forked from mia/Aegisub
6ca879938d
uchardet will report that a file is "ascii" if the first page has no bytes >127, so we need to actually look at the entire file in case the first higher byte is later in the file.
89 lines
2.8 KiB
C++
89 lines
2.8 KiB
C++
// Copyright (c) 2010, Amar Takhar <verm@aegisub.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.
|
|
|
|
/// @file charset.cpp
|
|
/// @brief Character set detection and manipulation utilities.
|
|
/// @ingroup libaegisub
|
|
|
|
#include "libaegisub/charset.h"
|
|
|
|
#include "libaegisub/file_mapping.h"
|
|
#include "libaegisub/scoped_ptr.h"
|
|
|
|
#ifdef WITH_UCHARDET
|
|
#include <uchardet/uchardet.h>
|
|
#endif
|
|
|
|
namespace agi { namespace charset {
|
|
std::string Detect(agi::fs::path const& file) {
|
|
agi::read_file_mapping fp(file);
|
|
|
|
// First check for known magic bytes which identify the file type
|
|
if (fp.size() >= 4) {
|
|
const char* header = fp.read(0, 4);
|
|
if (!strncmp(header, "\xef\xbb\xbf", 3))
|
|
return "utf-8";
|
|
if (!strncmp(header, "\x00\x00\xfe\xff", 4))
|
|
return "utf-32be";
|
|
if (!strncmp(header, "\xff\xfe\x00\x00", 4))
|
|
return "utf-32le";
|
|
if (!strncmp(header, "\xfe\xff", 2))
|
|
return "utf-16be";
|
|
if (!strncmp(header, "\xff\xfe", 2))
|
|
return "utf-16le";
|
|
if (!strncmp(header, "\x1a\x45\xdf\xa3", 4))
|
|
return "binary"; // Actually EBML/Matroska
|
|
}
|
|
|
|
// If it's over 100 MB it's either binary or big enough that we won't
|
|
// be able to do anything useful with it anyway
|
|
if (fp.size() > 100 * 1024 * 1024)
|
|
return "binary";
|
|
|
|
uint64_t binaryish = 0;
|
|
|
|
#ifdef WITH_UCHARDET
|
|
agi::scoped_holder<uchardet_t> ud(uchardet_new(), uchardet_delete);
|
|
for (uint64_t offset = 0; offset < fp.size(); ) {
|
|
auto read = std::min<uint64_t>(4096, fp.size() - offset);
|
|
auto buf = fp.read(offset, read);
|
|
uchardet_handle_data(ud, buf, read);
|
|
|
|
offset += read;
|
|
|
|
// A dumb heuristic to detect binary files
|
|
for (size_t i = 0; i < read; ++i) {
|
|
if ((unsigned char)buf[i] < 32 && (buf[i] != '\r' && buf[i] != '\n' && buf[i] != '\t'))
|
|
++binaryish;
|
|
}
|
|
|
|
if (binaryish > offset / 8)
|
|
return "binary";
|
|
}
|
|
uchardet_data_end(ud);
|
|
return uchardet_get_charset(ud);
|
|
#else
|
|
auto read = std::min<uint64_t>(4096, fp.size());
|
|
auto buf = fp.read(0, read);
|
|
for (size_t i = 0; i < read; ++i) {
|
|
if ((unsigned char)buf[i] < 32 && (buf[i] != '\r' && buf[i] != '\n' && buf[i] != '\t'))
|
|
++binaryish;
|
|
}
|
|
|
|
if (binaryish > read / 8)
|
|
return "binary";
|
|
return "utf-8";
|
|
#endif
|
|
}
|
|
} }
|