PAX buffer routines

2 files changed, 344 insertions, 0 deletions

diff --git a/lib/paxbuf.c b/lib/paxbuf.c
new file mode 100644
index 0000000..dfa89cb
--- /dev/null
+++ b/lib/paxbuf.c
@@ -0,0 +1,288 @@
+/* This file is part of GNU paxutils
+
+   Copyright (C) 2005 Free Software Foundation, Inc.
+
+   Written by Sergey Poznyakoff
+
+   GNU paxutils 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 2, or (at your option) any later
+   version.
+
+   GNU paxutils 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 GNU paxutils; if not, write to the Free Software Foundation, Inc.,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* PAX buffer structure */
+
+struct pax_buffer
+{
+  size_t record_size;         /* Size of a record, bytes */
+  size_t record_level;        /* Number of bytes stored in the record */
+  size_t pos;                 /* Current position in buffer */
+  char  *record;              /* Record buffer, record_size bytes long */
+
+    /* I/O functions */
+  paxbuf_io_fp writer;        /* Writes data */
+  paxbuf_io_fp reader;        /* Reads data */
+  paxbuf_seek_fp seek;        /* Seeks the underlying transport layer */
+    /* Terminal functions */
+  paxbuf_term_fp open;        /* Open a new volume */ 
+  paxbuf_term_fp close;       /* Close the existing volume */
+  paxbuf_term_fp destroy;     /* Destroy the closure data */ 
+    /* Other callbacks */
+  paxbuf_wrapper_fp wrapper;     /* Called when writer or reader returns EOF */
+
+  void *closure;              /* Implementation-specific data */
+  int mode;                   /* Working mode */
+};
+
+
+/* Default callbacks. Do nothing useful, except bailing out */
+
+static void
+noinit (const char *name)
+{
+  FATAL_ERROR ((0, 0,
+		_("INTERNAL ERROR: %s is not initialized. Please, report."),
+		name));
+}
+
+static pax_io_status_t
+default_reader (void *closure, void *data, size_t size, size_t *ret_size)
+{
+  noinit ("pax_buffer.reader");
+  return pax_io_failure;
+}
+
+static pax_io_status_t
+default_writer (void *closure, void *data, size_t size, size_t *ret_size)
+{
+  noinit ("pax_buffer.writer");
+  return pax_io_failure;
+}
+
+static int
+default_seek (void *closure, off_t offset, int whence)
+{
+  noinit ("pax_buffer.seek");
+  return -1;
+}
+
+static int
+default_open (void *closure)
+{
+  noinit ("pax_buffer.open");
+}
+
+static int
+default_close (void *closure)
+{
+  noinit ("pax_buffer.close");
+}
+
+static int
+default_destroy (void *closure)
+{
+  noinit ("pax_buffer.destroy");
+}
+
+static int
+default_wrapper (void *closure)
+{
+  noinit ("pax_buffer.wrapper");
+}
+
+
+/* Interface funtions */
+
+/* 1. Initialize/destroy */
+
+void
+paxbuf_create (paxbuf_t *pbuf, int mode, void *closure, size_t record_size)
+{
+  paxbuf_t buf;
+
+  buf = xmalloc (sizeof buf);
+  buf->record_size = record_size;
+  buf->record_level = 0;
+  buf->record = xmalloc (record_size);
+  buf->closure = closure;
+  buf->mode = mode;
+  
+  paxbuf_set_io (buf, default_reader, default_writer, default_seek);
+  paxbuf_set_term (buf, default_open, default_close, default_destroy);
+  paxbuf_set_wrapper (buf, default_wrapper);
+
+  *pbuf = buf;
+}
+
+void
+paxbuf_destroy (paxbuf_t *pbuf)
+{
+  paxbuf_t buf = *pbuf;
+  free (buf->record);
+  if (buf->destroy)
+    buf->destroy (buf->closure);
+  free (buf);
+  *pbuf = NULL;
+}
+
+void
+paxbuf_set_io (paxbuf_t buf,
+	       paxbuf_io_fp rd, paxbuf_io_fp wr, paxbuf_seek_fp seek)
+{
+  buf->writer = rd;
+  buf->reader = wr;
+  buf->seek = seek;
+}
+
+void
+paxbuf_set_term (paxbuf_t buf,
+		 paxbuf_term_fp open, paxbuf_term_fp close,
+		 paxbuf_term_fp destroy)
+{
+  buf->open = open;
+  buf->close = close;
+  buf->destroy = destroy;
+}
+
+void
+paxbuf_set_wrapper (paxbuf_t buf, paxbuf_wrapper_fp wrap)
+{
+  buf->wrapper = wrap;
+}
+
+
+/* 2. I/O operations and seek */
+
+static pax_io_status_t
+fill_buffer (paxbuf_t buf)
+{
+  pax_io_status_t status = pax_io_success;
+
+  buf->record_level = 0;
+  do
+    {
+      size_t s = 0;
+      
+      status = buf->reader (buf->closure, buf->record + buf->record_level,
+			    buf->record_size - buf->record_level, &s);
+      buf->record_level += s;
+    }
+  while ((status == pax_io_success && buf->record_level < buf->record_size)
+	 || (status == pax_io_eof
+	     && buf->wrapper
+	     && buf->wrapper (buf->closure) == 0));
+
+  buf->pos = 0;
+  return status;
+}
+
+static pax_io_status_t
+flush_buffer (paxbuf_t buf)
+{
+  pax_io_status_t status = pax_io_success;
+
+  buf->record_level = 0;
+  do
+    {
+      size_t s = 0;
+      status = buf->writer (buf->closure, buf->record + buf->record_level,
+			    buf->record_size - buf->record_level, &s);
+      buf->record_level += s;
+    }
+  while ((status == pax_io_success && buf->record_level < buf->record_size)
+	 || (status == pax_io_eof
+	     && buf->wrapper
+	     && buf->wrapper (buf->closure) == 0));
+  buf->pos = 0;
+  return status;
+}
+
+pax_io_status_t
+paxbuf_read (paxbuf_t buf, char *data, size_t size, size_t *rsize)
+{
+  pax_io_status_t status = pax_io_success;
+
+  *rsize = 0;
+  while (size && status == pax_io_success)
+    {
+      size_t s;
+
+      if (buf->pos == buf->record_level)
+	{
+	  status = fill_buffer (buf);
+	  if (status == pax_io_failure)
+	    break;
+	}
+      s = buf->record_level - buf->pos;
+      if (s > size)
+	s = size;
+      memcpy (data, buf->record + buf->pos, s);
+      data += s;
+      buf->pos += s;
+      size -= s;
+      *rsize += s;
+    }
+  return status;
+}
+
+pax_io_status_t
+paxbuf_write (paxbuf_t buf, char *data, size_t size, size_t *wsize)
+{
+  pax_io_status_t status = pax_io_success;
+
+  *wsize = 0;
+  while (size && status == pax_io_success)
+    {
+      size_t s;
+
+      if (buf->pos == buf->record_size)
+	{
+	  status = flush_buffer (buf);
+	  if (status == pax_io_failure)
+	    break;
+	}
+      s = buf->record_size - buf->pos;
+      if (s > size)
+	s = size;
+      memcpy (buf->record + buf->pos, data, s);
+      data += s;
+      buf->pos += s;
+      size -= s;
+      *wsize += s;
+    }
+  return status;
+}
+
+int
+paxbuf_seek (paxbuf_t buf, off_t offset)
+{
+  /* FIXME */
+  return buf->seek (buf->closure, offset);
+}
+
+
+/* 3. Open/close */
+int
+paxbuf_open (paxbuf_t buf)
+{
+  return buf->open (buf->closure);
+}
+
+int
+paxbuf_close (paxbuf_t buf)
+{
+  pax_io_status_t status;
+  if (buf->mode == PAXBUF_WRITE && buf->pos != 0)
+    status = flush_buffer (buf);
+  return buf->close (buf->closure) || status != pax_io_success;
+}
+
+
diff --git a/lib/paxbuf.h b/lib/paxbuf.h
new file mode 100644
index 0000000..b6557d7
--- /dev/null
+++ b/lib/paxbuf.h
@@ -0,0 +1,56 @@
+/* This file is part of GNU paxutils
+
+   Copyright (C) 2005 Free Software Foundation, Inc.
+
+   Written by Sergey Poznyakoff
+
+   GNU paxutils 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 2, or (at your option) any later
+   version.
+
+   GNU paxutils 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 GNU paxutils; if not, write to the Free Software Foundation, Inc.,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+typedef struct pax_buffer *paxbuf_t;
+
+typedef enum pax_io_status
+  {
+    pax_io_success,
+    pax_io_failure,
+    pax_io_eof
+  }
+pax_io_status_t;
+
+#define PAXBUF_READ 0
+#define PAXBUF_WRITE 1
+
+typedef pax_io_status_t (*paxbuf_io_fp) (void *closure,
+					 void *data, size_t size,
+					 size_t *ret_size);
+typedef int (*paxbuf_seek_fp) (void *closure, off_t offset);
+typedef int (*paxbuf_term_fp) (void *closure);
+typedef int (*paxbuf_wrapper_fp) (void *closure);
+
+void paxbuf_create (paxbuf_t *buf, int mode, void *closure, size_t record_size);
+int paxbuf_open (paxbuf_t buf);
+int paxbuf_close (paxbuf_t buf);
+void paxbuf_set_io (paxbuf_t buf, paxbuf_io_fp rd, paxbuf_io_fp wr,
+		    paxbuf_seek_fp seek);
+void paxbuf_set_term (paxbuf_t buf,
+		      paxbuf_term_fp open, paxbuf_term_fp close,
+		      paxbuf_term_fp destroy);
+void paxbuf_set_wrapper (paxbuf_t buf, paxbuf_wrapper_fp wrap);
+
+int paxbuf_read (paxbuf_t buf, char *buf, size_t size, size_t *rsize);
+int paxbuf_write (paxbuf_t buf, char *buf, size_t size,
+		      size_t *rsize);
+int paxbuf_seek (paxbuf_t buf, off_t offset);
+void paxbuf_destroy (paxbuf_t *buf);
+