ragel-6.9ragel-6.9

1 files changed, 207 insertions, 0 deletions

diff --git a/examples/mailbox.rl b/examples/mailbox.rl
new file mode 100644
index 0000000..94590fd
--- /dev/null
+++ b/examples/mailbox.rl
@@ -0,0 +1,207 @@
+/*
+ * Parses unix mail boxes into headers and bodies.
+ */
+
+#include <iostream>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+using namespace std;
+
+#define BUFSIZE 2048
+
+/* A growable buffer for collecting headers. */
+struct Buffer
+{
+	Buffer() : data(0), allocated(0), length(0) { }
+	~Buffer() { empty(); }
+
+	void append( char p ) {
+		if ( ++length > allocated )
+			upAllocate( length*2 );
+		data[length-1] = p;
+	}
+		
+	void clear() { length = 0; }
+	void upAllocate( int len );
+	void empty();
+
+	char *data;
+	int allocated;
+	int length;
+};
+
+
+struct MailboxScanner
+{
+	Buffer headName;
+	Buffer headContent;
+
+	int cs, top, stack[1];
+
+	int init( );
+	int execute( const char *data, int len, bool isEof );
+	int finish( );
+};
+
+%%{
+	machine MailboxScanner;
+
+	# Buffer the header names.
+	action bufHeadName { headName.append(fc); }
+
+	# Prints a blank line after the end of the headers of each message.
+	action blankLine { cout << endl; }
+	
+	# Helpers we will use in matching the date section of the from line.
+	day = /[A-Z][a-z][a-z]/;
+	month = /[A-Z][a-z][a-z]/;
+	year = /[0-9][0-9][0-9][0-9]/;
+	time = /[0-9][0-9]:[0-9][0-9]/ . ( /:[0-9][0-9]/ | '' );
+	letterZone = /[A-Z][A-Z][A-Z]/;
+	numZone = /[+\-][0-9][0-9][0-9][0-9]/;
+	zone = letterZone | numZone;
+	dayNum = /[0-9 ][0-9]/;
+
+	# These are the different formats of the date minus an obscure
+	# type that has a funny string 'remote from xxx' on the end. Taken
+	# from c-client in the imap-2000 distribution.
+	date = day . ' ' . month . ' ' . dayNum . ' ' . time . ' ' .
+		( year | year . ' ' . zone | zone . ' ' . year );
+
+	# From lines separate messages. We will exclude fromLine from a message
+	# body line.  This will cause us to stay in message line up until an
+	# entirely correct from line is matched.
+	fromLine = 'From ' . (any-'\n')* . ' ' . date . '\n';
+
+	# The types of characters that can be used as a header name.
+	hchar = print - [ :];
+
+	# Simply eat up an uninteresting header. Return at the first non-ws
+	# character following a newline.
+	consumeHeader := ( 
+			[^\n] | 
+			'\n' [ \t] |
+			'\n' [^ \t] @{fhold; fret;}
+		)*;
+
+	action hchar {headContent.append(fc);}
+	action hspace {headContent.append(' ');}
+
+	action hfinish {
+		headContent.append(0);
+		cout << headContent.data << endl;
+		headContent.clear();
+		fhold;
+		fret;
+	}
+
+	# Display the contents of a header as it is consumed. Collapses line
+	# continuations to a single space. 
+	printHeader := ( 
+		[^\n] @hchar  | 
+		( '\n' ( [ \t]+ '\n' )* [ \t]+ ) %hspace
+	)** $!hfinish;
+
+	action onHeader 
+	{
+		headName.append(0);
+		if ( strcmp( headName.data, "From" ) == 0 ||
+				strcmp( headName.data, "To" ) == 0 ||
+				strcmp( headName.data, "Subject" ) == 0 )
+		{
+			/* Print the header name, then jump to a machine the will display
+			 * the contents. */
+			cout << headName.data << ":";
+			headName.clear();
+			fcall printHeader;
+		}
+
+		headName.clear();
+		fcall consumeHeader;
+	}
+
+	header = hchar+ $bufHeadName ':' @onHeader;
+
+	# Exclude fromLine from a messageLine, otherwise when encountering a
+	# fromLine we will be simultaneously matching the old message and a new
+	# message.
+	messageLine = ( [^\n]* '\n' - fromLine );
+
+	# An entire message.
+	message = ( fromLine .  header* .  '\n' @blankLine .  messageLine* );
+
+	# File is a series of messages.
+	main := message*;
+}%%
+
+%% write data;
+
+int MailboxScanner::init( )
+{
+	%% write init;
+	return 1;
+}
+
+int MailboxScanner::execute( const char *data, int len, bool isEof )
+{
+	const char *p = data;
+	const char *pe = data + len;
+	const char *eof = isEof ? pe : 0;
+
+	%% write exec;
+
+	if ( cs == MailboxScanner_error )
+		return -1;
+	if ( cs >= MailboxScanner_first_final )
+		return 1;
+	return 0;
+}
+
+int MailboxScanner::finish( )
+{
+	if ( cs == MailboxScanner_error )
+		return -1;
+	if ( cs >= MailboxScanner_first_final )
+		return 1;
+	return 0;
+}
+
+
+void Buffer::empty()
+{
+	if ( data != 0 ) {
+		free( data );
+
+		data = 0;
+		length = 0;
+		allocated = 0;
+	}
+}
+
+void Buffer::upAllocate( int len )
+{
+	if ( data == 0 )
+		data = (char*) malloc( len );
+	else
+		data = (char*) realloc( data, len );
+	allocated = len;
+}
+
+MailboxScanner mailbox;
+char buf[BUFSIZE];
+
+int main()
+{
+	mailbox.init();
+	while ( 1 ) {
+		int len = fread( buf, 1, BUFSIZE, stdin );
+		mailbox.execute( buf, len, len != BUFSIZE );
+		if ( len != BUFSIZE )
+			break;
+	}
+	if ( mailbox.finish() <= 0 )
+		cerr << "mailbox: error parsing input" << endl;
+	return 0;
+}