From 4c84e14b9e6566e176e702f79e6e0bd66a62d33e Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <moritz@bunkus.org>
Date: Thu, 19 Apr 2007 07:50:15 +0000
Subject: [PATCH] Allow negative timecodes in "delay:" lines in VobSub
 subtitles. Fix for bug 241.

---
 ChangeLog              |  5 +++++
 src/common/common.cpp  | 23 +++++++++++++++++------
 src/common/common.h    |  3 ++-
 src/input/r_vobsub.cpp |  2 +-
 4 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 3a53a1b27..f7ab6ab82 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2007-04-19  Moritz Bunkus  <moritz@bunkus.org>
+
+	* mkvmerge: bug fix: Fixed the VobSub reader so that "delay:"
+	lines with negative timecodes are accepted. Fix for bug 241.
+
 2007-04-18  Moritz Bunkus  <moritz@bunkus.org>
 
 	* mkvmerge: bug fix: Improved the file type detection code for
diff --git a/src/common/common.cpp b/src/common/common.cpp
index 8bfe79f06..915847104 100644
--- a/src/common/common.cpp
+++ b/src/common/common.cpp
@@ -1611,7 +1611,8 @@ set_tcp_error(const string &error) {
 
 bool
 parse_timecode(const string &src,
-               int64_t &timecode) {
+               int64_t &timecode,
+               bool allow_negative) {
   // Recognized format:
   // 1. XXXXXXXu   with XXXXXX being a number followed
   //    by one of the units 's', 'ms', 'us' or 'ns'
@@ -1620,13 +1621,21 @@ parse_timecode(const string &src,
   // 2. HH:MM:SS:nnnnnnnnn  with up to nine digits 'n' for ns precision;
   // HH: is optional; HH, MM and SS can be either one or two digits.
   int h, m, s, n, i, values[4], num_values, num_digits, num_colons;
+  int offset = 0, negative = 1;
   bool decimal_point_found;
 
   if (src.empty())
     return false;
 
+  if ('-' == src[0]) {
+    if (!allow_negative)
+      return false;
+    negative = -1;
+    offset = 1;
+  }
+
   try {
-    if (src.length() < 2)
+    if (src.length() < (2 + offset))
       throw false;
 
     string unit = src.substr(src.length() - 2, 2);
@@ -1646,13 +1655,13 @@ parse_timecode(const string &src,
     else
       throw false;
 
-    if (src.length() < (unit_length + 1))
+    if (src.length() < (unit_length + 1 + offset))
       throw false;
 
-    if (!parse_int(src.substr(0, src.length() - unit_length), value))
+    if (!parse_int(src.substr(offset, src.length() - unit_length - offset), value))
       throw false;
 
-    timecode = value * multiplier;
+    timecode = value * multiplier * negative;
 
     return true;
   } catch (...) {
@@ -1664,7 +1673,7 @@ parse_timecode(const string &src,
   decimal_point_found = false;
   memset(&values, 0, sizeof(int) * 4);
 
-  for (i = 0; src.length() > i; ++i) {
+  for (i = offset; src.length() > i; ++i) {
     if (isdigit(src[i])) {
       if (decimal_point_found && (9 == num_digits))
         return set_tcp_error("Invalid format: More than nine nano-second "
@@ -1749,6 +1758,8 @@ parse_timecode(const string &src,
   timecode = ((int64_t)h * 60 * 60 + (int64_t)m * 60 + (int64_t)s) *
     1000000000ll + n;
 
+  timecode *= negative;
+
   timecode_parser_error = "no error";
   return true;
 }
diff --git a/src/common/common.h b/src/common/common.h
index 0ddb55717..fed3ae1fd 100644
--- a/src/common/common.h
+++ b/src/common/common.h
@@ -97,7 +97,8 @@ using namespace std;
                             (int32_t)((t) % 1000000000)
 #define ARG_TIMECODEN(t) ARG_TIMECODENINT((int64_t)(t))
 extern string MTX_DLL_API timecode_parser_error;
-extern bool MTX_DLL_API parse_timecode(const string &s, int64_t &timecode);
+extern bool MTX_DLL_API parse_timecode(const string &s, int64_t &timecode,
+                                       bool allow_negative = false);
 
 extern bool MTX_DLL_API suppress_warnings;
 void MTX_DLL_API fix_format(const char *fmt, string &new_fmt);
diff --git a/src/input/r_vobsub.cpp b/src/input/r_vobsub.cpp
index f7fc3c524..ca9a9e7ee 100644
--- a/src/input/r_vobsub.cpp
+++ b/src/input/r_vobsub.cpp
@@ -248,7 +248,7 @@ vobsub_reader_c::parse_headers() {
       line.erase(0, 6);
       strip(line);
 
-      if (!parse_timecode(line, timestamp))
+      if (!parse_timecode(line, timestamp, true))
         mxerror(PFX "'%s', line " LLD ": The 'delay' timestamp could not be "
                 "parsed.\n", ti.fname.c_str(), line_no);
       delay = timestamp;