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Fix transmission of float and double values in generic protocol

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gcc -Wall -Werror turned up some problems with the type-punning of pointers
used to write the message buffer; it turns out that truncated ints were being
written to the message buffer when values needed to be swapped to network byte
order.
This commit is contained in:
Tim Moore 2009-08-24 18:06:06 +02:00
parent 0a64405cad
commit 62620177aa
1 changed files with 25 additions and 10 deletions
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35
src/Network/generic.cxx
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@ -97,6 +97,15 @@ FGGeneric::FGGeneric(vector<string> tokens) : exitOnError(false)
FGGeneric::~FGGeneric() { FGGeneric::~FGGeneric() {
} }
union u32 {
uint32_t intVal;
float floatVal;
};
union u64 {
uint64_t longVal;
double doubleVal;
};
// generate the message // generate the message
bool FGGeneric::gen_message_binary() { bool FGGeneric::gen_message_binary() {
@ -146,9 +155,11 @@ bool FGGeneric::gen_message_binary() {
if (binary_byte_order == BYTE_ORDER_MATCHES_NETWORK_ORDER) { if (binary_byte_order == BYTE_ORDER_MATCHES_NETWORK_ORDER) {
*((float*)&buf[length]) = val; *((float*)&buf[length]) = val;
} else { } else {
*((float*)&buf[length]) = sg_bswap_32(*(uint32_t*)&val); u32 tmpun32;
tmpun32.floatVal = static_cast<float>(val);
*((uint32_t*)&buf[length]) = sg_bswap_32(tmpun32.intVal);
} }
length += sizeof(int32_t); length += sizeof(uint32_t);
break; break;
case FG_DOUBLE: case FG_DOUBLE:
@ -158,7 +169,9 @@ bool FGGeneric::gen_message_binary() {
if (binary_byte_order == BYTE_ORDER_MATCHES_NETWORK_ORDER) { if (binary_byte_order == BYTE_ORDER_MATCHES_NETWORK_ORDER) {
*((double*)&buf[length]) = val; *((double*)&buf[length]) = val;
} else { } else {
*((double*)&buf[length]) = sg_bswap_64(*(uint64_t*)&val); u64 tmpun64;
tmpun64.doubleVal = val;
*((uint64_t*)&buf[length]) = sg_bswap_64(tmpun64.longVal);
} }
length += sizeof(int64_t); length += sizeof(int64_t);
break; break;
@ -195,6 +208,7 @@ bool FGGeneric::gen_message_binary() {
break; break;
case FOOTER_MAGIC: case FOOTER_MAGIC:
case FOOTER_NONE:
break; break;
} }
@ -282,7 +296,6 @@ bool FGGeneric::gen_message() {
bool FGGeneric::parse_message_binary() { bool FGGeneric::parse_message_binary() {
char *p2, *p1 = buf; char *p2, *p1 = buf;
int32_t tmp32; int32_t tmp32;
int64_t tmp64;
double val; double val;
int i = -1; int i = -1;
@ -323,28 +336,30 @@ bool FGGeneric::parse_message_binary() {
break; break;
case FG_FLOAT: case FG_FLOAT:
u32 tmpun32;
if (binary_byte_order == BYTE_ORDER_NEEDS_CONVERSION) { if (binary_byte_order == BYTE_ORDER_NEEDS_CONVERSION) {
tmp32 = sg_bswap_32(*(int32_t *)p1); tmpun32.intVal = sg_bswap_32(*(uint32_t *)p1);
} else { } else {
tmp32 = *(int32_t *)p1; tmpun32.floatVal = *(float *)p1;
} }
val = _in_message[i].offset + val = _in_message[i].offset +
*(float *)&tmp32 * _in_message[i].factor; tmpun32.floatVal * _in_message[i].factor;
_in_message[i].prop->setFloatValue(val); _in_message[i].prop->setFloatValue(val);
p1 += sizeof(int32_t); p1 += sizeof(int32_t);
break; break;
case FG_DOUBLE: case FG_DOUBLE:
u64 tmpun64;
if (binary_byte_order == BYTE_ORDER_NEEDS_CONVERSION) { if (binary_byte_order == BYTE_ORDER_NEEDS_CONVERSION) {
tmp64 = sg_bswap_64(*(int64_t *)p1); tmpun64.longVal = sg_bswap_64(*(uint64_t *)p1);
} else { } else {
tmp64 = *(int64_t *)p1; tmpun64.doubleVal = *(double *)p1;
} }
val = _in_message[i].offset + val = _in_message[i].offset +
*(double *)&tmp64 * _in_message[i].factor; tmpun64.doubleVal * _in_message[i].factor;
_in_message[i].prop->setDoubleValue(val); _in_message[i].prop->setDoubleValue(val);
p1 += sizeof(int64_t); p1 += sizeof(int64_t);