/**

 * 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},

};