Began inevetable rewrite.

1 files changed, 69 insertions, 0 deletions

diff --git a/src/io.c b/src/io.c
new file mode 100644
index 0000000..2762180
--- /dev/null
+++ b/src/io.c
@@ -0,0 +1,69 @@
+/* io.c -- Code for file and memory I/O.
+
+   Copyright (C) 2017 Jakob Tsar-Fox, All Rights Reserved.
+
+   This file is part of Nekopack.
+
+   Nekopack is free software: you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation, either version 3 of the License, or (at
+   your option) any later version.
+
+   Nekopack is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with Nekopack. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <stdint.h>
+#include <string.h>
+
+#include "io.h"
+
+
+/* Allocates `len` bytes of memory and returns a new stream pointing to
+   it. The memory provided has not zeroed. */
+struct stream *stream_new(size_t len) {
+    stream *new = malloc(sizeof(stream));
+    new->len = len;
+    new->_start = malloc(len);
+    new->_cur = new->_start;
+    new->_location = HEAP;
+}
+
+
+/* Called to free or unmap the memory chunk associated with the given
+   stream, as well as the stream structure itself. */
+void stream_free(struct stream *s) {
+    switch (s->_loc) {
+        case HEAP:
+            free(s->_start);
+    }
+    free(s);
+}
+
+
+/* Copies `n` bytes from the given stream into the memory area specified
+   by `dest`. The stream is advanced appropriately. */
+void stream_read(void *dest, struct stream *s, size_t n) {
+    memcpy(dest, s->_cur, n);
+    (char *) s->_cur += n;
+}
+
+
+/* Copies `n` bytes into the given stream from the memory area specified
+   by `src`. The stream is advanced appropriately. */
+void stream_write(struct stream *s, void *src, size_t n) { 
+    if (s->cur + n > s->start + s->len) {
+        ptrdiff_t dist = (uintptr_t) s->_cur - (uintptr_t) s->_start;
+        switch(s->_loc) {
+            case HEAP:
+                s->_start = realloc(s->_start, s->len * 2);
+                s->_cur = s->_start + dist;
+        }
+    }
+    memcpy(s->cur, src, n);
+    s->cur += n;
+}