Import new Cytoplasm library based off of code from Telodendria.

Telodendria doesn't use this library yet, but it will soon.

src/Io/IoFd.c

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2022-2023 Jordan Bancino <@jordan:bancino.net>
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <Io.h>
+
+#include <Memory.h>
+
+#include <fcntl.h>
+
+static ssize_t
+IoReadFd(void *cookie, void *buf, size_t nBytes)
+{
+    int fd = *((int *) cookie);
+
+    return read(fd, buf, nBytes);
+}
+
+static ssize_t
+IoWriteFd(void *cookie, void *buf, size_t nBytes)
+{
+    int fd = *((int *) cookie);
+
+    return write(fd, buf, nBytes);
+}
+
+static off_t
+IoSeekFd(void *cookie, off_t offset, int whence)
+{
+    int fd = *((int *) cookie);
+
+    return lseek(fd, offset, whence);
+}
+
+static int
+IoCloseFd(void *cookie)
+{
+    int fd = *((int *) cookie);
+
+    Free(cookie);
+    return close(fd);
+}
+
+Io *
+IoFd(int fd)
+{
+    int *cookie = Malloc(sizeof(int));
+    IoFunctions f;
+
+    if (!cookie)
+    {
+        return NULL;
+    }
+
+    *cookie = fd;
+
+    f.read = IoReadFd;
+    f.write = IoWriteFd;
+    f.seek = IoSeekFd;
+    f.close = IoCloseFd;
+
+    return IoCreate(cookie, f);
+}
+
+Io *
+IoOpen(const char *path, int flags, mode_t mode)
+{
+    int fd = open(path, flags, mode);
+
+    if (fd == -1)
+    {
+        return NULL;
+    }
+
+    return IoFd(fd);
+}