Add some password-related feature (#92)

* Add Standalone Password Generator. Closes #18 
* Add an entropy meter for passwords. Closes #84
* Don't require password repeat when it is visible. Fixes #27

src/zxcvbn/zxcvbn.h

@@ -0,0 +1,139 @@
+#ifndef ZXCVBN_H_F98183CE2A01_INCLUDED
+#define ZXCVBN_H_F98183CE2A01_INCLUDED
+/**********************************************************************************
+ * C implementation of the zxcvbn password strength estimation method.
+ * Copyright (c) 2015, Tony Evans
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this list
+ *    of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice, this
+ *    list of conditions and the following disclaimer in the documentation and/or other
+ *    materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software without specific
+ *    prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ * 
+ **********************************************************************************/
+
+/* If this is defined, the dictiononary data is read from file. When undefined */
+/* dictionary data is included in the source code. */
+/*#define USE_DICT_FILE */
+
+/* If this is defined, C++ builds which read dictionary data from file will use */
+/* stdio FILE streams (and fopen,fread,fclose). When undefined, C++ builds will */
+/* use std::ifstream to read dictionary data. Ignored for C builds (stdio FILE  */
+/* streams are always used). */
+/*#define USE_FILE_IO */
+
+#ifndef __cplusplus
+/* C build. Use the standard malloc/free for heap memory */
+#include <stdlib.h>
+#define MallocFn(T,N) ((T *)malloc((N) * sizeof(T)))
+#define FreeFn(P)      free(P)
+
+#else
+
+/* C++ build. Use the new/delete operators for heap memory */
+#define MallocFn(T,N)   (new T[N])
+#define FreeFn(P)       (delete [] P)
+
+#endif
+
+/* Enum for the types of match returned in the Info arg to ZxcvbnMatch */
+typedef enum
+{
+    NON_MATCH,          /* 0 */
+    BRUTE_MATCH,        /* 1 */
+    DICTIONARY_MATCH,   /* 2 */
+    DICT_LEET_MATCH,    /* 3 */
+    USER_MATCH,         /* 4 */
+    USER_LEET_MATCH,    /* 5 */
+    REPEATS_MATCH,      /* 6 */
+    SEQUENCE_MATCH,     /* 7 */
+    SPATIAL_MATCH,      /* 8 */
+    DATE_MATCH,         /* 9 */
+    YEAR_MATCH,         /* 10 */
+    MULTIPLE_MATCH = 32 /* Added to above to indicate matching part has been repeated */
+} ZxcTypeMatch_t;
+
+/* Linked list of information returned in the Info arg to ZxcvbnMatch */
+struct ZxcMatch
+{
+    int             Begin;   /* Char position of begining of match */
+    int             Length;  /* Number of chars in the match */
+    double          Entrpy;  /* The entropy of the match */
+    double          MltEnpy; /* Entropy with additional allowance for multipart password */
+    ZxcTypeMatch_t  Type;    /* Type of match (Spatial/Dictionary/Order/Repeat) */
+    struct ZxcMatch *Next;
+};
+typedef struct ZxcMatch ZxcMatch_t;
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef USE_DICT_FILE
+
+/**********************************************************************************
+ * Read the dictionnary data from the given file. Returns 1 if OK, 0 if error.
+ * Called once at program startup.
+ */
+int ZxcvbnInit(const char *);
+
+/**********************************************************************************
+ * Free the dictionnary data after use. Called once at program shutdown.
+ */
+void ZxcvbnUnInit();
+
+#else
+
+/* As the dictionary data is included in the source, define these functions to do nothing. */
+#define ZxcvbnInit(s) 1
+#define ZxcvbnUnInit() do {} while(0)
+
+#endif
+
+/**********************************************************************************
+ * The main password matching function. May be called multiple times.
+ * The parameters are:
+ *  Passwd      The password to be tested. Null terminated string.
+ *  UserDict    User supplied dictionary words to be considered particulary bad. Passed
+ *               as a pointer to array of string pointers, with null last entry (like
+ *               the argv parameter to main()). May be null or point to empty array when
+ *               there are no user dictionary words.
+ *  Info        The address of a pointer variable to receive information on the parts
+ *               of the password. This parameter can be null if no information is wanted.
+ *               The data should be freed by calling ZxcvbnFreeInfo().
+ * 
+ * Returns the entropy of the password (in bits).
+ */
+double ZxcvbnMatch(const char *Passwd, const char *UserDict[], ZxcMatch_t **Info);
+
+/**********************************************************************************
+ * Free the data returned in the Info parameter to ZxcvbnMatch().
+ */
+void ZxcvbnFreeInfo(ZxcMatch_t *Info);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif