Aegisub/aegisub/src/subtitle_format_srt.cpp

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// Copyright (c) 2006, Rodrigo Braz Monteiro
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of the Aegisub Group nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Aegisub Project http://www.aegisub.org/
/// @file subtitle_format_srt.cpp
/// @brief Reading/writing SubRip format subtitles (.SRT)
/// @ingroup subtitle_io
///
#include "config.h"
#include "subtitle_format_srt.h"
#include "ass_attachment.h"
#include "ass_dialogue.h"
#include "ass_file.h"
#include "ass_style.h"
#include "utils.h"
#include "text_file_reader.h"
#include "text_file_writer.h"
#include <libaegisub/of_type_adaptor.h>
#include <boost/algorithm/string/case_conv.hpp>
#include <boost/algorithm/string/predicate.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <boost/algorithm/string/trim.hpp>
#include <boost/format.hpp>
#include <boost/regex.hpp>
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#include <map>
DEFINE_SIMPLE_EXCEPTION(SRTParseError, SubtitleFormatParseError, "subtitle_io/parse/srt")
namespace {
class SrtTagParser {
struct FontAttribs {
std::string face;
std::string size;
std::string color;
};
enum TagType {
// leave 0 unused so indexing an unknown tag in the map won't clash
TAG_BOLD_OPEN = 1,
TAG_BOLD_CLOSE,
TAG_ITALICS_OPEN,
TAG_ITALICS_CLOSE,
TAG_UNDERLINE_OPEN,
TAG_UNDERLINE_CLOSE,
TAG_STRIKEOUT_OPEN,
TAG_STRIKEOUT_CLOSE,
TAG_FONT_OPEN,
TAG_FONT_CLOSE
};
const boost::regex tag_matcher;
const boost::regex attrib_matcher;
const boost::regex is_quoted;
std::map<std::string, TagType> tag_name_cases;
public:
SrtTagParser()
: tag_matcher("^(.*?)<(/?b|/?i|/?u|/?s|/?font)([^>]*)>(.*)$", boost::regex::icase)
, attrib_matcher("^[[:space:]]+(face|size|color)=('[^']*'|\"[^\"]*\"|[^[:space:]]+)", boost::regex::icase)
, is_quoted("^(['\"]).*\\1$")
{
tag_name_cases["b"] = TAG_BOLD_OPEN;
tag_name_cases["/b"] = TAG_BOLD_CLOSE;
tag_name_cases["i"] = TAG_ITALICS_OPEN;
tag_name_cases["/i"] = TAG_ITALICS_CLOSE;
tag_name_cases["u"] = TAG_UNDERLINE_OPEN;
tag_name_cases["/u"] = TAG_UNDERLINE_CLOSE;
tag_name_cases["s"] = TAG_STRIKEOUT_OPEN;
tag_name_cases["/s"] = TAG_STRIKEOUT_CLOSE;
tag_name_cases["font"] = TAG_FONT_OPEN;
tag_name_cases["/font"] = TAG_FONT_CLOSE;
}
std::string ToAss(std::string srt)
{
int bold_level = 0;
int italics_level = 0;
int underline_level = 0;
int strikeout_level = 0;
std::vector<FontAttribs> font_stack;
std::string ass; // result to be built
while (!srt.empty())
{
boost::smatch result;
if (!regex_match(srt, result, tag_matcher))
{
// no more tags could be matched, end of string
ass.append(srt);
break;
}
// we found a tag, translate it
std::string pre_text = result.str(1);
std::string tag_name = result.str(2);
std::string tag_attrs = result.str(3);
std::string post_text = result.str(4);
// the text before the tag goes through unchanged
ass.append(pre_text);
// the text after the tag is the input for next iteration
srt = post_text;
boost::to_lower(tag_name);
switch (tag_name_cases[tag_name])
{
case TAG_BOLD_OPEN:
if (bold_level == 0)
ass.append("{\\b1}");
bold_level++;
break;
case TAG_BOLD_CLOSE:
if (bold_level == 1)
ass.append("{\\b}");
if (bold_level > 0)
bold_level--;
break;
case TAG_ITALICS_OPEN:
if (italics_level == 0)
ass.append("{\\i1}");
italics_level++;
break;
case TAG_ITALICS_CLOSE:
if (italics_level == 1)
ass.append("{\\i}");
if (italics_level > 0)
italics_level--;
break;
case TAG_UNDERLINE_OPEN:
if (underline_level == 0)
ass.append("{\\u1}");
underline_level++;
break;
case TAG_UNDERLINE_CLOSE:
if (underline_level == 1)
ass.append("{\\u}");
if (underline_level > 0)
underline_level--;
break;
case TAG_STRIKEOUT_OPEN:
if (strikeout_level == 0)
ass.append("{\\s1}");
strikeout_level++;
break;
case TAG_STRIKEOUT_CLOSE:
if (strikeout_level == 1)
ass.append("{\\s}");
if (strikeout_level > 0)
strikeout_level--;
break;
case TAG_FONT_OPEN:
{
// new attributes to fill in
FontAttribs new_attribs;
FontAttribs old_attribs;
// start out with any previous ones on stack
if (font_stack.size() > 0)
old_attribs = font_stack.back();
new_attribs = old_attribs;
// now find all attributes on this font tag
boost::smatch result;
while (regex_search(tag_attrs, result, attrib_matcher))
{
// get attribute name and values
std::string attr_name = result.str(1);
std::string attr_value = result.str(2);
// clean them
boost::to_lower(attr_name);
if (regex_match(attr_value, is_quoted))
attr_value = attr_value.substr(1, attr_value.size() - 2);
// handle the attributes
if (attr_name == "face")
new_attribs.face = str(boost::format("{\\fn%s}") % attr_value);
else if (attr_name == "size")
new_attribs.size = str(boost::format("{\\fs%s}") % attr_value);
else if (attr_name == "color")
new_attribs.color = str(boost::format("{\\c%s}") % agi::Color(attr_value).GetAssOverrideFormatted());
// remove this attribute to prepare for the next
tag_attrs = result.suffix().str();
}
// the attributes changed from old are then written out
if (new_attribs.face != old_attribs.face)
ass.append(new_attribs.face);
if (new_attribs.size != old_attribs.size)
ass.append(new_attribs.size);
if (new_attribs.color != old_attribs.color)
ass.append(new_attribs.color);
// lastly dump the new attributes state onto the stack
font_stack.push_back(new_attribs);
}
break;
case TAG_FONT_CLOSE:
{
// this requires a font stack entry
if (font_stack.empty())
break;
// get the current attribs
FontAttribs cur_attribs = font_stack.back();
// remove them from the stack
font_stack.pop_back();
// grab the old attributes if there are any
FontAttribs old_attribs;
if (font_stack.size() > 0)
old_attribs = font_stack.back();
// then restore the attributes to previous settings
if (cur_attribs.face != old_attribs.face)
{
if (old_attribs.face.empty())
ass.append("{\\fn}");
else
ass.append(old_attribs.face);
}
if (cur_attribs.size != old_attribs.size)
{
if (old_attribs.size.empty())
ass.append("{\\fs}");
else
ass.append(old_attribs.size);
}
if (cur_attribs.color != old_attribs.color)
{
if (old_attribs.color.empty())
ass.append("{\\c}");
else
ass.append(old_attribs.color);
}
}
break;
default:
// unknown tag, replicate it in the output
ass.append("<").append(tag_name).append(tag_attrs).append(">");
break;
}
}
// make it a little prettier, join tag groups
boost::replace_all(ass, "}{", "");
return ass;
}
};
AssTime ReadSRTTime(std::string const& ts)
{
// For the sake of your sanity, please do not read this function.
int d, h, m, s, ms;
d = h = m = s = ms = 0;
size_t ci = 0;
int ms_chars = 0;
for (; ci < ts.size(); ++ci)
{
switch (ts[ci])
{
case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
s = s * 10 + (ts[ci] - '0');
break;
case ':':
d = h;
h = m;
m = s;
s = 0;
break;
case ',':
ci++;
goto milliseconds;
default:
ci = ts.size();
}
}
milliseconds:
for (; ci < ts.size(); ++ci)
{
if (!isdigit(ts[ci])) break;
ms = ms * 10 + (ts[ci] - '0');
ms_chars++;
}
ms *= pow(10, 3 - ms_chars);
return ms + 1000*(s + 60*(m + 60*(h + d*24)));
}
std::string WriteSRTTime(AssTime const& ts)
{
return str(boost::format("%02d:%02d:%02d,%03d") % ts.GetTimeHours() % ts.GetTimeMinutes() % ts.GetTimeSeconds() % ts.GetTimeMiliseconds());
}
}
SRTSubtitleFormat::SRTSubtitleFormat()
: SubtitleFormat("SubRip")
{
}
std::vector<std::string> SRTSubtitleFormat::GetReadWildcards() const {
std::vector<std::string> formats;
formats.push_back("srt");
return formats;
}
std::vector<std::string> SRTSubtitleFormat::GetWriteWildcards() const {
return GetReadWildcards();
}
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enum ParseState {
STATE_INITIAL,
STATE_TIMESTAMP,
STATE_FIRST_LINE_OF_BODY,
STATE_REST_OF_BODY,
STATE_LAST_WAS_BLANK
};
void SRTSubtitleFormat::ReadFile(AssFile *target, agi::fs::path const& filename, std::string const& encoding) const {
using namespace std;
TextFileReader file(filename, encoding);
target->LoadDefault(false);
// See parsing algorithm at <http://devel.aegisub.org/wiki/SubtitleFormats/SRT>
// "hh:mm:ss,fff --> hh:mm:ss,fff" (e.g. "00:00:04,070 --> 00:00:10,04")
const boost::regex timestamp_regex("^([0-9]{1,2}:[0-9]{1,2}:[0-9]{1,2},[0-9]{1,}) --> ([0-9]{1,2}:[0-9]{1,2}:[0-9]{1,2},[0-9]{1,})");
SrtTagParser tag_parser;
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ParseState state = STATE_INITIAL;
int line_num = 0;
int linebreak_debt = 0;
AssDialogue *line = 0;
std::string text;
while (file.HasMoreLines()) {
std::string text_line = file.ReadLineFromFile();
++line_num;
boost::trim(text_line);
boost::smatch timestamp_match;
switch (state) {
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case STATE_INITIAL:
// ignore leading blank lines
if (text_line.empty()) break;
if (all(text_line, boost::is_digit())) {
// found the line number, throw it away and hope for timestamps
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state = STATE_TIMESTAMP;
break;
}
if (regex_search(text_line, timestamp_match, timestamp_regex))
goto found_timestamps;
throw SRTParseError(str(boost::format("Parsing SRT: Expected subtitle index at line %d") % line_num), 0);
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case STATE_TIMESTAMP:
if (!regex_search(text_line, timestamp_match, timestamp_regex))
throw SRTParseError(str(boost::format("Parsing SRT: Expected timestamp pair at line %d") % line_num), 0);
found_timestamps:
if (line) {
// finalize active line
line->Text = tag_parser.ToAss(text);
text.clear();
}
// create new subtitle
line = new AssDialogue;
line->Start = ReadSRTTime(timestamp_match.str(1));
line->End = ReadSRTTime(timestamp_match.str(2));
// store pointer to subtitle, we'll continue working on it
target->Line.push_back(*line);
// next we're reading the text
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state = STATE_FIRST_LINE_OF_BODY;
break;
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case STATE_FIRST_LINE_OF_BODY:
if (text_line.empty()) {
// that's not very interesting... blank subtitle?
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state = STATE_LAST_WAS_BLANK;
// no previous line that needs a line break after
linebreak_debt = 0;
break;
}
text.append(text_line);
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state = STATE_REST_OF_BODY;
break;
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case STATE_REST_OF_BODY:
if (text_line.empty()) {
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// Might be either the gap between two subtitles or just a
// blank line in the middle of a subtitle, so defer adding
// the line break until we check what's on the next line
state = STATE_LAST_WAS_BLANK;
linebreak_debt = 1;
break;
}
text.append("\\N");
text.append(text_line);
break;
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case STATE_LAST_WAS_BLANK:
++linebreak_debt;
if (text_line.empty()) break;
if (all(text_line, boost::is_digit())) {
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// Hopefully it's the start of a new subtitle, and the
// previous blank line(s) were the gap between subtitles
state = STATE_TIMESTAMP;
break;
}
if (regex_search(text_line, timestamp_match, timestamp_regex))
goto found_timestamps;
// assume it's a continuation of the subtitle text
// resolve our line break debt and append the line text
while (linebreak_debt-- > 0)
text.append("\\N");
text.append(text_line);
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state = STATE_REST_OF_BODY;
break;
}
}
if (state == 1 || state == 2)
throw SRTParseError("Parsing SRT: Incomplete file", 0);
if (line) // an unfinalized line
line->Text = tag_parser.ToAss(text);
}
void SRTSubtitleFormat::WriteFile(const AssFile *src, agi::fs::path const& filename, std::string const& encoding) const {
TextFileWriter file(filename, encoding);
// Convert to SRT
AssFile copy(*src);
copy.Sort();
StripComments(copy);
RecombineOverlaps(copy);
MergeIdentical(copy);
#ifdef _WIN32
ConvertNewlines(copy, "\r\n", false);
#else
ConvertNewlines(copy, "\n", false);
#endif
// Write lines
int i=0;
for (auto current : copy.Line | agi::of_type<AssDialogue>()) {
file.WriteLineToFile(std::to_string(++i));
file.WriteLineToFile(WriteSRTTime(current->Start) + " --> " + WriteSRTTime(current->End));
file.WriteLineToFile(ConvertTags(current));
file.WriteLineToFile("");
}
}
bool SRTSubtitleFormat::CanSave(const AssFile *file) const {
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std::string supported_tags[] = { "\\b", "\\i", "\\s", "\\u" };
AssStyle defstyle;
for (auto const& line : file->Line) {
// Check style, if anything non-default is found, return false
if (const AssStyle *curstyle = dynamic_cast<const AssStyle*>(&line)) {
if (curstyle->GetEntryData() != defstyle.GetEntryData())
return false;
}
// Check for attachments, if any is found, return false
if (dynamic_cast<const AssAttachment*>(&line)) return false;
// Check dialogue
if (const AssDialogue *curdiag = dynamic_cast<const AssDialogue*>(&line)) {
boost::ptr_vector<AssDialogueBlock> blocks(curdiag->ParseTags());
for (auto ovr : blocks | agi::of_type<AssDialogueBlockOverride>()) {
// Verify that all overrides used are supported
for (auto const& tag : ovr->Tags) {
if (!std::binary_search(supported_tags, std::end(supported_tags), tag.Name))
return false;
}
}
}
}
return true;
}
std::string SRTSubtitleFormat::ConvertTags(const AssDialogue *diag) const {
std::string final;
std::map<char, bool> tag_states;
tag_states['i'] = false;
tag_states['b'] = false;
tag_states['u'] = false;
tag_states['s'] = false;
boost::ptr_vector<AssDialogueBlock> blocks(diag->ParseTags());
for (auto& block : blocks) {
if (AssDialogueBlockOverride* ovr = dynamic_cast<AssDialogueBlockOverride*>(&block)) {
// Iterate through overrides
for (auto const& tag : ovr->Tags) {
if (tag.IsValid() && tag.Name.size() == 2) {
auto it = tag_states.find(tag.Name[1]);
if (it != tag_states.end()) {
bool temp = tag.Params[0].Get(false);
if (temp && !it->second)
final += str(boost::format("<%c>") % it->first);
if (!temp && it->second)
final += str(boost::format("</%c>") % it->first);
it->second = temp;
}
}
}
}
// Plain text
else if (AssDialogueBlockPlain *plain = dynamic_cast<AssDialogueBlockPlain*>(&block))
final += plain->GetText();
}
// Ensure all tags are closed
// Otherwise unclosed overrides might affect lines they shouldn't, see bug #809 for example
for (auto it : tag_states) {
if (it.second)
final += str(boost::format("</%c>") % it.first);
}
return final;
}