diff --git a/libc/tools/zoneinfo/ZoneCompactor.java b/libc/tools/zoneinfo/ZoneCompactor.java
index 9fb9cec..6ce24cf 100644
--- a/libc/tools/zoneinfo/ZoneCompactor.java
+++ b/libc/tools/zoneinfo/ZoneCompactor.java
@@ -7,8 +7,7 @@
 
 // usage: java ZoneCompiler <setup file> <data directory> <output directory> <tzdata version>
 //
-// Compile a set of tzfile-formatted files into a single file plus
-// an index file.
+// Compile a set of tzfile-formatted files into a single file containing an index.
 //
 // The compilation is controlled by a setup file, which is provided as a
 // command-line argument.  The setup file has the form:
@@ -18,195 +17,219 @@
 // <zone filename>
 // ...
 //
-// Note that the links must be declared prior to the zone names.  A
-// zone name is a filename relative to the source directory such as
+// Note that the links must be declared prior to the zone names.
+// A zone name is a filename relative to the source directory such as
 // 'GMT', 'Africa/Dakar', or 'America/Argentina/Jujuy'.
 //
 // Use the 'zic' command-line tool to convert from flat files
-// (e.g., 'africa', 'northamerica') into a suitable source directory
-// hierarchy for this tool (e.g., 'data/Africa/Abidjan').
+// (such as 'africa' or 'northamerica') to a directory
+// hierarchy suitable for this tool (containing files such as 'data/Africa/Abidjan').
 //
-// Example:
-//     zic -d data tz2007h
-//     javac ZoneCompactor.java
-//     java ZoneCompactor setup data
-//     <produces zoneinfo.dat and zoneinfo.idx>
 
 public class ZoneCompactor {
-    public static class ByteArrayBufferIteratorBE extends BufferIterator {
-        private final byte[] bytes;
-        private int offset = 0;
+  public static class ByteArrayBufferIteratorBE extends BufferIterator {
+    private final byte[] bytes;
+    private int offset = 0;
 
-        public ByteArrayBufferIteratorBE(byte[] bytes) {
-            this.bytes = bytes;
-            this.offset = 0;
-        }
-
-        public void seek(int offset) {
-            this.offset = offset;
-        }
-
-        public void skip(int byteCount) {
-            this.offset += byteCount;
-        }
-
-        public void readByteArray(byte[] dst, int dstOffset, int byteCount) {
-            System.arraycopy(bytes, offset, dst, dstOffset, byteCount);
-            offset += byteCount;
-        }
-
-        public byte readByte() {
-            return bytes[offset++];
-        }
-
-        public int readInt() {
-            return ((readByte() & 0xff) << 24) | ((readByte() & 0xff) << 16) | ((readByte() & 0xff) << 8) | (readByte() & 0xff);
-        }
-
-        public void readIntArray(int[] dst, int dstOffset, int intCount) {
-            for (int i = 0; i < intCount; ++i) {
-                dst[dstOffset++] = readInt();
-            }
-        }
-
-        public short readShort() {
-            throw new UnsupportedOperationException();
-        }
+    public ByteArrayBufferIteratorBE(byte[] bytes) {
+      this.bytes = bytes;
+      this.offset = 0;
     }
 
-    // Maximum number of characters in a zone name, including '\0' terminator
-    private static final int MAXNAME = 40;
-
-    // Zone name synonyms
-    private Map<String,String> links = new HashMap<String,String>();
-
-    // File starting bytes by zone name
-    private Map<String,Integer> starts = new HashMap<String,Integer>();
-
-    // File lengths by zone name
-    private Map<String,Integer> lengths = new HashMap<String,Integer>();
-
-    // Raw GMT offsets by zone name
-    private Map<String,Integer> offsets = new HashMap<String,Integer>();
-    private int start = 0;
-
-    // Concatenate the contents of 'inFile' onto 'out'
-    // and return the contents as a byte array.
-    private static byte[] copyFile(File inFile, OutputStream out) throws Exception {
-        byte[] ret = new byte[0];
-
-        InputStream in = new FileInputStream(inFile);
-        byte[] buf = new byte[8192];
-        while (true) {
-            int nbytes = in.read(buf);
-            if (nbytes == -1) {
-                break;
-            }
-            out.write(buf, 0, nbytes);
-
-            byte[] nret = new byte[ret.length + nbytes];
-            System.arraycopy(ret, 0, nret, 0, ret.length);
-            System.arraycopy(buf, 0, nret, ret.length, nbytes);
-            ret = nret;
-        }
-        out.flush();
-        return ret;
+    public void seek(int offset) {
+      this.offset = offset;
     }
 
-    // Write a 32-bit integer in network byte order
-    private void writeInt(OutputStream os, int x) throws IOException {
-        os.write((x >> 24) & 0xff);
-        os.write((x >> 16) & 0xff);
-        os.write((x >>  8) & 0xff);
-        os.write( x        & 0xff);
+    public void skip(int byteCount) {
+      this.offset += byteCount;
     }
 
-    public ZoneCompactor(String setupFile, String dataDirectory, String outputDirectory, String version) throws Exception {
-        File zoneInfoFile = new File(outputDirectory, "zoneinfo.dat");
-        zoneInfoFile.delete();
-        OutputStream zoneInfo = new FileOutputStream(zoneInfoFile);
-
-        BufferedReader rdr = new BufferedReader(new FileReader(setupFile));
-
-        String s;
-        while ((s = rdr.readLine()) != null) {
-            s = s.trim();
-            if (s.startsWith("Link")) {
-                StringTokenizer st = new StringTokenizer(s);
-                st.nextToken();
-                String to = st.nextToken();
-                String from = st.nextToken();
-                links.put(from, to);
-            } else {
-                String link = links.get(s);
-                if (link == null) {
-                    File f = new File(dataDirectory, s);
-                    long length = f.length();
-                    starts.put(s, new Integer(start));
-                    lengths.put(s, new Integer((int)length));
-
-                    start += length;
-                    byte[] data = copyFile(f, zoneInfo);
-
-                    BufferIterator it = new ByteArrayBufferIteratorBE(data);
-                    TimeZone tz = ZoneInfo.makeTimeZone(s, it);
-                    int gmtOffset = tz.getRawOffset();
-                    offsets.put(s, new Integer(gmtOffset));
-                }
-            }
-        }
-        zoneInfo.close();
-
-        // Fill in fields for links
-        Iterator<String> iter = links.keySet().iterator();
-        while (iter.hasNext()) {
-            String from = iter.next();
-            String to = links.get(from);
-
-            starts.put(from, starts.get(to));
-            lengths.put(from, lengths.get(to));
-            offsets.put(from, offsets.get(to));
-        }
-
-        File idxFile = new File(outputDirectory, "zoneinfo.idx");
-        idxFile.delete();
-        FileOutputStream idx = new FileOutputStream(idxFile);
-
-        ArrayList<String> l = new ArrayList<String>();
-        l.addAll(starts.keySet());
-        Collections.sort(l);
-        Iterator<String> ziter = l.iterator();
-        while (ziter.hasNext()) {
-            String zname = ziter.next();
-            if (zname.length() >= MAXNAME) {
-                System.err.println("Error - zone filename exceeds " +
-                                   (MAXNAME - 1) + " characters!");
-            }
-
-            byte[] znameBuf = new byte[MAXNAME];
-            for (int i = 0; i < zname.length(); i++) {
-                znameBuf[i] = (byte)zname.charAt(i);
-            }
-            idx.write(znameBuf);
-            writeInt(idx, starts.get(zname).intValue());
-            writeInt(idx, lengths.get(zname).intValue());
-            writeInt(idx, offsets.get(zname).intValue());
-        }
-        idx.close();
-
-        OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(new File(outputDirectory, "zoneinfo.version")), "US-ASCII");
-        writer.write(version);
-        writer.write('\n');
-        writer.close();
-
-        // System.out.println("maxLength = " + maxLength);
+    public void readByteArray(byte[] dst, int dstOffset, int byteCount) {
+      System.arraycopy(bytes, offset, dst, dstOffset, byteCount);
+      offset += byteCount;
     }
 
-    public static void main(String[] args) throws Exception {
-        if (args.length != 4) {
-            System.err.println("usage: java ZoneCompactor <setup file> <data directory> <output directory> <tzdata version>");
-            System.exit(0);
-        }
-        new ZoneCompactor(args[0], args[1], args[2], args[3]);
+    public byte readByte() {
+      return bytes[offset++];
     }
+
+    public int readInt() {
+      return ((readByte() & 0xff) << 24) | ((readByte() & 0xff) << 16) | ((readByte() & 0xff) << 8) | (readByte() & 0xff);
+    }
+
+    public void readIntArray(int[] dst, int dstOffset, int intCount) {
+      for (int i = 0; i < intCount; ++i) {
+        dst[dstOffset++] = readInt();
+      }
+    }
+
+    public short readShort() {
+      throw new UnsupportedOperationException();
+    }
+  }
+
+  // Maximum number of characters in a zone name, including '\0' terminator
+  private static final int MAXNAME = 40;
+
+  // Zone name synonyms
+  private Map<String,String> links = new HashMap<String,String>();
+
+  // File starting bytes by zone name
+  private Map<String,Integer> starts = new HashMap<String,Integer>();
+
+  // File lengths by zone name
+  private Map<String,Integer> lengths = new HashMap<String,Integer>();
+
+  // Raw GMT offsets by zone name
+  private Map<String,Integer> offsets = new HashMap<String,Integer>();
+  private int start = 0;
+
+  // Concatenate the contents of 'inFile' onto 'out'
+  // and return the contents as a byte array.
+  private static byte[] copyFile(File inFile, OutputStream out) throws Exception {
+    byte[] ret = new byte[0];
+
+    InputStream in = new FileInputStream(inFile);
+    byte[] buf = new byte[8192];
+    while (true) {
+      int nbytes = in.read(buf);
+      if (nbytes == -1) {
+        break;
+      }
+      out.write(buf, 0, nbytes);
+
+      byte[] nret = new byte[ret.length + nbytes];
+      System.arraycopy(ret, 0, nret, 0, ret.length);
+      System.arraycopy(buf, 0, nret, ret.length, nbytes);
+      ret = nret;
+    }
+    out.flush();
+    return ret;
+  }
+
+  public ZoneCompactor(String setupFile, String dataDirectory, String outputDirectory, String version) throws Exception {
+    // Read the setup file, and concatenate all the data.
+    ByteArrayOutputStream allData = new ByteArrayOutputStream();
+    BufferedReader reader = new BufferedReader(new FileReader(setupFile));
+    String s;
+    while ((s = reader.readLine()) != null) {
+      s = s.trim();
+      if (s.startsWith("Link")) {
+        StringTokenizer st = new StringTokenizer(s);
+        st.nextToken();
+        String to = st.nextToken();
+        String from = st.nextToken();
+        links.put(from, to);
+      } else {
+        String link = links.get(s);
+        if (link == null) {
+          File sourceFile = new File(dataDirectory, s);
+          long length = sourceFile.length();
+          starts.put(s, start);
+          lengths.put(s, (int) length);
+
+          start += length;
+          byte[] data = copyFile(sourceFile, allData);
+
+          BufferIterator it = new ByteArrayBufferIteratorBE(data);
+          TimeZone tz = ZoneInfo.makeTimeZone(s, it);
+          int gmtOffset = tz.getRawOffset();
+          offsets.put(s, gmtOffset);
+        }
+      }
+    }
+
+    // Fill in fields for links.
+    Iterator<String> it = links.keySet().iterator();
+    while (it.hasNext()) {
+      String from = it.next();
+      String to = links.get(from);
+
+      starts.put(from, starts.get(to));
+      lengths.put(from, lengths.get(to));
+      offsets.put(from, offsets.get(to));
+    }
+
+    // Create/truncate the destination file.
+    RandomAccessFile f = new RandomAccessFile(new File(outputDirectory, "tzdata"), "rw");
+    f.setLength(0);
+
+    // Write the header.
+
+    // byte[12] tzdata_version          -- 'tzdata2012f\0'
+    // int file_format_version          -- probably won't need this, but just in case
+    // int index_offset                 -- likewise
+    // int data_offset
+    // int zonetab_offset
+
+    // tzdata_version
+    f.write(toAscii(new byte[12], version));
+
+    // file_format_version
+    f.writeInt(1);
+
+    // Write dummy values for the three offsets, and remember where we need to seek back to later
+    // when we have the real values.
+    int index_offset_offset = (int) f.getFilePointer();
+    f.writeInt(0);
+    int data_offset_offset = (int) f.getFilePointer();
+    f.writeInt(0);
+    int zonetab_offset_offset = (int) f.getFilePointer();
+    f.writeInt(0);
+
+    int index_offset = (int) f.getFilePointer();
+
+    // Write the index.
+    ArrayList<String> sortedOlsonIds = new ArrayList<String>();
+    sortedOlsonIds.addAll(starts.keySet());
+    Collections.sort(sortedOlsonIds);
+    it = sortedOlsonIds.iterator();
+    while (it.hasNext()) {
+      String zoneName = it.next();
+      if (zoneName.length() >= MAXNAME) {
+        throw new RuntimeException("zone filename too long: " + zoneName.length());
+      }
+
+      f.write(toAscii(new byte[MAXNAME], zoneName));
+      f.writeInt(starts.get(zoneName));
+      f.writeInt(lengths.get(zoneName));
+      f.writeInt(offsets.get(zoneName));
+    }
+
+    int data_offset = (int) f.getFilePointer();
+
+    // Write the data.
+    f.write(allData.toByteArray());
+
+    // TODO: append the zonetab.
+    int zonetab_offset = 0;
+
+    // Go back and fix up the offsets in the header.
+    f.seek(index_offset_offset);
+    f.writeInt(index_offset);
+    f.seek(data_offset_offset);
+    f.writeInt(data_offset);
+    f.seek(zonetab_offset_offset);
+    f.writeInt(zonetab_offset);
+
+    f.close();
+  }
+
+  private static byte[] toAscii(byte[] dst, String src) {
+    for (int i = 0; i < src.length(); ++i) {
+      if (src.charAt(i) > '~') {
+        throw new RuntimeException("non-ASCII string: " + src);
+      }
+      dst[i] = (byte) src.charAt(i);
+    }
+    return dst;
+  }
+
+  public static void main(String[] args) throws Exception {
+    if (args.length != 4) {
+      System.err.println("usage: java ZoneCompactor <setup file> <data directory> <output directory> <tzdata version>");
+      System.exit(0);
+    }
+    new ZoneCompactor(args[0], args[1], args[2], args[3]);
+  }
 }
diff --git a/libc/tools/zoneinfo/generate b/libc/tools/zoneinfo/generate
index 1dfbd8e..e9ff59b 100755
--- a/libc/tools/zoneinfo/generate
+++ b/libc/tools/zoneinfo/generate
@@ -1,12 +1,10 @@
 #!/usr/bin/python
-# Run with no arguments from any directory, with no special setup required.
+
+"""Updates the tzdata file."""
 
 import ftplib
-import hashlib
 import os
 import re
-import shutil
-import string
 import subprocess
 import sys
 import tarfile
@@ -18,41 +16,58 @@
 bionic_libc_dir = os.path.dirname(bionic_libc_tools_dir)
 bionic_dir = os.path.dirname(bionic_libc_dir)
 bionic_libc_zoneinfo_dir = '%s/libc/zoneinfo' % bionic_dir
-if not os.path.isdir(bionic_libc_tools_zoneinfo_dir) or not os.path.isdir(bionic_libc_zoneinfo_dir):
+
+if not os.path.isdir(bionic_libc_tools_zoneinfo_dir):
   print "Couldn't find bionic/libc/tools/zoneinfo!"
   sys.exit(1)
+if not os.path.isdir(bionic_libc_zoneinfo_dir):
+  print "Couldn't find bionic/libc/zoneinfo!"
+  sys.exit(1)
+
 print 'Found bionic in %s...' % bionic_dir
 
 
-regions = ['africa', 'antarctica', 'asia', 'australasia', 'backward', 'etcetera', 'europe', 'northamerica', 'southamerica']
+regions = ['africa', 'antarctica', 'asia', 'australasia', 'backward',
+           'etcetera', 'europe', 'northamerica', 'southamerica']
 
 
-def current_tzdata_version():
-  return open('%s/zoneinfo.version' % bionic_libc_zoneinfo_dir).readline().rstrip('\n')
+def GetCurrentTzDataVersion():
+  return open('%s/tzdata' % bionic_libc_zoneinfo_dir).read().split('\0', 1)[0]
 
 
-def md5_file(filename):
-  md5 = hashlib.md5()
-  f = open(filename, 'rb')
-  while True:
-    data = f.read(8192)
-    if not data:
-      break
-    md5.update(data)
-  return md5.hexdigest()
+def WriteSetupFile():
+  links = []
+  zones = []
+  for region in regions:
+    for line in open('extracted/%s' % region):
+      fields = line.split()
+      if len(fields) == 0:
+        continue
+      elif fields[0] == 'Link':
+        links.append('%s %s %s\n' % (fields[0], fields[1], fields[2]))
+        zones.append(fields[2])
+      elif fields[0] == 'Zone':
+        zones.append(fields[1])
+  zones.sort()
+
+  setup = open('setup', 'w')
+  for link in links:
+    setup.write(link)
+  for zone in zones:
+    setup.write('%s\n' % zone)
+  setup.close()
 
 
-def upgrade_to(ftp, filename):
-  version = re.search('tzdata(.+)\.tar\.gz', filename).group(1)
+def UpgradeTo(ftp, filename):
+  new_version = re.search('(tzdata.+)\.tar\.gz', filename).group(1)
 
   # Switch to a temporary directory.
   tmp_dir = tempfile.mkdtemp('-tzdata')
   os.chdir(tmp_dir)
   print 'Created temporary directory "%s"...' % tmp_dir
 
-  print 'Downloading %s...' % filename
+  print 'Downloading...'
   ftp.retrbinary('RETR %s' % filename, open(filename, 'wb').write)
-  print 'MD5: %s' % md5_file(filename)
 
   print 'Extracting...'
   os.mkdir('extracted')
@@ -65,58 +80,46 @@
     if region != 'backward':
       subprocess.check_call(['zic', '-d', 'data', 'extracted/%s' % region])
 
-  # Collect the data ZoneCompactor needs.
-  links = []
-  zones = []
-  for region in regions:
-    for line in open('extracted/%s' % region).readlines():
-      fields = string.split(line)
-      if len(fields) == 0:
-        continue
-      elif fields[0] == 'Link':
-        links.append('%s %s %s\n' % (fields[0], fields[1], fields[2]))
-        zones.append(fields[2])
-      elif fields[0] == 'Zone':
-        zones.append(fields[1])
-  zones.sort()
+  WriteSetupFile()
 
-  # Write it into the "setup" file.
-  setup = open('setup', 'w')
-  for link in links:
-    setup.write(link)
-  for zone in zones:
-    setup.write('%s\n' % zone)
-  setup.close()
-
-  print 'Calling ZoneCompactor to update bionic from %s to %s...' % (current_tzdata_version(), version)
+  print 'Calling ZoneCompactor to update bionic to %s...' % new_version
   libcore_src_dir = '%s/../libcore/luni/src/main/java/' % bionic_dir
   subprocess.check_call(['javac', '-d', '.',
                          '%s/ZoneCompactor.java' % bionic_libc_tools_zoneinfo_dir,
                          '%s/libcore/util/ZoneInfo.java' % libcore_src_dir,
                          '%s/libcore/io/BufferIterator.java' % libcore_src_dir])
-  subprocess.check_call(['java', 'ZoneCompactor', 'setup', 'data', bionic_libc_zoneinfo_dir, version])
+  subprocess.check_call(['java', 'ZoneCompactor',
+                         'setup', 'data', bionic_libc_zoneinfo_dir, new_version])
 
 
-# URL from "Sources for Time Zone and Daylight Saving Time Data"
-# http://www.twinsun.com/tz/tz-link.htm
+# Run with no arguments from any directory, with no special setup required.
+def main():
+  # URL from "Sources for Time Zone and Daylight Saving Time Data"
+  # http://www.twinsun.com/tz/tz-link.htm
 
-print 'Looking for new tzdata...'
-ftp = ftplib.FTP('ftp.iana.org')
-ftp.login()
-ftp.cwd('tz/releases')
-tzdata_filenames = []
-for filename in ftp.nlst():
-  if filename.startswith('tzdata20'):
-    tzdata_filenames.append(filename)
-tzdata_filenames.sort()
+  print 'Looking for new tzdata...'
+  ftp = ftplib.FTP('ftp.iana.org')
+  ftp.login()
+  ftp.cwd('tz/releases')
+  tzdata_filenames = []
+  for filename in ftp.nlst():
+    if filename.startswith('tzdata20'):
+      tzdata_filenames.append(filename)
+  tzdata_filenames.sort()
 
-# If you're several releases behind, we'll walk you through the upgrades one by one.
-current_version = current_tzdata_version()
-current_filename = 'tzdata%s.tar.gz' % current_version
-for filename in tzdata_filenames:
-  if filename > current_filename:
-    upgrade_to(ftp, filename)
-    sys.exit(0)
+  # If you're several releases behind, we'll walk you through the upgrades
+  # one by one.
+  current_version = GetCurrentTzDataVersion()
+  current_filename = '%s.tar.gz' % current_version
+  for filename in tzdata_filenames:
+    if filename > current_filename:
+      print 'Found new tzdata: %s' % filename
+      UpgradeTo(ftp, filename)
+      sys.exit(0)
 
-print 'You already have the latest tzdata (%s)!' % current_version
-sys.exit(0)
+  print 'You already have the latest tzdata (%s)!' % current_version
+  sys.exit(0)
+
+
+if __name__ == '__main__':
+  main()
diff --git a/libc/tools/zoneinfo/generate-single-file b/libc/tools/zoneinfo/generate-single-file
deleted file mode 100755
index a67713c..0000000
--- a/libc/tools/zoneinfo/generate-single-file
+++ /dev/null
@@ -1,77 +0,0 @@
-#!/usr/bin/python
-# Run with no arguments from any directory, with no special setup required.
-
-import ftplib
-import hashlib
-import os
-import re
-import shutil
-import string
-import struct
-import subprocess
-import sys
-import tarfile
-import tempfile
-
-# Find the bionic directory, searching upward from this script.
-bionic_libc_tools_zoneinfo_dir = os.path.realpath(os.path.dirname(sys.argv[0]))
-bionic_libc_tools_dir = os.path.dirname(bionic_libc_tools_zoneinfo_dir)
-bionic_libc_dir = os.path.dirname(bionic_libc_tools_dir)
-bionic_dir = os.path.dirname(bionic_libc_dir)
-bionic_libc_zoneinfo_dir = '%s/libc/zoneinfo' % bionic_dir
-if not os.path.isdir(bionic_libc_tools_zoneinfo_dir) or not os.path.isdir(bionic_libc_zoneinfo_dir):
-  print "Couldn't find bionic/libc/tools/zoneinfo!"
-  sys.exit(1)
-
-
-
-
-def current_tzdata_version():
-  return open('%s/zoneinfo.version' % bionic_libc_zoneinfo_dir).readline().rstrip('\n')
-
-
-# TODO: make the regular "generate" script just output this format directly.
-
-# Open the output file.
-f = open('%s/tzdata' % bionic_libc_zoneinfo_dir, 'wb+')
-
-#  -- header
-# char[12] tzdata_version          -- 'tzdata2012f\0'
-# u32 file_format_version          -- probably won't need this, but just in case
-# u32 index_offset                 -- likewise
-# u32 data_offset
-# u32 zonetab_offset
-header_format = "! 12s i i i i"
-header_size = struct.calcsize(header_format)
-
-index_offset = header_size
-index_bytes = open('%s/zoneinfo.idx' % bionic_libc_zoneinfo_dir, "rb").read()
-index_size = len(index_bytes)
-
-data_offset = index_offset + index_size
-data_bytes = open('%s/zoneinfo.dat' % bionic_libc_zoneinfo_dir).read()
-data_size = len(data_bytes)
-
-zonetab_offset = 0 # TODO: data_offset + data_size
-
-tzdata_version = current_tzdata_version()
-file_format_version = 1
-
-header = struct.pack(header_format, 'tzdata%s' % tzdata_version, file_format_version, index_offset, data_offset, zonetab_offset)
-f.write(header)
-
-# -- index (@index_offset)
-# u8* index_bytes
-f.write(index_bytes)
-
-# -- data (@data_offset)
-# u8* data_bytes
-f.write(data_bytes)
-
-# TODO: zonetab
-# -- zonetab (@zonetab_offset)
-# u8* zonetab_bytes
-
-f.close()
-
-sys.exit(0)