libc: Add readdir_multi

This is a faster, zero allocation function for reading directory
entries. It has massive speed increases for certain applications since
malloc(especially my implementation) is really slow in comparison.

1 files changed, 13 insertions, 0 deletions

diff --git a/userland/libc/dirent/readdir.c b/userland/libc/dirent/readdir.c
index 8b825cb..9a9f8fa 100644
--- a/userland/libc/dirent/readdir.c
+++ b/userland/libc/dirent/readdir.c
@@ -1,6 +1,19 @@
 #include <dirent.h>
 #include <unistd.h>
 
+int readdir_multi(DIR *dir, struct dirent *entries, int num_entries) {
+  size_t offset = dir->dir_num * sizeof(struct dirent);
+  int rc;
+  if (-1 == (rc = pread(dir->fd, entries, num_entries * sizeof(struct dirent),
+                        offset))) {
+    return -1;
+  }
+
+  int num_read_entries = rc / sizeof(struct dirent);
+  dir->dir_num += num_read_entries;
+  return num_read_entries;
+}
+
 struct dirent *readdir(DIR *dir) {
   size_t offset = dir->dir_num * sizeof(struct dirent);
   int rc;