/* io.c: This file contains the i/o routines for the ed line editor */
/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1993 Andrew Moore, Talke Studio.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include "ed.h"

/* read_file: read a named file/pipe into the buffer; return line count */
long
read_file(char *fn, long n)
{
        FILE *fp;
        long size;
        int cs;

        fp = (*fn == '!') ? popen(fn + 1, "r") : fopen(strip_escapes(fn), "r");
        if (fp == NULL) {
                fprintf(stderr, "%s: %s\n", fn, strerror(errno));
                errmsg = "cannot open input file";
                return ERR;
        }
        if ((size = read_stream(fp, n)) < 0) {
                fprintf(stderr, "%s: %s\n", fn, strerror(errno));
                errmsg = "error reading input file";
        }
        if ((cs = (*fn == '!') ?  pclose(fp) : fclose(fp)) < 0) {
                fprintf(stderr, "%s: %s\n", fn, strerror(errno));
                errmsg = "cannot close input file";
        }
        if (size < 0 || cs < 0)
                return ERR;
        if (!scripted)
                fprintf(stdout, "%lu\n", size);
        return current_addr - n;
}

static char *sbuf;              /* file i/o buffer */
static int sbufsz;              /* file i/o buffer size */
int newline_added;              /* if set, newline appended to input file */

/* read_stream: read a stream into the editor buffer; return status */
long
read_stream(FILE *fp, long n)
{
        line_t *lp = get_addressed_line_node(n);
        undo_t *up = NULL;
        unsigned long size = 0;
        int o_newline_added = newline_added;
        int o_isbinary = isbinary;
        int appended = (n == addr_last);
        int len;

        isbinary = newline_added = 0;
        for (current_addr = n; (len = get_stream_line(fp)) > 0; size += len) {
                SPL1();
                if (put_sbuf_line(sbuf) == NULL) {
                        SPL0();
                        return ERR;
                }
                lp = lp->q_forw;
                if (up)
                        up->t = lp;
                else if ((up = push_undo_stack(UADD, current_addr,
                    current_addr)) == NULL) {
                        SPL0();
                        return ERR;
                }
                SPL0();
        }
        if (len < 0)
                return ERR;
        if (appended && size && o_isbinary && o_newline_added)
                fputs("newline inserted\n", stderr);
        else if (newline_added && (!appended || (!isbinary && !o_isbinary)))
                fputs("newline appended\n", stderr);
        if (isbinary && newline_added && !appended)
                size += 1;
        if (!size)
                newline_added = 1;
        newline_added = appended ? newline_added : o_newline_added;
        isbinary = isbinary | o_isbinary;
        return size;
}


/* get_stream_line: read a line of text from a stream; return line length */
int
get_stream_line(FILE *fp)
{
        int c;
        int i = 0;

        while (((c = getc(fp)) != EOF || (!feof(fp) && !ferror(fp))) &&
            c != '\n') {
                REALLOC(sbuf, sbufsz, i + 1, ERR);
                if (!(sbuf[i++] = c))
                        isbinary = 1;
        }
        REALLOC(sbuf, sbufsz, i + 2, ERR);
        if (c == '\n')
                sbuf[i++] = c;
        else if (ferror(fp)) {
                fprintf(stderr, "%s\n", strerror(errno));
                errmsg = "cannot read input file";
                return ERR;
        } else if (i) {
                sbuf[i++] = '\n';
                newline_added = 1;
        }
        sbuf[i] = '\0';
        return (isbinary && newline_added && i) ? --i : i;
}


/* write_file: write a range of lines to a named file/pipe; return line count */
long
write_file(char *fn, const char *mode, long n, long m)
{
        FILE *fp;
        long size;
        int cs;

        fp = (*fn == '!') ? popen(fn+1, "w") : fopen(strip_escapes(fn), mode);
        if (fp == NULL) {
                fprintf(stderr, "%s: %s\n", fn, strerror(errno));
                errmsg = "cannot open output file";
                return ERR;
        }
        if ((size = write_stream(fp, n, m)) < 0) {
                fprintf(stderr, "%s: %s\n", fn, strerror(errno));
                errmsg = "error writing output file";
        }
        if ((cs = (*fn == '!') ?  pclose(fp) : fclose(fp)) < 0) {
                fprintf(stderr, "%s: %s\n", fn, strerror(errno));
                errmsg = "cannot close output file";
        }
        if (size < 0 || cs < 0)
                return ERR;
        if (!scripted)
                fprintf(stdout, "%lu\n", size);
        return n ? m - n + 1 : 0;
}


/* write_stream: write a range of lines to a stream; return status */
long
write_stream(FILE *fp, long n, long m)
{
        line_t *lp = get_addressed_line_node(n);
        unsigned long size = 0;
        char *s;
        int len;

        for (; n && n <= m; n++, lp = lp->q_forw) {
                if ((s = get_sbuf_line(lp)) == NULL)
                        return ERR;
                len = lp->len;
                if (n != addr_last || !isbinary || !newline_added)
                        s[len++] = '\n';
                if (put_stream_line(fp, s, len) < 0)
                        return ERR;
                size += len;
        }
        return size;
}


/* put_stream_line: write a line of text to a stream; return status */
int
put_stream_line(FILE *fp, const char *s, int len)
{
        while (len--)
                if (fputc(*s++, fp) < 0) {
                        fprintf(stderr, "%s\n", strerror(errno));
                        errmsg = "cannot write file";
                        return ERR;
                }
        return 0;
}

/* get_extended_line: get an extended line from stdin */
char *
get_extended_line(int *sizep, int nonl)
{
        static char *cvbuf = NULL;              /* buffer */
        static int cvbufsz = 0;                 /* buffer size */

        int l, n;
        char *t = ibufp;

        while (*t++ != '\n')
                ;
        if ((l = t - ibufp) < 2 || !has_trailing_escape(ibufp, ibufp + l - 1)) {
                *sizep = l;
                return ibufp;
        }
        *sizep = -1;
        REALLOC(cvbuf, cvbufsz, l, NULL);
        memcpy(cvbuf, ibufp, l);
        *(cvbuf + --l - 1) = '\n';      /* strip trailing esc */
        if (nonl) l--;                  /* strip newline */
        for (;;) {
                if ((n = get_tty_line()) < 0)
                        return NULL;
                else if (n == 0 || ibuf[n - 1] != '\n') {
                        errmsg = "unexpected end-of-file";
                        return NULL;
                }
                REALLOC(cvbuf, cvbufsz, l + n, NULL);
                memcpy(cvbuf + l, ibuf, n);
                l += n;
                if (n < 2 || !has_trailing_escape(cvbuf, cvbuf + l - 1))
                        break;
                *(cvbuf + --l - 1) = '\n';      /* strip trailing esc */
                if (nonl) l--;                  /* strip newline */
        }
        REALLOC(cvbuf, cvbufsz, l + 1, NULL);
        cvbuf[l] = '\0';
        *sizep = l;
        return cvbuf;
}


/* get_tty_line: read a line of text from stdin; return line length */
int
get_tty_line(void)
{
        int oi = 0;
        int i = 0;
        int c;

        for (;;)
                switch (c = getchar()) {
                default:
                        oi = 0;
                        REALLOC(ibuf, ibufsz, i + 2, ERR);
                        if (!(ibuf[i++] = c)) isbinary = 1;
                        if (c != '\n')
                                continue;
                        lineno++;
                        ibuf[i] = '\0';
                        ibufp = ibuf;
                        return i;
                case EOF:
                        if (ferror(stdin)) {
                                fprintf(stderr, "stdin: %s\n", strerror(errno));
                                errmsg = "cannot read stdin";
                                clearerr(stdin);
                                ibufp = NULL;
                                return ERR;
                        } else {
                                clearerr(stdin);
                                if (i != oi) {
                                        oi = i;
                                        continue;
                                } else if (i)
                                        ibuf[i] = '\0';
                                ibufp = ibuf;
                                return i;
                        }
                }
}



#define ESCAPES "\a\b\f\n\r\t\v\\"
#define ESCCHARS "abfnrtv\\"

/* put_tty_line: print text to stdout */
int
put_tty_line(const char *s, int l, long n, int gflag)
{
        int col = 0;
        int lc = 0;
        char *cp;
        wchar_t wc;
        mbstate_t mbs;
        size_t clen;
        int w;

        if (gflag & GNP) {
                printf("%ld\t", n);
                col = 8;
        }
        for (; l > 0;) {
                if (!(gflag & GLS)) {
                        putchar(*s++);
                        l--;
                        continue;
                }
                /* GLS mode: try to decode a multibyte character */
                memset(&mbs, 0, sizeof(mbs));
                clen = mbrtowc(&wc, s, l, &mbs);
                if (clen != (size_t)-1 && clen != (size_t)-2 &&
                    clen > 1 && iswprint(wc) && (w = wcwidth(wc)) >= 0) {
                        /* printable multibyte character */
                        if (col + w > cols) {
                                fputs("\\\n", stdout);
                                col = 0;
#ifndef BACKWARDS
                                if (!scripted && !isglobal && ++lc > rows) {
                                        lc = 0;
                                        fputs("Press <RETURN> to continue... ",
                                            stdout);
                                        fflush(stdout);
                                        if (get_tty_line() < 0)
                                                return ERR;
                                }
#endif
                        }
                        col += w;
                        fwrite(s, 1, clen, stdout);
                        s += clen;
                        l -= clen;
                        continue;
                }
                /* single byte: ASCII printable, escape sequence, or octal */
                if (++col > cols) {
                        fputs("\\\n", stdout);
                        col = 1;
#ifndef BACKWARDS
                        if (!scripted && !isglobal && ++lc > rows) {
                                lc = 0;
                                fputs("Press <RETURN> to continue... ", stdout);
                                fflush(stdout);
                                if (get_tty_line() < 0)
                                        return ERR;
                        }
#endif
                }
                if (31 < *s && *s < 127 && *s != '\\')
                        putchar(*s);
                else {
                        putchar('\\');
                        col++;
                        if (*s && (cp = strchr(ESCAPES, *s)) != NULL)
                                putchar(ESCCHARS[cp - ESCAPES]);
                        else {
                                putchar((((unsigned char) *s & 0300) >> 6) + '0');
                                putchar((((unsigned char) *s & 070) >> 3) + '0');
                                putchar(((unsigned char) *s & 07) + '0');
                                col += 2;
                        }
                }
                s++;
                l--;
        }
#ifndef BACKWARDS
        if (gflag & GLS)
                putchar('$');
#endif
        putchar('\n');
        return 0;
}