m/grafX2
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Save_GIF(): fix update of nb_bits after writing last code

Browse Source 
fixes http://pulkomandy.tk/projects/GrafX2/ticket/125
This commit is contained in:
Thomas Bernard 2019-05-30 08:25:30 +02:00
parent a0b60f2e49
commit 2680ee40a0
No known key found for this signature in database
GPG Key ID: 0FF11B67A5C0863C
1 changed files with 14 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
src/fileformats.c
View File

@ -5313,10 +5313,20 @@ void Save_GIF(T_IO_Context * context)
// Write the last code (before EOF)
GIF_set_code(GIF_file, &GIF, GIF_buffer, current_string);
// We think we don't need to update GIF.nb_bits here because
// we are writing a string already in the table,
// but we may be wrong as the table grow for each code...
// So in very rare cases there might be a problem.
// we need to update alphabet_free / GIF.nb_bits here because
// the decoder will update them after each code,
// so in very rare cases there might be a problem if we
// don't do it.
// see http://pulkomandy.tk/projects/GrafX2/ticket/125
if(alphabet_free < 4096)
{
alphabet_free++;
if ((alphabet_free > alphabet_max+1) && (GIF.nb_bits < 12))
{
GIF.nb_bits++;
alphabet_max = (1 << GIF.nb_bits) - 1;
}
}
GIF_set_code(GIF_file, &GIF, GIF_buffer, eof); // 257 for 8bpp // Code de End d'image
if (GIF.remainder_bits!=0)