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162 lines
3.5 KiB
C
162 lines
3.5 KiB
C
/*
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*
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* buffer.c
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*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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*
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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*
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* Created: Sat Mar 18 04:15:33 1995 ylo
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*
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* Functions for manipulating fifo buffers (that can grow if needed).
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*
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*/
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#include "includes.h"
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RCSID("$Id: buffer.c,v 1.6 2000/04/14 10:30:30 markus Exp $");
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#include "xmalloc.h"
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#include "buffer.h"
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#include "ssh.h"
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/* Initializes the buffer structure. */
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void
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buffer_init(Buffer *buffer)
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{
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buffer->alloc = 4096;
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buffer->buf = xmalloc(buffer->alloc);
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buffer->offset = 0;
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buffer->end = 0;
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}
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/* Frees any memory used for the buffer. */
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void
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buffer_free(Buffer *buffer)
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{
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memset(buffer->buf, 0, buffer->alloc);
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xfree(buffer->buf);
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}
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/*
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* Clears any data from the buffer, making it empty. This does not actually
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* zero the memory.
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*/
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void
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buffer_clear(Buffer *buffer)
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{
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buffer->offset = 0;
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buffer->end = 0;
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}
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/* Appends data to the buffer, expanding it if necessary. */
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void
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buffer_append(Buffer *buffer, const char *data, unsigned int len)
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{
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char *cp;
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buffer_append_space(buffer, &cp, len);
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memcpy(cp, data, len);
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}
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/*
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* Appends space to the buffer, expanding the buffer if necessary. This does
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* not actually copy the data into the buffer, but instead returns a pointer
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* to the allocated region.
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*/
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void
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buffer_append_space(Buffer *buffer, char **datap, unsigned int len)
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{
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/* If the buffer is empty, start using it from the beginning. */
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if (buffer->offset == buffer->end) {
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buffer->offset = 0;
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buffer->end = 0;
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}
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restart:
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/* If there is enough space to store all data, store it now. */
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if (buffer->end + len < buffer->alloc) {
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*datap = buffer->buf + buffer->end;
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buffer->end += len;
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return;
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}
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/*
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* If the buffer is quite empty, but all data is at the end, move the
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* data to the beginning and retry.
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*/
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if (buffer->offset > buffer->alloc / 2) {
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memmove(buffer->buf, buffer->buf + buffer->offset,
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buffer->end - buffer->offset);
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buffer->end -= buffer->offset;
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buffer->offset = 0;
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goto restart;
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}
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/* Increase the size of the buffer and retry. */
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buffer->alloc += len + 32768;
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buffer->buf = xrealloc(buffer->buf, buffer->alloc);
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goto restart;
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}
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/* Returns the number of bytes of data in the buffer. */
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unsigned int
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buffer_len(Buffer *buffer)
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{
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return buffer->end - buffer->offset;
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}
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/* Gets data from the beginning of the buffer. */
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void
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buffer_get(Buffer *buffer, char *buf, unsigned int len)
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{
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if (len > buffer->end - buffer->offset)
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fatal("buffer_get: trying to get more bytes than in buffer");
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memcpy(buf, buffer->buf + buffer->offset, len);
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buffer->offset += len;
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}
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/* Consumes the given number of bytes from the beginning of the buffer. */
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void
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buffer_consume(Buffer *buffer, unsigned int bytes)
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{
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if (bytes > buffer->end - buffer->offset)
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fatal("buffer_consume: trying to get more bytes than in buffer");
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buffer->offset += bytes;
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}
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/* Consumes the given number of bytes from the end of the buffer. */
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void
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buffer_consume_end(Buffer *buffer, unsigned int bytes)
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{
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if (bytes > buffer->end - buffer->offset)
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fatal("buffer_consume_end: trying to get more bytes than in buffer");
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buffer->end -= bytes;
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}
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/* Returns a pointer to the first used byte in the buffer. */
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char *
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buffer_ptr(Buffer *buffer)
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{
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return buffer->buf + buffer->offset;
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}
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/* Dumps the contents of the buffer to stderr. */
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void
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buffer_dump(Buffer *buffer)
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{
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int i;
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unsigned char *ucp = (unsigned char *) buffer->buf;
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for (i = buffer->offset; i < buffer->end; i++)
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fprintf(stderr, " %02x", ucp[i]);
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fprintf(stderr, "\n");
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}
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