1 /* 2 * Elementary input utilities. 3 * 4 * Copyright (C) 2022 Paul Boddie <paul@boddie.org.uk> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation; either version 2 of 9 * the License, or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, 19 * Boston, MA 02110-1301, USA 20 */ 21 22 #include <string.h> 23 24 #include "input.h" 25 26 27 28 /* Read a line from a file into the given buffer. */ 29 30 char *read_line(FILE *fp, struct read_line_state *state) 31 { 32 size_t nread; 33 34 do 35 { 36 do 37 { 38 /* Search for a newline character in any available text. */ 39 40 if (state->end > state->start) 41 { 42 state->eolp = strchr(state->start, '\n'); 43 44 if (state->eolp != NULL) 45 { 46 *(state->eolp) = '\0'; 47 return state->eolp; 48 } 49 } 50 51 /* Obtain more text if necessary. */ 52 53 nread = fread(state->end, sizeof(char), state->remaining, fp); 54 55 /* Handle end of file condition. */ 56 57 if (!nread) 58 { 59 if (state->end > state->start) 60 return state->end; 61 else 62 return NULL; 63 } 64 65 /* Zero-terminate the string for searching. */ 66 67 *(state->end + nread) = '\0'; 68 69 /* Advance the end of string and subtract remaining space. */ 70 71 state->end += nread; 72 state->remaining -= nread; 73 } 74 while (state->remaining); 75 76 /* Copy the remaining text to the start of the buffer. */ 77 78 if (state->start > state->buffer) 79 { 80 strcpy(state->buffer, state->start); 81 82 state->end -= (state->start - state->buffer); 83 state->start = state->buffer; 84 state->remaining = state->buffer_size - 1 - (state->end - state->buffer); 85 } 86 } 87 while (state->remaining); 88 89 return NULL; 90 } 91 92 /* Parse the text in the given region, returning details of arguments. */ 93 94 void parse_line(char *start, char *end, int *num_args, char *args[], const int max_args) 95 { 96 *num_args = 0; 97 98 while ((start != NULL) && (start < end) && (*num_args < max_args)) 99 { 100 args[*num_args] = start; 101 (*num_args)++; 102 103 /* NOTE: Only handling spaces as delimiters. */ 104 105 start = strchr(start, ' '); 106 107 if (start != NULL) 108 { 109 *start = '\0'; 110 111 if (start < end) 112 start++; 113 } 114 } 115 } 116 117 /* vim: tabstop=4 expandtab shiftwidth=4 118 */