Feature: Added stubs and interface for new buffer_t that should replace refbuf_t some day.

src/Makefile.am

@@ -31,6 +31,7 @@ noinst_HEADERS = \
     matchfile.h \
     tls.h \
     refobject.h \
+    buffer.h \
     module.h \
     reportxml.h \
     listensocket.h \
@@ -76,6 +77,7 @@ icecast_SOURCES = \
     matchfile.c \
     tls.c \
     refobject.c \
+    buffer.c \
     module.c \
     reportxml.c \
     listensocket.c \

src/buffer.c

+/* Icecast
+ *
+ * This program is distributed under the GNU General Public License, version 2.
+ * A copy of this license is included with this source.
+ *
+ * Copyright 2018,      Philipp "ph3-der-loewe" Schafft <lion@lion.leolix.org>,
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "buffer.h"
+#include "refobject.h"

src/buffer.h

+/* Icecast
+ *
+ * This program is distributed under the GNU General Public License, version 2.
+ * A copy of this license is included with this source.
+ *
+ * Copyright 2018,      Philipp "ph3-der-loewe" Schafft <lion@lion.leolix.org>,
+ */
+
+/*
+ * This file contains the API for a refobject based buffer object.
+ * It can be used to store data and allows on the fly re-allocation.
+ */
+
+#ifndef __BUFFER_H__
+#define __BUFFER_H__
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "icecasttypes.h"
+#include "compat.h"
+#include "refobject.h"
+
+/* About thread safety:
+ * This set of functions is intentinally not thread safe.
+ */
+
+/* This creates a new buffer object.
+ * Parameters:
+ *  preallocation
+ *      The number of bytes to allocate for use later on. See buffer_preallocate() for details.
+ *  userdata, name, associated
+ *      See refobject_new().
+ */
+buffer_t *  buffer_new(ssize_t preallocation, void *userdata, const char *name, refobject_t associated);
+
+/* This creates a new buffer with defaults.
+ * This is the same as:
+ *  buffer_new(-1, NULL, NULL, REFOBJECT_NULL)
+ */
+buffer_t *  buffer_new_simple(void);
+
+/* This function preallocates space for later use.
+ * Parameters:
+ *  buffer
+ *      The buffer to operate on.
+ *  request
+ *      Number of bytes to additionally allocate.
+ * Notes:
+ *  This function is very usedful when adding a large number of smaller buffers to avoid
+ *  internal reallocation calls happening to often. However it is not required to call
+ *  this function before adding data to the buffer.
+ */
+void        buffer_preallocate(buffer_t *buffer, size_t request);
+
+/* Gets data and length of the buffer.
+ * Parameters:
+ *  buffer
+ *      The buffer to operate on.
+ *  data
+ *      Pointer to the stored data. If NULL the pointer is not returned.
+ *  length
+ *      Pointer to the length of how many bytes are in the buffer. If NULL
+ *      length is not returned.
+ */
+int         buffer_get_data(buffer_t *buffer, const void **data, size_t *length);
+
+/* Gets data as a string. The string is '\0'-terminated.
+ * Parameters:
+ *  buffery
+ *      The buffer to operate on.
+ *  string
+ *      The string representing the data hold by the buffer.
+ */
+int         buffer_get_string(buffer_t *buffer, const char **string);
+
+/* Sets the length of the buffer.
+ * Parameters:
+ *  buffer
+ *      The buffer to operate on.
+ *  length
+ *      New length of the buffer.
+ * Notes:
+ *  This can only be used to reduce the size of the buffer. To add data to
+ *  the buffer use buffer_push_*().
+ *
+ *  Calling this with length set to 0 clears the buffer but does not deallocate it.
+ */
+int         buffer_set_length(buffer_t *buffer, size_t length);
+
+/* Shifts data out of the buffer.
+ * Parameters:
+ *  buffer
+ *      The buffer to operate on.
+ *  amount
+ *      The amount of bytes to be removed from the begin of the buffer.
+ * Notes:
+ *  This function can be useful for skipping some small header. However this
+ *  must not be used to implement a kind of ring buffer as it will result in
+ *  poor performance caused by massive reallocations and memory copies.
+ */
+int         buffer_shift(buffer_t *buffer, size_t amount);
+
+/* This pushes data to the end of the buffer.
+ * Parameters:
+ *  buffer
+ *      The buffer to operate on.
+ *  data
+ *      The data to push.
+ *  length
+ *      The length of the data to push in byte.
+ * Notes:
+ *  Consider using buffer_zerocopy_*().
+ */
+int         buffer_push_data(buffer_t *buffer, const void *data, size_t length);
+
+/* This pushes a string to the end of the buffer.
+ * Parameters:
+ *  buffer
+ *      The buffer to operate on.
+ *  string
+ *      The string to be pushed. The tailing '\0'-termination will not be
+ *      part of the buffer.
+ * Notes:
+ *  Consider using buffer_zerocopy_*().
+ */
+int         buffer_push_string(buffer_t *buffer, const char *string);
+
+/* This requests for a memory buffer that can be pushed to without the need for copy.
+ * Parameters:
+ *  buffer
+ *      The buffer to operate on.
+ *  data
+ *      Pointer to memory that can be written and will become part of the buffer object.
+ *  request
+ *      Size of the memory area that is returned by data in bytes.
+ * Notes:
+ *  This is the first step of the zero copy push. After the memory returned by data has been
+ *  written (e.g. used in a call to read(2)) buffer_zerocopy_push_complete() must be called.
+ */
+int         buffer_zerocopy_push_request(buffer_t *buffer, void **data, size_t request);
+
+/* This is the final step of a zero copy push.
+ * Parameters:
+ *  buffer
+ *      The buffer to operate on.
+ *  done
+ *      Amount of data in bytes that has actually been written into the memory area.
+ *      Maybe zero to what has been requested with request.
+ */
+int         buffer_zerocopy_push_complete(buffer_t *buffer, size_t done);
+
+#endif

src/icecasttypes.h

@@ -93,6 +93,10 @@ typedef enum {
 
 typedef struct relay_tag relay_t;
 
+/* ---[ buffer.[ch] ]--- */
+
+typedef struct buffer_tag buffer_t;
+
 /* ---[ module.[ch] ]--- */
 
 typedef struct module_tag module_t;
@@ -117,6 +121,7 @@ typedef struct refobject_base_tag refobject_base_t;
 #ifdef HAVE_TYPE_ATTRIBUTE_TRANSPARENT_UNION
 typedef union __attribute__ ((__transparent_union__)) {
     refobject_base_t *refobject_base;
+    buffer_t *buffer;
     module_t *module;
     module_container_t *module_container;
     reportxml_t *reportxml;