| paul@294 | 1 | /* |
| paul@294 | 2 | * Elementary input utilities. |
| paul@294 | 3 | * |
| paul@294 | 4 | * Copyright (C) 2022 Paul Boddie <paul@boddie.org.uk> |
| paul@294 | 5 | * |
| paul@294 | 6 | * This program is free software; you can redistribute it and/or |
| paul@294 | 7 | * modify it under the terms of the GNU General Public License as |
| paul@294 | 8 | * published by the Free Software Foundation; either version 2 of |
| paul@294 | 9 | * the License, or (at your option) any later version. |
| paul@294 | 10 | * |
| paul@294 | 11 | * This program is distributed in the hope that it will be useful, |
| paul@294 | 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| paul@294 | 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| paul@294 | 14 | * GNU General Public License for more details. |
| paul@294 | 15 | * |
| paul@294 | 16 | * You should have received a copy of the GNU General Public License |
| paul@294 | 17 | * along with this program; if not, write to the Free Software |
| paul@294 | 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| paul@294 | 19 | * Boston, MA 02110-1301, USA |
| paul@294 | 20 | */ |
| paul@294 | 21 | |
| paul@294 | 22 | #include <string.h> |
| paul@294 | 23 | |
| paul@294 | 24 | #include "input.h" |
| paul@294 | 25 | |
| paul@294 | 26 | |
| paul@294 | 27 | |
| paul@294 | 28 | /* Read a line from a file into the given buffer. */ |
| paul@294 | 29 | |
| paul@294 | 30 | char *read_line(FILE *fp, struct read_line_state *state) |
| paul@294 | 31 | { |
| paul@294 | 32 | size_t nread; |
| paul@294 | 33 | |
| paul@294 | 34 | do |
| paul@294 | 35 | { |
| paul@294 | 36 | do |
| paul@294 | 37 | { |
| paul@294 | 38 | /* Search for a newline character in any available text. */ |
| paul@294 | 39 | |
| paul@294 | 40 | if (state->end > state->start) |
| paul@294 | 41 | { |
| paul@294 | 42 | state->eolp = strchr(state->start, '\n'); |
| paul@294 | 43 | |
| paul@294 | 44 | if (state->eolp != NULL) |
| paul@294 | 45 | { |
| paul@294 | 46 | *(state->eolp) = '\0'; |
| paul@294 | 47 | return state->eolp; |
| paul@294 | 48 | } |
| paul@294 | 49 | } |
| paul@294 | 50 | |
| paul@294 | 51 | /* Obtain more text if necessary. */ |
| paul@294 | 52 | |
| paul@294 | 53 | nread = fread(state->end, sizeof(char), state->remaining, fp); |
| paul@294 | 54 | |
| paul@294 | 55 | /* Handle end of file condition. */ |
| paul@294 | 56 | |
| paul@294 | 57 | if (!nread) |
| paul@294 | 58 | { |
| paul@294 | 59 | if (state->end > state->start) |
| paul@294 | 60 | return state->end; |
| paul@294 | 61 | else |
| paul@294 | 62 | return NULL; |
| paul@294 | 63 | } |
| paul@294 | 64 | |
| paul@294 | 65 | /* Zero-terminate the string for searching. */ |
| paul@294 | 66 | |
| paul@294 | 67 | *(state->end + nread) = '\0'; |
| paul@294 | 68 | |
| paul@294 | 69 | /* Advance the end of string and subtract remaining space. */ |
| paul@294 | 70 | |
| paul@294 | 71 | state->end += nread; |
| paul@294 | 72 | state->remaining -= nread; |
| paul@294 | 73 | } |
| paul@294 | 74 | while (state->remaining); |
| paul@294 | 75 | |
| paul@294 | 76 | /* Copy the remaining text to the start of the buffer. */ |
| paul@294 | 77 | |
| paul@294 | 78 | if (state->start > state->buffer) |
| paul@294 | 79 | { |
| paul@294 | 80 | strcpy(state->buffer, state->start); |
| paul@294 | 81 | |
| paul@294 | 82 | state->end -= (state->start - state->buffer); |
| paul@294 | 83 | state->start = state->buffer; |
| paul@294 | 84 | state->remaining = state->buffer_size - 1 - (state->end - state->buffer); |
| paul@294 | 85 | } |
| paul@294 | 86 | } |
| paul@294 | 87 | while (state->remaining); |
| paul@294 | 88 | |
| paul@294 | 89 | return NULL; |
| paul@294 | 90 | } |
| paul@294 | 91 | |
| paul@294 | 92 | /* Parse the text in the given region, returning details of arguments. */ |
| paul@294 | 93 | |
| paul@294 | 94 | void parse_line(char *start, char *end, int *num_args, char *args[], const int max_args) |
| paul@294 | 95 | { |
| paul@294 | 96 | *num_args = 0; |
| paul@294 | 97 | |
| paul@294 | 98 | while ((start != NULL) && (start < end) && (*num_args < max_args)) |
| paul@294 | 99 | { |
| paul@294 | 100 | args[*num_args] = start; |
| paul@294 | 101 | (*num_args)++; |
| paul@294 | 102 | |
| paul@294 | 103 | /* NOTE: Only handling spaces as delimiters. */ |
| paul@294 | 104 | |
| paul@294 | 105 | start = strchr(start, ' '); |
| paul@294 | 106 | |
| paul@294 | 107 | if (start != NULL) |
| paul@294 | 108 | { |
| paul@294 | 109 | *start = '\0'; |
| paul@294 | 110 | |
| paul@294 | 111 | if (start < end) |
| paul@294 | 112 | start++; |
| paul@294 | 113 | } |
| paul@294 | 114 | } |
| paul@294 | 115 | } |
| paul@294 | 116 | |
| paul@294 | 117 | /* vim: tabstop=4 expandtab shiftwidth=4 |
| paul@294 | 118 | */ |
