Fix some issues and do some code cleanup

libc/stdio/getdelim_unlocked.c

@@ -0,0 +1,81 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/errno.h"
+#include "libc/stdio/stdio.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/o.h"
+
+/**
+ * Reads string from unlocked stream.
+ * @see getdelim() for documentation
+ */
+ssize_t getdelim_unlocked(char **s, size_t *n, int delim, FILE *f) {
+  ssize_t rc;
+  char *p, *s2;
+  size_t i, m, n2;
+  if ((f->iomode & O_ACCMODE) == O_WRONLY) {
+    f->state = errno = EBADF;
+    return -1;
+  }
+  if (f->beg > f->end) {
+    f->state = errno = EINVAL;
+    return -1;
+  }
+  if (!*s) *n = 0;
+  for (i = 0;; i += m) {
+    m = f->end - f->beg;
+    if ((p = memchr(f->buf + f->beg, delim, m))) {
+      m = p + 1 - (f->buf + f->beg);
+    }
+    if (i + m + 1 > *n) {
+      n2 = i + m + 1;
+      s2 = realloc(*s, n2);
+      if (s2) {
+        *s = s2;
+        *n = n2;
+      } else {
+        f->state = errno;
+        return -1;
+      }
+    }
+    memcpy(*s + i, f->buf + f->beg, m);
+    (*s)[i + m] = '\0';
+    if ((f->beg += m) == f->end) {
+      f->beg = f->end = 0;
+    }
+    if (p) {
+      return i + m;
+    } else if (f->fd == -1) {
+      break;
+    } else if ((rc = read(f->fd, f->buf, f->size)) != -1) {
+      if (!rc) break;
+      f->end = rc;
+    } else if (errno != EINTR) {
+      f->state = errno;
+      return -1;
+    }
+  }
+  f->state = -1;
+  if (i + m) {
+    return i + m;
+  } else {
+    return -1;
+  }
+}