/**

 * vim: set ts=4 sw=4 tw=99 et :

 * =============================================================================

 * SourceMod

 * Copyright (C) 2004-2009 AlliedModders LLC.  All rights reserved.

 * =============================================================================

 *

 * This program is free software; you can redistribute it and/or modify it under

 * the terms of the GNU General Public License, version 3.0, as published by the

 * Free Software Foundation.

 * 

 * 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, see <http://www.gnu.org/licenses/>.

 *

 * As a special exception, AlliedModders LLC gives you permission to link the

 * code of this program (as well as its derivative works) to "Half-Life 2," the

 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

 * by the Valve Corporation.  You must obey the GNU General Public License in

 * all respects for all other code used.  Additionally, AlliedModders LLC grants

 * this exception to all derivative works.  AlliedModders LLC defines further

 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

 * or <http://www.sourcemod.net/license.php>.

 *

 * Version: $Id$

 */

#include <string.h>

#include <ctype.h>

#include "stringutil.h"

const char *stristr(const char *str, const char *substr)

{

	if (!*substr)

	{

		return ((char *)str);

	}

	char *needle = (char *)substr;

	char *prevloc = (char *)str;

	char *haystack = (char *)str;

	while (*haystack)

	{

		if (tolower(*haystack) == tolower(*needle))

		{

			haystack++;

			if (!*++needle)

			{

				return prevloc;

			}

		}

		else

		{

			haystack = ++prevloc;

			needle = (char *)substr;

		}

	}

	return NULL;

}

unsigned int strncopy(char *dest, const char *src, size_t count)

{

	if (!count)

	{

		return 0;

	}

	char *start = dest;

	while ((*src) && (--count))

	{

		*dest++ = *src++;

	}

	*dest = '\0';

	return (dest - start);

}

unsigned int UTIL_ReplaceAll(char *subject, size_t maxlength, const char *search, const char *replace, bool caseSensitive)

{

	size_t searchLen = strlen(search);

	size_t replaceLen = strlen(replace);

	char *ptr = subject;

	unsigned int total = 0;

	while ((ptr = UTIL_ReplaceEx(ptr, maxlength, search, searchLen, replace, replaceLen, caseSensitive)) != NULL)

	{

		total++;

		if (*ptr == '\0')

		{

			break;

		}

	}

	return total;

}

/**

 * NOTE: Do not edit this for the love of god unless you have 

 * read the test cases and understand the code behind each one.

 * While I don't guarantee there aren't mistakes, I do guarantee

 * that plugins will end up relying on tiny idiosyncrasies of this

 * function, just like they did with AMX Mod X.

 *

 * There are explicitly more cases than the AMX Mod X version because

 * we're not doing a blind copy.  Each case is specifically optimized

 * for what needs to be done.  Even better, we don't have to error on

 * bad buffer sizes.  Instead, this function will smartly cut off the 

 * string in a way that pushes old data out.

 */

char *UTIL_ReplaceEx(char *subject, size_t maxLen, const char *search, size_t searchLen, const char *replace, size_t replaceLen, bool caseSensitive)

{

	char *ptr = subject;

	size_t browsed = 0;

	size_t textLen = strlen(subject);

	/* It's not possible to search or replace */

	if (searchLen > textLen)

	{

		return NULL;

	}

	/* Handle the case of one byte replacement.

	 * It's only valid in one case.

	 */

	if (maxLen == 1)

	{

		/* If the search matches and the replace length is 0, 

		 * we can just terminate the string and be done.

		 */

		if ((caseSensitive ? strcmp(subject, search) : strcasecmp(subject, search)) == 0 && replaceLen == 0)

		{

			*subject = '\0';

			return subject;

		}

		else

		{

			return NULL;

		}

	}

	/* Subtract one off the maxlength so we can include the null terminator */

	maxLen--;

	while (*ptr != '\0' && (browsed <= textLen - searchLen))

	{

		/* See if we get a comparison */

		if ((caseSensitive ? strncmp(ptr, search, searchLen) : strncasecmp(ptr, search, searchLen)) == 0)

		{

			if (replaceLen > searchLen)

			{

				/* First, see if we have enough space to do this operation */

				if (maxLen - textLen < replaceLen - searchLen)

				{

					/* First, see if the replacement length goes out of bounds. */

					if (browsed + replaceLen >= maxLen)

					{

						/* EXAMPLE CASE:

						 * Subject: AABBBCCC

						 * Buffer : 12 bytes

						 * Search : BBB

						 * Replace: DDDDDDDDDD

						 * OUTPUT : AADDDDDDDDD

						 * POSITION:           ^

						 */

						/* If it does, we'll just bound the length and do a strcpy. */

						replaceLen = maxLen - browsed;

						/* Note, we add one to the final result for the null terminator */

						strncopy(ptr, replace, replaceLen+1);

					}

					else

					{

						/* EXAMPLE CASE:

						 * Subject: AABBBCCC

						 * Buffer : 12 bytes

						 * Search : BBB

						 * Replace: DDDDDDD

						 * OUTPUT : AADDDDDDDCC

						 * POSITION:         ^

						 */

						/* We're going to have some bytes left over... */

						size_t origBytesToCopy = (textLen - (browsed + searchLen)) + 1;

						size_t realBytesToCopy = (maxLen - (browsed + replaceLen)) + 1;

						char *moveFrom = ptr + searchLen + (origBytesToCopy - realBytesToCopy);

						char *moveTo = ptr + replaceLen;

						/* First, move our old data out of the way. */

						memmove(moveTo, moveFrom, realBytesToCopy);

						/* Now, do our replacement. */

						memcpy(ptr, replace, replaceLen);

					}

				}

				else

				{

					/* EXAMPLE CASE:

					 * Subject: AABBBCCC

					 * Buffer : 12 bytes

					 * Search : BBB

					 * Replace: DDDD

					 * OUTPUT : AADDDDCCC

					 * POSITION:      ^

					 */

					/* Yes, we have enough space.  Do a normal move operation. */

					char *moveFrom = ptr + searchLen;

					char *moveTo = ptr + replaceLen;

					/* First move our old data out of the way. */

					size_t bytesToCopy = (textLen - (browsed + searchLen)) + 1;

					memmove(moveTo, moveFrom, bytesToCopy);

					/* Now do our replacement. */

					memcpy(ptr, replace, replaceLen);

				}

			}

			else if (replaceLen < searchLen)

			{

				/* EXAMPLE CASE:

				 * Subject: AABBBCCC

				 * Buffer : 12 bytes

				 * Search : BBB

				 * Replace: D

				 * OUTPUT : AADCCC

				 * POSITION:   ^

				 */

				/* If the replacement does not grow the string length, we do not

				 * need to do any fancy checking at all.  Yay!

				 */

				char *moveFrom = ptr + searchLen;		/* Start after the search pointer */

				char *moveTo = ptr + replaceLen;		/* Copy to where the replacement ends */

				/* Copy our replacement in, if any */

				if (replaceLen)

				{

					memcpy(ptr, replace, replaceLen);

				}

				/* Figure out how many bytes to move down, including null terminator */

				size_t bytesToCopy = (textLen - (browsed + searchLen)) + 1;

				/* Move the rest of the string down */

				memmove(moveTo, moveFrom, bytesToCopy);

			}

			else

			{

				/* EXAMPLE CASE:

				 * Subject: AABBBCCC

				 * Buffer : 12 bytes

				 * Search : BBB

				 * Replace: DDD

				 * OUTPUT : AADDDCCC

				 * POSITION:     ^

				 */

				/* We don't have to move anything around, just do a straight copy */

				memcpy(ptr, replace, replaceLen);

			}

			return ptr + replaceLen;

		}

		ptr++;

		browsed++;

	}

	return NULL;

}