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#include <dirent.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
int nop_compar(const struct dirent **d1, const struct dirent **d2) {
*d2 = *d1;
return 0;
}
// Differs from scandir in the sense that the namelist has its own way
// of allocating its entries(in this case it allocates it as a large
// chunk). As a result the usual free() operation can not be ran on
// the elements.
//
// Instead scandir_sane_free() should be used to deallocate the
// namelist.
int scandir_sane(const char *dir, struct dirent ***namelist,
int (*sel)(const struct dirent *),
int (*compar)(const struct dirent **,
const struct dirent **)) {
if (!compar) {
compar = nop_compar;
}
int fd = open(dir, O_RDONLY);
if (-1 == fd) {
// TODO: Figure out what to set errno to
return -1;
}
size_t capacity = 128;
size_t num_entries;
struct dirent *chunk = NULL;
for (;;) {
chunk = realloc(chunk, sizeof(struct dirent) * capacity);
int rc = pread(fd, chunk, sizeof(struct dirent) * capacity, 0);
if (-1 == rc) {
free(chunk);
// TODO: Figure out what to set errno to
return -1;
}
if (sizeof(struct dirent) * capacity == (size_t)rc) {
// The directory **may** contain more entries.
// Redo
capacity *= 2;
continue;
}
num_entries = rc / (sizeof(struct dirent));
break;
}
*namelist = allocarray(num_entries, sizeof(struct dirent *));
for (size_t i = 0; i < num_entries; i++) {
(*namelist)[i] = &chunk[i];
}
close(fd);
return num_entries;
}
void scandir_sane_free(struct dirent **namelist) {
free(namelist[0]); // First pointer is the start of the chunk in the
// current implementation
free(namelist);
}
int scandir(const char *dir, struct dirent ***namelist,
int (*sel)(const struct dirent *),
int (*compar)(const struct dirent **, const struct dirent **)) {
if (!compar) {
compar = nop_compar;
}
DIR *d = opendir(dir);
if (!d) {
return -1;
}
struct dirent **list = NULL;
struct dirent *e;
int rc = 0;
for (; (e = readdir(d));) {
if (sel) {
if (!sel(e)) {
continue;
}
}
struct dirent *p = malloc(sizeof(struct dirent));
memcpy(p, e, sizeof(struct dirent));
list = realloc(list, (rc + 1) * sizeof(struct dirent *));
list[rc] = p;
rc++;
}
*namelist = list;
closedir(d);
return rc;
}
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