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- /*
- 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;
- /* guard against overflow */
- GNUNET_assert (new_capacity >= buf->position);
- 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;
- memset (buf, 0, sizeof (struct GNUNET_Buffer));
- return res;
- }
- /**
- * Clear the buffer and return its contents.
- * The caller is responsible to eventually #GNUNET_free
- * the returned data.
- *
- * @param buf the buffer to reap the contents from
- * @param size where to store the size of the returned data
- * @returns the data contained in the string
- */
- void *
- GNUNET_buffer_reap (struct GNUNET_Buffer *buf, size_t *size)
- {
- *size = buf->position;
- void *res = buf->mem;
- memset (buf, 0, sizeof (struct GNUNET_Buffer));
- 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 (buf->mem);
- memset (buf, 0, sizeof (struct GNUNET_Buffer));
- }
- /**
- * 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);
- }
- /**
- * Write data encoded via #GNUNET_STRINGS_data_to_string to the buffer.
- *
- * Grows the buffer if necessary.
- *
- * @param buf buffer to write to
- * @param data data to read from
- * @param data_len number of bytes to copy from @a data to @a buf
- */
- void
- GNUNET_buffer_write_data_encoded (struct GNUNET_Buffer *buf,
- const void *data,
- size_t data_len)
- {
- size_t outlen = data_len * 8;
- if (outlen % 5 > 0)
- outlen += 5 - outlen % 5;
- outlen /= 5;
- GNUNET_buffer_ensure_remaining (buf,
- outlen);
- GNUNET_assert (NULL !=
- GNUNET_STRINGS_data_to_string (data,
- data_len,
- (buf->mem
- + buf->position),
- outlen));
- buf->position += outlen;
- GNUNET_assert (buf->position <= buf->capacity);
- }
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