diff --git a/buffer.c b/buffer.c new file mode 100644 index 0000000000000000000000000000000000000000..fcf947b11246f9d32fd6cee069e828f2995a16b0 --- /dev/null +++ b/buffer.c @@ -0,0 +1,109 @@ +/* buffer.c + * + * 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. + */ + +#include "buffer.h" + +#include <stdlib.h> +#include <string.h> + +static int +grow_realloc(struct nettle_buffer *buffer, + unsigned length) +{ + if (!length) + { + realloc(buffer->contents, 0); + buffer->contents = NULL; + buffer->alloc = 0; + buffer->size = 0; + + return 1; + } + else + { + unsigned alloc = buffer->alloc * 2 + length + 100; + uint8_t *p = realloc(buffer->contents, alloc); + if (!p) + return 0; + + buffer->contents = p; + buffer->alloc = alloc; + + return 1; + } +} + +void +nettle_buffer_init(struct nettle_buffer *buffer) +{ + buffer->contents = NULL; + buffer->alloc = 0; + buffer->grow = grow_realloc; + buffer->size = 0; +} + +void +nettle_buffer_init_size(struct nettle_buffer *buffer, + unsigned length, uint8_t *space) +{ + buffer->contents = space; + buffer->alloc = length; + buffer->grow = NULL; + buffer->size = 0; +} + +void +nettle_buffer_clear(struct nettle_buffer *buffer) +{ + NETTLE_BUFFER_GROW(buffer, 0); +} + +uint8_t * +nettle_buffer_space(struct nettle_buffer *buffer, + unsigned length) +{ + uint8_t *p; + if (buffer->size + length > buffer->alloc) + if (!NETTLE_BUFFER_GROW(buffer, length)) + return NULL; + + p = buffer->contents + buffer->size; + buffer->size += length; + return p; +} + +int +nettle_buffer_write(struct nettle_buffer *buffer, + unsigned length, const uint8_t *data) +{ + uint8_t *p = nettle_buffer_space(buffer, length); + if (p) + { + memcpy(p, data, length); + return 1; + } + else + return 0; +} diff --git a/buffer.h b/buffer.h new file mode 100644 index 0000000000000000000000000000000000000000..febabfcfd77eb8ff3e2227bd664821b13f2adc76 --- /dev/null +++ b/buffer.h @@ -0,0 +1,78 @@ +/* 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); + +#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 */