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A quick java program to check proper matching of braces in a file.
import java.io.*;
public class CheckBraces{
// Print errors and set exit status
public static void die(String msg){
System.err.println(msg);
System.exit(1);
}
// Process a file named with a CLI arg
public static void main(String[] args){
// Check inputs
if (args.length < 1) CheckBraces.die("No file provided to check.");
BufferedReader reader = null;
try{ reader = new BufferedReader(new FileReader(args[0])); }
catch(Exception e){ die("Could not open file '" + args[0] + "'."); }
// Set up variables
String braces = "{}[]()";
int len = 0;
int index = -1;
int lastIndex = -1;
int stackEnd = 0;
int MAX_READ = 1024;
int MAX_STACK = 128;
char[] buf = new char[MAX_READ];
char[] stack = new char[MAX_STACK];
// Read input from file
while(true){
try { len = reader.read(buf, 0, MAX_READ); }
catch(Exception e){ die("Error reading file '" + args[0] + "'."); }
if (len < 1) break;
// Check read characters for braces
for(int i=0; i<len; ++i){
int temp = braces.indexOf(buf[i]);
if(temp == -1) continue;
index = temp;
// Open braces
if(index%2 == 0){
stack[stackEnd++] = buf[i];
lastIndex = index;
// Close braces
}else{
if(stackEnd <= 0) die("Found close '" + buf[i] + "' with no open '" + braces.charAt(index - 1) + "'.");
if(index-lastIndex != 1) die("Found '" + buf[i] + "' when expecting '" + braces.charAt(lastIndex + 1) + "'.");
if(--stackEnd == 0){
lastIndex = -1;
}else{
lastIndex = braces.indexOf(stack[stackEnd-1]);
}
}
}
}
// Final check
if (stackEnd > 0) die("End of file while still expecting '" + braces.charAt(lastIndex + 1) + "'.");
}
}
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