144 lines
3.8 KiB
C
144 lines
3.8 KiB
C
/*
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* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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/**
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* @file
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*
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* Line buffering
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*
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*/
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#include <stdint.h>
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#include <string.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <ipxe/linebuf.h>
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/**
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* Retrieve buffered-up line
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*
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* @v linebuf Line buffer
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* @ret line Buffered line, or NULL if no line ready to read
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*/
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char * buffered_line ( struct line_buffer *linebuf ) {
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char *line = &linebuf->data[ linebuf->len ];
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/* Fail unless we have a newly completed line to retrieve */
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if ( ( linebuf->len == 0 ) || ( linebuf->consumed == 0 ) ||
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( *(--line) != '\0' ) )
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return NULL;
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/* Identify start of line */
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while ( ( line > linebuf->data ) && ( line[-1] != '\0' ) )
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line--;
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return line;
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}
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/**
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* Discard line buffer contents
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*
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* @v linebuf Line buffer
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*/
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void empty_line_buffer ( struct line_buffer *linebuf ) {
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free ( linebuf->data );
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linebuf->data = NULL;
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linebuf->len = 0;
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linebuf->consumed = 0;
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}
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/**
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* Buffer up received data by lines
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*
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* @v linebuf Line buffer
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* @v data New data to add
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* @v len Length of new data to add
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* @ret len Consumed length, or negative error number
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*
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* After calling line_buffer(), use buffered_line() to determine
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* whether or not a complete line is available. Carriage returns and
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* newlines will have been stripped, and the line will be
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* NUL-terminated. This buffered line is valid only until the next
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* call to line_buffer() (or to empty_line_buffer()).
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*
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* Note that line buffers use dynamically allocated storage; you
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* should call empty_line_buffer() before freeing a @c struct @c
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* line_buffer.
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*/
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int line_buffer ( struct line_buffer *linebuf, const char *data, size_t len ) {
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const char *eol;
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size_t consume;
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size_t new_len;
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char *new_data;
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char *lf;
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char *cr;
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/* Search for line terminator */
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if ( ( eol = memchr ( data, '\n', len ) ) ) {
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consume = ( eol - data + 1 );
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} else {
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consume = len;
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}
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/* Reject any embedded NULs within the data to be consumed */
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if ( memchr ( data, '\0', consume ) )
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return -EINVAL;
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/* Reallocate data buffer and copy in new data */
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new_len = ( linebuf->len + consume );
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new_data = realloc ( linebuf->data, ( new_len + 1 ) );
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if ( ! new_data )
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return -ENOMEM;
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memcpy ( ( new_data + linebuf->len ), data, consume );
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new_data[new_len] = '\0';
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linebuf->data = new_data;
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linebuf->len = new_len;
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/* If we have reached end of line, terminate the line */
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if ( eol ) {
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/* Overwrite trailing LF (which must exist at this point) */
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assert ( linebuf->len > 0 );
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lf = &linebuf->data[ linebuf->len - 1 ];
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assert ( *lf == '\n' );
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*lf = '\0';
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/* Trim (and overwrite) trailing CR, if present */
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if ( linebuf->len > 1 ) {
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cr = ( lf - 1 );
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if ( *cr == '\r' ) {
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linebuf->len--;
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*cr = '\0';
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}
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}
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}
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/* Record consumed length */
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linebuf->consumed = consume;
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return consume;
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}
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