From 5fbd9b519e082fc235a8a57c6cf761e6cefbfb62 Mon Sep 17 00:00:00 2001
From: Anton Kling <anton@kling.gg>
Date: Sat, 22 Jun 2024 21:41:46 +0200
Subject: LibC: Fix bugs relating to fseek

---
 userland/libc/stdio/fgetc.c  |  1 +
 userland/libc/stdio/fseek.c  | 21 ++++-----------------
 userland/libc/stdio/ftell.c  |  2 +-
 userland/libc/stdio/stdin.c  |  3 +++
 userland/libc/stdio/ungetc.c |  1 +
 5 files changed, 10 insertions(+), 18 deletions(-)

(limited to 'userland/libc/stdio')

diff --git a/userland/libc/stdio/fgetc.c b/userland/libc/stdio/fgetc.c
index c69211f..afa299f 100644
--- a/userland/libc/stdio/fgetc.c
+++ b/userland/libc/stdio/fgetc.c
@@ -4,6 +4,7 @@
 int fgetc(FILE *stream) {
   if (stream->has_buffered_char) {
     stream->has_buffered_char = 0;
+    fseek(stream, 1, SEEK_CUR);
     return stream->buffered_char;
   }
   char c;
diff --git a/userland/libc/stdio/fseek.c b/userland/libc/stdio/fseek.c
index fb891ec..cbccbb8 100644
--- a/userland/libc/stdio/fseek.c
+++ b/userland/libc/stdio/fseek.c
@@ -1,21 +1,8 @@
-#include <stdio.h>
 #include <assert.h>
+#include <stdio.h>
 
 int fseek(FILE *stream, long offset, int whence) {
-    return stream->seek(stream, offset, whence);
-    /*
-  switch (whence) {
-  case SEEK_SET:
-    stream->offset_in_file = offset;
-    break;
-  case SEEK_CUR:
-    stream->offset_in_file += offset;
-    break;
-  case SEEK_END:
-    // FIXME
-    assert(0);
-    break;
-  }
-  // FIXME: Error checking
-  return 0;*/
+  stream->read_buffer_stored = 0;
+  assert(stream->seek);
+  return stream->seek(stream, offset, whence);
 }
diff --git a/userland/libc/stdio/ftell.c b/userland/libc/stdio/ftell.c
index 35076d0..1729d74 100644
--- a/userland/libc/stdio/ftell.c
+++ b/userland/libc/stdio/ftell.c
@@ -1,5 +1,5 @@
 #include <stdio.h>
 
 long ftell(FILE *stream) {
-    return stream->offset_in_file;
+  return fseek(stream, 0, SEEK_CUR);
 }
diff --git a/userland/libc/stdio/stdin.c b/userland/libc/stdio/stdin.c
index fcfc71e..e497167 100644
--- a/userland/libc/stdio/stdin.c
+++ b/userland/libc/stdio/stdin.c
@@ -71,10 +71,13 @@ size_t read_fd(FILE *f, unsigned char *s, size_t l) {
     f->read_buffer_has_read += read_len;
     s += read_len;
     l -= read_len;
+    lseek(f->fd, read_len, SEEK_CUR);
     return read_len + read_fd(f, s, l);
   }
   if (0 == f->read_buffer_stored) {
+    int offset = lseek(f->fd, 0, SEEK_CUR);
     f->read_buffer_stored = non_cache_read_fd(f, f->read_buffer, 4096);
+    lseek(f->fd, offset, SEEK_SET);
     f->read_buffer_has_read = 0;
     if (0 == f->read_buffer_stored) {
       return 0;
diff --git a/userland/libc/stdio/ungetc.c b/userland/libc/stdio/ungetc.c
index 8d649bc..3b93b70 100644
--- a/userland/libc/stdio/ungetc.c
+++ b/userland/libc/stdio/ungetc.c
@@ -5,5 +5,6 @@ int ungetc(int c, FILE *stream) {
     return EOF;
   stream->buffered_char = c;
   stream->has_buffered_char = 1;
+  fseek(stream, -1, SEEK_CUR);
   return c;
 }
-- 
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