1 /* 2 * Copyright (C) 2007 Michael Brown <mbrown (at) fensystems.co.uk>. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License as 6 * published by the Free Software Foundation; either version 2 of the 7 * License, or any later version. 8 * 9 * This program is distributed in the hope that it will be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 17 */ 18 19 FILE_LICENCE ( GPL2_OR_LATER ); 20 21 /** 22 * @file 23 * 24 * Line buffering 25 * 26 */ 27 28 #include <stdint.h> 29 #include <string.h> 30 #include <stdlib.h> 31 #include <errno.h> 32 #include <gpxe/linebuf.h> 33 34 /** 35 * Retrieve buffered-up line 36 * 37 * @v linebuf Line buffer 38 * @ret line Buffered line, or NULL if no line ready to read 39 */ 40 char * buffered_line ( struct line_buffer *linebuf ) { 41 return ( linebuf->ready ? linebuf->data : NULL ); 42 } 43 44 /** 45 * Discard line buffer contents 46 * 47 * @v linebuf Line buffer 48 */ 49 void empty_line_buffer ( struct line_buffer *linebuf ) { 50 free ( linebuf->data ); 51 linebuf->data = NULL; 52 linebuf->len = 0; 53 linebuf->ready = 0; 54 } 55 56 /** 57 * Buffer up received data by lines 58 * 59 * @v linebuf Line buffer 60 * @v data New data to add 61 * @v len Length of new data to add 62 * @ret len Consumed length, or negative error number 63 * 64 * After calling line_buffer(), use buffered_line() to determine 65 * whether or not a complete line is available. Carriage returns and 66 * newlines will have been stripped, and the line will be 67 * NUL-terminated. This buffered line is valid only until the next 68 * call to line_buffer() (or to empty_line_buffer()). 69 * 70 * Note that line buffers use dynamically allocated storage; you 71 * should call empty_line_buffer() before freeing a @c struct @c 72 * line_buffer. 73 */ 74 ssize_t line_buffer ( struct line_buffer *linebuf, 75 const char *data, size_t len ) { 76 const char *eol; 77 size_t consume; 78 size_t new_len; 79 char *new_data; 80 81 /* Free any completed line from previous iteration */ 82 if ( linebuf->ready ) 83 empty_line_buffer ( linebuf ); 84 85 /* Search for line terminator */ 86 if ( ( eol = memchr ( data, '\n', len ) ) ) { 87 consume = ( eol - data + 1 ); 88 } else { 89 consume = len; 90 } 91 92 /* Reallocate data buffer and copy in new data */ 93 new_len = ( linebuf->len + consume ); 94 new_data = realloc ( linebuf->data, ( new_len + 1 ) ); 95 if ( ! new_data ) 96 return -ENOMEM; 97 memcpy ( ( new_data + linebuf->len ), data, consume ); 98 new_data[new_len] = '\0'; 99 linebuf->data = new_data; 100 linebuf->len = new_len; 101 102 /* If we have reached end of line, trim the line and mark as ready */ 103 if ( eol ) { 104 linebuf->data[--linebuf->len] = '\0'; /* trim NL */ 105 if ( linebuf->data[linebuf->len - 1] == '\r' ) 106 linebuf->data[--linebuf->len] = '\0'; /* trim CR */ 107 linebuf->ready = 1; 108 } 109 110 return consume; 111 } 112
