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Clean up the SRT reader/writer a bit

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This commit is contained in:
Thomas Goyne 2014-07-05 16:57:44 -07:00
parent 8576c4993f
commit 8c7fd37aa9
1 changed files with 128 additions and 165 deletions
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293
src/subtitle_format_srt.cpp
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@ -49,11 +49,76 @@
#include <boost/algorithm/string/replace.hpp>
#include <boost/algorithm/string/trim.hpp>
#include <boost/regex.hpp>
#include <map>
DEFINE_EXCEPTION(SRTParseError, SubtitleFormatParseError);
namespace {
enum class TagType {
UNKNOWN,
BOLD_OPEN,
BOLD_CLOSE,
ITALICS_OPEN,
ITALICS_CLOSE,
UNDERLINE_OPEN,
UNDERLINE_CLOSE,
STRIKEOUT_OPEN,
STRIKEOUT_CLOSE,
FONT_OPEN,
FONT_CLOSE
};
TagType type_from_name(std::string const& tag) {
switch (tag.size()) {
case 1:
switch (tag[0]) {
case 'b': return TagType::BOLD_OPEN;
case 'i': return TagType::ITALICS_OPEN;
case 'u': return TagType::UNDERLINE_OPEN;
case 's': return TagType::STRIKEOUT_OPEN;
default: return TagType::UNKNOWN;
}
case 2:
if (tag[0] != '/') return TagType::UNKNOWN;
switch (tag[1]) {
case 'b': return TagType::BOLD_CLOSE;
case 'i': return TagType::ITALICS_CLOSE;
case 'u': return TagType::UNDERLINE_CLOSE;
case 's': return TagType::STRIKEOUT_CLOSE;
default: return TagType::UNKNOWN;
}
default:
if (tag == "font") return TagType::FONT_OPEN;
if (tag == "/font") return TagType::FONT_CLOSE;
return TagType::UNKNOWN;
}
}
struct ToggleTag {
char tag;
int level = 0;
ToggleTag(char tag) : tag(tag) { }
void Open(std::string& out) {
if (level == 0) {
out += "{\\";
out += tag;
out += "1}";
}
++level;
}
void Close(std::string& out) {
if (level == 1) {
out += "{\\";
out += tag;
out += '}';
}
if (level > 0)
--level;
}
};
class SrtTagParser {
struct FontAttribs {
std::string face;
@ -61,24 +126,9 @@ class SrtTagParser {
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()
@ -86,24 +136,14 @@ public:
, attrib_matcher(R"(^[[:space:]]+(face|size|color)=('[^']*'|"[^"]*"|[^[:space:]]+))", boost::regex::icase)
, is_quoted(R"(^(['"]).*\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;
ToggleTag bold('b');
ToggleTag italic('i');
ToggleTag underline('u');
ToggleTag strikeout('s');
std::vector<FontAttribs> font_stack;
std::string ass; // result to be built
@ -130,53 +170,17 @@ public:
srt = post_text;
boost::to_lower(tag_name);
switch (tag_name_cases[tag_name])
switch (type_from_name(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:
case TagType::BOLD_OPEN: bold.Open(ass); break;
case TagType::BOLD_CLOSE: bold.Close(ass); break;
case TagType::ITALICS_OPEN: italic.Open(ass); break;
case TagType::ITALICS_CLOSE: italic.Close(ass); break;
case TagType::UNDERLINE_OPEN: underline.Open(ass); break;
case TagType::UNDERLINE_CLOSE: underline.Close(ass); break;
case TagType::STRIKEOUT_OPEN: strikeout.Open(ass); break;
case TagType::STRIKEOUT_CLOSE: strikeout.Close(ass); break;
case TagType::FONT_OPEN:
{
// new attributes to fill in
FontAttribs new_attribs;
@ -222,7 +226,7 @@ public:
font_stack.push_back(new_attribs);
}
break;
case TAG_FONT_CLOSE:
case TagType::FONT_CLOSE:
{
// this requires a font stack entry
if (font_stack.empty())
@ -273,50 +277,6 @@ public:
}
};
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 (bool milliseconds = false; ci < ts.size() && !milliseconds; ++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 ',':
milliseconds = true;
break;
default:
ci = ts.size();
}
}
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 agi::format("%02d:%02d:%02d,%03d", ts.GetTimeHours(), ts.GetTimeMinutes(), ts.GetTimeSeconds(), ts.GetTimeMiliseconds());
@ -337,12 +297,12 @@ std::vector<std::string> SRTSubtitleFormat::GetWriteWildcards() const {
return GetReadWildcards();
}
enum ParseState {
STATE_INITIAL,
STATE_TIMESTAMP,
STATE_FIRST_LINE_OF_BODY,
STATE_REST_OF_BODY,
STATE_LAST_WAS_BLANK
enum class ParseState {
INITIAL,
TIMESTAMP,
FIRST_LINE_OF_BODY,
REST_OF_BODY,
LAST_WAS_BLANK
};
void SRTSubtitleFormat::ReadFile(AssFile *target, agi::fs::path const& filename, agi::vfr::Framerate const& fps, std::string const& encoding) const {
@ -358,7 +318,7 @@ void SRTSubtitleFormat::ReadFile(AssFile *target, agi::fs::path const& filename,
SrtTagParser tag_parser;
ParseState state = STATE_INITIAL;
ParseState state = ParseState::INITIAL;
int line_num = 0;
int linebreak_debt = 0;
AssDialogue *line = nullptr;
@ -370,12 +330,12 @@ void SRTSubtitleFormat::ReadFile(AssFile *target, agi::fs::path const& filename,
boost::smatch timestamp_match;
switch (state) {
case STATE_INITIAL:
case ParseState::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
state = STATE_TIMESTAMP;
state = ParseState::TIMESTAMP;
break;
}
if (regex_search(text_line, timestamp_match, timestamp_regex))
@ -383,7 +343,7 @@ void SRTSubtitleFormat::ReadFile(AssFile *target, agi::fs::path const& filename,
throw SRTParseError(agi::format("Parsing SRT: Expected subtitle index at line %d", line_num));
case STATE_TIMESTAMP:
case ParseState::TIMESTAMP:
if (!regex_search(text_line, timestamp_match, timestamp_regex))
throw SRTParseError(agi::format("Parsing SRT: Expected timestamp pair at line %d", line_num));
found_timestamps:
@ -395,32 +355,32 @@ found_timestamps:
// create new subtitle
line = new AssDialogue;
line->Start = ReadSRTTime(timestamp_match.str(1));
line->End = ReadSRTTime(timestamp_match.str(2));
line->Start = timestamp_match.str(1);
line->End = timestamp_match.str(2);
// store pointer to subtitle, we'll continue working on it
target->Events.push_back(*line);
// next we're reading the text
state = STATE_FIRST_LINE_OF_BODY;
state = ParseState::FIRST_LINE_OF_BODY;
break;
case STATE_FIRST_LINE_OF_BODY:
case ParseState::FIRST_LINE_OF_BODY:
if (text_line.empty()) {
// that's not very interesting... blank subtitle?
state = STATE_LAST_WAS_BLANK;
state = ParseState::LAST_WAS_BLANK;
// no previous line that needs a line break after
linebreak_debt = 0;
break;
}
text.append(text_line);
state = STATE_REST_OF_BODY;
state = ParseState::REST_OF_BODY;
break;
case STATE_REST_OF_BODY:
case ParseState::REST_OF_BODY:
if (text_line.empty()) {
// 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;
state = ParseState::LAST_WAS_BLANK;
linebreak_debt = 1;
break;
}
@ -428,13 +388,13 @@ found_timestamps:
text.append(text_line);
break;
case STATE_LAST_WAS_BLANK:
case ParseState::LAST_WAS_BLANK:
++linebreak_debt;
if (text_line.empty()) break;
if (all(text_line, boost::is_digit())) {
// Hopefully it's the start of a new subtitle, and the
// previous blank line(s) were the gap between subtitles
state = STATE_TIMESTAMP;
state = ParseState::TIMESTAMP;
break;
}
if (regex_search(text_line, timestamp_match, timestamp_regex))
@ -445,12 +405,12 @@ found_timestamps:
while (linebreak_debt-- > 0)
text.append("\\N");
text.append(text_line);
state = STATE_REST_OF_BODY;
state = ParseState::REST_OF_BODY;
break;
}
}
if (state == 1 || state == 2)
if (state == ParseState::TIMESTAMP || state == ParseState::FIRST_LINE_OF_BODY)
throw SRTParseError("Parsing SRT: Incomplete file");
if (line) // an unfinalized line
@ -483,8 +443,6 @@ void SRTSubtitleFormat::WriteFile(const AssFile *src, agi::fs::path const& filen
}
bool SRTSubtitleFormat::CanSave(const AssFile *file) const {
std::string supported_tags[] = { "\\b", "\\i", "\\s", "\\u" };
if (!file->Attachments.empty())
return false;
@ -497,7 +455,9 @@ bool SRTSubtitleFormat::CanSave(const AssFile *file) const {
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))
if (tag.Name.size() != 2)
return false;
if (!strchr("bisu", tag.Name[1]))
return false;
}
}
@ -507,27 +467,30 @@ bool SRTSubtitleFormat::CanSave(const AssFile *file) const {
}
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;
struct tag_state { char tag; bool value; };
tag_state tag_states[] = {
{'b', false},
{'i', false},
{'s', false},
{'u', false}
};
std::string final;
for (auto& block : diag->ParseTags()) {
if (AssDialogueBlockOverride* ovr = dynamic_cast<AssDialogueBlockOverride*>(block.get())) {
// 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 += agi::format("<%c>", it->first);
if (!temp && it->second)
final += agi::format("</%c>", it->first);
it->second = temp;
}
if (!tag.IsValid() || tag.Name.size() != 2)
continue;
for (auto& state : tag_states) {
if (state.tag != tag.Name[1]) continue;
bool temp = tag.Params[0].Get(false);
if (temp && !state.value)
final += agi::format("<%c>", state.tag);
if (!temp && state.value)
final += agi::format("</%c>", state.tag);
state.value = temp;
}
}
}
@ -538,9 +501,9 @@ std::string SRTSubtitleFormat::ConvertTags(const AssDialogue *diag) const {
// 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 += agi::format("</%c>", it.first);
for (auto state : tag_states) {
if (state.value)
final += agi::format("</%c>", state.tag);
}
return final;