flavien/Projet_JAVA_P2P_STRI2A
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Code Issues 11 Pull Requests Releases 13 Activity

Fix bug in BytesArrayTools reading

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This commit is contained in:
Louis Royer 2020-02-03 14:33:58 +01:00
parent 859c9146d9
commit 460964bd6e
2 changed files with 17 additions and 12 deletions
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22
src/protocolP2P/ProtocolP2PDatagram.java
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@ -243,28 +243,32 @@ public class ProtocolP2PDatagram {
this.hostR = hostR; this.hostR = hostR;
} }
private int computeCheckSum(byte [] datagram){ private int computeCheckSum(byte [] datagram) throws SizeError {
int checksum = 0; int checksum = 0;
for (int i=CHECKSUM_POSITION+2; i<datagram.length; ++i){ for (int i=CHECKSUM_POSITION+2; i<CHECKSUM_POSITION+2+4+Payload.getPayloadSize(datagram); ++i){
checksum += BytesArrayTools.readInt16Bits(datagram,i); checksum += BytesArrayTools.readInt16Bits(datagram,i);
checksum &= 0xffff; checksum &= 0xffff;
} }
return checksum ^ 0xffff; return checksum ^ 0xffff;
} }
private void setCheckSum(byte [] datagram) throws InternalError{ private void setCheckSum(byte [] datagram) throws InternalError {
int checksum = computeCheckSum(datagram); try {
try{ int checksum = computeCheckSum(datagram);
BytesArrayTools.write16Bits(datagram,CHECKSUM_POSITION,checksum); BytesArrayTools.write16Bits(datagram,CHECKSUM_POSITION,checksum);
} catch (SizeError e) { } catch (SizeError e) {
throw new InternalError(); throw new InternalError();
} }
} }
private void checkCheckSum(byte [] datagram) throws TransmissionError{ private void checkCheckSum(byte [] datagram) throws TransmissionError {
int checksum = BytesArrayTools.readInt16Bits(datagram,CHECKSUM_POSITION); try {
int computedCheckSum = computeCheckSum(datagram); int checksum = BytesArrayTools.readInt16Bits(datagram,CHECKSUM_POSITION);
if (computedCheckSum != checksum){ int computedCheckSum = computeCheckSum(datagram);
if (computedCheckSum != checksum){
throw new TransmissionError();
}
} catch(SizeError e) {
throw new TransmissionError(); throw new TransmissionError();
} }
} }

7
src/tools/BytesArrayTools.java
View File

@ -53,7 +53,7 @@ public class BytesArrayTools {
public static int readInt(byte[] array, int start) throws SizeError { public static int readInt(byte[] array, int start) throws SizeError {
int size = 0; int size = 0;
for(int i=0;i<4;i++) { for(int i=0;i<4;i++) {
size |= ((int)array[start + i]) << (8* (3 -i)); size |= (0xFF & (int)array[start + i]) << (8* (3 -i));
} }
if (size < 0) { if (size < 0) {
// Size in array is probably correct // Size in array is probably correct
@ -72,11 +72,12 @@ public class BytesArrayTools {
int size = 0; int size = 0;
for(int i=0;i<2;i++) { for(int i=0;i<2;i++) {
try { try {
size |= ((int)array[start + i]) << (8* (1 -i)); size |= (0xFF & (int)array[start + i]) << (8* (1 -i));
} catch (ArrayIndexOutOfBoundsException e){ } catch (ArrayIndexOutOfBoundsException e){
// 0 padding // 0 padding
} }
} }
assert (size & 0xFFFF0000) == 0 : "Read on more than 16 bits";
return size; return size;
} }
@ -89,7 +90,7 @@ public class BytesArrayTools {
public static long readLong(byte[] array, int start) throws SizeError { public static long readLong(byte[] array, int start) throws SizeError {
long size = 0; long size = 0;
for(int i=0;i<8;i++) { for(int i=0;i<8;i++) {
size |= ((int)array[start + i]) << (8* (7 - i)); size |= (0xFF & (int)array[start + i]) << (8* (7 - i));
} }
if (size < 0) { if (size < 0) {
// Size in array is probably correct // Size in array is probably correct