/**

  * vim: set ts=4 :

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

  * SourceMod

  * Copyright (C) 2004-2007 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 "sm_globals.h"

 #include <IHandleSys.h>

 #include <stdlib.h>

 #include <string.h>

 /***********************************

  *   About the double array hack   *

      ***************************   

  Double arrays in Pawn are vectors offset by the current offset.  For example:

  new array[2][2]

    In this array, index 0 contains the offset from the current offset which

  results in the final vector [2] (at [0][2]).  Meaning, to dereference [1][2], 

  it is equivalent to:

  address = &array[1] + array[1] + 2 * sizeof(cell)

    The fact that each offset is from the _current_ position rather than the _base_

  position is very important.  It means that if you to try to swap vector positions,

  the offsets will no longer match, because their current position has changed.  A 

  simple and ingenious way around this is to back up the positions in a separate array,

  then to overwrite each position in the old array with absolute indices.  Pseudo C++ code:

  cell *array; //assumed to be set to the 2+D array

  cell *old_offsets = new cell[2];

  for (int i=0; i<2; i++)

  {

     old_offsets = array[i];

 	array[i] = i;

  }

    Now, you can swap the array indices with no problem, and do a reverse-lookup to find the original addresses.

  After sorting/modification is done, you must relocate the new indices.  For example, if the two vectors in our

  demo array were swapped, array[0] would be 1 and array[1] would be 0.  This is invalid to the virtual machine.

  Luckily, this is also simple -- all the information is there.

  for (int i=0; i<2; i++)

  {

 	//get the # of the vector we want to relocate in

 	cell vector_index = array[i];			

 	//get the real address of this vector

 	char *real_address = (char *)array + (vector_index * sizeof(cell)) + old_offsets[vector_index];

 	//calc and store the new distance offset

 	array[i] = real_address - ( (char *)array + (vector_index + sizeof(cell)) )

  }

  Note that the inner expression can be heavily reduced; it is expanded for readability.

  **********************************/

 enum SortOrder

 {

 	Sort_Ascending = 0,

 	Sort_Descending = 1,

 };

 int sort_ints_asc(const void *int1, const void *int2)

 {

 	return (*(int *)int1) - (*(int *)int2);

 }

 int sort_ints_desc(const void *int1, const void *int2)

 {

 	return (*(int *)int2) - (*(int *)int1);

 }

 static cell_t sm_SortIntegers(IPluginContext *pContext, const cell_t *params)

 {

 	cell_t *array;

 	cell_t array_size = params[2];

 	cell_t type = params[3];

 	pContext->LocalToPhysAddr(params[1], &array);

 	if (type == Sort_Ascending)

 	{

 		qsort(array, array_size, sizeof(cell_t), sort_ints_asc);

 	} else {

 		qsort(array, array_size, sizeof(cell_t), sort_ints_desc);

 	}

 	return 1;

 }

 int sort_floats_asc(const void *float1, const void *float2)

 {

 	float r1 = *(float *)float1;

 	float r2 = *(float *)float2;

 	if (r1 < r2)

 	{

 		return -1;

 	} else if (r2 < r1) {

 		return 1;

 	} else {

 		return 0;

 	}

 }

 int sort_floats_desc(const void *float1, const void *float2)

 {

 	float r1 = *(float *)float1;

 	float r2 = *(float *)float2;

 	if (r1 < r2)

 	{

 		return 1;

 	} else if (r2 < r1) {

 		return -1;

 	} else {

 		return 0;

 	}

 }

 static cell_t sm_SortFloats(IPluginContext *pContext, const cell_t *params)

 {

 	cell_t *array;

 	cell_t array_size = params[2];

 	cell_t type = params[3];

 	pContext->LocalToPhysAddr(params[1], &array);

 	if (type == Sort_Ascending)

 	{

 		qsort(array, array_size, sizeof(cell_t), sort_floats_asc);

 	} else {

 		qsort(array, array_size, sizeof(cell_t), sort_floats_desc);

 	}

 	return 1;

 }

 static cell_t *g_CurStringArray = NULL;

 static cell_t *g_CurRebaseMap = NULL;

 int sort_strings_asc(const void *blk1, const void *blk2)

 {

 	cell_t reloc1 = *(cell_t *)blk1;

 	cell_t reloc2 = *(cell_t *)blk2;

 	char *str1 = ((char *)(&g_CurStringArray[reloc1]) + g_CurRebaseMap[reloc1]);

 	char *str2 = ((char *)(&g_CurStringArray[reloc2]) + g_CurRebaseMap[reloc2]);

 	return strcmp(str1, str2);

 }

 int sort_strings_desc(const void *blk1, const void *blk2)

 {

 	cell_t reloc1 = *(cell_t *)blk1;

 	cell_t reloc2 = *(cell_t *)blk2;

 	char *str1 = ((char *)(&g_CurStringArray[reloc1]) + g_CurRebaseMap[reloc1]);

 	char *str2 = ((char *)(&g_CurStringArray[reloc2]) + g_CurRebaseMap[reloc2]);

 	return strcmp(str2, str1);

 }

 static cell_t sm_SortStrings(IPluginContext *pContext, const cell_t *params)

 {

 	cell_t *array;

 	cell_t array_size = params[2];

 	cell_t type = params[3];

 	pContext->LocalToPhysAddr(params[1], &array);

 	/** HACKHACK - back up the old indices, replace the indices with something easier */

 	cell_t amx_addr, *phys_addr;

 	int err;

 	if ((err=pContext->HeapAlloc(array_size, &amx_addr, &phys_addr)) != SP_ERROR_NONE)

 	{

 		pContext->ThrowNativeErrorEx(err, "Ran out of memory to sort");

 	}

 	g_CurStringArray = array;

 	g_CurRebaseMap = phys_addr;

 	for (int i=0; i<array_size; i++)

 	{

 		phys_addr[i] = array[i];

 		array[i] = i;

 	}

 	if (type == Sort_Ascending)

 	{

 		qsort(array, array_size, sizeof(cell_t), sort_strings_asc);

 	} else {

 		qsort(array, array_size, sizeof(cell_t), sort_strings_desc);

 	}

 	/* END HACKHACK - restore what we damaged so Pawn doesn't throw up.

 	 * We'll browse through each index of the array and patch up the distance.

 	 */

 	for (int i=0; i<array_size; i++)

 	{

 		/* Compute the final address of the old array and subtract the new location.

 		 * This is the fixed up distance.

 		 */

 		array[i] = ((char *)&array[array[i]] + phys_addr[array[i]]) - (char *)&array[i];

 	}

 	pContext->HeapPop(amx_addr);

 	g_CurStringArray = NULL;

 	g_CurRebaseMap = NULL;

 	return 1;

 }

 struct sort_info

 {

 	IPluginFunction *pFunc;

 	Handle_t hndl;

 	cell_t array_addr;

 	cell_t *array_base;

 	cell_t *array_remap;

 };

 sort_info g_SortInfo;

 int sort1d_amx_custom(const void *elem1, const void *elem2)

 {

 	cell_t c1 = *(cell_t *)elem1;

 	cell_t c2 = *(cell_t *)elem2;

 	cell_t result = 0;

 	IPluginFunction *pf = g_SortInfo.pFunc;

 	pf->PushCell(c1);

 	pf->PushCell(c2);

 	pf->PushCell(g_SortInfo.array_addr);

 	pf->PushCell(g_SortInfo.hndl);

 	pf->Execute(&result);

 	return result;

 }

 static cell_t sm_SortCustom1D(IPluginContext *pContext, const cell_t *params)

 {

 	cell_t *array;

 	cell_t array_size = params[2];

 	IPluginFunction *pFunction = pContext->GetFunctionById(params[3]);

 	if (!pFunction)

 	{

 		return pContext->ThrowNativeError("Function %x is not a valid function", params[3]);

 	}

 	pContext->LocalToPhysAddr(params[1], &array);

 	sort_info oldinfo = g_SortInfo;

 	g_SortInfo.hndl = params[4];

 	g_SortInfo.array_addr = params[1];

 	g_SortInfo.array_remap = NULL;

 	g_SortInfo.array_base = NULL;

 	g_SortInfo.pFunc = pFunction;

 	qsort(array, array_size, sizeof(cell_t), sort1d_amx_custom);

 	g_SortInfo = oldinfo;

 	return 1;

 }

 int sort2d_amx_custom(const void *elem1, const void *elem2)

 {

 	cell_t c1 = *(cell_t *)elem1;

 	cell_t c2 = *(cell_t *)elem2;

 	cell_t c1_addr = g_SortInfo.array_addr + (c1 * sizeof(cell_t)) + g_SortInfo.array_remap[c1];

 	cell_t c2_addr = g_SortInfo.array_addr + (c2 * sizeof(cell_t)) + g_SortInfo.array_remap[c2];

 	IPluginContext *pContext = g_SortInfo.pFunc->GetParentContext();

 	cell_t *c1_r, *c2_r;

 	pContext->LocalToPhysAddr(c1_addr, &c1_r);

 	pContext->LocalToPhysAddr(c2_addr, &c2_r);

 	cell_t result = 0;

 	g_SortInfo.pFunc->PushCell(c1_addr);

 	g_SortInfo.pFunc->PushCell(c2_addr);

 	g_SortInfo.pFunc->PushCell(g_SortInfo.array_addr);

 	g_SortInfo.pFunc->PushCell(g_SortInfo.hndl);

 	g_SortInfo.pFunc->Execute(&result);

 	return result;

 }

 static cell_t sm_SortCustom2D(IPluginContext *pContext, const cell_t *params)

 {

 	cell_t *array;

 	cell_t array_size = params[2];

 	IPluginFunction *pFunction;

 	pContext->LocalToPhysAddr(params[1], &array);

 	if ((pFunction=pContext->GetFunctionById(params[3])) == NULL)

 	{

 		return pContext->ThrowNativeError("Function %x is not a valid function", params[3]);

 	}

 	/** back up the old indices, replace the indices with something easier */

 	cell_t amx_addr, *phys_addr;

 	int err;

 	if ((err=pContext->HeapAlloc(array_size, &amx_addr, &phys_addr)) != SP_ERROR_NONE)

 	{

 		pContext->ThrowNativeErrorEx(err, "Ran out of memory to sort");

 		return 0;

 	}

 	sort_info oldinfo = g_SortInfo;

 	g_SortInfo.pFunc = pFunction;

 	g_SortInfo.hndl = params[4];

 	g_SortInfo.array_addr = params[1];

 	/** Same process as in strings, back up the old indices for later fixup */

 	g_SortInfo.array_base = array;

 	g_SortInfo.array_remap = phys_addr;

 	for (int i=0; i<array_size; i++)

 	{

 		phys_addr[i] = array[i];

 		array[i] = i;

 	}

 	qsort(array, array_size, sizeof(cell_t), sort2d_amx_custom);

 	/** Fixup process! */

 	for (int i=0; i<array_size; i++)

 	{

 		/* Compute the final address of the old array and subtract the new location.

 		 * This is the fixed up distance.

 		 */

 		array[i] = ((char *)&array[array[i]] + phys_addr[array[i]]) - (char *)&array[i];

 	}

 	pContext->HeapPop(amx_addr);

 	g_SortInfo = oldinfo;

 	return 1;

 }

 REGISTER_NATIVES(sortNatives)

 {

 	{"SortIntegers",			sm_SortIntegers},

 	{"SortFloats",				sm_SortFloats},

 	{"SortStrings",				sm_SortStrings},

 	{"SortCustom1D",			sm_SortCustom1D},

 	{"SortCustom2D",			sm_SortCustom2D},

 	{NULL,						NULL},

 };