recoll/src/utils/transcode.cpp
2020-05-11 07:02:46 +01:00

155 lines
4.3 KiB
C++

/* Copyright (C) 2004-2019 J.F.Dockes
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "autoconfig.h"
#include <string>
#include <iostream>
#include <mutex>
#include <errno.h>
#include <iconv.h>
#include "transcode.h"
#include "log.h"
using namespace std;
// We gain approximately 25% exec time for word at a time conversions by
// caching the iconv_open thing.
//
// We may also lose some concurrency on multiproc because of the
// necessary locking, but we only have one processing-intensive
// possible thread for now (the indexing one), so this is probably not
// an issue (and could be worked around with a slightly more
// sohisticated approach).
#define ICONV_CACHE_OPEN
bool transcode(const string &in, string &out, const string &icode,
const string &ocode, int *ecnt)
{
LOGDEB2("Transcode: " << icode << " -> " << ocode << "\n");
#ifdef ICONV_CACHE_OPEN
static iconv_t ic = (iconv_t)-1;
static string cachedicode;
static string cachedocode;
static std::mutex o_cachediconv_mutex;
std::unique_lock<std::mutex> lock(o_cachediconv_mutex);
#else
iconv_t ic;
#endif
bool ret = false;
const int OBSIZ = 8192;
char obuf[OBSIZ], *op;
bool icopen = false;
int mecnt = 0;
out.erase();
size_t isiz = in.length();
out.reserve(isiz);
const char *ip = in.c_str();
#ifdef ICONV_CACHE_OPEN
if (cachedicode.compare(icode) || cachedocode.compare(ocode)) {
if (ic != (iconv_t)-1) {
iconv_close(ic);
ic = (iconv_t)-1;
}
#endif
if((ic = iconv_open(ocode.c_str(), icode.c_str())) == (iconv_t)-1) {
out = string("iconv_open failed for ") + icode
+ " -> " + ocode;
#ifdef ICONV_CACHE_OPEN
cachedicode.erase();
cachedocode.erase();
#endif
goto error;
}
#ifdef ICONV_CACHE_OPEN
cachedicode.assign(icode);
cachedocode.assign(ocode);
}
#endif
icopen = true;
while (isiz > 0) {
size_t osiz;
op = obuf;
osiz = OBSIZ;
if(iconv(ic, (ICONV_CONST char **)&ip, &isiz, &op, &osiz) == (size_t)-1
&& errno != E2BIG) {
#if 0
out.erase();
out = string("iconv failed for ") + icode + " -> " + ocode +
" : " + strerror(errno);
#endif
if (errno == EILSEQ) {
LOGDEB1("transcode:iconv: bad input seq.: shift, retry\n");
LOGDEB1(" Input consumed " << ip - in << " output produced " <<
out.length() + OBSIZ - osiz << "\n");
out.append(obuf, OBSIZ - osiz);
out += "?";
mecnt++;
ip++;isiz--;
continue;
}
// Normally only EINVAL is possible here: incomplete
// multibyte sequence at the end. This is not fatal. Any
// other is supposedly impossible, we return an error
if (errno == EINVAL)
goto out;
else
goto error;
}
out.append(obuf, OBSIZ - osiz);
}
#ifndef ICONV_CACHE_OPEN
icopen = false;
if(iconv_close(ic) == -1) {
out.erase();
out = string("iconv_close failed for ") + icode + " -> " + ocode;
goto error;
}
#endif
out:
ret = true;
error:
if (icopen) {
#ifndef ICONV_CACHE_OPEN
iconv_close(ic);
#else
// Just reset conversion
iconv(ic, 0, 0, 0, 0);
#endif
}
if (mecnt)
LOGDEB("transcode: [" << icode << "]->[" << ocode << "] " <<
mecnt << " errors\n");
if (ecnt)
*ecnt = mecnt;
return ret;
}