--- /dev/null
+/* -*- Mode: java; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+
+ * Copyright (C) 2011 George Yunaev @ Ulduzsoft
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+
+ http://www.ulduzsoft.com/2012/01/enumerating-the-fonts-on-android-platform/
+ */
+
+package org.jwz.xscreensaver;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.util.HashMap;
+
+// The class which loads the TTF file, parses it and returns the TTF font name
+class TTFAnalyzer
+{
+ // This function parses the TTF file and returns the font name specified in the file
+ public String getTtfFontName( String fontFilename )
+ {
+ try
+ {
+ // Parses the TTF file format.
+ // See http://developer.apple.com/fonts/ttrefman/rm06/Chap6.html
+ m_file = new RandomAccessFile( fontFilename, "r" );
+
+ // Read the version first
+ int version = readDword();
+
+ // The version must be either 'true' (0x74727565) or 0x00010000 or 'OTTO' (0x4f54544f) for CFF style fonts.
+ if ( version != 0x74727565 && version != 0x00010000 && version != 0x4f54544f)
+ return null;
+
+ // The TTF file consist of several sections called "tables", and we need to know how many of them are there.
+ int numTables = readWord();
+
+ // Skip the rest in the header
+ readWord(); // skip searchRange
+ readWord(); // skip entrySelector
+ readWord(); // skip rangeShift
+
+ // Now we can read the tables
+ for ( int i = 0; i < numTables; i++ )
+ {
+ // Read the table entry
+ int tag = readDword();
+ readDword(); // skip checksum
+ int offset = readDword();
+ int length = readDword();
+
+ // Now here' the trick. 'name' field actually contains the textual string name.
+ // So the 'name' string in characters equals to 0x6E616D65
+ if ( tag == 0x6E616D65 )
+ {
+ // Here's the name section. Read it completely into the allocated buffer
+ byte[] table = new byte[ length ];
+
+ m_file.seek( offset );
+ read( table );
+
+ // This is also a table. See http://developer.apple.com/fonts/ttrefman/rm06/Chap6name.html
+ // According to Table 36, the total number of table records is stored in the second word, at the offset 2.
+ // Getting the count and string offset - remembering it's big endian.
+ int count = getWord( table, 2 );
+ int string_offset = getWord( table, 4 );
+
+ // Record starts from offset 6
+ for ( int record = 0; record < count; record++ )
+ {
+ // Table 37 tells us that each record is 6 words -> 12 bytes, and that the nameID is 4th word so its offset is 6.
+ // We also need to account for the first 6 bytes of the header above (Table 36), so...
+ int nameid_offset = record * 12 + 6;
+ int platformID = getWord( table, nameid_offset );
+ int nameid_value = getWord( table, nameid_offset + 6 );
+
+ // Table 42 lists the valid name Identifiers. We're interested in 4 but not in Unicode encoding (for simplicity).
+ // The encoding is stored as PlatformID and we're interested in Mac encoding
+ if ( nameid_value == 4 && platformID == 1 )
+ {
+ // We need the string offset and length, which are the word 6 and 5 respectively
+ int name_length = getWord( table, nameid_offset + 8 );
+ int name_offset = getWord( table, nameid_offset + 10 );
+
+ // The real name string offset is calculated by adding the string_offset
+ name_offset = name_offset + string_offset;
+
+ // Make sure it is inside the array
+ if ( name_offset >= 0 && name_offset + name_length < table.length )
+ return new String( table, name_offset, name_length );
+ }
+ }
+ }
+ }
+
+ return null;
+ }
+ catch (FileNotFoundException e)
+ {
+ // Permissions?
+ return null;
+ }
+ catch (IOException e)
+ {
+ // Most likely a corrupted font file
+ return null;
+ }
+ }
+
+ // Font file; must be seekable
+ private RandomAccessFile m_file = null;
+
+ // Helper I/O functions
+ private int readByte() throws IOException
+ {
+ return m_file.read() & 0xFF;
+ }
+
+ private int readWord() throws IOException
+ {
+ int b1 = readByte();
+ int b2 = readByte();
+
+ return b1 << 8 | b2;
+ }
+
+ private int readDword() throws IOException
+ {
+ int b1 = readByte();
+ int b2 = readByte();
+ int b3 = readByte();
+ int b4 = readByte();
+
+ return b1 << 24 | b2 << 16 | b3 << 8 | b4;
+ }
+
+ private void read( byte [] array ) throws IOException
+ {
+ if ( m_file.read( array ) != array.length )
+ throw new IOException();
+ }
+
+ // Helper
+ private int getWord( byte [] array, int offset )
+ {
+ int b1 = array[ offset ] & 0xFF;
+ int b2 = array[ offset + 1 ] & 0xFF;
+
+ return b1 << 8 | b2;
+ }
+}
projects / xscreensaver / blobdiff