WAD directory checksum generation code

Subversion-branch: /trunk/chocolate-doom
Subversion-revision: 686

4 files changed, 440 insertions, 0 deletions

diff --git a/src/md5.c b/src/md5.c
new file mode 100644
index 00000000..4abeca2a
--- /dev/null
+++ b/src/md5.c
@@ -0,0 +1,257 @@
+/*
+ * This code implements the MD5 message-digest algorithm.
+ * The algorithm is due to Ron Rivest.  This code was
+ * written by Colin Plumb in 1993, no copyright is claimed.
+ * This code is in the public domain; do with it what you wish.
+ *
+ * Equivalent code is available from RSA Data Security, Inc.
+ * This code has been tested against that, and is equivalent,
+ * except that you don't need to include two pages of legalese
+ * with every copy.
+ *
+ * To compute the message digest of a chunk of bytes, declare an
+ * MD5Context structure, pass it to MD5_Init, call MD5_Update as
+ * needed on buffers full of bytes, and then call MD5_Final, which
+ * will fill a supplied 16-byte array with the digest.
+ *
+ * Changed so as no longer to depend on Colin Plumb's `usual.h' header
+ * definitions; now uses stuff from dpkg's config.h.
+ *  - Ian Jackson <ian@chiark.greenend.org.uk>.
+ * Still in the public domain.
+ */
+#include "config.h"
+
+#include <string.h>             /* for memcpy() */
+#include <sys/types.h>          /* for stupid systems */
+
+#include "md5.h"
+
+#ifdef WORDS_BIGENDIAN
+void
+byteSwap(UWORD32 *buf, unsigned words)
+{
+        md5byte *p = (md5byte *)buf;
+
+        do {
+                *buf++ = (UWORD32)((unsigned)p[3] << 8 | p[2]) << 16 |
+                        ((unsigned)p[1] << 8 | p[0]);
+                p += 4;
+        } while (--words);
+}
+#else
+#define byteSwap(buf,words)
+#endif
+
+/*
+ * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
+ * initialization constants.
+ */
+void
+MD5_Init(md5_context_t *ctx)
+{
+        ctx->buf[0] = 0x67452301;
+        ctx->buf[1] = 0xefcdab89;
+        ctx->buf[2] = 0x98badcfe;
+        ctx->buf[3] = 0x10325476;
+
+        ctx->bytes[0] = 0;
+        ctx->bytes[1] = 0;
+}
+
+/*
+ * Update context to reflect the concatenation of another buffer full
+ * of bytes.
+ */
+void
+MD5_Update(md5_context_t *ctx, md5byte const *buf, unsigned len)
+{
+        UWORD32 t;
+
+        /* Update byte count */
+
+        t = ctx->bytes[0];
+        if ((ctx->bytes[0] = t + len) < t)
+                ctx->bytes[1]++;        /* Carry from low to high */
+
+        t = 64 - (t & 0x3f);    /* Space available in ctx->in (at least 1) */
+        if (t > len) {
+                memcpy((md5byte *)ctx->in + 64 - t, buf, len);
+                return;
+        }
+        /* First chunk is an odd size */
+        memcpy((md5byte *)ctx->in + 64 - t, buf, t);
+        byteSwap(ctx->in, 16);
+        MD5_Transform(ctx->buf, ctx->in);
+        buf += t;
+        len -= t;
+
+        /* Process data in 64-byte chunks */
+        while (len >= 64) {
+                memcpy(ctx->in, buf, 64);
+                byteSwap(ctx->in, 16);
+                MD5_Transform(ctx->buf, ctx->in);
+                buf += 64;
+                len -= 64;
+        }
+
+        /* Handle any remaining bytes of data. */
+        memcpy(ctx->in, buf, len);
+}
+
+void MD5_UpdateInt32(md5_context_t *context, unsigned int val)
+{
+        md5byte buf[4];
+
+        buf[0] = (val >> 24) & 0xff;
+        buf[1] = (val >> 16) & 0xff;
+        buf[2] = (val >> 8) & 0xff;
+        buf[3] = val & 0xff;
+
+        MD5_Update(context, buf, 4);
+}
+
+void MD5_UpdateString(md5_context_t *context, char *str)
+{
+        MD5_Update(context, (md5byte *) str, strlen(str) + 1);
+}
+
+/*
+ * Final wrapup - pad to 64-byte boundary with the bit pattern 
+ * 1 0* (64-bit count of bits processed, MSB-first)
+ */
+void
+MD5_Final(md5byte digest[16], md5_context_t *ctx)
+{
+        int count = ctx->bytes[0] & 0x3f;       /* Number of bytes in ctx->in */
+        md5byte *p = (md5byte *)ctx->in + count;
+
+        /* Set the first char of padding to 0x80.  There is always room. */
+        *p++ = 0x80;
+
+        /* Bytes of padding needed to make 56 bytes (-8..55) */
+        count = 56 - 1 - count;
+
+        if (count < 0) {        /* Padding forces an extra block */
+                memset(p, 0, count + 8);
+                byteSwap(ctx->in, 16);
+                MD5_Transform(ctx->buf, ctx->in);
+                p = (md5byte *)ctx->in;
+                count = 56;
+        }
+        memset(p, 0, count);
+        byteSwap(ctx->in, 14);
+
+        /* Append length in bits and transform */
+        ctx->in[14] = ctx->bytes[0] << 3;
+        ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
+        MD5_Transform(ctx->buf, ctx->in);
+
+        byteSwap(ctx->buf, 4);
+        memcpy(digest, ctx->buf, 16);
+        memset(ctx, 0, sizeof(ctx));    /* In case it's sensitive */
+}
+
+#ifndef ASM_MD5
+
+/* The four core functions - F1 is optimized somewhat */
+
+/* #define F1(x, y, z) (x & y | ~x & z) */
+#define F1(x, y, z) (z ^ (x & (y ^ z)))
+#define F2(x, y, z) F1(z, x, y)
+#define F3(x, y, z) (x ^ y ^ z)
+#define F4(x, y, z) (y ^ (x | ~z))
+
+/* This is the central step in the MD5 algorithm. */
+#define MD5STEP(f,w,x,y,z,in,s) \
+         (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
+
+/*
+ * The core of the MD5 algorithm, this alters an existing MD5 hash to
+ * reflect the addition of 16 longwords of new data.  MD5_Update blocks
+ * the data and converts bytes into longwords for this routine.
+ */
+void
+MD5_Transform(UWORD32 buf[4], UWORD32 const in[16])
+{
+        register UWORD32 a, b, c, d;
+
+        a = buf[0];
+        b = buf[1];
+        c = buf[2];
+        d = buf[3];
+
+        MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
+        MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
+        MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
+        MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
+        MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
+        MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
+        MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
+        MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
+        MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
+        MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
+        MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
+        MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
+        MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
+        MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
+        MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
+        MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
+
+        MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
+        MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
+        MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
+        MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
+        MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
+        MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
+        MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
+        MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
+        MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
+        MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
+        MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
+        MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
+        MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
+        MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
+        MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
+        MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
+
+        MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
+        MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
+        MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
+        MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
+        MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
+        MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
+        MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
+        MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
+        MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
+        MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
+        MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
+        MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
+        MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
+        MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
+        MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
+        MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
+
+        MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
+        MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
+        MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
+        MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
+        MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
+        MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
+        MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
+        MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
+        MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
+        MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
+        MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
+        MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
+        MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
+        MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
+        MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
+        MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
+
+        buf[0] += a;
+        buf[1] += b;
+        buf[2] += c;
+        buf[3] += d;
+}
+
+#endif
diff --git a/src/md5.h b/src/md5.h
new file mode 100644
index 00000000..a541296a
--- /dev/null
+++ b/src/md5.h
@@ -0,0 +1,51 @@
+/*
+ * This is the header file for the MD5 message-digest algorithm.
+ * The algorithm is due to Ron Rivest.  This code was
+ * written by Colin Plumb in 1993, no copyright is claimed.
+ * This code is in the public domain; do with it what you wish.
+ *
+ * Equivalent code is available from RSA Data Security, Inc.
+ * This code has been tested against that, and is equivalent,
+ * except that you don't need to include two pages of legalese
+ * with every copy.
+ *
+ * To compute the message digest of a chunk of bytes, declare an
+ * md5_context_s structure, pass it to MD5_Init, call MD5_Update as
+ * needed on buffers full of bytes, and then call MD5_Final, which
+ * will fill a supplied 16-byte array with the digest.
+ *
+ * Changed so as no longer to depend on Colin Plumb's `usual.h'
+ * header definitions; now uses stuff from dpkg's config.h
+ *  - Ian Jackson <ian@chiark.greenend.org.uk>.
+ * Still in the public domain.
+ */
+
+#ifndef MD5_H
+#define MD5_H
+
+#ifdef _MSC_VER
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#define UWORD32 DWORD
+#else
+#include <inttypes.h>
+#define UWORD32 uint32_t
+#endif
+#define md5byte unsigned char
+
+typedef struct md5_context_s md5_context_t;
+
+struct md5_context_s {
+        UWORD32 buf[4];
+        UWORD32 bytes[2];
+        UWORD32 in[16];
+};
+
+void MD5_Init(md5_context_t *context);
+void MD5_Update(md5_context_t *context, md5byte const *buf, unsigned len);
+void MD5_UpdateInt32(md5_context_t *context, unsigned int val);
+void MD5_UpdateString(md5_context_t *context, char *str);
+void MD5_Final(unsigned char digest[16], md5_context_t *context);
+void MD5_Transform(UWORD32 buf[4], UWORD32 const in[16]);
+
+#endif /* !MD5_H */
diff --git a/src/w_checksum.c b/src/w_checksum.c
new file mode 100644
index 00000000..faa6108a
--- /dev/null
+++ b/src/w_checksum.c
@@ -0,0 +1,96 @@
+// Emacs style mode select   -*- C++ -*- 
+//-----------------------------------------------------------------------------
+//
+// $Id: w_wad.h 596 2006-09-02 19:10:07Z fraggle $
+//
+// Copyright(C) 1993-1996 Id Software, Inc.
+// Copyright(C) 2005 Simon Howard
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+// 02111-1307, USA.
+//
+// DESCRIPTION:
+//       Generate a checksum of the WAD directory.
+//
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "md5.h"
+#include "w_checksum.h"
+#include "w_wad.h"
+
+static FILE **open_wadfiles = NULL;
+static int num_open_wadfiles = 0;
+
+static int GetFileNumber(FILE *handle)
+{
+    int i;
+    int result;
+
+    for (i=0; i<num_open_wadfiles; ++i)
+    {
+        if (open_wadfiles[i] == handle)
+        {
+            return i;
+        }
+    }
+
+    // Not found in list.  This is a new file we haven't seen yet.
+    // Allocate another slot for this file.
+
+    open_wadfiles = realloc(open_wadfiles,
+                            sizeof(FILE *) * (num_open_wadfiles + 1));
+    open_wadfiles[num_open_wadfiles] = handle;
+
+    result = num_open_wadfiles;
+    ++num_open_wadfiles;
+
+    return result;
+}
+
+static void ChecksumAddLump(md5_context_t *md5_context, lumpinfo_t *lump)
+{
+    char buf[9];
+
+    strncpy(buf, lump->name, 8);
+    buf[8] = '\0';
+    MD5_UpdateString(md5_context, buf);
+    MD5_UpdateInt32(md5_context, GetFileNumber(lump->handle));
+    MD5_UpdateInt32(md5_context, lump->position);
+    MD5_UpdateInt32(md5_context, lump->size);
+}
+
+void W_Checksum(byte digest[16])
+{
+    md5_context_t md5_context;
+    int i;
+
+    MD5_Init(&md5_context);
+
+    num_open_wadfiles = 0;
+
+    // Go through each entry in the WAD directory, adding information
+    // about each entry to the MD5 hash.
+
+    for (i=0; i<numlumps; ++i)
+    {
+        ChecksumAddLump(&md5_context, &lumpinfo[i]);
+    }
+    
+    MD5_Final(digest, &md5_context);
+}
+
diff --git a/src/w_checksum.h b/src/w_checksum.h
new file mode 100644
index 00000000..7967a36d
--- /dev/null
+++ b/src/w_checksum.h
@@ -0,0 +1,36 @@
+// Emacs style mode select   -*- C++ -*- 
+//-----------------------------------------------------------------------------
+//
+// $Id: w_wad.h 596 2006-09-02 19:10:07Z fraggle $
+//
+// Copyright(C) 1993-1996 Id Software, Inc.
+// Copyright(C) 2005 Simon Howard
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+// 02111-1307, USA.
+//
+// DESCRIPTION:
+//       Generate a checksum of the WAD directory.
+//
+
+#ifndef W_CHECKSUM_H
+#define W_CHECKSUM_H
+
+#include "doomtype.h"
+
+extern void W_Checksum(byte digest[16]);
+
+#endif /* #ifndef W_CHECKSUM_H */
+