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

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fixes http://pulkomandy.tk/projects/GrafX2/ticket/125
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Thomas Bernard 2019-05-30 08:25:30 +02:00
parent a0b60f2e49
commit 2680ee40a0
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1 changed files with 14 additions and 4 deletions
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18
src/fileformats.c
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@ -5313,10 +5313,20 @@ void Save_GIF(T_IO_Context * context)
// Write the last code (before EOF) // Write the last code (before EOF)
GIF_set_code(GIF_file, &GIF, GIF_buffer, current_string); GIF_set_code(GIF_file, &GIF, GIF_buffer, current_string);
// We think we don't need to update GIF.nb_bits here because // we need to update alphabet_free / GIF.nb_bits here because
// we are writing a string already in the table, // the decoder will update them after each code,
// but we may be wrong as the table grow for each code... // so in very rare cases there might be a problem if we
// So in very rare cases there might be a problem. // 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 GIF_set_code(GIF_file, &GIF, GIF_buffer, eof); // 257 for 8bpp // Code de End d'image
if (GIF.remainder_bits!=0) if (GIF.remainder_bits!=0)