From 12e09f9f85ac48ff891adf92f3b2c9a5fea27273 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Sat, 4 Dec 2021 14:10:21 -0800
Subject: Chore(REMOVE): finished deprecation of old io functions.

The old methods were simple wrappers of C standard library functions.
We've moved (painfully) over to a new interface that allows for files to
live on the stack. All users of the functionality are ported over.
---
 src/base/io/seek.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 52 insertions(+), 2 deletions(-)

(limited to 'src/base/io/seek.c')

diff --git a/src/base/io/seek.c b/src/base/io/seek.c
index 1be4ee7..4fa1aff 100644
--- a/src/base/io/seek.c
+++ b/src/base/io/seek.c
@@ -1,7 +1,57 @@
 #include "internal.h"
 
 int
-io·seek(io·Stream *s, long off, int whence)
+io·seek(io·Header *io, intptr offset, int whence, intptr *pos)
 {
-    return fseek(s, off, whence);
+    intptr n,d,cap;
+
+    switch(io->state){
+    default:
+        fmt·fprint(2, "seek: unknown state %d\n", io->state);
+        return io·BufEof;
+    case io·BufEnd:
+        io->state = io·BufRdr;
+        io->ilen = 0;
+        io->g = io->e;
+        /* fallthrough */
+    case io·BufRdr:
+        n = offset;
+        if(whence == sys·SeekCur){
+            n += io·offset(io);
+            whence = sys·SeekSet;
+        }
+
+        /* can we seek inside our buffer */
+        if(whence == sys·SeekSet){
+            d = n - io·offset(io);
+            cap = io->e - io->g;
+            if(-cap <= d && d <= cap){
+                io->ilen += d;
+                if(d >= 0){
+                    if(io->ilen <= 0){
+                        *pos = n;
+                        return 0;
+                    }
+                }else{
+                    if(io->e - io->g >= -io->ilen){
+                        *pos = n;
+                        return 0;
+                    }
+                }
+            }
+        }
+
+        /* nope, call the kernel to do it for us */
+        sys·seek(io->fd, offset, whence, &n);
+        io->ilen = 0;
+        io->g = io->e;
+        break;
+
+    case io·BufWtr:
+        io·flush(io);
+        sys·seek(io->fd, offset, whence, &n);
+        break;
+    }
+    io->pos = *pos = n;
+    return 0;
 }
-- 
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