1 files changed, 103 insertions, 0 deletions
diff --git a/lib/linebuffer.c b/lib/linebuffer.c
new file mode 100644
index 0000000..a679b97
--- /dev/null
+++ b/lib/linebuffer.c
@@ -0,0 +1,103 @@
+/* linebuffer.c -- read arbitrarily long lines
+
+   Copyright (C) 1986, 1991, 1998-1999, 2001, 2003-2004, 2006-2007, 2009-2022
+   Free Software Foundation, Inc.
+
+   This program 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.
+
+   This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Richard Stallman. */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include "linebuffer.h"
+#include "xalloc.h"
+
+#if USE_UNLOCKED_IO
+# include "unlocked-io.h"
+#endif
+
+/* Initialize linebuffer LINEBUFFER for use. */
+
+void
+initbuffer (struct linebuffer *linebuffer)
+{
+  memset (linebuffer, 0, sizeof *linebuffer);
+}
+
+struct linebuffer *
+readlinebuffer (struct linebuffer *linebuffer, FILE *stream)
+{
+  return readlinebuffer_delim (linebuffer, stream, '\n');
+}
+
+/* Read an arbitrarily long line of text from STREAM into LINEBUFFER.
+   Consider lines to be terminated by DELIMITER.
+   Keep the delimiter; append DELIMITER if it's the last line of a file
+   that ends in a character other than DELIMITER.  Do not NUL-terminate.
+   Therefore the stream can contain NUL bytes, and the length
+   (including the delimiter) is returned in linebuffer->length.
+   Return NULL when stream is empty.  Return NULL and set errno upon
+   error; callers can distinguish this case from the empty case by
+   invoking ferror (stream).
+   Otherwise, return LINEBUFFER.  */
+struct linebuffer *
+readlinebuffer_delim (struct linebuffer *linebuffer, FILE *stream,
+                      char delimiter)
+{
+  int c;
+  char *buffer = linebuffer->buffer;
+  char *p = linebuffer->buffer;
+  char *end = buffer + linebuffer->size; /* Sentinel. */
+
+  if (feof (stream))
+    return NULL;
+
+  do
+    {
+      c = getc (stream);
+      if (c == EOF)
+        {
+          if (p == buffer || ferror (stream))
+            return NULL;
+          if (p[-1] == delimiter)
+            break;
+          c = delimiter;
+        }
+      if (p == end)
+        {
+          idx_t oldsize = linebuffer->size;
+          buffer = xpalloc (buffer, &linebuffer->size, 1, -1, 1);
+          p = buffer + oldsize;
+          linebuffer->buffer = buffer;
+          end = buffer + linebuffer->size;
+        }
+      *p++ = c;
+    }
+  while (c != delimiter);
+
+  linebuffer->length = p - buffer;
+  return linebuffer;
+}
+
+/* Free the buffer that was allocated for linebuffer LINEBUFFER.  */
+
+void
+freebuffer (struct linebuffer *linebuffer)
+{
+  free (linebuffer->buffer);
+}