WIP: scroll(1) #127
9
Makefile
9
Makefile
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@ -32,7 +32,7 @@ RUSTLIBS = --extern getopt=build/o/libgetopt.rlib \
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CFLAGS += -I$(SYSEXITS)
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.PHONY: all
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all: dj false fop hru intcmp mm npc rpn scrut str strcmp swab true
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all: dj false fop hru intcmp mm npc rpn scroll scrut str strcmp swab true
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# keep build/include until bindgen(1) has stdin support
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# https://github.com/rust-lang/rust-bindgen/issues/2703
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@ -120,7 +120,12 @@ build/bin/mm: src/mm.rs build rustlibs
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.PHONY: npc
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npc: build/bin/npc
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build/bin/npc: src/npc.c build
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$(CC) $(CFLAGAS) -o $@ src/npc.c
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$(CC) $(CFLAGS) -o $@ src/npc.c
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.PHONY: scroll
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scroll: build/bin/scroll
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build/bin/scroll: src/scroll.c build
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$(CC) $(CFLAGS) -o $@ src/scroll.c
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.PHONY: rpn
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rpn: build/bin/rpn
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52
docs/scroll.1
Normal file
52
docs/scroll.1
Normal file
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@ -0,0 +1,52 @@
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.\" Copyright (c) 2024 DTB <trinity@trinity.moe>
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.\" Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
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.\"
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.\" This work is licensed under CC BY-SA 4.0. To see a copy of this license,
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.\" visit <http://creativecommons.org/licenses/by-sa/4.0/>.
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.\"
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.TH PG 1 2024-07-31 "Harakit X.X.X"
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.SH NAME
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scroll \(en present output
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.\"
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.SH SYNOPSIS
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scroll
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.RB ( -p
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.RB [ prompt ])
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.\"
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.SH DESCRIPTION
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Print standard input to standard output, accepting commands between pages.
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.\"
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.SH OPTIONS
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.IP -p
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Replace the default prompt (\(lq: \(rq) with the option argument.
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.\"
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.SH DIAGNOSTICS
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In the event of an error, a debug message will be printed and the program will
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exit with the appropriate
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.BR sysexits.h (3)
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error code.
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.\"
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.SH RATIONALE
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Plan 9 from Bell Labs had
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.BR p (1),
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a similar \(lqcooked\(rq-mode paginator (as opposed to \(lqraw\(rq mode, which a
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vast majority of paginators use).
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.\"
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.SH AUTHOR
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Written by DTB
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.MT trinity@trinity.moe
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.ME .
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.\"
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.SH COPYRIGHT
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Copyright \(co 2024 DTB. License AGPLv3+: GNU AGPL version 3 or later
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<https://gnu.org/licenses/agpl.html>.
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.\"
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.SH SEE ALSO
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.BR more (1p)
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288
src/scroll.c
Normal file
288
src/scroll.c
Normal file
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@ -0,0 +1,288 @@
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/*
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* Copyright (c) 2024 DTB <trinity@trinity.moe>
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*
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* This program is free software: you can redistribute it and/or modify it under
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* the terms of the GNU Affero General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see https://www.gnu.org/licenses/.
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*/
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#include <assert.h> /* assert(3) */
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#include <errno.h> /* errno */
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#include <stdbool.h> /* bool */
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#include <stdio.h> /* fclose(3), feof(3), fgetc(3), fgets(3), fopen(3),
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* fprintf(3), fputc(3), perror(3), stderr, stdin, stdout,
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* EOF, FILE, NULL */
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#include <stdlib.h> /* size_t */
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#include <string.h> /* strchr(3), strcmp(3) */
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#include <unistd.h> /* getopt(3) */
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/* Commands start with cmd_. They take an argc and NULL-terminated argv, like
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* main, and return a status from <sysexits.h>. Return values other than EX_OK
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* and EX_USAGE cause pg(1) to exit with that value, except EX_UNAVAILABLE,
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* which causes pg(1) to exit with the status EX_OK. */
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#include <sysexits.h>
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#define CMDLINE_MAX 99+1 /* Maximum length of command line. */
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static char *whitespace = " \n\r\t\v";
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//static
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struct Tube {
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char *name; // command line
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FILE *in; // process stdin
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FILE *out; // process stdoout
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size_t index; // in pipeline
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};
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static struct {
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size_t quantity;
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enum { LINES = 0, BYTES = 1 } type;
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} default_page_unit = { 22, LINES } /* Plan 9 default */;
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static char *prompt = ": ";
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static char *program_name = "pg";
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static char *
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permute_out(char *s, size_t i) {
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for (
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;
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s[i] != '\0';
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s[i] = s[i + 1], ++i
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);
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return s;
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}
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/* strtok(3p), but supports double-quotes and escapes (but only for escaping
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* quotes). Unmatched quotes in str are considered literal. The behavior of
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* strtok_quoted when '\'', '"', or '\\' are in sep is undefined. Use of UTF-8
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* separators with strtok_quoted is undefined. */
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static char *
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strtok_quoted(char *str, char *sep) {
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static char *s;
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if (str != NULL) { s = str; }
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while (strchr(sep, *s) != NULL) { // skip beginning whitespace
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if(*++s == '\0') { return NULL; } // no remaining except seps
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}
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{
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bool in_escape = 0; // previous char was '\\'
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char quote = '\0'; // quotation mark used, or '\0' if none
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for (int i = 0; s[i] != '\0'; ++i)
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switch (s[i]) {
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case '\\':
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// if literal "\\", permute out a backslash
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if (in_escape) { (void)permute_out(s, i--); }
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in_escape = !in_escape;
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break;
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case '\'': case '"':
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if (in_escape) { // \"
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s[i] = s[i - 1];
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(void)permute_out(s, i--); // permute out backslash
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} else if (s[i] == quote) {
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quote = '\0';
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(void)permute_out(s, i--); // second quote
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} else {
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quote = s[i];
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if (strchr(&s[i + 1], quote) != NULL) { // has a match
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(void)permute_out(s, i--); // permute out lquote
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}
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}
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break;
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case '\0': return s;
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default:
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if (!in_escape
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&& quote == '\0'
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&& (strchr(sep, s[i]) != NULL || s[i] == '\0')) {
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char *t; // start of current token
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t = s;
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s = s[i] != '\0'
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? &t[i + 1] // store start of next token,
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: &t[i]; // or the address of the nul if found
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s[i] = '\0'; // NUL terminate current token
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return t;
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}
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}
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}
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return s;
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}
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/* Page at most l bytes from f without consideration of a buffer (print them to
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* stdout). */
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static int
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pg_b_u(FILE *f, size_t l) {
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int c;
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while ((c = fgetc(f)) != EOF) {
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if ((c = fputc(c, stdout)) == EOF || --l == 0) { break; }
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}
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return c;
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}
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/* Page at most l lines, which are lengths of characters terminated by nl, from
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* f without consideration of a buffer (print them to stdout). */
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static int
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pg_l_u(FILE *f, size_t l, char nl) {
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int c;
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while ((c = fgetc(f)) != EOF) {
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if ((c = fputc(c, stdout)) == EOF || (l -= (c == nl)) == 0) { break; }
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}
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return c;
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}
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static int
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cmd_quit(int argc, char **argv, char **envp) { return EX_UNAVAILABLE; }
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static int
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cmd_default_page(int argc, char **argv, char **envp) {
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if (argc > 1) { return EX_USAGE; } // should be impossible
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else if (default_page_unit.type == BYTES) {
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return pg_b_u(stdin, default_page_unit.quantity) == EOF
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? EX_UNAVAILABLE
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: EX_OK;
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} else if (default_page_unit.type == LINES) {
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return pg_l_u(stdin, default_page_unit.quantity, '\n') == EOF
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? EX_UNAVAILABLE
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: EX_OK;
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} else { return EX_SOFTWARE; }
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}
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static int
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cmd_page_down_lines(int argc, char **argv, char **envp) {
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switch (argc) {
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case 1: return cmd_default_page(argc, argv, envp);
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case 2: /* not implemented */
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default:
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(void)fprintf(stderr, "Usage: %s" /*" (lines)"*/ "\n", argv[0]);
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return EX_USAGE;
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}
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}
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/* A CmdMap must be NULL-terminated. */
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static struct CmdMap{ char *name; int (*fn)(int, char **, char **); }
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builtins[] = {
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/* don't make the user feel trapped */
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{ ":q", cmd_quit }, { ":q!", cmd_quit },
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{ "exit", cmd_quit }, { "q", cmd_quit }, { "Q", cmd_quit },
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{ "quit", cmd_quit }, { "ZZ", cmd_quit },
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{ NULL, NULL }
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};
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#define ARGV_MAX 10
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/* Find and execute the command in the command map, given a corresponding
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* command line. */
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static int
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cmdline_exec(struct CmdMap *map, char *cmdline, char **envp) {
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static int argc;
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static char *argv[ARGV_MAX];
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if ((argv[(argc = 0)] = strtok_quoted(cmdline, whitespace)) == NULL) {
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while (cmdline[0] != '\0') { cmdline = &cmdline[1]; }
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argv[argc] = cmdline;
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argv[++argc] = NULL;
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} else {
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while (
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(argv[++argc] = strtok_quoted(NULL, whitespace)) != NULL
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&& argc < ARGV_MAX
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);
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}
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for (; map->name != NULL; map = &map[1]) {
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if(strcmp(map->name, argv[0]) == 0) {
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return map->fn(argc, argv, envp);
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}
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}
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(void)fprintf(stderr, "%s: %s: not found\n", program_name, argv[0]);
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return EX_USAGE;
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}
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static int
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ioerr(char *argv0) {
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perror(argv0);
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return EX_IOERR;
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}
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static int
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usage(char *argv0) {
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(void)fprintf(stderr, "Usage: %s [-p prompt]\n", argv0);
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return EX_USAGE;
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}
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int main(int argc, char *argv[]) {
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unsigned char cmd[CMDLINE_MAX];
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FILE *t;
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if (argc > 0) {
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int c;
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program_name = argv[0];
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while ((c = getopt(argc, argv, "p:")) != -1) {
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switch (c) {
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case 'p': prompt = optarg; break;
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default: return usage(program_name);
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}
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}
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}
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if (argc > optind) { return usage(program_name); }
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if ((t = fopen("/dev/tty", "rb")) == NULL) {
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perror(program_name);
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return EX_OSERR;
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}
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for (;;) {
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if (fputs(prompt, stderr) == EOF) { return ioerr(program_name); }
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// if the line...
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if (fgets((char *)cmd, (sizeof cmd) / (sizeof *cmd), t) != NULL) {
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if (strchr((char *)cmd, '\n') == NULL) { // was taken incompletely
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int c;
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while ((c = fgetc(t)) != '\n') { // ...fast-forward stream
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if (c == EOF) { break; }
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}
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}
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} else { fputc('\n', stdout); } // EOF at start of line; finish prompt
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if (feof(t)) { return EX_OK; }
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{
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int r;
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switch ((r = cmdline_exec(builtins, (char *)cmd, NULL))){
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case EX_OK: case EX_USAGE: break;
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case EX_UNAVAILABLE: return EX_OK;
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default: return r;
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}
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}
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}
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/* UNREACHABLE */ assert(0);
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}
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Reference in New Issue
Block a user