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// Copyright (C) 2004-2022 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 <https://www.gnu.org/licenses/agpl-3.0.en.html>
//
// Alternative licensing terms are available from the licensor.
// For commercial licensing, see <https://www.artifex.com/> or contact
// Artifex Software, Inc., 1305 Grant Avenue - Suite 200, Novato,
// CA 94945, U.S.A., +1(415)492-9861, for further information.
#include "mupdf/fitz.h"
#include "html-imp.h"
#include <string.h>
#define FORMAT_HTML 1
#define FORMAT_TEXT 2
#define COMPRESSION_NONE 1
#define COMPRESSION_PALMDOC 2
#define COMPRESSION_HUFF_CDIC 17480
#define TEXT_ENCODING_LATIN_1 0
#define TEXT_ENCODING_1252 1252
#define TEXT_ENCODING_UTF8 65001
static void
mobi_read_text_none(fz_context *ctx, fz_buffer *out, fz_stream *stm, uint32_t size)
{
unsigned char buf[4096];
if (size > 4096)
fz_throw(ctx, FZ_ERROR_GENERIC, "text block too large");
fz_read(ctx, stm, buf, size);
fz_append_data(ctx, out, buf, size);
}
static void
mobi_read_text_palmdoc(fz_context *ctx, fz_buffer *out, fz_stream *stm, uint32_t size)
{
// https://wiki.mobileread.com/wiki/PalmDOC
uint32_t end = out->len + size;
while (out->len < end)
{
int c = fz_read_byte(ctx, stm);
if (c == EOF)
break;
if (c >= 0x01 && c <= 0x08)
{
unsigned char buf[8];
fz_read(ctx, stm, buf, c);
fz_append_data(ctx, out, buf, c);
}
else if (c <= 0x7f)
{
fz_append_byte(ctx, out, c);
}
else if (c >= 0x80 && c <= 0xbf)
{
int x = (c << 8) | fz_read_byte(ctx, stm);
int distance = (x >> 3) & 0x7ff;
int length = (x & 7) + 3;
int p = out->len - distance;
if (p >= 0 && p < (int)out->len)
{
int i;
for (i = 0; i < length; ++i)
fz_append_byte(ctx, out, out->data[p + i]);
}
}
else if (c >= 0xc0 && c <= 0xff)
{
fz_append_byte(ctx, out, ' ');
fz_append_byte(ctx, out, c ^ 0x80);
}
}
}
static uint32_t
mobi_read_data(fz_context *ctx, fz_buffer *out, fz_stream *stm, uint32_t *offset, uint32_t total_count, int format)
{
// https://wiki.mobileread.com/wiki/MOBI
uint32_t compression, text_length, record_count, text_encoding;
uint32_t i;
unsigned char buf[4];
fz_seek(ctx, stm, offset[0], 0);
// PalmDOC header
compression = fz_read_uint16(ctx, stm);
fz_skip(ctx, stm, 2);
text_length = fz_read_uint32(ctx, stm);
record_count = fz_read_uint16(ctx, stm);
fz_skip(ctx, stm, 2);
fz_skip(ctx, stm, 2); // encryption
fz_skip(ctx, stm, 2);
// Optional MOBI header
fz_read(ctx, stm, buf, 4);
if (!memcmp(buf, "MOBI", 4))
{
fz_skip(ctx, stm, 8);
text_encoding = fz_read_uint32(ctx, stm);
}
else
{
text_encoding = TEXT_ENCODING_LATIN_1;
}
if (compression != COMPRESSION_NONE && compression != COMPRESSION_PALMDOC)
fz_throw(ctx, FZ_ERROR_GENERIC, "unknown compression method");
if (text_encoding != TEXT_ENCODING_LATIN_1 &&
text_encoding != TEXT_ENCODING_1252 &&
text_encoding != TEXT_ENCODING_UTF8)
fz_throw(ctx, FZ_ERROR_GENERIC, "unknown text encoding");
for (i = 1; i <= record_count && i < total_count; ++i)
{
uint32_t remain = text_length - out->len;
uint32_t size = remain < 4096 ? remain : 4096;
fz_seek(ctx, stm, offset[i], 0);
if (compression == COMPRESSION_NONE)
mobi_read_text_none(ctx, out, stm, size);
else
mobi_read_text_palmdoc(ctx, out, stm, size);
}
if (format == FORMAT_TEXT && out->len > 6)
{
if (!memcmp(out->data, "<html>", 6) || !memcmp(out->data, "<HTML>", 6))
format = FORMAT_HTML;
}
if (text_encoding != TEXT_ENCODING_UTF8 || format == FORMAT_TEXT)
{
unsigned char *p;
int i, n = fz_buffer_extract(ctx, out, &p);
fz_resize_buffer(ctx, out, 0);
if (format == FORMAT_TEXT)
fz_append_string(ctx, out, "<html><head><style>body{white-space:pre-wrap}</style></head><body>");
for (i = 0; i < n; ++i)
{
int c = p[i];
if (format == FORMAT_TEXT && (c == '<' || c == '>' || c == '&'))
{
if (c == '<')
fz_append_string(ctx, out, "<");
else if (c == '>')
fz_append_string(ctx, out, ">");
else if (c == '&')
fz_append_string(ctx, out, "&");
}
else
{
switch (text_encoding)
{
case TEXT_ENCODING_UTF8:
fz_append_byte(ctx, out, c);
break;
case TEXT_ENCODING_LATIN_1:
fz_append_rune(ctx, out, c);
break;
case TEXT_ENCODING_1252:
fz_append_rune(ctx, out, fz_unicode_from_windows_1252[c]);
break;
}
}
}
if (format == FORMAT_TEXT)
fz_append_string(ctx, out, "</body></html>");
fz_free(ctx, p);
}
return record_count;
}
static void drop_tree_entry(fz_context *ctx, void *ent)
{
fz_drop_buffer(ctx, ent);
}
fz_archive *
fz_extract_html_from_mobi(fz_context *ctx, fz_buffer *mobi)
{
fz_stream *stm = NULL;
fz_buffer *buffer = NULL;
fz_tree *tree = NULL;
uint32_t *offset = NULL;
char buf[32];
uint32_t i, n, extra;
uint32_t recindex;
int format = FORMAT_TEXT;
// https://wiki.mobileread.com/wiki/PalmDOC
fz_var(stm);
fz_var(buffer);
fz_var(offset);
fz_var(tree);
fz_try(ctx)
{
stm = fz_open_buffer(ctx, mobi);
fz_skip(ctx, stm, 32); // database name
fz_skip(ctx, stm, 28); // database attributes, version, dates, etc
fz_read(ctx, stm, (unsigned char *)buf, 8); // database type and creator
buf[8] = 0;
if (!memcmp(buf, "BOOKMOBI", 8))
format = FORMAT_HTML;
else if (!memcmp(buf, "TEXtREAd", 8))
format = FORMAT_TEXT;
else
fz_warn(ctx, "Unknown MOBI/PRC format: %s.", buf);
fz_skip(ctx, stm, 8); // database internal fields
// record info list
n = fz_read_uint16(ctx, stm);
offset = fz_malloc_array(ctx, n + 1, uint32_t);
for (i = 0; i < n; ++i)
{
offset[i] = fz_read_uint32(ctx, stm);
fz_skip(ctx, stm, 4);
}
offset[n] = mobi->len;
// decompress text data
buffer = fz_new_buffer(ctx, 128 << 10);
extra = mobi_read_data(ctx, buffer, stm, offset, n, format);
fz_terminate_buffer(ctx, buffer);
#ifndef NDEBUG
if (fz_atoi(getenv("FZ_DEBUG_MOBI")))
fz_save_buffer(ctx, buffer, "mobi.xhtml");
#endif
tree = fz_tree_insert(ctx, tree, "index.html", buffer);
buffer = NULL;
// copy image data records into tree
recindex = 1;
for (i = extra; i < n; ++i)
{
uint32_t size = offset[i+1] - offset[i];
if (size > 8)
{
unsigned char *data = mobi->data + offset[i];
if (fz_recognize_image_format(ctx, data))
{
buffer = fz_new_buffer_from_copied_data(ctx, data, size);
fz_snprintf(buf, sizeof buf, "%05d", recindex);
tree = fz_tree_insert(ctx, tree, buf, buffer);
buffer = NULL;
recindex++;
}
}
}
}
fz_always(ctx)
{
fz_drop_stream(ctx, stm);
fz_free(ctx, offset);
}
fz_catch(ctx)
{
fz_drop_buffer(ctx, buffer);
fz_drop_tree(ctx, tree, drop_tree_entry);
fz_rethrow(ctx);
}
return fz_new_tree_archive(ctx, tree);
}
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