move buffer library from GNU Taler to GNUnet

4 files changed, 406 insertions, 1 deletions

diff --git a/src/include/Makefile.am b/src/include/Makefile.am
index c81f8e7d8..d79bc45b6 100644
--- a/src/include/Makefile.am
+++ b/src/include/Makefile.am
@@ -12,6 +12,7 @@ EXTRA_DIST = \
 if TALER_ONLY
 gnunetinclude_HEADERS = \
   platform.h gettext.h \
+  gnunet_buffer_lib.h \
   gnunet_common.h \
   gnunet_container_lib.h \
   gnunet_crypto_lib.h \
@@ -35,6 +36,7 @@ gnunetinclude_HEADERS = \
   gnunet_block_lib.h \
   gnunet_block_group_lib.h \
   gnunet_block_plugin.h \
+  gnunet_buffer_lib.h \
   gnunet_client_lib.h \
   gnunet_common.h \
   gnunet_constants.h \
@@ -101,7 +103,7 @@ gnunetinclude_HEADERS = \
   gnunet_regex_service.h \
   gnunet_rest_lib.h \
   gnunet_rest_plugin.h \
-        gnunet_rps_service.h \
+  gnunet_rps_service.h \
   gnunet_revocation_service.h \
   gnunet_scalarproduct_service.h \
   gnunet_scheduler_lib.h \
diff --git a/src/include/gnunet_buffer_lib.h b/src/include/gnunet_buffer_lib.h
new file mode 100644
index 000000000..c0ae06d77
--- /dev/null
+++ b/src/include/gnunet_buffer_lib.h
@@ -0,0 +1,176 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C) 2020 GNUnet e.V.
+
+     GNUnet is free software: you can redistribute it and/or modify it
+     under the terms of the GNU Affero General Public License as published
+     by the Free Software Foundation, either version 3 of the License,
+     or (at your option) any later version.
+
+     GNUnet 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
+     Affero General Public License for more details.
+
+     You should have received a copy of the GNU Affero General Public License
+     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * Common buffer management functions.
+ *
+ * @author Florian Dold
+ */
+
+#ifndef GNUNET_BUFFER_LIB_H
+#define GNUNET_BUFFER_LIB_H
+
+/**
+ * Dynamically growing buffer.  Can be used to construct
+ * strings and other objects with dynamic size.
+ *
+ * This structure should, in most cases, be stack-allocated and
+ * zero-initialized, like:
+ *
+ *   struct GNUNET_Buffer my_buffer = { 0 };
+ */
+struct GNUNET_Buffer
+{
+  /**
+   * Capacity of the buffer.
+   */
+  size_t capacity;
+
+  /**
+   * Current write position.
+   */
+  size_t position;
+
+  /**
+   * Backing memory.
+   */
+  char *mem;
+
+  /**
+   * Log a warning if the buffer is grown over its initially allocated capacity.
+   */
+  int warn_grow;
+};
+
+
+/**
+ * Initialize a buffer with the given capacity.
+ *
+ * When a buffer is allocated with this function, a warning is logged
+ * when the buffer exceeds the initial capacity.
+ *
+ * @param buf the buffer to initialize
+ * @param capacity the capacity (in bytes) to allocate for @a buf
+ */
+void
+GNUNET_buffer_prealloc (struct GNUNET_Buffer *buf, size_t capacity);
+
+
+/**
+ * Make sure that at least @a n bytes remaining in the buffer.
+ *
+ * @param buf buffer to potentially grow
+ * @param n number of bytes that should be available to write
+ */
+void
+GNUNET_buffer_ensure_remaining (struct GNUNET_Buffer *buf, size_t n);
+
+
+/**
+ * Write bytes to the buffer.
+ *
+ * Grows the buffer if necessary.
+ *
+ * @param buf buffer to write to
+ * @param data data to read from
+ * @param len number of bytes to copy from @a data to @a buf
+ *
+ */
+void
+GNUNET_buffer_write (struct GNUNET_Buffer *buf, const char *data, size_t len);
+
+
+/**
+ * Write a 0-terminated string to a buffer, excluding the 0-terminator.
+ *
+ * Grows the buffer if necessary.
+ *
+ * @param buf the buffer to write to
+ * @param str the string to write to @a buf
+ */
+void
+GNUNET_buffer_write_str (struct GNUNET_Buffer *buf, const char *str);
+
+
+/**
+ * Write a path component to a buffer, ensuring that
+ * there is exactly one slash between the previous contents
+ * of the buffer and the new string.
+ *
+ * @param buf buffer to write to
+ * @param str string containing the new path component
+ */
+void
+GNUNET_buffer_write_path (struct GNUNET_Buffer *buf, const char *str);
+
+
+/**
+ * Write a 0-terminated formatted string to a buffer, excluding the
+ * 0-terminator.
+ *
+ * Grows the buffer if necessary.
+ *
+ * @param buf the buffer to write to
+ * @param fmt format string
+ * @param ... format arguments
+ */
+void
+GNUNET_buffer_write_fstr (struct GNUNET_Buffer *buf, const char *fmt, ...);
+
+
+/**
+ * Write a 0-terminated formatted string to a buffer, excluding the
+ * 0-terminator.
+ *
+ * Grows the buffer if necessary.
+ *
+ * @param buf the buffer to write to
+ * @param fmt format string
+ * @param args format argument list
+ */
+void
+GNUNET_buffer_write_vfstr (struct GNUNET_Buffer *buf, const char *fmt, va_list
+                          args);
+
+
+/**
+ * Clear the buffer and return the string it contained.
+ * The caller is responsible to eventually #GNUNET_free
+ * the returned string.
+ *
+ * The returned string is always 0-terminated.
+ *
+ * @param buf the buffer to reap the string from
+ * @returns the buffer contained in the string
+ */
+char *
+GNUNET_buffer_reap_str (struct GNUNET_Buffer *buf);
+
+
+/**
+ * Free the backing memory of the given buffer.
+ * Does not free the memory of the buffer control structure,
+ * which is typically stack-allocated.
+ */
+void
+GNUNET_buffer_clear (struct GNUNET_Buffer *buf);
+
+
+#endif
diff --git a/src/util/Makefile.am b/src/util/Makefile.am
index 387f22a9f..369fcc6c1 100644
--- a/src/util/Makefile.am
+++ b/src/util/Makefile.am
@@ -39,6 +39,7 @@ libgnunetutil_la_SOURCES = \
   bandwidth.c \
   $(BENCHMARK) \
   bio.c \
+  buffer.c \
   client.c \
   common_allocation.c \
   common_endian.c \
diff --git a/src/util/buffer.c b/src/util/buffer.c
new file mode 100644
index 000000000..d89565d68
--- /dev/null
+++ b/src/util/buffer.c
@@ -0,0 +1,226 @@
+/*
+  This file is part of GNUnet
+  Copyright (C) 2020 GNUnet e.V.
+
+  GNUnet is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Affero General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  GNUnet 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 Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  GNUnet; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file buffer.c
+ * @brief Common buffer management functions.
+ * @author Florian Dold
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_buffer_lib.h"
+
+/**
+ * Initialize a buffer with the given capacity.
+ *
+ * When a buffer is allocated with this function, a warning is logged
+ * when the buffer exceeds the initial capacity.
+ *
+ * @param buf the buffer to initialize
+ * @param capacity the capacity (in bytes) to allocate for @a buf
+ */
+void
+GNUNET_buffer_prealloc (struct GNUNET_Buffer *buf, size_t capacity)
+{
+  /* Buffer should be zero-initialized */
+  GNUNET_assert (0 == buf->mem);
+  GNUNET_assert (0 == buf->capacity);
+  GNUNET_assert (0 == buf->position);
+  buf->mem = GNUNET_malloc (capacity);
+  buf->capacity = capacity;
+  buf->warn_grow = GNUNET_YES;
+}
+
+
+/**
+ * Make sure that at least @a n bytes remaining in the buffer.
+ *
+ * @param buf buffer to potentially grow
+ * @param n number of bytes that should be available to write
+ */
+void
+GNUNET_buffer_ensure_remaining (struct GNUNET_Buffer *buf, size_t n)
+{
+  size_t new_capacity = buf->position + n;
+
+  if (new_capacity <= buf->capacity)
+    return;
+  /* warn if calculation of expected size was wrong */
+  GNUNET_break (GNUNET_YES != buf->warn_grow);
+  if (new_capacity < buf->capacity * 2)
+    new_capacity = buf->capacity * 2;
+  buf->capacity = new_capacity;
+  if (NULL != buf->mem)
+    buf->mem = GNUNET_realloc (buf->mem, new_capacity);
+  else
+    buf->mem = GNUNET_malloc (new_capacity);
+}
+
+
+/**
+ * Write bytes to the buffer.
+ *
+ * Grows the buffer if necessary.
+ *
+ * @param buf buffer to write to
+ * @param data data to read from
+ * @param len number of bytes to copy from @a data to @a buf
+ *
+ */
+void
+GNUNET_buffer_write (struct GNUNET_Buffer *buf, const char *data, size_t len)
+{
+  GNUNET_buffer_ensure_remaining (buf, len);
+  memcpy (buf->mem + buf->position, data, len);
+  buf->position += len;
+}
+
+
+/**
+ * Write a 0-terminated string to a buffer, excluding the 0-terminator.
+ *
+ * @param buf the buffer to write to
+ * @param str the string to write to @a buf
+ */
+void
+GNUNET_buffer_write_str (struct GNUNET_Buffer *buf, const char *str)
+{
+  size_t len = strlen (str);
+
+  GNUNET_buffer_write (buf, str, len);
+}
+
+
+/**
+ * Clear the buffer and return the string it contained.
+ * The caller is responsible to eventually #GNUNET_free
+ * the returned string.
+ *
+ * The returned string is always 0-terminated.
+ *
+ * @param buf the buffer to reap the string from
+ * @returns the buffer contained in the string
+ */
+char *
+GNUNET_buffer_reap_str (struct GNUNET_Buffer *buf)
+{
+  char *res;
+
+  /* ensure 0-termination */
+  if ( (0 == buf->position) || ('\0' != buf->mem[buf->position - 1]))
+  {
+    GNUNET_buffer_ensure_remaining (buf, 1);
+    buf->mem[buf->position++] = '\0';
+  }
+  res = buf->mem;
+  *buf = (struct GNUNET_Buffer) { 0 };
+  return res;
+}
+
+
+/**
+ * Free the backing memory of the given buffer.
+ * Does not free the memory of the buffer control structure,
+ * which is typically stack-allocated.
+ */
+void
+GNUNET_buffer_clear (struct GNUNET_Buffer *buf)
+{
+  GNUNET_free_non_null (buf->mem);
+  *buf = (struct GNUNET_Buffer) { 0 };
+}
+
+
+/**
+ * Write a path component to a buffer, ensuring that
+ * there is exactly one slash between the previous contents
+ * of the buffer and the new string.
+ *
+ * @param buf buffer to write to
+ * @param str string containing the new path component
+ */
+void
+GNUNET_buffer_write_path (struct GNUNET_Buffer *buf, const char *str)
+{
+  size_t len = strlen (str);
+
+  while ( (0 != len) && ('/' == str[0]) )
+  {
+    str++;
+    len--;
+  }
+  if ( (0 == buf->position) || ('/' != buf->mem[buf->position - 1]) )
+  {
+    GNUNET_buffer_ensure_remaining (buf, 1);
+    buf->mem[buf->position++] = '/';
+  }
+  GNUNET_buffer_write (buf, str, len);
+}
+
+
+/**
+ * Write a 0-terminated formatted string to a buffer, excluding the
+ * 0-terminator.
+ *
+ * Grows the buffer if necessary.
+ *
+ * @param buf the buffer to write to
+ * @param fmt format string
+ * @param ... format arguments
+ */
+void
+GNUNET_buffer_write_fstr (struct GNUNET_Buffer *buf, const char *fmt, ...)
+{
+  va_list args;
+
+  va_start (args, fmt);
+  GNUNET_buffer_write_vfstr (buf, fmt, args);
+  va_end (args);
+}
+
+
+/**
+ * Write a 0-terminated formatted string to a buffer, excluding the
+ * 0-terminator.
+ *
+ * Grows the buffer if necessary.
+ *
+ * @param buf the buffer to write to
+ * @param fmt format string
+ * @param args format argument list
+ */
+void
+GNUNET_buffer_write_vfstr (struct GNUNET_Buffer *buf,
+                          const char *fmt,
+                          va_list args)
+{
+  int res;
+  va_list args2;
+
+  va_copy (args2, args);
+  res = vsnprintf (NULL, 0, fmt, args2);
+  va_end (args2);
+
+  GNUNET_assert (res >= 0);
+  GNUNET_buffer_ensure_remaining (buf, res + 1);
+
+  va_copy (args2, args);
+  res = vsnprintf (buf->mem + buf->position, res + 1, fmt, args2);
+  va_end (args2);
+
+  GNUNET_assert (res >= 0);
+  buf->position += res;
+  GNUNET_assert (buf->position <= buf->capacity);
+}