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  • /* buffer.h
     *
     * A bare-bones string stream.
     */
    
    /* nettle, low-level cryptographics library
     *
     * Copyright (C) 2002 Niels Möller
     *  
     * The nettle library is free software; you can redistribute it and/or modify
     * it under the terms of the GNU Lesser General Public License as published by
     * the Free Software Foundation; either version 2.1 of the License, or (at your
     * option) any later version.
     * 
     * The nettle library 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 Lesser General Public
     * License for more details.
     * 
     * You should have received a copy of the GNU Lesser General Public License
     * along with the nettle library; see the file COPYING.LIB.  If not, write to
     * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
     * MA 02111-1307, USA.
     */
     
    #ifndef NETTLE_BUFFER_H_INCLUDED
    #define NETTLE_BUFFER_H_INCLUDED
    
    #include <inttypes.h>
    
    struct nettle_buffer
    {
      uint8_t *contents;
      /* Allocated size */
      unsigned alloc;
      
      /* If GROW is NULL, no reallocation is done. Otherwise, it should be
       * a function that reallocates the contents to at least the size SIZE
       * + LENGTH. It can return 0 if allocation fails. Furthermore, if
       * GROW is called with LENGTH = 0, it should deallocate the buffer
       * space. */
      int (*grow)(struct nettle_buffer *buffer, unsigned length);
    
      /* Current size */
      unsigned size;
    };
    
    /* Initializes a buffer that uses plain realloc */
    void
    nettle_buffer_init(struct nettle_buffer *buffer);
    
    /* Initializes a buffer of fix size */
    void
    nettle_buffer_init_size(struct nettle_buffer *buffer,
    			unsigned length, uint8_t *space);
    
    void
    nettle_buffer_clear(struct nettle_buffer *buffer);
    
    
    Niels Möller's avatar
    Niels Möller committed
    /* FIXME: Put the comparison buffer->size + length > buffer->alloc
     * inside this macro. */
    
    #define NETTLE_BUFFER_GROW(o, l) ((o)->grow && (o)->grow((o), l))
    
    #define NETTLE_BUFFER_PUTC(buffer, c) \
    ( (((buffer)->size < (buffer)->alloc) || NETTLE_BUFFER_GROW((buffer), 1)) \
      && ((buffer)->contents[(buffer)->size++] = (c), 1) )
    
    int
    nettle_buffer_write(struct nettle_buffer *buffer,
    		    unsigned length, const uint8_t *data);
    
    /* Like nettle_buffer_write, but instead of copying data to the
     * buffer, it returns a pointer to the area where the caller can copy
     * the data. The pointer is valid only until the next call that can
     * reallocate the buffer. */
    uint8_t *
    nettle_buffer_space(struct nettle_buffer *buffer,
    		    unsigned length);
    
    #endif /* NETTLE_BUFFER_H_INCLUDED */