silence warning 'possible loss of data' (win64) #44
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lodepng.cpp
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| @@ -3460,7 +3460,7 @@ unsigned lodepng_convert(unsigned char* out, const unsigned char* in, | |||
| const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in, | |||
| unsigned w, unsigned h) | |||
| { | |||
| size_t i; | |||
| unsigned i; | |||
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This just doesn't seem right: everywhere (?) i is used in this function it is compared with size_t or passed to a function taking size_t. So there shouldn't be any compiler warnings to begin with?
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Comparing with size_t doesn't generate a warning (no data loss actually), and the patch changes the readChunk_??Xt() functions passing i as argument to to unsigned as well. The warnings start with passing i to color_tree_add(), which casts the unsigned index to signed. And the readChunk_??Xt() take size_t chunkLength , but assign to unsigned length as well, triggering the warning. Alternative would be to use ssize_t (signed size_t) for the ColorTree::index, but ssize_t is not available on some platforms, nor is it used anywhere within lodepng yet. |
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Good point, should have checked more in detail. |
When compiling for 64bit Windows, size_t and unsigned int are of different size, leading cl.exe to warning C4267: conversion from 'size_t' to 'unsigned int', possible loss of data
When compiling for 64bit Windows, size_t and unsigned int are of
different size, leading cl.exe to warning C4267:
conversion from 'size_t' to 'unsigned int', possible loss of data
#34 contains a different solution, but this one feels more straightforward.