diff --git a/bin/Makefile b/bin/Makefile
index 77808b5..e2c6b50 100644
--- a/bin/Makefile
+++ b/bin/Makefile
@@ -6,13 +6,10 @@ VERSION = -DVMAJOR=0 -DVMINOR=0 -DVREV=1
 OBJS := $(shell find ../src/ -name '*.c' -print)
 OBJS := $(OBJS:../src/%.c=../src/%.o)
 
-DATA = data
-DATAFILES = $(shell find ../gfx/ ../dat/ -name '*.png' -o -name '*.xml' -print)
-
 CLUA = -I/usr/include/lua5.1
-CSDL = `sdl-config --cflags`
-CXML = `xml2-config --cflags`
-CTTF = `freetype-config --cflags`
+CSDL = $(shell sdl-config --cflags)
+CXML = $(shell xml2-config --cflags)
+CTTF = $(shell freetype-config --cflags)
 CGL  =
 CFLAGS = -Wall $(CLUA) $(CSDL) $(CXML) $(CTTF) $(CGL) $(VERSION)
 ifdef DEBUG
@@ -28,6 +25,9 @@ LDTTF = `freetype-config --libs`
 LDGL	= -lGL
 LDFLAGS = -lm $(LDLUA) $(LDSDL) $(LDXML) $(LDTTF) $(LDGL)
 
+DATA = data
+DATAFILES = $(shell find ../scripts/ai/ ../gfx/ ../dat/ -name '*.lua' -o -name '*.png' -o -name '*.xml')
+
 %.o: ../src/%.c
 	@gcc -c $(CFLAGS) -o $@ $<
 	@echo -e "\tCC $@"
@@ -38,7 +38,7 @@ all: data $(OBJS)
 
 data: $(DATAFILES)
 	@echo -e "\tCreating data..\n"
-	@ls -1 $(DATAFILES) | cpio --quiet -o > $(DATA)
+	@ls -1 $(DATAFILES) | cpio  --quiet --format crc -o > $(DATA)
 
 clean:
 	@echo -e "\tRemoving data.."
diff --git a/src/ship.c b/src/ship.c
index f2dc9e4..1bb46b6 100644
--- a/src/ship.c
+++ b/src/ship.c
@@ -1,5 +1,5 @@
 #include <string.h>
-#include "libxml/xmlreader.h"
+#include <libxml/xmlreader.h>
 
 #include "log.h"
 #include "ship.h"
diff --git a/utils/pack/Makefile b/utils/pack/Makefile
index c7de177..32b8fcc 100644
--- a/utils/pack/Makefile
+++ b/utils/pack/Makefile
@@ -1,4 +1,7 @@
-CFLAGS += -g
+CFLAGS += -O2 -Wall
 
 all:
-	$(CC) $(CFLAGS) -o pack pack.c
\ No newline at end of file
+	$(CC) $(CFLAGS) -o pack main.c pack.c md5.c
+
+clean:
+	rm -rf pack
diff --git a/utils/pack/main.c b/utils/pack/main.c
new file mode 100644
index 0000000..b39c2ed
--- /dev/null
+++ b/utils/pack/main.c
@@ -0,0 +1,41 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "pack.h"
+
+#define USAGE "Usage is: %s output input\n", argv[0]
+
+int main(int argc, char** argv) {
+  switch(argc) {
+    case 1:
+      fprintf(stderr, "Missing output file\n");
+    case 2:
+      fprintf(stderr, "Missing input file/s\n");
+      goto usage;
+      break;
+  }
+  
+  char* outfile = argv[1];
+  uint32_t nfiles = (uint32_t)argc - 2;
+  argv += 2;
+
+  printf("%d\n", pack_check(outfile));
+  pack_files(outfile, argv, nfiles);
+
+  Packfile packfile;
+
+  printf("%s\n", argv[0]);
+  pack_open(&packfile, outfile, argv[2]);
+
+  char* buf = calloc(100, 1);
+  nfiles = pack_read(&packfile, buf, 100);
+  printf("%d -> <%s>\n", nfiles, buf);
+  free(buf);
+
+  exit(EXIT_SUCCESS);
+
+usage:
+  printf(USAGE);
+  exit(EXIT_SUCCESS);
+}
+
diff --git a/utils/pack/md5.c b/utils/pack/md5.c
new file mode 100644
index 0000000..c35d96c
--- /dev/null
+++ b/utils/pack/md5.c
@@ -0,0 +1,381 @@
+/*
+  Copyright (C) 1999, 2000, 2002 Aladdin Enterprises.  All rights reserved.
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+
+  L. Peter Deutsch
+  ghost@aladdin.com
+
+ */
+/* $Id: md5.c,v 1.6 2002/04/13 19:20:28 lpd Exp $ */
+/*
+  Independent implementation of MD5 (RFC 1321).
+
+  This code implements the MD5 Algorithm defined in RFC 1321, whose
+  text is available at
+	http://www.ietf.org/rfc/rfc1321.txt
+  The code is derived from the text of the RFC, including the test suite
+  (section A.5) but excluding the rest of Appendix A.  It does not include
+  any code or documentation that is identified in the RFC as being
+  copyrighted.
+
+  The original and principal author of md5.c is L. Peter Deutsch
+  <ghost@aladdin.com>.  Other authors are noted in the change history
+  that follows (in reverse chronological order):
+
+  2002-04-13 lpd Clarified derivation from RFC 1321; now handles byte order
+	either statically or dynamically; added missing #include <string.h>
+	in library.
+  2002-03-11 lpd Corrected argument list for main(), and added int return
+	type, in test program and T value program.
+  2002-02-21 lpd Added missing #include <stdio.h> in test program.
+  2000-07-03 lpd Patched to eliminate warnings about "constant is
+	unsigned in ANSI C, signed in traditional"; made test program
+	self-checking.
+  1999-11-04 lpd Edited comments slightly for automatic TOC extraction.
+  1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5).
+  1999-05-03 lpd Original version.
+ */
+
+#include "md5.h"
+#include <string.h>
+
+#undef BYTE_ORDER	/* 1 = big-endian, -1 = little-endian, 0 = unknown */
+#ifdef ARCH_IS_BIG_ENDIAN
+#  define BYTE_ORDER (ARCH_IS_BIG_ENDIAN ? 1 : -1)
+#else
+#  define BYTE_ORDER 0
+#endif
+
+#define T_MASK ((md5_word_t)~0)
+#define T1 /* 0xd76aa478 */ (T_MASK ^ 0x28955b87)
+#define T2 /* 0xe8c7b756 */ (T_MASK ^ 0x173848a9)
+#define T3    0x242070db
+#define T4 /* 0xc1bdceee */ (T_MASK ^ 0x3e423111)
+#define T5 /* 0xf57c0faf */ (T_MASK ^ 0x0a83f050)
+#define T6    0x4787c62a
+#define T7 /* 0xa8304613 */ (T_MASK ^ 0x57cfb9ec)
+#define T8 /* 0xfd469501 */ (T_MASK ^ 0x02b96afe)
+#define T9    0x698098d8
+#define T10 /* 0x8b44f7af */ (T_MASK ^ 0x74bb0850)
+#define T11 /* 0xffff5bb1 */ (T_MASK ^ 0x0000a44e)
+#define T12 /* 0x895cd7be */ (T_MASK ^ 0x76a32841)
+#define T13    0x6b901122
+#define T14 /* 0xfd987193 */ (T_MASK ^ 0x02678e6c)
+#define T15 /* 0xa679438e */ (T_MASK ^ 0x5986bc71)
+#define T16    0x49b40821
+#define T17 /* 0xf61e2562 */ (T_MASK ^ 0x09e1da9d)
+#define T18 /* 0xc040b340 */ (T_MASK ^ 0x3fbf4cbf)
+#define T19    0x265e5a51
+#define T20 /* 0xe9b6c7aa */ (T_MASK ^ 0x16493855)
+#define T21 /* 0xd62f105d */ (T_MASK ^ 0x29d0efa2)
+#define T22    0x02441453
+#define T23 /* 0xd8a1e681 */ (T_MASK ^ 0x275e197e)
+#define T24 /* 0xe7d3fbc8 */ (T_MASK ^ 0x182c0437)
+#define T25    0x21e1cde6
+#define T26 /* 0xc33707d6 */ (T_MASK ^ 0x3cc8f829)
+#define T27 /* 0xf4d50d87 */ (T_MASK ^ 0x0b2af278)
+#define T28    0x455a14ed
+#define T29 /* 0xa9e3e905 */ (T_MASK ^ 0x561c16fa)
+#define T30 /* 0xfcefa3f8 */ (T_MASK ^ 0x03105c07)
+#define T31    0x676f02d9
+#define T32 /* 0x8d2a4c8a */ (T_MASK ^ 0x72d5b375)
+#define T33 /* 0xfffa3942 */ (T_MASK ^ 0x0005c6bd)
+#define T34 /* 0x8771f681 */ (T_MASK ^ 0x788e097e)
+#define T35    0x6d9d6122
+#define T36 /* 0xfde5380c */ (T_MASK ^ 0x021ac7f3)
+#define T37 /* 0xa4beea44 */ (T_MASK ^ 0x5b4115bb)
+#define T38    0x4bdecfa9
+#define T39 /* 0xf6bb4b60 */ (T_MASK ^ 0x0944b49f)
+#define T40 /* 0xbebfbc70 */ (T_MASK ^ 0x4140438f)
+#define T41    0x289b7ec6
+#define T42 /* 0xeaa127fa */ (T_MASK ^ 0x155ed805)
+#define T43 /* 0xd4ef3085 */ (T_MASK ^ 0x2b10cf7a)
+#define T44    0x04881d05
+#define T45 /* 0xd9d4d039 */ (T_MASK ^ 0x262b2fc6)
+#define T46 /* 0xe6db99e5 */ (T_MASK ^ 0x1924661a)
+#define T47    0x1fa27cf8
+#define T48 /* 0xc4ac5665 */ (T_MASK ^ 0x3b53a99a)
+#define T49 /* 0xf4292244 */ (T_MASK ^ 0x0bd6ddbb)
+#define T50    0x432aff97
+#define T51 /* 0xab9423a7 */ (T_MASK ^ 0x546bdc58)
+#define T52 /* 0xfc93a039 */ (T_MASK ^ 0x036c5fc6)
+#define T53    0x655b59c3
+#define T54 /* 0x8f0ccc92 */ (T_MASK ^ 0x70f3336d)
+#define T55 /* 0xffeff47d */ (T_MASK ^ 0x00100b82)
+#define T56 /* 0x85845dd1 */ (T_MASK ^ 0x7a7ba22e)
+#define T57    0x6fa87e4f
+#define T58 /* 0xfe2ce6e0 */ (T_MASK ^ 0x01d3191f)
+#define T59 /* 0xa3014314 */ (T_MASK ^ 0x5cfebceb)
+#define T60    0x4e0811a1
+#define T61 /* 0xf7537e82 */ (T_MASK ^ 0x08ac817d)
+#define T62 /* 0xbd3af235 */ (T_MASK ^ 0x42c50dca)
+#define T63    0x2ad7d2bb
+#define T64 /* 0xeb86d391 */ (T_MASK ^ 0x14792c6e)
+
+
+static void
+md5_process(md5_state_t *pms, const md5_byte_t *data /*[64]*/)
+{
+    md5_word_t
+	a = pms->abcd[0], b = pms->abcd[1],
+	c = pms->abcd[2], d = pms->abcd[3];
+    md5_word_t t;
+#if BYTE_ORDER > 0
+    /* Define storage only for big-endian CPUs. */
+    md5_word_t X[16];
+#else
+    /* Define storage for little-endian or both types of CPUs. */
+    md5_word_t xbuf[16];
+    const md5_word_t *X;
+#endif
+
+    {
+#if BYTE_ORDER == 0
+	/*
+	 * Determine dynamically whether this is a big-endian or
+	 * little-endian machine, since we can use a more efficient
+	 * algorithm on the latter.
+	 */
+	static const int w = 1;
+
+	if (*((const md5_byte_t *)&w)) /* dynamic little-endian */
+#endif
+#if BYTE_ORDER <= 0		/* little-endian */
+	{
+	    /*
+	     * On little-endian machines, we can process properly aligned
+	     * data without copying it.
+	     */
+	    if (!((data - (const md5_byte_t *)0) & 3)) {
+		/* data are properly aligned */
+		X = (const md5_word_t *)data;
+	    } else {
+		/* not aligned */
+		memcpy(xbuf, data, 64);
+		X = xbuf;
+	    }
+	}
+#endif
+#if BYTE_ORDER == 0
+	else			/* dynamic big-endian */
+#endif
+#if BYTE_ORDER >= 0		/* big-endian */
+	{
+	    /*
+	     * On big-endian machines, we must arrange the bytes in the
+	     * right order.
+	     */
+	    const md5_byte_t *xp = data;
+	    int i;
+
+#  if BYTE_ORDER == 0
+	    X = xbuf;		/* (dynamic only) */
+#  else
+#    define xbuf X		/* (static only) */
+#  endif
+	    for (i = 0; i < 16; ++i, xp += 4)
+		xbuf[i] = xp[0] + (xp[1] << 8) + (xp[2] << 16) + (xp[3] << 24);
+	}
+#endif
+    }
+
+#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
+
+    /* Round 1. */
+    /* Let [abcd k s i] denote the operation
+       a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
+#define F(x, y, z) (((x) & (y)) | (~(x) & (z)))
+#define SET(a, b, c, d, k, s, Ti)\
+  t = a + F(b,c,d) + X[k] + Ti;\
+  a = ROTATE_LEFT(t, s) + b
+    /* Do the following 16 operations. */
+    SET(a, b, c, d,  0,  7,  T1);
+    SET(d, a, b, c,  1, 12,  T2);
+    SET(c, d, a, b,  2, 17,  T3);
+    SET(b, c, d, a,  3, 22,  T4);
+    SET(a, b, c, d,  4,  7,  T5);
+    SET(d, a, b, c,  5, 12,  T6);
+    SET(c, d, a, b,  6, 17,  T7);
+    SET(b, c, d, a,  7, 22,  T8);
+    SET(a, b, c, d,  8,  7,  T9);
+    SET(d, a, b, c,  9, 12, T10);
+    SET(c, d, a, b, 10, 17, T11);
+    SET(b, c, d, a, 11, 22, T12);
+    SET(a, b, c, d, 12,  7, T13);
+    SET(d, a, b, c, 13, 12, T14);
+    SET(c, d, a, b, 14, 17, T15);
+    SET(b, c, d, a, 15, 22, T16);
+#undef SET
+
+     /* Round 2. */
+     /* Let [abcd k s i] denote the operation
+          a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
+#define G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
+#define SET(a, b, c, d, k, s, Ti)\
+  t = a + G(b,c,d) + X[k] + Ti;\
+  a = ROTATE_LEFT(t, s) + b
+     /* Do the following 16 operations. */
+    SET(a, b, c, d,  1,  5, T17);
+    SET(d, a, b, c,  6,  9, T18);
+    SET(c, d, a, b, 11, 14, T19);
+    SET(b, c, d, a,  0, 20, T20);
+    SET(a, b, c, d,  5,  5, T21);
+    SET(d, a, b, c, 10,  9, T22);
+    SET(c, d, a, b, 15, 14, T23);
+    SET(b, c, d, a,  4, 20, T24);
+    SET(a, b, c, d,  9,  5, T25);
+    SET(d, a, b, c, 14,  9, T26);
+    SET(c, d, a, b,  3, 14, T27);
+    SET(b, c, d, a,  8, 20, T28);
+    SET(a, b, c, d, 13,  5, T29);
+    SET(d, a, b, c,  2,  9, T30);
+    SET(c, d, a, b,  7, 14, T31);
+    SET(b, c, d, a, 12, 20, T32);
+#undef SET
+
+     /* Round 3. */
+     /* Let [abcd k s t] denote the operation
+          a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
+#define H(x, y, z) ((x) ^ (y) ^ (z))
+#define SET(a, b, c, d, k, s, Ti)\
+  t = a + H(b,c,d) + X[k] + Ti;\
+  a = ROTATE_LEFT(t, s) + b
+     /* Do the following 16 operations. */
+    SET(a, b, c, d,  5,  4, T33);
+    SET(d, a, b, c,  8, 11, T34);
+    SET(c, d, a, b, 11, 16, T35);
+    SET(b, c, d, a, 14, 23, T36);
+    SET(a, b, c, d,  1,  4, T37);
+    SET(d, a, b, c,  4, 11, T38);
+    SET(c, d, a, b,  7, 16, T39);
+    SET(b, c, d, a, 10, 23, T40);
+    SET(a, b, c, d, 13,  4, T41);
+    SET(d, a, b, c,  0, 11, T42);
+    SET(c, d, a, b,  3, 16, T43);
+    SET(b, c, d, a,  6, 23, T44);
+    SET(a, b, c, d,  9,  4, T45);
+    SET(d, a, b, c, 12, 11, T46);
+    SET(c, d, a, b, 15, 16, T47);
+    SET(b, c, d, a,  2, 23, T48);
+#undef SET
+
+     /* Round 4. */
+     /* Let [abcd k s t] denote the operation
+          a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
+#define I(x, y, z) ((y) ^ ((x) | ~(z)))
+#define SET(a, b, c, d, k, s, Ti)\
+  t = a + I(b,c,d) + X[k] + Ti;\
+  a = ROTATE_LEFT(t, s) + b
+     /* Do the following 16 operations. */
+    SET(a, b, c, d,  0,  6, T49);
+    SET(d, a, b, c,  7, 10, T50);
+    SET(c, d, a, b, 14, 15, T51);
+    SET(b, c, d, a,  5, 21, T52);
+    SET(a, b, c, d, 12,  6, T53);
+    SET(d, a, b, c,  3, 10, T54);
+    SET(c, d, a, b, 10, 15, T55);
+    SET(b, c, d, a,  1, 21, T56);
+    SET(a, b, c, d,  8,  6, T57);
+    SET(d, a, b, c, 15, 10, T58);
+    SET(c, d, a, b,  6, 15, T59);
+    SET(b, c, d, a, 13, 21, T60);
+    SET(a, b, c, d,  4,  6, T61);
+    SET(d, a, b, c, 11, 10, T62);
+    SET(c, d, a, b,  2, 15, T63);
+    SET(b, c, d, a,  9, 21, T64);
+#undef SET
+
+     /* Then perform the following additions. (That is increment each
+        of the four registers by the value it had before this block
+        was started.) */
+    pms->abcd[0] += a;
+    pms->abcd[1] += b;
+    pms->abcd[2] += c;
+    pms->abcd[3] += d;
+}
+
+void
+md5_init(md5_state_t *pms)
+{
+    pms->count[0] = pms->count[1] = 0;
+    pms->abcd[0] = 0x67452301;
+    pms->abcd[1] = /*0xefcdab89*/ T_MASK ^ 0x10325476;
+    pms->abcd[2] = /*0x98badcfe*/ T_MASK ^ 0x67452301;
+    pms->abcd[3] = 0x10325476;
+}
+
+void
+md5_append(md5_state_t *pms, const md5_byte_t *data, int nbytes)
+{
+    const md5_byte_t *p = data;
+    int left = nbytes;
+    int offset = (pms->count[0] >> 3) & 63;
+    md5_word_t nbits = (md5_word_t)(nbytes << 3);
+
+    if (nbytes <= 0)
+	return;
+
+    /* Update the message length. */
+    pms->count[1] += nbytes >> 29;
+    pms->count[0] += nbits;
+    if (pms->count[0] < nbits)
+	pms->count[1]++;
+
+    /* Process an initial partial block. */
+    if (offset) {
+	int copy = (offset + nbytes > 64 ? 64 - offset : nbytes);
+
+	memcpy(pms->buf + offset, p, copy);
+	if (offset + copy < 64)
+	    return;
+	p += copy;
+	left -= copy;
+	md5_process(pms, pms->buf);
+    }
+
+    /* Process full blocks. */
+    for (; left >= 64; p += 64, left -= 64)
+	md5_process(pms, p);
+
+    /* Process a final partial block. */
+    if (left)
+	memcpy(pms->buf, p, left);
+}
+
+void
+md5_finish(md5_state_t *pms, md5_byte_t digest[16])
+{
+    static const md5_byte_t pad[64] = {
+	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+    };
+    md5_byte_t data[8];
+    int i;
+
+    /* Save the length before padding. */
+    for (i = 0; i < 8; ++i)
+	data[i] = (md5_byte_t)(pms->count[i >> 2] >> ((i & 3) << 3));
+    /* Pad to 56 bytes mod 64. */
+    md5_append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
+    /* Append the length. */
+    md5_append(pms, data, 8);
+    for (i = 0; i < 16; ++i)
+	digest[i] = (md5_byte_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
+}
diff --git a/utils/pack/md5.h b/utils/pack/md5.h
new file mode 100644
index 0000000..995208d
--- /dev/null
+++ b/utils/pack/md5.h
@@ -0,0 +1,88 @@
+/*
+  Copyright (C) 1999, 2002 Aladdin Enterprises.  All rights reserved.
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+
+  L. Peter Deutsch
+  ghost@aladdin.com
+
+ */
+/* $Id$ */
+/*
+  Independent implementation of MD5 (RFC 1321).
+
+  This code implements the MD5 Algorithm defined in RFC 1321, whose
+  text is available at
+	http://www.ietf.org/rfc/rfc1321.txt
+  The code is derived from the text of the RFC, including the test suite
+  (section A.5) but excluding the rest of Appendix A.  It does not include
+  any code or documentation that is identified in the RFC as being
+  copyrighted.
+
+  The original and principal author of md5.h is L. Peter Deutsch
+  <ghost@aladdin.com>.  Other authors are noted in the change history
+  that follows (in reverse chronological order):
+
+  2007-04-15 bobbens using uint8_t and uint32_t for compatibility.
+   removed C++ conditionalization.
+  2002-04-13 lpd Removed support for non-ANSI compilers; removed
+	references to Ghostscript; clarified derivation from RFC 1321;
+	now handles byte order either statically or dynamically.
+  1999-11-04 lpd Edited comments slightly for automatic TOC extraction.
+  1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5);
+	added conditionalization for C++ compilation from Martin
+	Purschke <purschke@bnl.gov>.
+  1999-05-03 lpd Original version.
+ */
+
+#ifndef MD5_H
+#  define MD5_H
+
+#include <stdint.h>
+
+/*
+ * This package supports both compile-time and run-time determination of CPU
+ * byte order.  If ARCH_IS_BIG_ENDIAN is defined as 0, the code will be
+ * compiled to run only on little-endian CPUs; if ARCH_IS_BIG_ENDIAN is
+ * defined as non-zero, the code will be compiled to run only on big-endian
+ * CPUs; if ARCH_IS_BIG_ENDIAN is not defined, the code will be compiled to
+ * run on either big- or little-endian CPUs, but will run slightly less
+ * efficiently on either one than if ARCH_IS_BIG_ENDIAN is defined.
+ */
+
+typedef uint8_t md5_byte_t; /* 8-bit byte */
+typedef uint32_t md5_word_t; /* 32-bit word */
+
+/* Define the state of the MD5 Algorithm. */
+typedef struct md5_state_s {
+    md5_word_t count[2];	/* message length in bits, lsw first */
+    md5_word_t abcd[4];		/* digest buffer */
+    md5_byte_t buf[64];		/* accumulate block */
+} md5_state_t;
+
+
+/* Initialize the algorithm. */
+void md5_init(md5_state_t *pms);
+
+/* Append a string to the message. */
+void md5_append(md5_state_t *pms, const md5_byte_t *data, int nbytes);
+
+/* Finish the message and return the digest. */
+void md5_finish(md5_state_t *pms, md5_byte_t digest[16]);
+
+
+#endif /* MD5_H */
diff --git a/utils/pack/pack b/utils/pack/pack
index 2404313..ac22a13 100755
Binary files a/utils/pack/pack and b/utils/pack/pack differ
diff --git a/utils/pack/pack.c b/utils/pack/pack.c
index f2ab738..68f31f0 100644
--- a/utils/pack/pack.c
+++ b/utils/pack/pack.c
@@ -1,75 +1,250 @@
 #include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <fcntl.h> // creat() and co.
 #include <sys/stat.h> // S_IRUSR
 #include <unistd.h>
 #include <errno.h>
 #include <string.h>
+#include <malloc.h>
+
+#include "pack.h"
+#include "md5.h"
+
+// == Store data in a funky format. =======================
+// Format:
+//  -- Index (in 512 byte chunks).
+//    -- Magic number (16 bytes).
+//    -- Number of files (uint32_t).
+//    -- Files in format name/location.
+//      -- File name (128 bytes max, ending in \0).
+//      -- File location (uint32_t).
+//  -- File data in format Size/Data.
+//    -- File size (uint32_t).
+//    -- File data (char*).
+//    -- File MD5 (16 byte char*).
+//  -- EOF
+//
+// -- Write magic number and number of files.
+// -- Write the index.
+// -- Pack the files.
+// ========================================================
+
+// The read/write block size.
+#define BLOCKSIZE 128*1024
+
+// Max filename length.
+#define MAX_FILENAME 100
+
+#define LOG(str, args...)(fprintf(stdout, str"\n", ## args))
+#define WARN(str, args...)(fprintf(stderr, "[%d] "str"\n", SDL_GetTicks(), ## args))
+#define ERR(str, args...) (fprintf(stderr, "%s:%d: "str"\n", __FILE__, __LINE__, ## args))
+
+#ifdef DEBUG
+#  undef DEBUG
+#  define DEBUG(str, args...) LOG(str, ## args)
+#  define DEBUGGING
+#else
+#  define DEBUG(str, args...) do {;} while(0)
+#endif
 
-#define USAGE "Usage: %s output input\n", argv[0]
 #define PERMS S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH
 
 const uint64_t magic = 0x25524573; // sER%
 
-off_t getfilesize(const char* filename);
-int fileexists(const char* filename);
-
-int main(int argc, char** argv) {
-  switch(argc) {
-    case 1:
-      printf("Missing output file\n");
-    case 2:
-      printf("Missing input file/s\n\n");
-      goto usage;
-      break;
-  }
-
-  int i, namesize;
-  int outfd, infd;
-  uint32_t nfiles = (uint32_t)argc - 2;
-
-  for(namesize = 0; i < nfiles; i++) {
-    // Make sure file exists before writing.
-    if(!fileexists(argv[i+2])) {
-      printf("File %s does not exist!\n", argv[i+2]);
-      goto failure;
-    }
-    namesize += strlen(argv[i+2]);
-  }
-
-  // Create the output file.
-  outfd = creat(argv[1], PERMS);
-  if(outfd == -1) goto failure;
-
-  // Magic number.
-  write(outfd, &magic, sizeof(magic));
-
-  close(outfd);
-
-  exit(EXIT_SUCCESS);
-
-usage:
-  printf(USAGE);
-failure:
-  exit(EXIT_FAILURE);
-}
-
-// Grab file size.
-off_t getfilesize(const char* filename) {
+// Grab the filesize.
+static off_t getfilesize(const char* filename) {
   struct stat file;
+
   if(!stat(filename, &file))
     return file.st_size;
 
-  printf("Unable to get filesize of %s\n", filename);
+  ERR("Unable to get filesize of %s", filename);
   return 0;
 }
 
-// Does the file exist?
-int fileexists(const char* filename) {
+// Return true if filename is a Packfile.
+int pack_check(char* filename) {
+  int fd = open(filename, O_RDONLY);
+  if(fd == -1) {
+    ERR("Error opening %s: %s", filename, strerror(errno));
+    return -1;
+  }
+
+  char* buf = malloc(sizeof(magic));
+  if(read(fd, buf, sizeof(magic)) != sizeof(magic)) {
+    ERR("Error reading magic number: %s", strerror(errno));
+    free(buf);
+    return -1;
+  }
+
+  int ret = (memcmp(buf, &magic, sizeof(magic))==0) ? 0 : 1;
+  free(buf);
+  return ret;
+}
+
+// Pack nfiles, infiles into outfile.
+#define WRITE(f,b,n) if(write(f,b,n)==-1) { \
+  ERR("Error writing to file: %s", strerror(errno)); \
+  free(buf); return -1; }
+
+int pack_files(char* outfile, char** infiles, uint32_t nfiles) {
+  void* buf;
   struct stat file;
-  if(!stat(filename, &file))
-    return 1;
+  int i, namesize;
+  int outfd, infd;
+  uint32_t indexsize, pointer;
+  int bytes;
+  const uint8_t b = '\0';
+
+  for(namesize = 0, i = 0; i < nfiles; i++) {
+    // Make sure file exists before writing.
+    if(stat(infiles[i], &file)) {
+      ERR("File %s does not exist", infiles[i]);
+      return -1;
+    }
+    if(strlen(infiles[i]) < MAX_FILENAME) {
+      ERR("filename '%s' is too long, should be only %d characters", infiles[i], MAX_FILENAME);
+      return -1;
+    }
+    namesize += strlen(infiles[i]);
+  }
+
+  indexsize = (sizeof(magic) + 4 + // Magic number and number of files.
+              namesize + // Total length of file names.
+              (1+4)*nfiles);  // File size and extra end of string char '\0'.
+  DEBUG("Index size is %d", indexsize);
+
+  // Create the output file.
+  outfd = creat(outfile, PERMS);
+  if(outfd == -1) {
+    ERR("Unable to open %s for writing", outfile);
+    return -1;
+  }
+
+  // Index!
+  buf = malloc(BLOCKSIZE);
+  
+  // Magic number.
+  WRITE(outfd, &magic, sizeof(magic));
+  DEBUG("Wrote magic number");
+  // Number of files.
+  WRITE(outfd, &nfiles, sizeof(nfiles));
+  DEBUG("Wrote number of files: %d", nfiles);
+  // Create file dependent index part.
+  pointer = indexsize;
+  for(i = 0; i < nfiles; i++) {
+    WRITE(outfd, infiles[i], strlen(infiles[i]));
+    DEBUG("File: '%s' at %d", infiles[i], pointer);
+    WRITE(outfd, &b, 1);
+    WRITE(outfd, &pointer, 4);
+    pointer += getfilesize(infiles[i]) + 8; // Set pointer to be next file pos.
+  }
+
+  // Data!
+  md5_state_t md5;
+  md5_byte_t* md5val = malloc(16);
+  for(i = 0; i < nfiles; i++) {
+    bytes = (uint32_t)getfilesize(infiles[i]);
+    WRITE(outfd, &bytes, 4); // filesize.
+    DEBUG("About to write '%s' of %d bytes", infiles[i], bytes);
+    infd = open(infiles[i], O_RDONLY);
+    md5_init(&md5);
+    while((bytes = read(infd, buf, BLOCKSIZE))) {
+      WRITE(outfd, buf, bytes); // Data.
+      md5_append(&md5, buf, bytes);
+    }
+    md5_finish(&md5, md5val);
+    WRITE(outfd, md5val, sizeof(md5val));
+    close(infd);
+    DEBUG("Wrote file '%s'", infiles[i]);
+  }
+  free(md5val);
+
+  close(outfd);
+  free(buf);
+
+  DEBUG("Packfile success\n\t%d files\n\t%d bytes", nfiles, (int)getfilesize(outfile));
   return 0;
 }
+#undef WRITE
+
+// Opens the filename in packfile for reading.
+#define READ(f,b,n) if(read(f,b,n) != n) { \
+  ERR("Too few bytes read. Expected more."); \
+  free(buf); return -1; }
+int pack_open(Packfile* file, char* packfile, char* filename) {
+  int i, j;
+  uint32_t nfiles;
+  char* buf = (char*)malloc(MAX_FILENAME);
+
+  file = (Packfile*)malloc(sizeof(Packfile));
+
+  file->start = file->end = 0;
+
+  file->fd = open(packfile, O_RDONLY);
+  if(file->fd == -1) {
+    ERR("Error opening %s: %s", filename, strerror(errno));
+    return -1;
+  }
+
+  READ(file->fd, buf, sizeof(magic)); // Make sure it's a packfile.
+  if(memcmp(buf, &magic, sizeof(magic))) {
+    ERR("File %s is not a valid packfile", filename);
+    return -1;
+  }
+
+  READ(file->fd, &nfiles, 4);
+  for(i = 0; i < nfiles; i++) {
+    // Start to search files.
+    j = 0;
+    READ(file->fd, &buf[j], 1); // Get the name.
+    while(buf[j++] != '\0')
+      READ(file->fd, &buf[j], 1);
+
+    if(strcmp(filename, buf) == 0) {
+      // We found the file.
+      READ(file->fd, &file->start, 4);
+      DEBUG("'%s' found at %d", filename, file->start);
+      break;
+    }
+    lseek(file->fd, 4, SEEK_CUR); // Ignore the file location.
+  }
+  free(buf);
+  
+  if(file->start) {
+    // Go to the beginning of the file.
+    if(lseek(file->fd, file->start, SEEK_SET) != file->start) {
+      ERR("Failure to seek to file start: %s", strerror(errno));
+      return -1;
+    }
+    if(read(file->fd, &file->end, 4) != 4) {
+      ERR("Too few bytes read. Expected more.");
+      return -1;
+    }
+    DEBUG("\t%d bytes", file->end);
+    file->pos = file->start;
+    file->end += file->start;
+  }
+
+  return 0;
+}
+#undef READ
+
+// Read count bytes from file and put them into buf.
+ssize_t pack_read(Packfile* file, void* buf, size_t count) {
+  if(file->pos + count > file->end) count = file->end - file->pos; // Can't go past the end!
+  if(count == 0) return 0;
+
+  int bytes;
+
+  bytes = read(file->fd, buf, count);
+  file->pos += bytes;
+
+  return bytes;
+}
+
+// Close the packfile.
+int pack_close(Packfile* file) {
+  int i = close(file->fd);
+  free(file);
+  return (i) ? -1 : 0;
+}
 
diff --git a/utils/pack/pack.h b/utils/pack/pack.h
new file mode 100644
index 0000000..2d753ba
--- /dev/null
+++ b/utils/pack/pack.h
@@ -0,0 +1,17 @@
+#pragma once
+#include <fcntl.h>
+#include <stdint.h>
+
+typedef struct {
+  int fd; // File descriptor.
+  uint32_t pos; // position.
+  uint32_t start, end; // file limits.
+} Packfile;
+
+// Packfile manipulation. Automatically allocated and freed (with open and close).
+int pack_check(char* filename);
+int pack_files(char* outfile, char** infiles, uint32_t nfiles);
+int pack_open(Packfile* file, char* packfile, char* filename);
+ssize_t pack_read(Packfile* file, void* buf, size_t count);
+int pack_close(Packfile* file);
+