Description:
------------
I've ported the relevant code from libketama into pecl-memcache-3.0.4, tested and is 100% compatible.

Actual result:
--------------
diff -ruN memcache-3.0.4/config9.m4 memcache-3.0.4-ketama/config9.m4
--- memcache-3.0.4/config9.m4	2009-02-22 17:01:43.000000000 +0100
+++ memcache-3.0.4-ketama/config9.m4	2009-12-31 11:26:19.000000000 +0100
@@ -92,7 +92,7 @@
     AC_MSG_RESULT([enabled])
     AC_DEFINE(HAVE_MEMCACHE_SESSION,1,[Whether memcache session handler is enabled])
     AC_DEFINE(HAVE_MEMCACHE,1,[Whether you want memcache support])
-    PHP_NEW_EXTENSION(memcache, memcache.c memcache_pool.c memcache_queue.c memcache_ascii_protocol.c memcache_binary_protocol.c memcache_standard_hash.c memcache_consistent_hash.c memcache_session.c, $ext_shared,,-I$session_inc_path)
+    PHP_NEW_EXTENSION(memcache, memcache.c memcache_pool.c memcache_queue.c memcache_ascii_protocol.c memcache_binary_protocol.c memcache_standard_hash.c memcache_consistent_hash.c memcache_ketama_hash.c md5.c memcache_session.c, $ext_shared,,-I$session_inc_path)
     ifdef([PHP_ADD_EXTENSION_DEP],
     [
       PHP_ADD_EXTENSION_DEP(memcache, session)
@@ -100,7 +100,7 @@
   else 
     AC_MSG_RESULT([disabled])
     AC_DEFINE(HAVE_MEMCACHE,1,[Whether you want memcache support])
-    PHP_NEW_EXTENSION(memcache, memcache.c memcache_pool.c memcache_queue.c memcache_ascii_protocol.c memcache_binary_protocol.c memcache_standard_hash.c memcache_consistent_hash.c, $ext_shared)
+    PHP_NEW_EXTENSION(memcache, memcache.c memcache_pool.c memcache_queue.c memcache_ascii_protocol.c memcache_binary_protocol.c memcache_standard_hash.c memcache_consistent_hash.c memcache_ketama_hash.c md5.c, $ext_shared)
   fi
 
 dnl this is needed to build the extension with phpize and -Wall
@@ -109,4 +109,5 @@
     CFLAGS="$CFLAGS -Wall"
   fi
 
+  LDFLAGS="$LDFLAGS -lm"
 fi
diff -ruN memcache-3.0.4/md5.c memcache-3.0.4-ketama/md5.c
--- memcache-3.0.4/md5.c	1970-01-01 01:00:00.000000000 +0100
+++ memcache-3.0.4-ketama/md5.c	2009-12-31 11:26:04.000000000 +0100
@@ -0,0 +1,403 @@
+/*
+  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));
+}
+
+void md5_digest(const char* inString, unsigned char md5pword[16])
+{
+    md5_state_t md5state;
+
+	md5_init(&md5state);
+	md5_append(&md5state, (unsigned char *)inString, strlen(inString));
+	md5_finish(&md5state, md5pword);
+}
+
+unsigned int hash_key(const char* inString)
+{
+    unsigned char digest[16];
+
+    md5_digest(inString, digest);
+
+    return (unsigned int)(( digest[3] << 24 )
+                        | ( digest[2] << 16 )
+                        | ( digest[1] << 8 )
+                        | digest[0]);
+}
+
diff -ruN memcache-3.0.4/md5.h memcache-3.0.4-ketama/md5.h
--- memcache-3.0.4/md5.h	1970-01-01 01:00:00.000000000 +0100
+++ memcache-3.0.4-ketama/md5.h	2009-12-31 11:26:04.000000000 +0100
@@ -0,0 +1,102 @@
+/*
+  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: md5.h,v 1.4 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.h 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 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_INCLUDED
+#  define md5_INCLUDED
+
+/*
+ * 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 unsigned char md5_byte_t; /* 8-bit byte */
+typedef unsigned int 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;
+
+#ifdef __cplusplus
+extern "C" 
+{
+#endif
+
+/* Initialize the algorithm. */
+
+#ifdef WIN32
+_declspec(dllexport)
+#endif
+void md5_init(md5_state_t *pms);
+
+/* Append a string to the message. */
+#ifdef WIN32
+_declspec(dllexport)
+#endif
+void md5_append(md5_state_t *pms, const md5_byte_t *data, int nbytes);
+
+/* Finish the message and return the digest. */
+#ifdef WIN32
+_declspec(dllexport)
+#endif
+void md5_finish(md5_state_t *pms, md5_byte_t digest[16]);
+void md5_digest(const char* inString, unsigned char md5pword[16]);
+unsigned int hash_key(const char* inString);
+#ifdef __cplusplus
+}  /* end extern "C" */
+#endif
+
+#endif /* md5_INCLUDED */
diff -ruN memcache-3.0.4/memcache.c memcache-3.0.4-ketama/memcache.c
--- memcache-3.0.4/memcache.c	2009-02-22 17:01:43.000000000 +0100
+++ memcache-3.0.4-ketama/memcache.c	2009-12-31 11:40:59.000000000 +0100
@@ -180,8 +180,11 @@
 	else if (!strcasecmp(new_value, "consistent")) {
 		MEMCACHE_G(hash_strategy) = MMC_CONSISTENT_HASH;
 	}
+	else if (!strcasecmp(new_value, "ketama")) {
+		MEMCACHE_G(hash_strategy) = MMC_KETAMA_HASH;
+	}
 	else {
-		php_error_docref(NULL TSRMLS_CC, E_WARNING, "memcache.hash_strategy must be in set {standard, consistent} ('%s' given)", new_value);
+		php_error_docref(NULL TSRMLS_CC, E_WARNING, "memcache.hash_strategy must be in set {standard, consistent, ketama} ('%s' given)", new_value);
 		return FAILURE;
 	}
 
@@ -197,8 +200,11 @@
 	else if (!strcasecmp(new_value, "fnv")) {
 		MEMCACHE_G(hash_function) = MMC_HASH_FNV1A;
 	}
+	else if (!strcasecmp(new_value, "md5")) {
+		MEMCACHE_G(hash_function) = MMC_HASH_MD5;
+	}
 	else {
-		php_error_docref(NULL TSRMLS_CC, E_WARNING, "memcache.hash_function must be in set {crc32, fnv} ('%s' given)", new_value);
+		php_error_docref(NULL TSRMLS_CC, E_WARNING, "memcache.hash_function must be in set {crc32, fnv, md5} ('%s' given)", new_value);
 		return FAILURE;
 	}
 
diff -ruN memcache-3.0.4/memcache_ketama_hash.c memcache-3.0.4-ketama/memcache_ketama_hash.c
--- memcache-3.0.4/memcache_ketama_hash.c	1970-01-01 01:00:00.000000000 +0100
+++ memcache-3.0.4-ketama/memcache_ketama_hash.c	2009-12-31 11:25:59.000000000 +0100
@@ -0,0 +1,209 @@
+/*
+  +----------------------------------------------------------------------+
+  | PHP Version 5                                                        |
+  +----------------------------------------------------------------------+
+  | Copyright (c) 1997-2007 The PHP Group                                |
+  +----------------------------------------------------------------------+
+  | This source file is subject to version 3.0 of the PHP license,       |
+  | that is bundled with this package in the file LICENSE, and is        |
+  | available through the world-wide-web at the following url:           |
+  | http://www.php.net/license/3_0.txt.                                  |
+  | If you did not receive a copy of the PHP license and are unable to   |
+  | obtain it through the world-wide-web, please send a note to          |
+  | license@php.net so we can mail you a copy immediately.               |
+  +----------------------------------------------------------------------+
+  | Author: Marlon de Boer <marlon AT hyves DOT nl>                      |
+  +----------------------------------------------------------------------+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <math.h>
+
+#include "php.h"
+#include "php_memcache.h"
+#include "md5.h"
+
+ZEND_EXTERN_MODULE_GLOBALS(memcache)
+
+struct mcs {
+	mmc_t					*server;
+	unsigned int			point;
+};
+
+struct mmc_servers {
+	mmc_t					*server;
+	int						weight;
+	struct mmc_servers		*next;
+};
+
+typedef struct mmc_ketama_state {
+	int						num_servers;
+	struct mmc_servers		*servers;
+	int						cont_points;
+	unsigned int			total_weight;
+	mmc_hash_function_t		*hash;
+} mmc_ketama_state_t;
+
+struct mcs *continuum = NULL;
+
+void *mmc_ketama_create_state(mmc_hash_function_t *hash) /* {{{ */
+{
+	mmc_ketama_state_t *state = emalloc(sizeof(mmc_ketama_state_t));
+	memset(state, 0, sizeof(mmc_ketama_state_t));
+	
+	state->hash = hash;
+	state->servers = NULL;
+	
+	return state;
+}
+/* }}} */
+
+void mmc_ketama_free_state(void *s) /* {{{ */
+{
+	mmc_ketama_state_t *state = s;
+	struct mmc_servers *ptr = NULL, *ptr_old = NULL;
+
+	if (state->servers != NULL) {
+		ptr = state->servers;
+		ptr_old = ptr;
+
+		while (ptr->next != NULL) {
+			ptr_old = ptr;
+			ptr = ptr->next;
+			efree(ptr_old);
+		}
+
+		efree(ptr);
+	}
+
+	if (continuum != NULL)
+		efree(continuum);
+	
+	efree(state);
+}
+/* }}} */
+static int mmc_ketama_compare(const void *a, const void *b) /* {{{ */
+{
+	return (((struct mcs *)a)->point < ((struct mcs *)b)->point) ? -1 : (((struct mcs *)a)->point > ((struct mcs *)b)->point ? 1 : 0);
+}
+/* }}} */
+
+mmc_t *mmc_ketama_find_server(void *s, const char *key, unsigned int key_len TSRMLS_DC) /* {{{ */
+{
+	mmc_ketama_state_t *state = s;
+	unsigned int midval, midval1, cont_point = hash_key(key);
+	int midp, lowp = 0, highp = state->cont_points;
+	
+	while (1) {
+		midp = (int)( ( lowp+highp ) / 2 );
+		if (midp == state->cont_points) {
+			return continuum[0].server;
+		}
+		midval = continuum[midp].point;
+		midval1 = midp == 0 ? 0 : continuum[midp-1].point;
+
+		if (cont_point < midval && cont_point > midval1)
+			return continuum[midp].server;
+
+		if (midval < cont_point) {
+			lowp = midp + 1;
+		} else {
+			highp = midp - 1;
+		}
+
+		if (lowp > highp)
+			return continuum[0].server;
+	}
+}
+/* }}} */
+
+void mmc_ketama_add_server(void *s, mmc_t *mmc, unsigned int weight) /* {{{ */
+{
+	mmc_ketama_state_t *state = s;
+	unsigned int hash;
+
+	int k, cont_points = 0;
+	struct mmc_servers *ptr = NULL;
+
+	if (state->servers == NULL) {
+		state->servers = emalloc(sizeof(struct mmc_servers));
+		state->servers->server = mmc;
+		state->servers->weight = weight;
+		state->servers->next = NULL;
+	}
+	else {
+		ptr = state->servers;
+
+		while (ptr->next != NULL) {
+			ptr = ptr->next;
+		}
+	
+		ptr->next = emalloc(sizeof(struct mmc_servers));
+		ptr->next->server = mmc;
+		ptr->next->weight = weight;
+		ptr->next->next = NULL;
+	}
+
+	ptr = state->servers;
+	state->cont_points = cont_points;
+	state->total_weight += weight;
+	state->num_servers++;
+
+	continuum = erealloc(continuum, state->num_servers  * 160 * sizeof(struct mcs));
+	unsigned char digest[16];
+	int t;
+
+	for (t = 1; t <= state->num_servers; t++) {
+		float pct = (float) ptr->weight / (float) state->total_weight;
+		unsigned int ks = (unsigned int)floorf(pct * 40.0 * (float) state->num_servers);
+		unsigned char digest[16];
+		int ss_length, h;
+		
+		for (k = 0; k < ks; k++)
+		{
+			/* max length string: hostname + port + ks + \0 */
+			ss_length = strlen(ptr->server->host) + sizeof(int) * 8 + 2 + 1;
+			char *ss = emalloc(ss_length);
+			sprintf(ss, "%s:%d-%d", ptr->server->host, ptr->server->tcp.port, k);
+			ss[ss_length-1] = '\0';
+			md5_digest(ss, digest);
+			
+			for (h = 0; h < 4; h++) {
+				continuum[cont_points].point = (unsigned int)( digest[3+h*4] << 24 )
+										| ( digest[2+h*4] << 16 )
+										| ( digest[1+h*4] <<  8 )
+										| digest[h*4];
+				continuum[cont_points].server = ptr->server;
+				cont_points++;
+			}
+			efree(ss);
+		}
+
+		ptr = ptr->next;
+	}
+
+	state->cont_points = cont_points;
+	qsort((void*) continuum, cont_points, sizeof(struct mcs), mmc_ketama_compare);
+}
+
+/* }}} */
+
+mmc_hash_strategy_t mmc_ketama_hash = {
+	mmc_ketama_create_state,
+	mmc_ketama_free_state,
+	mmc_ketama_find_server,
+	mmc_ketama_add_server
+};
+
+/*
+ * Local variables:
+ * tab-width: 4
+ * c-basic-offset: 4
+ * End:
+ * vim600: noet sw=4 ts=4 fdm=marker
+ * vim<600: noet sw=4 ts=4
+ */
diff -ruN memcache-3.0.4/memcache_pool.c memcache-3.0.4-ketama/memcache_pool.c
--- memcache-3.0.4/memcache_pool.c	2009-12-31 11:44:11.000000000 +0100
+++ memcache-3.0.4-ketama/memcache_pool.c	2009-12-31 11:33:15.000000000 +0100
@@ -33,6 +33,7 @@
 #include "ext/standard/php_string.h"
 #include "ext/standard/php_smart_str.h"
 #include "memcache_pool.h"
+#include "md5.h"
 
 ZEND_DECLARE_MODULE_GLOBALS(memcache)
 
@@ -53,6 +54,22 @@
 }
 /* }}} */
 
+static unsigned int mmc_hash_md5_init()						{ return 0; }
+static unsigned int mmc_hash_md5_finish(unsigned int seed)	{ return seed; }
+
+static unsigned int mmc_hash_md5_combine(unsigned int seed, const void *key, unsigned int key_len) /*
+	MD5 hash {{{ */
+{
+	return hash_key((const char *)key);
+}
+/* }}} */
+
+mmc_hash_function_t mmc_hash_md5 = {
+	mmc_hash_md5_init,
+	mmc_hash_md5_combine,
+	mmc_hash_md5_finish
+};
+
 static unsigned int mmc_hash_crc32_init()						{ return ~0; }
 static unsigned int mmc_hash_crc32_finish(unsigned int seed)	{ return ~seed; }
 
@@ -844,6 +861,9 @@
 		case MMC_CONSISTENT_HASH:
 			pool->hash = &mmc_consistent_hash;
 			break;
+		case MMC_KETAMA_HASH:
+			pool->hash = &mmc_ketama_hash;
+			break;
 		default:
 			pool->hash = &mmc_standard_hash;
 	}
@@ -852,6 +872,9 @@
 		case MMC_HASH_FNV1A:
 			hash = &mmc_hash_fnv1a;
 			break;
+		case MMC_HASH_MD5:
+			hash = &mmc_hash_md5;
+			break;
 		default:
 			hash = &mmc_hash_crc32;
 	}
diff -ruN memcache-3.0.4/memcache_pool.h memcache-3.0.4-ketama/memcache_pool.h
--- memcache-3.0.4/memcache_pool.h	2009-12-31 11:44:12.000000000 +0100
+++ memcache-3.0.4-ketama/memcache_pool.h	2009-12-31 11:29:40.000000000 +0100
@@ -92,8 +92,10 @@
 
 #define MMC_STANDARD_HASH 		1
 #define MMC_CONSISTENT_HASH 	2
+#define MMC_KETAMA_HASH			3
 #define MMC_HASH_CRC32 			1			/* CRC32 hash function */
 #define MMC_HASH_FNV1A 			2			/* FNV-1a hash function */
+#define MMC_HASH_MD5			3			/* MD5 hash function */
 
 #define MMC_CONSISTENT_POINTS	160			/* points per server */
 #define MMC_CONSISTENT_BUCKETS	1024		/* number of precomputed buckets, should be power of 2 */
@@ -272,6 +274,7 @@
 
 extern mmc_hash_function_t mmc_hash_crc32;
 extern mmc_hash_function_t mmc_hash_fnv1a;
+extern mmc_hash_function_t mmc_hash_md5;
 
 #define mmc_hash(hash, key, key_len) ((hash)->finish((hash)->combine((hash)->init(), (key), (key_len))))
 
@@ -289,6 +292,7 @@
 
 extern mmc_hash_strategy_t mmc_standard_hash;
 extern mmc_hash_strategy_t mmc_consistent_hash;
+extern mmc_hash_strategy_t mmc_ketama_hash;
 
 /* 32 bit magic FNV-1a prime and init */
 #define FNV_32_PRIME	0x01000193