// Copyright (C) 2023-2024 Artifex Software, Inc. // // This file is part of MuPDF. // // MuPDF is free software: you can redistribute it and/or modify it under the // terms of the GNU Affero General Public License as published by the Free // Software Foundation, either version 3 of the License, or (at your option) // any later version. // // MuPDF is distributed in the hope that it will be useful, but WITHOUT ANY // WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS // FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more // details. // // You should have received a copy of the GNU Affero General Public License // along with MuPDF. If not, see // // Alternative licensing terms are available from the licensor. // For commercial licensing, see or contact // Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco, // CA 94129, USA, for further information. #include "mupdf/fitz.h" #include "mupdf/html.h" enum { ENCODING_ASCII, ENCODING_UTF8, ENCODING_UTF8_BOM, ENCODING_UTF16_LE, ENCODING_UTF16_BE }; static int detect_txt_encoding(fz_context *ctx, fz_buffer *buf) { const uint8_t *d = buf->data; size_t len = buf->len; const uint8_t *end = buf->data + len; int count_tabs = 0; int count_hi = 0; int count_controls = 0; int plausibly_utf8 = 1; /* If we find a BOM, believe it. */ if (len >= 3 && d[0] == 0xef && d[1] == 0xbb && d[2] == 0xBF) return ENCODING_UTF8_BOM; else if (len >= 2 && d[0] == 0xff && d[1] == 0xfe) return ENCODING_UTF16_LE; else if (len >= 2 && d[0] == 0xfe && d[1] == 0xff) return ENCODING_UTF16_BE; while (d < end) { uint8_t c = *d++; if (c == 9) count_tabs++; else if (c == 12) { /* Form feed. Ignore that. */ } else if (c == 10) { if (d < end && d[0] == 13) d++; } else if (c == 13) { if (d < end && d[0] == 10) d++; } else if (c < 32 || c == 0x7f) count_controls++; else if (c < 0x7f) { /* Reasonable ASCII value */ } else { count_hi++; if ((c & 0xf8) == 0xF0) { /* Could be UTF8 with 3 following bytes */ if (d+2 >= end || (d[0] & 0xC0) != 0x80 || (d[1] & 0xC0) != 0x80 || (d[2] & 0xC0) != 0x80) plausibly_utf8 = 0; else d += 3; } else if ((c & 0xf0) == 0xE0) { /* Could be UTF8 with 2 following bytes */ if (d+1 >= end || (d[0] & 0xC0) != 0x80 || (d[1] & 0xC0) != 0x80) plausibly_utf8 = 0; else d += 2; } else if ((c & 0xE0) == 0xC0) { /* Could be UTF8 with 1 following bytes */ if (d+1 >= end || (d[0] & 0xC0) != 0x80) plausibly_utf8 = 0; else d++; } else plausibly_utf8 = 0; } } (void)count_tabs; (void)count_hi; (void)count_controls; if (plausibly_utf8) return ENCODING_UTF8; return ENCODING_ASCII; } fz_buffer * fz_txt_buffer_to_html(fz_context *ctx, fz_buffer *in) { int encoding = detect_txt_encoding(ctx, in); fz_stream *stream = fz_open_buffer(ctx, in); fz_buffer *outbuf = NULL; fz_output *out = NULL; int col = 0; fz_var(outbuf); fz_var(out); fz_try(ctx) { outbuf = fz_new_buffer(ctx, 1024); out = fz_new_output_with_buffer(ctx, outbuf); fz_write_string(ctx, out, "

");

		if (encoding == ENCODING_UTF16_LE || encoding == ENCODING_UTF16_BE)
		{
			fz_read_byte(ctx, stream);
			fz_read_byte(ctx, stream);
		}
		else if (encoding == ENCODING_UTF8_BOM)
		{
			fz_read_byte(ctx, stream);
			fz_read_byte(ctx, stream);
			fz_read_byte(ctx, stream);
		}

		while (!fz_is_eof(ctx, stream))
		{
			int c;
			switch (encoding)
			{
			default:
			case ENCODING_ASCII:
				c = fz_read_byte(ctx, stream);
				break;
			case ENCODING_UTF8:
			case ENCODING_UTF8_BOM:
				c = fz_read_rune(ctx, stream);
				break;
			case ENCODING_UTF16_LE:
				c = fz_read_utf16_le(ctx, stream);
				break;
			case ENCODING_UTF16_BE:
				c = fz_read_utf16_be(ctx, stream);
			}

			if (c == 10 || c == 13)
			{
				col = -1;
				fz_write_byte(ctx, out, c);
			}
			else if (c == 9)
			{
				int n = (8 - col) & 7;
				if (n == 0)
					n = 8;
				col += n-1;
				while (n--)
					fz_write_byte(ctx, out, ' ');
			}
			else if (c == 12)
			{
				col = -1;
				fz_write_string(ctx, out, "

\n");
			}
			else if (c == '<')
				fz_write_string(ctx, out, "<");
			else if (c == '>')
				fz_write_string(ctx, out, ">");
			else if (c == '"')
				fz_write_string(ctx, out, """);
			else
				fz_write_rune(ctx, out, c);

			++col;
		}

		fz_close_output(ctx, out);
	}
	fz_always(ctx)
	{
		fz_drop_stream(ctx, stream);
		fz_drop_output(ctx, out);
	}
	fz_catch(ctx)
	{
		fz_drop_buffer(ctx, outbuf);
		fz_rethrow(ctx);
	}

	return outbuf;
}

static fz_buffer *
txt_to_html(fz_context *ctx, fz_html_font_set *set, fz_buffer *buf, fz_archive *zip, const char *user_css)
{
	return fz_txt_buffer_to_html(ctx, buf);
}

static const fz_htdoc_format_t fz_htdoc_txt =
{
	"Text",
	txt_to_html,
	0, 1, 0
};

static fz_document *
txt_open_document(fz_context *ctx, const fz_document_handler *handler, fz_stream *file, fz_stream *accel, fz_archive *zip, void *state)
{
	return fz_htdoc_open_document_with_stream_and_dir(ctx, file, zip, &fz_htdoc_txt);
}

static const char *txt_extensions[] =
{
	"txt",
	"text",
	"log",
	NULL
};

static const char *txt_mimetypes[] =
{
	"text.plain",
	NULL
};

fz_document_handler txt_document_handler =
{
	NULL,
	txt_open_document,
	txt_extensions,
	txt_mimetypes
};