/*
 * Copyright (c) 2009 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#include <string.h>
#include <sys/types.h>
#include <AssertMacros.h>

#if !KERNEL
    #include <stdio.h>
    #include <stdlib.h>
    #include "kxld.h"
    #include "kxld_types.h"
#else 
    #include <libkern/libkern.h>
    #include <libkern/kxld.h>
    #include <libkern/kxld_types.h>
#endif /* KERNEL */

#include "kxld_util.h"

/******************************************************************************
* Macros
******************************************************************************/

#define kCopyrightToken "Copyright © "
#define kRightsToken " Apple Inc. All rights reserved."

/******************************************************************************
* Globals
******************************************************************************/

#if TEST

#include <CoreFoundation/CoreFoundation.h>

CFStringRef passes[] = {
    CFSTR("Copyright © 2008 Apple Inc. All rights reserved."),
    CFSTR("Copyright © 2004-2008 Apple Inc. All rights reserved."),
    CFSTR("Copyright © 2004,2006 Apple Inc. All rights reserved."),
    CFSTR("Copyright © 2004,2006-2008 Apple Inc. All rights reserved."),
    CFSTR("Copyright © 2004 , 2006-2008 Apple Inc. All rights reserved."),
    CFSTR("Copyright © 1998,2000-2002,2004,2006-2008 Apple Inc. All rights reserved."),
    CFSTR("IOPCIFamily 2.1; Copyright © 2004,2006-2008 Apple Inc. All rights reserved."),
    CFSTR("Copyright © 2004,2006-2008 Apple Inc. All rights reserved.  The quick brown fox jumped over the lazy dog."),
    CFSTR("IOPCIFamily 2.1; Copyright © 2004,2006-2008 Apple Inc. All rights reserved.  The quick brown fox jumped over the lazy dog.")
};

CFStringRef fails[] = {
    CFSTR("Copyright © 2007-08 Apple Inc. All rights reserved."),
    CFSTR("Copyright (c) 2007 Apple Inc. All rights reserved."),
    CFSTR("Copyright © 2007- Apple Inc. All rights reserved."),
    CFSTR("Copyright © 2007 - 2008 Apple Inc. All rights reserved.")
};

extern char *createUTF8CStringForCFString(CFStringRef aString);

#endif /* TEST */

/******************************************************************************
* Prototypes
******************************************************************************/

static boolean_t is_space(const char c) 
    __attribute__((const));
static boolean_t is_token_delimiter(const char c)
    __attribute__((const));
static boolean_t is_token_break(const char *str) 
    __attribute__((pure, nonnull));
static boolean_t token_is_year(const char *str)
    __attribute__((pure, nonnull));
static boolean_t token_is_yearRange(const char *str)
    __attribute__((pure, nonnull));
static boolean_t dates_are_valid(const char *str, const u_long len)
    __attribute__((pure, nonnull));

/******************************************************************************
******************************************************************************/
static boolean_t
is_space(const char c)
{
    switch (c) {
    case ' ':
    case '\t':
    case '\n':
    case '\v':
    case '\f':
    case '\r':
        return TRUE;
    }

    return FALSE;
}

/******************************************************************************
******************************************************************************/
static boolean_t
is_token_delimiter(const char c)
{
    return (is_space(c) || (',' == c) || ('\0' == c));
}

/******************************************************************************
* A token break is defined to be the boundary where the current character is
* not a token delimiter and the next character is a token delimiter.
******************************************************************************/
static boolean_t
is_token_break(const char *str) 
{
    /* This is safe because '\0' is a token delimiter, so the second check
     * will not execute if we reach the end of the string.
     */
    return (!is_token_delimiter(str[0]) && is_token_delimiter(str[1]));
}

/******************************************************************************
* A year is defined by the following regular expression:
*   /[0-9]{4}$/
******************************************************************************/
#define kYearLen 5
static boolean_t
token_is_year(const char *str)
{
    boolean_t result = FALSE;
    u_int i = 0;

    for (i = 0; i < kYearLen - 1; ++i) {
        if (str[i] < '0' || str[i] > '9') goto finish;
    }

    if (str[i] != '\0') goto finish;
    
    result = TRUE;
finish:
    return result;
}

/******************************************************************************
* A year range is defined by the following regular expression:
*   /[0-9]{4}[-][0-9]{4}$/
******************************************************************************/
#define kYearRangeLen 10
static boolean_t
token_is_yearRange(const char *str)
{
    boolean_t result = FALSE;
    u_int i = 0;

    for (i = 0; i < kYearLen - 1; ++i) {
        if (str[i] < '0' || str[i] > '9') goto finish;
    }

    if (str[i] != '-') goto finish;
    
    for (i = kYearLen; i < kYearRangeLen - 1; ++i) {
        if (str[i] < '0' || str[i] > '9') goto finish;
    }

    if (str[i] != '\0') goto finish;

    result = TRUE;
finish:
    return result;
}

/******************************************************************************
* The dates_are_valid function takes as input a comma-delimited list of years
* and year ranges, and returns TRUE if all years and year ranges are valid
* and well-formed.
******************************************************************************/
static boolean_t
dates_are_valid(const char *str, const u_long len)
{
    boolean_t result = FALSE;
    const char *token_ptr = NULL;
    char token_buffer[kYearRangeLen];
    u_int token_index = 0;

    token_index = 0;
    for (token_ptr = str; token_ptr < str + len; ++token_ptr) {
        if (is_token_delimiter(*token_ptr) && !token_index) continue;

        /* If we exceed the length of a year range, the test will not succeed,
         * so just fail now.  This limits the length of the token buffer that
         * we have to keep around.
         */
        if (token_index == kYearRangeLen) goto finish;

        token_buffer[token_index++] = *token_ptr;
        if (is_token_break(token_ptr)) {
            if (!token_index) continue;

            token_buffer[token_index] = '\0';

            if (!token_is_year(token_buffer) && 
                !token_is_yearRange(token_buffer)) 
            {
                goto finish;
            }

            token_index = 0;
        }
    }

    result = TRUE;
finish:
    return result;
}

/******************************************************************************
* The copyright string is composed of three parts:
*   1) A copyright notice, "Copyright ©"
*   2) One or more years or year ranges, e.g., "2004,2006-2008"
*   3) A rights reserved notice, "Apple Inc. All Rights Reserved."
* We check the validity of the string by searching for both the copyright

* notice and the rights reserved notice.  If both are found, we then check that
* the text between the two notices contains only valid years and year ranges.
******************************************************************************/
boolean_t 
kxld_validate_copyright_string(const char *str)
{
    boolean_t result = FALSE;
    const char *copyright = NULL;
    const char *rights = NULL;
    char *date_str = NULL;
    u_long len = 0;

    copyright = kxld_strstr(str, kCopyrightToken);
    rights = kxld_strstr(str, kRightsToken);

    if (!copyright || !rights || copyright > rights) goto finish;

    str = copyright + const_strlen(kCopyrightToken);

    len = rights - str;
    date_str = kxld_alloc(len+1);
    if (!date_str) goto finish;

    strncpy(date_str, str, len);
    date_str[len] = '\0';

    if (!dates_are_valid(date_str, len)) goto finish;

    result = TRUE;
finish:
    if (date_str) kxld_free(date_str, len+1);
    return result;
}

#if TEST

/******************************************************************************
******************************************************************************/
int
main(int argc __unused, char *argv[] __unused)
{
    int result = 1;
    CFStringRef the_string = NULL;
    const char *str = NULL;
    u_int i = 0;

    printf("The following %lu strings should pass\n", 
        const_array_len(passes));

    for (i = 0; i < const_array_len(passes); ++i) {
        the_string = passes[i];
        str = createUTF8CStringForCFString(the_string);
        if (!str) goto finish;

        printf("%s: %s\n", 
            (kxld_validate_copyright_string(str)) ? "pass" : "fail", str);
    }

    printf("\nThe following %lu strings should fail\n", 
        const_array_len(fails));

    for (i = 0; i < const_array_len(fails); ++i) {
        the_string = fails[i];
        str = createUTF8CStringForCFString(the_string);
        if (!str) goto finish;

        printf("%s: %s\n", 
            (kxld_validate_copyright_string(str)) ? "pass" : "fail", str);
    }

    result = 0;

finish:
    return result;
}
#endif /* TEST */