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Aegisub
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Rewrite encoding detection 

Now feeds all data to uchardet, when uchardet is available. The file
size limit is removed.

When uchardet is not available, we look for UTF-8 BOM.
This should make loading UTF-8-BOM files faster.
Because Aegisub always save file in UTF-8-BOM, this should also
guarentee Aegisub will load large (>100MB) file saved by itself.

See Aegisub/Aegisub#110
This commit is contained in:
wangqr 2019-05-18 20:10:32 -04:00
parent 4c6d370d51
commit f733297499
1 changed files with 21 additions and 25 deletions
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46
libaegisub/common/charset.cpp
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@ -29,37 +29,33 @@ namespace agi { namespace charset {
std::string Detect(agi::fs::path const& file) {
agi::read_file_mapping fp(file);
#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>(65536, fp.size() - offset);
auto buf = fp.read(offset, read);
uchardet_handle_data(ud, buf, read);
offset += read;
}
uchardet_data_end(ud);
std::string encoding = uchardet_get_charset(ud);
return encoding.empty() ? "binary" : encoding;
#else
// Look for utf-8 BOM
if (fp.size() >= 3) {
const char* buf = fp.read(0, 3);
if (!strncmp(buf, "\xef\xbb\xbf", 3))
return "utf-8";
}
// 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);
uchardet_data_end(ud);
if (*uchardet_get_charset(ud))
return uchardet_get_charset(ud);
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";
}
return uchardet_get_charset(ud);
#else
auto read = std::min<uint64_t>(4096, fp.size());
auto read = std::min<uint64_t>(65536, 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'))