amxmodx/amxmodx/sorting.cpp
2007-04-25 14:10:47 +00:00

361 lines
8.9 KiB
C++

#include "amxmodx.h"
#include <stdlib.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 AMX_NATIVE_CALL SortIntegers(AMX *amx, cell *params)
{
cell *array = get_amxaddr(amx, params[1]);
cell array_size = params[2];
cell type = params[3];
if (type == Sort_Ascending)
{
qsort(array, array_size, sizeof(cell), sort_ints_asc);
} else {
qsort(array, array_size, sizeof(cell), sort_ints_desc);
}
return 1;
}
int sort_floats_asc(const void *float1, const void *float2)
{
REAL r1 = *(REAL *)float1;
REAL r2 = *(REAL *)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)
{
REAL r1 = *(REAL *)float1;
REAL r2 = *(REAL *)float2;
if (r1 < r2)
{
return 1;
} else if (r2 < r1) {
return -1;
} else {
return 0;
}
}
static cell AMX_NATIVE_CALL SortFloats(AMX *amx, cell *params)
{
cell *array = get_amxaddr(amx, params[1]);
cell array_size = params[2];
cell type = params[3];
if (type == Sort_Ascending)
{
qsort(array, array_size, sizeof(cell), sort_floats_asc);
} else {
qsort(array, array_size, sizeof(cell), sort_floats_desc);
}
return 1;
}
static cell *g_CurStringArray = NULL;
static cell *g_CurRebaseMap = NULL;
int sort_strings_asc(const void *blk1, const void *blk2)
{
cell reloc1 = *(cell *)blk1;
cell reloc2 = *(cell *)blk2;
register cell *str1 = (cell *)((char *)(&g_CurStringArray[reloc1]) + g_CurRebaseMap[reloc1]);
register cell *str2 = (cell *)((char *)(&g_CurStringArray[reloc2]) + g_CurRebaseMap[reloc2]);
while (*str1 == *str2++)
{
if (*str1++ == 0)
{
return 0;
}
}
return (*str1 - *(str2 - 1));
}
int sort_strings_desc(const void *blk1, const void *blk2)
{
cell reloc1 = *(cell *)blk1;
cell reloc2 = *(cell *)blk2;
register cell *str1 = (cell *)((char *)(&g_CurStringArray[reloc1]) + g_CurRebaseMap[reloc1]);
register cell *str2 = (cell *)((char *)(&g_CurStringArray[reloc2]) + g_CurRebaseMap[reloc2]);
while (*str1 == *str2++)
{
if (*str1++ == 0)
{
return 0;
}
}
return (*(str2 - 1) - *str1);
}
static cell AMX_NATIVE_CALL SortStrings(AMX *amx, cell *params)
{
cell *array = get_amxaddr(amx, params[1]);
cell array_size = params[2];
cell type = params[3];
/** HACKHACK - back up the old indices, replace the indices with something easier */
cell amx_addr, *phys_addr;
int err;
if ((err=amx_Allot(amx, array_size, &amx_addr, &phys_addr)) != AMX_ERR_NONE)
{
LogError(amx, err, "Ran out of memory");
return 0;
}
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), sort_strings_asc);
} else {
qsort(array, array_size, sizeof(cell), 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];
}
amx_Release(amx, amx_addr);
g_CurStringArray = NULL;
g_CurRebaseMap = NULL;
return 1;
}
struct sort_info
{
int pfn;
cell data_addr;
cell data_size;
cell array_addr;
cell *array_base;
cell *array_remap;
AMX *amx;
};
static CStack<sort_info *> g_AMXSortStack;
int sort1d_amx_custom(const void *elem1, const void *elem2)
{
cell c1 = *(cell *)elem1;
cell c2 = *(cell *)elem2;
sort_info *pInfo = g_AMXSortStack.front();
return executeForwards(pInfo->pfn, c1, c2, pInfo->array_addr, pInfo->data_addr, pInfo->data_size);
}
static cell AMX_NATIVE_CALL SortCustom1D(AMX *amx, cell *params)
{
cell *array = get_amxaddr(amx, params[1]);
cell array_size = params[2];
int len;
const char *funcname = get_amxstring(amx, params[3], 0, len);
int pfn = registerSPForwardByName(amx, funcname, FP_CELL, FP_CELL, FP_CELL, FP_CELL, FP_CELL, FP_DONE);
if (pfn < 0)
{
LogError(amx, AMX_ERR_NATIVE, "The public function \"%s\" was not found.", funcname);
return 0;
}
sort_info *pInfo = new sort_info;
pInfo->pfn = pfn;
pInfo->data_addr = params[4];
pInfo->data_size = params[5];
pInfo->array_addr = params[1];
pInfo->array_remap = NULL;
pInfo->array_base = NULL;
g_AMXSortStack.push(pInfo);
qsort(array, array_size, sizeof(cell), sort1d_amx_custom);
g_AMXSortStack.pop();
unregisterSPForward(pfn);
delete pInfo;
return 1;
}
int sort2d_amx_custom(const void *elem1, const void *elem2)
{
cell c1 = *(cell *)elem1;
cell c2 = *(cell *)elem2;
sort_info *pInfo = g_AMXSortStack.front();
cell c1_addr = pInfo->array_addr + (c1 * sizeof(cell)) + pInfo->array_remap[c1];
cell c2_addr = pInfo->array_addr + (c2 * sizeof(cell)) + pInfo->array_remap[c2];
//cell *c1_r = get_amxaddr(pInfo->amx, c1_addr);
//cell *c2_r = get_amxaddr(pInfo->amx, c2_addr);
return executeForwards(pInfo->pfn, c1_addr, c2_addr, pInfo->array_addr, pInfo->data_addr, pInfo->data_size);
}
static cell AMX_NATIVE_CALL SortCustom2D(AMX *amx, cell *params)
{
cell *array = get_amxaddr(amx, params[1]);
cell array_size = params[2];
int len;
const char *funcname = get_amxstring(amx, params[3], 0, len);
/** back up the old indices, replace the indices with something easier */
cell amx_addr, *phys_addr;
int err;
if ((err=amx_Allot(amx, array_size, &amx_addr, &phys_addr)) != AMX_ERR_NONE)
{
LogError(amx, err, "Ran out of memory");
return 0;
}
int pfn = registerSPForwardByName(amx, funcname, FP_CELL, FP_CELL, FP_CELL, FP_CELL, FP_CELL, FP_DONE);
if (pfn < 0)
{
amx_Release(amx, amx_addr);
LogError(amx, AMX_ERR_NATIVE, "The public function \"%s\" was not found.", funcname);
return 0;
}
sort_info *pInfo = new sort_info;
pInfo->pfn = pfn;
pInfo->data_addr = params[4];
pInfo->data_size = params[5];
pInfo->array_addr = params[1];
pInfo->amx = amx;
/** Same process as in strings, back up the old indices for later fixup */
pInfo->array_base = array;
pInfo->array_remap = phys_addr;
for (int i=0; i<array_size; i++)
{
phys_addr[i] = array[i];
array[i] = i;
}
g_AMXSortStack.push(pInfo);
qsort(array, array_size, sizeof(cell), sort2d_amx_custom);
g_AMXSortStack.pop();
/** 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];
}
amx_Release(amx, amx_addr);
unregisterSPForward(pInfo->pfn);
delete pInfo;
return 1;
}
AMX_NATIVE_INFO g_SortNatives[] =
{
{"SortIntegers", SortIntegers},
{"SortFloats", SortFloats},
{"SortStrings", SortStrings},
{"SortCustom1D", SortCustom1D},
{"SortCustom2D", SortCustom2D},
{NULL, NULL},
};