108 lines
3 KiB
C
108 lines
3 KiB
C
/*
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buffer.c -- buffer management
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Copyright (C) 2011 Guus Sliepen <guus@tinc-vpn.org>,
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "system.h"
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#include "buffer.h"
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#include "xalloc.h"
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void buffer_compact(buffer_t *buffer, int maxsize) {
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if(buffer->len >= maxsize || buffer->offset / 7 > buffer->len / 8) {
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memmove(buffer->data, buffer->data + buffer->offset, buffer->len - buffer->offset);
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buffer->len -= buffer->offset;
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buffer->offset = 0;
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}
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}
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// Make sure we can add size bytes to the buffer, and return a pointer to the start of those bytes.
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char *buffer_prepare(buffer_t *buffer, int size) {
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if(!buffer->data) {
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buffer->maxlen = size;
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buffer->data = xmalloc(size);
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} else {
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if(buffer->offset && buffer->len + size > buffer->maxlen) {
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memmove(buffer->data, buffer->data + buffer->offset, buffer->len - buffer->offset);
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buffer->len -= buffer->offset;
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buffer->offset = 0;
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}
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if(buffer->len + size > buffer->maxlen) {
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buffer->maxlen = buffer->len + size;
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buffer->data = xrealloc(buffer->data, buffer->maxlen);
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}
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}
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char *start = buffer->data + buffer->len;
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buffer->len += size;
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return start;
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}
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// Copy data into the buffer.
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void buffer_add(buffer_t *buffer, const char *data, int size) {
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memcpy(buffer_prepare(buffer, size), data, size);
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}
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// Remove given number of bytes from the buffer, return a pointer to the start of them.
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static char *buffer_consume(buffer_t *buffer, int size) {
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char *start = buffer->data + buffer->offset;
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buffer->offset += size;
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if(buffer->offset >= buffer->len) {
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buffer->offset = 0;
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buffer->len = 0;
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}
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return start;
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}
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// Check if there is a complete line in the buffer, and if so, return it NULL-terminated.
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char *buffer_readline(buffer_t *buffer) {
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char *newline = memchr(buffer->data + buffer->offset, '\n', buffer->len - buffer->offset);
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if(!newline)
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return NULL;
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int len = newline + 1 - (buffer->data + buffer->offset);
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*newline = 0;
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return buffer_consume(buffer, len);
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}
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// Check if we have enough bytes in the buffer, and if so, return a pointer to the start of them.
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char *buffer_read(buffer_t *buffer, int size) {
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if(buffer->len - buffer->offset < size)
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return NULL;
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return buffer_consume(buffer, size);
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}
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void buffer_clear(buffer_t *buffer) {
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free(buffer->data);
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buffer->data = NULL;
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buffer->maxlen = 0;
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buffer->len = 0;
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buffer->offset = 0;
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}
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