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refactored the encode and decode of unsigned16 and unsigned32.

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This commit is contained in:
skarg
2005-03-16 16:17:35 +00:00
parent 1190ff8380
commit ceaae8ca5e
2 changed files with 101 additions and 131 deletions
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bacnet-stack/bacdcode.c
+97 -130
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@@ -35,15 +35,12 @@
#include <string.h>
#include <assert.h>
#include "bacdef.h"
#include "bacdcode.h"
#include "bacenum.h"
#include "bits.h"
#include "bigend.h"
#ifndef MAX_APDU
#define MAX_APDU 480
#endif
// NOTE: byte order plays a role in decoding multibyte values
// http://www.unixpapa.com/incnote/byteorder.html
@@ -121,36 +118,91 @@ uint8_t encode_max_segs_max_apdu(int max_segs, int max_apdu)
return octet;
}
int encode_bacnet_unsigned16(uint8_t * apdu, uint16_t value)
int encode_unsigned16(uint8_t * apdu, uint16_t value)
{
int len = 0; // return value
union {
uint8_t byte[2];
uint16_t value;
} short_data = {{0}};
if (value < 0x100) {
apdu[0] = value;
apdu[1] = 0;
len = 2;
short_data.value = value;
if (big_endian()) {
apdu[0] = short_data.byte[0];
apdu[1] = short_data.byte[1];
} else {
apdu[0] = value / 0x100;
apdu[1] = value - (apdu[0] * 0x100);
len = 2;
apdu[0] = short_data.byte[1];
apdu[1] = short_data.byte[0];
}
return len;
return 2;
}
int decode_unsigned16(uint8_t * apdu, uint16_t *value)
{
int len = 0; // return value
union {
uint8_t byte[2];
uint16_t value;
} short_data = {{0}};
if (value)
{
*value = (apdu[len] * 0x100) + apdu[len + 1];
len = 2;
if (big_endian()) {
short_data.byte[0] = apdu[0];
short_data.byte[1] = apdu[1];
} else {
short_data.byte[1] = apdu[0];
short_data.byte[0] = apdu[1];
}
if (value)
*value = short_data.value;
return len;
return 2;
}
int encode_unsigned32(uint8_t * apdu, uint32_t value)
{
union {
uint8_t byte[4];
uint32_t value;
} long_data = {{0}};
long_data.value = value;
if (big_endian()) {
apdu[0] = long_data.byte[0];
apdu[1] = long_data.byte[1];
apdu[2] = long_data.byte[2];
apdu[3] = long_data.byte[3];
} else {
apdu[0] = long_data.byte[3];
apdu[1] = long_data.byte[2];
apdu[2] = long_data.byte[1];
apdu[3] = long_data.byte[0];
}
return 4;
}
int decode_unsigned32(uint8_t * apdu, uint32_t *value)
{
union {
uint8_t byte[4];
uint32_t value;
} long_data = {{0}};
if (big_endian()) {
long_data.byte[0] = apdu[0];
long_data.byte[1] = apdu[1];
long_data.byte[2] = apdu[2];
long_data.byte[3] = apdu[3];
} else {
long_data.byte[3] = apdu[0];
long_data.byte[2] = apdu[1];
long_data.byte[1] = apdu[2];
long_data.byte[0] = apdu[3];
}
if (value)
*value = long_data.value;
return 4;
}
// from clause 20.2.1 General Rules for Encoding BACnet Tags
// returns the number of apdu bytes consumed
@@ -158,16 +210,6 @@ int encode_tag(uint8_t * apdu, uint8_t tag_number, bool context_specific,
uint32_t len_value_type)
{
int len = 1; // return value
union {
uint8_t byte[2];
uint16_t value;
} short_data = { {
0}};
union {
uint8_t byte[4];
uint32_t value;
} long_data = { {
0}};
apdu[0] = 0;
if (context_specific)
@@ -190,36 +232,13 @@ int encode_tag(uint8_t * apdu, uint8_t tag_number, bool context_specific,
else {
apdu[0] |= 5;
if (len_value_type <= 253) {
apdu[len] = len_value_type;
len++;
apdu[len++] = len_value_type;
} else if (len_value_type <= 65535) {
apdu[len] = 254;
len++;
short_data.value = len_value_type;
if (big_endian()) {
apdu[len + 0] = short_data.byte[0];
apdu[len + 1] = short_data.byte[1];
} else {
apdu[len + 0] = short_data.byte[1];
apdu[len + 1] = short_data.byte[0];
}
len += 2;
apdu[len++] = 254;
len += encode_unsigned16(&apdu[len], len_value_type);
} else {
apdu[len] = 255;
len++;
long_data.value = len_value_type;
if (big_endian()) {
apdu[len + 0] = long_data.byte[0];
apdu[len + 1] = long_data.byte[1];
apdu[len + 2] = long_data.byte[2];
apdu[len + 3] = long_data.byte[3];
} else {
apdu[len + 0] = long_data.byte[3];
apdu[len + 1] = long_data.byte[2];
apdu[len + 2] = long_data.byte[1];
apdu[len + 3] = long_data.byte[0];
}
len += 4;
apdu[len++] = 255;
len += encode_unsigned32(&apdu[len], len_value_type);
}
}
@@ -329,16 +348,8 @@ int decode_tag_number_and_value(uint8_t * apdu,
uint8_t * tag_number, uint32_t * value)
{
int len = 1;
union {
uint8_t byte[2];
uint16_t value;
} short_data = { {
0}};
union {
uint8_t byte[4];
uint32_t value;
} long_data = { {
0}};
uint16_t value16;
uint32_t value32;
len = decode_tag_number(&apdu[0], tag_number);
// decode the value
@@ -346,36 +357,16 @@ int decode_tag_number_and_value(uint8_t * apdu,
// tagged as uint32_t
if (apdu[len] == 255) {
len++;
if (big_endian()) {
long_data.byte[0] = apdu[len + 0];
long_data.byte[1] = apdu[len + 1];
long_data.byte[2] = apdu[len + 2];
long_data.byte[3] = apdu[len + 3];
} else {
long_data.byte[3] = apdu[len + 0];
long_data.byte[2] = apdu[len + 1];
long_data.byte[1] = apdu[len + 2];
long_data.byte[0] = apdu[len + 3];
}
len += decode_unsigned32(&apdu[len], &value32);
if (value)
*value = long_data.value;
len += 4;
*value = value32;
}
// tagged as uint16_t
else if (apdu[len] == 254) {
len++;
if (big_endian()) {
short_data.byte[0] = apdu[len + 0];
short_data.byte[1] = apdu[len + 1];
} else {
short_data.byte[1] = apdu[len + 0];
short_data.byte[0] = apdu[len + 1];
}
len += decode_unsigned16(&apdu[len], &value16);
if (value)
*value = short_data.value;
len += 2;
*value = value16;
}
// no tag - must be uint8_t
else {
@@ -502,55 +493,29 @@ int encode_tagged_real(uint8_t * apdu, float value)
// from clause 20.2.14 Encoding of an Object Identifier Value
// returns the number of apdu bytes consumed
int decode_object_id(uint8_t * apdu, int *object_type, uint32_t *instance)
int decode_object_id(uint8_t *apdu, int *object_type, uint32_t *instance)
{
union {
uint8_t byte[4];
uint32_t value;
} my_data;
uint32_t value = 0;
int len = 0;
if (big_endian()) {
my_data.byte[0] = apdu[0];
my_data.byte[1] = apdu[1];
my_data.byte[2] = apdu[2];
my_data.byte[3] = apdu[3];
} else {
my_data.byte[0] = apdu[3];
my_data.byte[1] = apdu[2];
my_data.byte[2] = apdu[1];
my_data.byte[3] = apdu[0];
}
len = decode_unsigned32(apdu,&value);
*object_type = ((value >> 22) & 0x3FF);
*instance = (value & 0x3FFFFF);
*object_type = ((my_data.value >> 22) & 0x3FF);
*instance = (my_data.value & 0x3FFFFF);
return 4;
return len;
}
// from clause 20.2.14 Encoding of an Object Identifier Value
// returns the number of apdu bytes consumed
int encode_bacnet_object_id(uint8_t * apdu, int object_type, uint32_t instance)
{
union {
uint8_t byte[4];
uint32_t value;
} my_data;
uint32_t value = 0;
int len = 0;
my_data.value = ((object_type & 0x3FF) << 22) | (instance & 0x3FFFFF);
value = ((object_type & 0x3FF) << 22) | (instance & 0x3FFFFF);
len = encode_unsigned32(apdu,value);
if (big_endian()) {
apdu[0] = my_data.byte[0];
apdu[1] = my_data.byte[1];
apdu[2] = my_data.byte[2];
apdu[3] = my_data.byte[3];
} else {
apdu[0] = my_data.byte[3];
apdu[1] = my_data.byte[2];
apdu[2] = my_data.byte[1];
apdu[3] = my_data.byte[0];
}
return 4;
return len;
}
// from clause 20.2.14 Encoding of an Object Identifier Value
@@ -664,6 +629,7 @@ int decode_character_string(uint8_t * apdu, uint32_t len_value,
// from clause 20.2.4 Encoding of an Unsigned Integer Value
// and 20.2.1 General Rules for Encoding BACnet Tags
// returns the number of apdu bytes consumed
// FIXME: What about endian?
int encode_bacnet_unsigned(uint8_t * apdu, unsigned int value)
{
int len = 0; // return value
@@ -724,6 +690,7 @@ int encode_tagged_unsigned(uint8_t * apdu, unsigned int value)
// from clause 20.2.4 Encoding of an Unsigned Integer Value
// and 20.2.1 General Rules for Encoding BACnet Tags
// returns the number of apdu bytes consumed
// FIXME: What about endian?
int decode_unsigned(uint8_t * apdu, uint32_t len_value, unsigned *value)
{
int len = 0; // return value