sd2snes/src/sort.c

127 lines
3.7 KiB
C

#include <arm/NXP/LPC17xx/LPC17xx.h>
#include <string.h>
#include <stdlib.h>
#include "config.h"
#include "uart.h"
#include "memory.h"
#include "sort.h"
/*
heap sort algorithm for data located outside RAM
addr: start address of pointer table
i: index (in 32-bit elements)
heapsize: size of heap (in 32-bit elements)
*/
uint32_t stat_getstring = 0;
static char sort_str1[SORT_STRLEN+1], sort_str2[SORT_STRLEN+1];
uint32_t ptrcache[QSORT_MAXELEM] IN_AHBRAM;
/* get element from pointer table in external RAM*/
uint32_t sort_get_elem(uint32_t base, unsigned int index) {
return sram_readlong(base+4*index);
}
/* put element from pointer table in external RAM */
void sort_put_elem(uint32_t base, unsigned int index, uint32_t elem) {
sram_writelong(elem, base+4*index);
}
/* compare strings pointed to by elements of pointer table */
int sort_cmp_idx(uint32_t base, unsigned int index1, unsigned int index2) {
uint32_t elem1, elem2;
elem1 = sort_get_elem(base, index1);
elem2 = sort_get_elem(base, index2);
return sort_cmp_elem((void*)&elem1, (void*)&elem2);
}
int sort_cmp_elem(const void* elem1, const void* elem2) {
uint32_t el1 = *(uint32_t*)elem1;
uint32_t el2 = *(uint32_t*)elem2;
sort_getstring_for_dirent(sort_str1, el1);
sort_getstring_for_dirent(sort_str2, el2);
/*printf("i1=%d i2=%d elem1=%lx elem2=%lx ; compare %s --- %s\n", index1, index2, elem1, elem2, sort_str1, sort_str2); */
if ((el1 & 0x80000000) && !(el2 & 0x80000000)) {
return -1;
}
if (!(el1 & 0x80000000) && (el2 & 0x80000000)) {
return 1;
}
if (*sort_str1 == '.') return -1;
if (*sort_str2 == '.') return 1;
/* Do not compare trailing slashes of directory names */
if ((el1 & 0x80000000) && (el2 & 0x80000000)) {
char *str1_slash = strrchr(sort_str1, '/');
char *str2_slash = strrchr(sort_str2, '/');
if(str1_slash != NULL) *str1_slash = 0;
if(str2_slash != NULL) *str2_slash = 0;
}
return strcasecmp(sort_str1, sort_str2);
}
/* get truncated string from database */
void sort_getstring_for_dirent(char *ptr, uint32_t addr) {
uint8_t leaf_offset;
if(addr & 0x80000000) {
/* is directory link, name offset 4 */
leaf_offset = sram_readbyte(addr + 4 + SRAM_MENU_ADDR);
sram_readstrn(ptr, addr + 5 + leaf_offset + SRAM_MENU_ADDR, SORT_STRLEN);
} else {
/* is file link, name offset 6 */
leaf_offset = sram_readbyte(addr + 6 + SRAM_MENU_ADDR);
sram_readstrn(ptr, addr + 7 + leaf_offset + SRAM_MENU_ADDR, SORT_STRLEN);
}
}
void sort_heapify(uint32_t addr, unsigned int i, unsigned int heapsize)
{
while(1) {
unsigned int l = 2*i+1;
unsigned int r = 2*i+2;
unsigned int largest = (l < heapsize && sort_cmp_idx(addr, i, l) < 0) ? l : i;
if(r < heapsize && sort_cmp_idx(addr, largest, r) < 0)
largest = r;
if(largest != i) {
uint32_t tmp = sort_get_elem(addr, i);
sort_put_elem(addr, i, sort_get_elem(addr, largest));
sort_put_elem(addr, largest, tmp);
i = largest;
}
else break;
}
}
void sort_dir(uint32_t addr, unsigned int size)
{
stat_getstring=0;
if(size > QSORT_MAXELEM) {
printf("more than %d dir entries, doing slower in-place sort\n", QSORT_MAXELEM);
ext_heapsort(addr, size);
} else {
/* retrieve, sort, and store dir table */
sram_readblock(ptrcache, addr, size*4);
qsort((void*)ptrcache, size, 4, sort_cmp_elem);
sram_writeblock(ptrcache, addr, size*4);
}
}
void ext_heapsort(uint32_t addr, unsigned int size) {
for(unsigned int i = size/2; i > 0;) sort_heapify(addr, --i, size);
for(unsigned int i = size-1; i>0; --i) {
uint32_t tmp = sort_get_elem(addr, 0);
sort_put_elem(addr, 0, sort_get_elem(addr, i));
sort_put_elem(addr, i, tmp);
sort_heapify(addr, 0, i);
}
}