
switch (val_type) {
case 'O':
val = (mp_uint_t)val_in;
break;
default:
// we handle large ints here by calling the truncated accessor
if (MP_OBJ_IS_TYPE(val_in, &mp_type_int)) {
val = mp_obj_int_get_truncated(val_in);
} else {
val = mp_obj_get_int(val_in);
}
}
mp_binary_set_int(MIN(size, sizeof(val)), struct_type == '>', p, val);
}
void mp_binary_set_val_array(char typecode, void *p, mp_uint_t index, mp_obj_t val_in) {
switch (typecode) {
#if MICROPY_PY_BUILTINS_FLOAT
case 'f':
((float*)p)[index] = mp_obj_get_float(val_in);
break;
case 'd':
((double*)p)[index] = mp_obj_get_float(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, mp_uint_t index, mp_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_PY_BUILTINS_FLOAT
case 'f':
((float*)p)[index] = val;
break;
case 'd':
((double*)p)[index] = val;
break;
#endif
}
}
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