LibC: Fix bugs relating to fseek

6 files changed, 41 insertions, 23 deletions

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;
 }
diff --git a/userland/libc/string/sscanf.c b/userland/libc/string/sscanf.c
index 28e1ce1..e1ede63 100644
--- a/userland/libc/string/sscanf.c
+++ b/userland/libc/string/sscanf.c
@@ -150,20 +150,21 @@ int vfscanf(FILE *stream, const char *format, va_list ap) {
 
 struct sscanf_cookie {
   const char *s;
+  unsigned long offset;
 };
 
 size_t sscanf_read(FILE *f, unsigned char *s, size_t l) {
   struct sscanf_cookie *c = f->cookie;
-  if (!*(c->s)) {
+  if (!*(c->s + c->offset)) {
     return 0;
   }
   size_t r = 0;
-  for (; l && *(c->s); l--, c->s += 1) {
-    *s = *(c->s);
+  for (; l && *(c->s); l--, c->offset += 1) {
+    *s = *(c->s + c->offset);
     s++;
     r++;
   }
-  if (!(*(c->s)))
+  if (!(*(c->s + c->offset)))
     f->is_eof = 1;
   /*
   memcpy(s, c->s, l);
@@ -171,10 +172,35 @@ size_t sscanf_read(FILE *f, unsigned char *s, size_t l) {
   return r;
 }
 
+int sscanf_seek(FILE *stream, long offset, int whence) {
+  struct sscanf_cookie *c = stream->cookie;
+  off_t ret_offset = c->offset;
+  switch (whence) {
+  case SEEK_SET:
+    // TODO: Avoid running past the pointer
+    // Should that even be checked?
+    ret_offset = offset;
+    break;
+  case SEEK_CUR:
+    ret_offset += offset;
+    break;
+  case SEEK_END:
+    for (; *(c->s + ret_offset); ret_offset++)
+      ;
+    break;
+  default:
+    return -EINVAL;
+    break;
+  }
+  c->offset = ret_offset;
+  return ret_offset;
+}
+
 int vsscanf(const char *s, const char *restrict format, va_list ap) {
-  struct sscanf_cookie c = {.s = s};
+  struct sscanf_cookie c = {.s = s, .offset = 0};
   FILE f = {
       .read = sscanf_read,
+      .seek = sscanf_seek,
       .cookie = &c,
       .has_buffered_char = 0,
       .is_eof = 0,