Separate general I/O from parsing.

3 files changed, 503 insertions, 0 deletions

diff --git a/BJC-Utils2/src/main/java/bjc/utils/ioutils/BlockReader.java b/BJC-Utils2/src/main/java/bjc/utils/ioutils/BlockReader.java
new file mode 100644
index 0000000..33bbbd5
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/ioutils/BlockReader.java
@@ -0,0 +1,208 @@
+package bjc.utils.ioutils;
+
+import java.io.LineNumberReader;
+import java.io.Reader;
+import java.util.NoSuchElementException;
+import java.util.Scanner;
+import java.util.function.Consumer;
+import java.util.regex.Pattern;
+
+/**
+ * Implements reading numbered blocks from a source.
+ * 
+ * A block is a series of characters, seperated by some regular expression.
+ * 
+ * NOTE: The EOF marker is always treated as a delimiter. You are expected to
+ * handle blocks that may be shorter than you expect.
+ * 
+ * @author EVE
+ *
+ */
+public class BlockReader implements AutoCloseable {
+	/**
+	 * Represents a block of text read in from a source.
+	 * 
+	 * @author EVE
+	 *
+	 */
+	public static class Block {
+		/**
+		 * The contents of this block.
+		 */
+		public final String contents;
+
+		/**
+		 * The line of the source this block started on.
+		 */
+		public final int startLine;
+
+		/**
+		 * The line of the source this block ended on.
+		 */
+		public final int endLine;
+
+		/**
+		 * The number of this block.
+		 */
+		public final int blockNo;
+
+		/**
+		 * Create a new block.
+		 * 
+		 * @param blockNo
+		 *                The number of this block.
+		 * @param contents
+		 *                The contents of this block.
+		 * @param startLine
+		 *                The line this block started on.
+		 * @param endLine
+		 *                The line this block ended.
+		 */
+		public Block(int blockNo, String contents, int startLine, int endLine) {
+			this.contents = contents;
+			this.startLine = startLine;
+			this.endLine = endLine;
+			this.blockNo = blockNo;
+		}
+
+		@Override
+		public int hashCode() {
+			final int prime = 31;
+			int result = 1;
+
+			result = prime * result + blockNo;
+			result = prime * result + ((contents == null) ? 0 : contents.hashCode());
+			result = prime * result + endLine;
+			result = prime * result + startLine;
+
+			return result;
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if(this == obj) return true;
+			if(obj == null) return false;
+			if(!(obj instanceof Block)) return false;
+
+			Block other = (Block) obj;
+
+			if(blockNo != other.blockNo) return false;
+
+			if(contents == null) {
+				if(other.contents != null) return false;
+			} else if(!contents.equals(other.contents)) return false;
+
+			if(endLine != other.endLine) return false;
+			if(startLine != other.startLine) return false;
+
+			return true;
+		}
+
+		@Override
+		public String toString() {
+			return String.format("Block #%d (from lines %d to %d) length: %d characters", blockNo, startLine,
+					endLine, contents.length());
+		}
+	}
+
+	/*
+	 * I/O source for blocks.
+	 */
+	private LineNumberReader	lnReader;
+	private Scanner			blockReader;
+
+	/*
+	 * The current block.
+	 */
+	private Block	currBlock;
+	private int	blockNo;
+
+	/**
+	 * Create a new block reader.
+	 * 
+	 * @param blockDelim
+	 *                The pattern that separates blocks. Note that the end
+	 *                of file is always considered to end a block.
+	 * 
+	 * @param source
+	 *                The source to read blocks from.
+	 */
+	public BlockReader(String blockDelim, Reader source) {
+		lnReader = new LineNumberReader(source);
+
+		blockReader = new Scanner(lnReader);
+		
+		String pattern = String.format("(?:%s)|\\Z", blockDelim);
+		Pattern pt = Pattern.compile(pattern, Pattern.MULTILINE);
+		
+		blockReader.useDelimiter(pt);
+	}
+
+	/**
+	 * Check if this reader has an available block.
+	 * 
+	 * @return Whether or not another block is available.
+	 */
+	public boolean hasNextBlock() {
+		return blockReader.hasNext();
+	}
+
+	/**
+	 * Get the current block.
+	 * 
+	 * @return The current block, or null if there is no current block.
+	 */
+	public Block getBlock() {
+		return currBlock;
+	}
+
+	/**
+	 * Move to the next block.
+	 * 
+	 * @return Whether or not the next block was succesfully read.
+	 */
+	public boolean nextBlock() {
+		try {
+			int blockStartLine = lnReader.getLineNumber();
+			String blockContents = blockReader.next();
+			int blockEndLine = lnReader.getLineNumber();
+			blockNo += 1;
+
+			currBlock = new Block(blockNo, blockContents, blockStartLine, blockEndLine);
+
+			return true;
+		} catch(NoSuchElementException nseex) {
+			return false;
+		}
+	}
+
+	/**
+	 * Execute an action for each remaining block.
+	 * 
+	 * @param action
+	 *                The action to execute for each block
+	 */
+	public void forEachBlock(Consumer<Block> action) {
+		while(hasNextBlock()) {
+			nextBlock();
+
+			action.accept(currBlock);
+		}
+	}
+
+	/**
+	 * Retrieve the number of blocks that have been read so far.
+	 * 
+	 * @return The number of blocks read so far.
+	 */
+	public int getBlockCount() {
+		return blockNo;
+	}
+
+	@Override
+	public void close() throws Exception {
+		blockReader.close();
+
+		lnReader.close();
+	}
+}
diff --git a/BJC-Utils2/src/main/java/bjc/utils/ioutils/RuleBasedConfigReader.java b/BJC-Utils2/src/main/java/bjc/utils/ioutils/RuleBasedConfigReader.java
new file mode 100644
index 0000000..b4d56a1
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/ioutils/RuleBasedConfigReader.java
@@ -0,0 +1,215 @@
+package bjc.utils.ioutils;
+
+import bjc.utils.data.IHolder;
+import bjc.utils.data.IPair;
+import bjc.utils.data.Identity;
+import bjc.utils.data.Pair;
+import bjc.utils.exceptions.UnknownPragmaException;
+import bjc.utils.funcdata.FunctionalMap;
+import bjc.utils.funcdata.FunctionalStringTokenizer;
+import bjc.utils.funcdata.IMap;
+
+import java.io.InputStream;
+import java.util.InputMismatchException;
+import java.util.Scanner;
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+
+/**
+ * This class parses a rules based config file, and uses it to drive a provided
+ * set of actions
+ *
+ * @author ben
+ *
+ * @param <E>
+ *                The type of the state object to use
+ *
+ */
+public class RuleBasedConfigReader<E> {
+	// Function to execute when starting a rule
+	// Takes the tokenizer, and a pair of the read token and application
+	// state
+	private BiConsumer<FunctionalStringTokenizer, IPair<String, E>> start;
+
+	// Function to use when continuing a rule
+	// Takes a tokenizer and application state
+	private BiConsumer<FunctionalStringTokenizer, E> continueRule;
+
+	// Function to use when ending a rule
+	// Takes an application state
+	private Consumer<E> end;
+
+	// Map of pragma names to pragma actions
+	// Pragma actions are functions taking a tokenizer and application state
+	private IMap<String, BiConsumer<FunctionalStringTokenizer, E>> pragmas;
+
+	/**
+	 * Create a new rule-based config reader
+	 *
+	 * @param start
+	 *                The action to fire when starting a rule
+	 * @param continueRule
+	 *                The action to fire when continuing a rule
+	 * @param end
+	 *                The action to fire when ending a rule
+	 */
+	public RuleBasedConfigReader(BiConsumer<FunctionalStringTokenizer, IPair<String, E>> start,
+			BiConsumer<FunctionalStringTokenizer, E> continueRule, Consumer<E> end) {
+		this.start = start;
+		this.continueRule = continueRule;
+		this.end = end;
+
+		this.pragmas = new FunctionalMap<>();
+	}
+
+	/**
+	 * Add a pragma to this reader
+	 *
+	 * @param name
+	 *                The name of the pragma to add
+	 * @param action
+	 *                The function to execute when this pragma is read
+	 */
+	public void addPragma(String name, BiConsumer<FunctionalStringTokenizer, E> action) {
+		if(name == null)
+			throw new NullPointerException("Pragma name must not be null");
+		else if(action == null) throw new NullPointerException("Pragma action must not be null");
+
+		pragmas.put(name, action);
+	}
+
+	private void continueRule(E state, boolean isRuleOpen, String line) {
+		// Make sure our input is correct
+		if(isRuleOpen == false)
+			throw new InputMismatchException("Cannot continue rule with no rule open");
+		else if(continueRule == null)
+			throw new InputMismatchException("Rule continuation not supported for current grammar");
+
+		// Accept the rule
+		continueRule.accept(new FunctionalStringTokenizer(line.substring(1), " "), state);
+	}
+
+	private boolean endRule(E state, boolean isRuleOpen) {
+		// Ignore blank line without an open rule
+		if(isRuleOpen == false)
+			// Do nothing
+			return false;
+		else {
+			// Nothing happens on rule end
+			if(end != null) {
+				// Process the rule ending
+				end.accept(state);
+			}
+
+			// Return a closed rule
+			return false;
+		}
+	}
+
+	/**
+	 * Run a stream through this reader
+	 *
+	 * @param input
+	 *                The stream to get input
+	 * @param initialState
+	 *                The initial state of the reader
+	 * @return The final state of the reader
+	 */
+	public E fromStream(InputStream input, E initialState) {
+		if(input == null) throw new NullPointerException("Input stream must not be null");
+
+		// Application state: We're giving this back later
+		E state = initialState;
+
+		// Prepare our input source
+		try(Scanner source = new Scanner(input)) {
+			source.useDelimiter("\n");
+			// This is true when a rule's open
+			IHolder<Boolean> isRuleOpen = new Identity<>(false);
+
+			// Do something for every line of the file
+			source.forEachRemaining((line) -> {
+				// Skip comment lines
+				if(line.startsWith("#") || line.startsWith("//"))
+					// It's a comment
+					return;
+				else if(line.equals("")) {
+					// End the rule
+					isRuleOpen.replace(endRule(state, isRuleOpen.getValue()));
+				} else if(line.startsWith("\t")) {
+					// Continue the rule
+					continueRule(state, isRuleOpen.getValue(), line);
+				} else {
+					// Open a rule
+					isRuleOpen.replace(startRule(state, isRuleOpen.getValue(), line));
+				}
+			});
+		}
+
+		// Return the state that the user has created
+		return state;
+
+	}
+
+	/**
+	 * Set the action to execute when continuing a rule
+	 *
+	 * @param continueRule
+	 *                The action to execute on continuation of a rule
+	 */
+	public void setContinueRule(BiConsumer<FunctionalStringTokenizer, E> continueRule) {
+		this.continueRule = continueRule;
+	}
+
+	/**
+	 * Set the action to execute when ending a rule
+	 *
+	 * @param end
+	 *                The action to execute on ending of a rule
+	 */
+	public void setEndRule(Consumer<E> end) {
+		this.end = end;
+	}
+
+	/**
+	 * Set the action to execute when starting a rule
+	 *
+	 * @param start
+	 *                The action to execute on starting of a rule
+	 */
+	public void setStartRule(BiConsumer<FunctionalStringTokenizer, IPair<String, E>> start) {
+		if(start == null) throw new NullPointerException("Action on rule start must be non-null");
+
+		this.start = start;
+	}
+
+	private boolean startRule(E state, boolean isRuleOpen, String line) {
+		// Create the line tokenizer
+		FunctionalStringTokenizer tokenizer = new FunctionalStringTokenizer(line, " ");
+
+		// Get the initial token
+		String nextToken = tokenizer.nextToken();
+
+		// Handle pragmas
+		if(nextToken.equals("pragma")) {
+			// Get the pragma name
+			String token = tokenizer.nextToken();
+
+			// Handle pragmas
+			pragmas.getOrDefault(token, (tokenzer, stat) -> {
+				throw new UnknownPragmaException("Unknown pragma " + token);
+			}).accept(tokenizer, state);
+		} else {
+			// Make sure input is correct
+			if(isRuleOpen == true)
+				throw new InputMismatchException("Nested rules are currently not supported");
+
+			// Start a rule
+			start.accept(tokenizer, new Pair<>(nextToken, state));
+
+			isRuleOpen = true;
+		}
+
+		return isRuleOpen;
+	}
+}
diff --git a/BJC-Utils2/src/main/java/bjc/utils/ioutils/RuleBasedReaderPragmas.java b/BJC-Utils2/src/main/java/bjc/utils/ioutils/RuleBasedReaderPragmas.java
new file mode 100644
index 0000000..f19eb2c
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/ioutils/RuleBasedReaderPragmas.java
@@ -0,0 +1,80 @@
+package bjc.utils.ioutils;
+
+import bjc.utils.exceptions.PragmaFormatException;
+import bjc.utils.funcdata.FunctionalStringTokenizer;
+import bjc.utils.funcutils.ListUtils;
+
+import java.util.function.BiConsumer;
+
+/**
+ * Contains factory methods for common pragma types
+ *
+ * @author ben
+ *
+ */
+public class RuleBasedReaderPragmas {
+
+	/**
+	 * Creates a pragma that takes a single integer argument
+	 *
+	 * @param <StateType>
+	 *                The type of state that goes along with this pragma
+	 * @param name
+	 *                The name of this pragma, for error message purpose
+	 * @param consumer
+	 *                The function to invoke with the parsed integer
+	 * @return A pragma that functions as described above.
+	 */
+	public static <StateType> BiConsumer<FunctionalStringTokenizer, StateType> buildInteger(String name,
+			BiConsumer<Integer, StateType> consumer) {
+		return (tokenizer, state) -> {
+			// Check our input is correct
+			if(!tokenizer.hasMoreTokens())
+				throw new PragmaFormatException("Pragma " + name + " requires one integer argument");
+
+			// Read the argument
+			String token = tokenizer.nextToken();
+
+			try {
+				// Run the pragma
+				consumer.accept(Integer.parseInt(token), state);
+			} catch(NumberFormatException nfex) {
+				// Tell the user their argument isn't correct
+				PragmaFormatException pfex = new PragmaFormatException(
+						"Argument " + token + " to " + name + " pragma isn't a valid integer. "
+								+ "This pragma requires a integer argument");
+
+				pfex.initCause(nfex);
+
+				throw pfex;
+			}
+		};
+	}
+
+	/**
+	 * Creates a pragma that takes any number of arguments and collapses
+	 * them all into a single string
+	 *
+	 * @param <StateType>
+	 *                The type of state that goes along with this pragma
+	 * @param name
+	 *                The name of this pragma, for error message purpose
+	 * @param consumer
+	 *                The function to invoke with the parsed string
+	 * @return A pragma that functions as described above.
+	 */
+	public static <StateType> BiConsumer<FunctionalStringTokenizer, StateType> buildStringCollapser(String name,
+			BiConsumer<String, StateType> consumer) {
+		return (tokenizer, state) -> {
+			// Check our input
+			if(!tokenizer.hasMoreTokens()) throw new PragmaFormatException(
+					"Pragma " + name + " requires one or more string arguments");
+
+			// Build our argument
+			String collapsed = ListUtils.collapseTokens(tokenizer.toList());
+
+			// Run the pragma
+			consumer.accept(collapsed, state);
+		};
+	}
+}