Skip to content

fix #59: ContestScanner#nextLong does not detect overflow #60

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
NASU41 merged 2 commits into from
Mar 9, 2021
Merged

fix #59: ContestScanner#nextLong does not detect overflow #60

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
fc06289
fix #59
suisen-cp Mar 9, 2021
69adbaa
fix #59
suisen-cp Mar 9, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
45 changes: 41 additions & 4 deletions ContestIO/ContestScanner.java
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,8 +1,13 @@
class ContestScanner{
class ContestScanner {
private final java.io.InputStream in;
private final byte[] buffer = new byte[1024];
private int ptr = 0;
private int buflen = 0;

private static final long LONG_MAX_TENTHS = 922337203685477580L;
private static final int LONG_MAX_LAST_DIGIT = 7;
private static final int LONG_MIN_LAST_DIGIT = 8;

public ContestScanner(java.io.InputStream in){
this.in = in;
}
Expand Down Expand Up @@ -59,10 +64,42 @@ public long nextLong() {
if (b < '0' || '9' < b) {
throw new NumberFormatException();
}
while(true){
while (true) {
if ('0' <= b && b <= '9') {
n *= 10;
n += b - '0';
int digit = b - '0';
if (n >= LONG_MAX_TENTHS) {
if (n == LONG_MAX_TENTHS) {
if (minus) {
if (digit <= LONG_MIN_LAST_DIGIT) {
n = -n * 10 - digit;
b = readByte();
if (!isPrintableChar(b)) {
return n;
} else if (b < '0' || '9' < b) {
throw new NumberFormatException(
String.format("%d%s... is not number", n, Character.toString(b))
);
}
}
} else {
if (digit <= LONG_MAX_LAST_DIGIT) {
n = n * 10 + digit;
b = readByte();
if (!isPrintableChar(b)) {
return n;
} else if (b < '0' || '9' < b) {
throw new NumberFormatException(
String.format("%d%s... is not number", n, Character.toString(b))
);
}
}
}
}
throw new ArithmeticException(
String.format("%s%d%d... overflows long.", minus ? "-" : "", n, digit)
);
}
n = n * 10 + digit;
}else if(b == -1 || !isPrintableChar(b)){
return minus ? -n : n;
}else{
Expand Down