1 files changed, 104 insertions, 0 deletions

diff --git a/contrib/minizip/crypt.h b/contrib/minizip/crypt.h
new file mode 100644
index 0000000..e5bc627
--- /dev/null
+++ b/contrib/minizip/crypt.h
@@ -0,0 +1,104 @@
+
+#define CRC32(c, b) ((*(pcrc_32_tab+(((int)(c) ^ (b)) & 0xff))) ^ ((c) >> 8))
+
+/***********************************************************************
+ * Return the next byte in the pseudo-random sequence
+ */
+static int decrypt_byte(unsigned long* pkeys, const unsigned long* pcrc_32_tab)
+{
+    unsigned temp;  /* POTENTIAL BUG:  temp*(temp^1) may overflow in an
+                     * unpredictable manner on 16-bit systems; not a problem
+                     * with any known compiler so far, though */
+
+    temp = ((unsigned)(*(pkeys+2)) & 0xffff) | 2;
+    return (int)(((temp * (temp ^ 1)) >> 8) & 0xff);
+}
+
+/***********************************************************************
+ * Update the encryption keys with the next byte of plain text
+ */
+static int update_keys(unsigned long* pkeys,const unsigned long* pcrc_32_tab,int c)
+{
+    (*(pkeys+0)) = CRC32((*(pkeys+0)), c);
+    (*(pkeys+1)) += (*(pkeys+0)) & 0xff;
+    (*(pkeys+1)) = (*(pkeys+1)) * 134775813L + 1;
+    {
+      register int keyshift = (int)((*(pkeys+1)) >> 24);
+      (*(pkeys+2)) = CRC32((*(pkeys+2)), keyshift);
+    }
+    return c;
+}
+
+
+/***********************************************************************
+ * Initialize the encryption keys and the random header according to
+ * the given password.
+ */
+static void init_keys(const char* passwd,unsigned long* pkeys,const unsigned long* pcrc_32_tab)
+{
+    *(pkeys+0) = 305419896L;
+    *(pkeys+1) = 591751049L;
+    *(pkeys+2) = 878082192L;
+    while (*passwd != '\0') {
+        update_keys(pkeys,pcrc_32_tab,(int)*passwd);
+        passwd++;
+    }
+}
+
+#define zdecode(pkeys,pcrc_32_tab,c) \
+    (update_keys(pkeys,pcrc_32_tab,c ^= decrypt_byte(pkeys,pcrc_32_tab)))
+
+#define zencode(pkeys,pcrc_32_tab,c,t) \
+    (t=decrypt_byte(pkeys,pcrc_32_tab), update_keys(pkeys,pcrc_32_tab,c), t^(c))
+
+#ifdef INCLUDECRYPTINGCODE_IFCRYPTALLOWED
+
+#define RAND_HEAD_LEN  12
+   /* "last resort" source for second part of crypt seed pattern */
+#  ifndef ZCR_SEED2
+#    define ZCR_SEED2 (unsigned long)3141592654L     /* use PI as default pattern */
+#  endif
+
+static int crypthead(passwd, buf, bufSize, pkeys, pcrc_32_tab, crcForCrypting)
+    const char *passwd;         /* password string */
+    unsigned char *buf;         /* where to write header */
+    int bufSize;
+    unsigned long* pkeys;
+    const unsigned long* pcrc_32_tab;
+    unsigned long crcForCrypting;
+{
+    int n;                       /* index in random header */
+    int t;                       /* temporary */
+    int c;                       /* random byte */
+    unsigned char header[RAND_HEAD_LEN-2]; /* random header */
+    static unsigned calls = 0;   /* ensure different random header each time */
+
+    if (bufSize<RAND_HEAD_LEN)
+      return 0;
+
+    /* First generate RAND_HEAD_LEN-2 random bytes. We encrypt the
+     * output of rand() to get less predictability, since rand() is
+     * often poorly implemented.
+     */
+    if (++calls == 1)
+    {
+        srand((unsigned)(time(NULL) ^ ZCR_SEED2));
+    }
+    init_keys(passwd, pkeys, pcrc_32_tab);
+    for (n = 0; n < RAND_HEAD_LEN-2; n++)
+    {
+        c = (rand() >> 7) & 0xff;
+        header[n] = (unsigned char)zencode(pkeys, pcrc_32_tab, c, t);
+    }
+    /* Encrypt random header (last two bytes is high word of crc) */
+    init_keys(passwd, pkeys, pcrc_32_tab);
+    for (n = 0; n < RAND_HEAD_LEN-2; n++)
+    {
+        buf[n] = (unsigned char)zencode(pkeys, pcrc_32_tab, header[n], t);
+    }
+    buf[n++] = zencode(pkeys, pcrc_32_tab, (int)(crcForCrypting >> 16) & 0xff, t);
+    buf[n++] = zencode(pkeys, pcrc_32_tab, (int)(crcForCrypting >> 24) & 0xff, t);
+    return n;
+}
+
+#endif