3DPrinting/PrusaSlicer-NonPlainar
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Be compatible with earlier libpng versions.

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This commit is contained in:
tamasmeszaros 2020-08-03 18:50:43 +02:00
parent b09552e56f
commit ad0df8fd09
1 changed files with 12 additions and 2 deletions
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14
src/libslic3r/PNGRead.cpp
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@ -27,8 +27,18 @@ bool is_png(const ReadBuf &rb)
{
static const constexpr int PNG_SIG_BYTES = 8;
return rb.sz >= PNG_SIG_BYTES &&
!png_sig_cmp(static_cast<png_const_bytep>(rb.buf), 0, PNG_SIG_BYTES);
#if PNG_LIBPNG_VER_MINOR <= 2
// Earlier libpng versions had png_sig_cmp(png_bytep, ...) which is not
// a const pointer. It is not possible to cast away the const qualifier from
// the input buffer so... yes... life is challenging...
png_byte buf[PNG_SIG_BYTES];
auto inbuf = static_cast<const std::uint8_t *>(rb.buf);
std::copy(inbuf, inbuf + PNG_SIG_BYTES, buf);
#else
auto buf = static_cast<png_const_bytep>(rb.buf);
#endif
return rb.sz >= PNG_SIG_BYTES && !png_sig_cmp(buf, 0, PNG_SIG_BYTES);
}
// A wrapper around ReadBuf to be read repeatedly like a stream. libpng needs