cmd/mandoc/preconv.c

/*  $Id: preconv.c,v 1.15 2015/10/06 18:32:19 schwarze Exp $ */
/*
 * Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2014 Ingo Schwarze <schwarze@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include "config.h"

#include <sys/types.h>

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include "mandoc.h"
#include "libmandoc.h"

int
preconv_encode(struct buf *ib, size_t *ii, struct buf *ob, size_t *oi,
    int *filenc)
{
    unsigned char   *cu;
    int      nby;
    unsigned int     accum;

    cu = (unsigned char *)ib->buf + *ii;
    assert(*cu & 0x80);

    if ( ! (*filenc & MPARSE_UTF8))
        goto latin;

    nby = 1;
    while (nby < 5 && *cu & (1 << (7 - nby)))
        nby++;

    switch (nby) {
    case 2:
        accum = *cu & 0x1f;
        if (accum < 0x02)  /* Obfuscated ASCII. */
            goto latin;
        break;
    case 3:
        accum = *cu & 0x0f;
        break;
    case 4:
        accum = *cu & 0x07;
        if (accum > 0x04) /* Beyond Unicode. */
            goto latin;
        break;
    default:  /* Bad sequence header. */
        goto latin;
    }

    cu++;
    switch (nby) {
    case 3:
        if ((accum == 0x00 && ! (*cu & 0x20)) ||  /* Use 2-byte. */
            (accum == 0x0d && *cu & 0x20))  /* Surrogates. */
            goto latin;
        break;
    case 4:
        if ((accum == 0x00 && ! (*cu & 0x30)) ||  /* Use 3-byte. */
            (accum == 0x04 && *cu & 0x30))  /* Beyond Unicode. */
            goto latin;
        break;
    default:
        break;
    }

    while (--nby) {
        if ((*cu & 0xc0) != 0x80)  /* Invalid continuation. */
            goto latin;
        accum <<= 6;
        accum += *cu & 0x3f;
        cu++;
    }

    assert(accum > 0x7f);
    assert(accum < 0x110000);
    assert(accum < 0xd800 || accum > 0xdfff);

    *oi += snprintf(ob->buf + *oi, 11, "\\[u%.4X]", accum);
    *ii = (char *)cu - ib->buf;
    *filenc &= ~MPARSE_LATIN1;
    return 1;

latin:
    if ( ! (*filenc & MPARSE_LATIN1))
        return 0;

    *oi += snprintf(ob->buf + *oi, 11,
        "\\[u%.4X]", (unsigned char)ib->buf[(*ii)++]);

    *filenc &= ~MPARSE_UTF8;
    return 1;
}

int
preconv_cue(const struct buf *b, size_t offset)
{
    const char  *ln, *eoln, *eoph;
    size_t       sz, phsz;

    ln = b->buf + offset;
    sz = b->sz - offset;

    /* Look for the end-of-line. */

    if (NULL == (eoln = memchr(ln, '\n', sz)))
        eoln = ln + sz;

    /* Check if we have the correct header/trailer. */

    if ((sz = (size_t)(eoln - ln)) < 10 ||
        memcmp(ln, ".\\\" -*-", 7) || memcmp(eoln - 3, "-*-", 3))
        return MPARSE_UTF8 | MPARSE_LATIN1;

    /* Move after the header and adjust for the trailer. */

    ln += 7;
    sz -= 10;

    while (sz > 0) {
        while (sz > 0 && ' ' == *ln) {
            ln++;
            sz--;
        }
        if (0 == sz)
            break;

        /* Find the end-of-phrase marker (or eoln). */

        if (NULL == (eoph = memchr(ln, ';', sz)))
            eoph = eoln - 3;
        else
            eoph++;

        /* Only account for the "coding" phrase. */

        if ((phsz = eoph - ln) < 7 ||
            strncasecmp(ln, "coding:", 7)) {
            sz -= phsz;
            ln += phsz;
            continue;
        }

        sz -= 7;
        ln += 7;

        while (sz > 0 && ' ' == *ln) {
            ln++;
            sz--;
        }
        if (0 == sz)
            return 0;

        /* Check us against known encodings. */

        if (phsz > 4 && !strncasecmp(ln, "utf-8", 5))
            return MPARSE_UTF8;
        if (phsz > 10 && !strncasecmp(ln, "iso-latin-1", 11))
            return MPARSE_LATIN1;
        return 0;
    }
    return MPARSE_UTF8 | MPARSE_LATIN1;
}