From 2fae0009942970f6331e2739bdcbd4b14a2485b0 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Sun, 26 Apr 2020 08:52:29 +0200 Subject: swscale/vscale: Increase type strictness libswscale/vscale.c makes extensive use of function pointers and in doing so it converts these function pointers to and from a pointer to void. Yet this is actually against the C standard: C90 only guarantees that one can convert a pointer to any incomplete type or object type to void* and back with the result comparing equal to the original which makes pointers to void generic pointers to incomplete or object type. Yet C90 lacks a generic function pointer type. C99 additionally guarantees that a pointer to a function of one type may be converted to a pointer to a function of another type with the result and the original comparing equal when converting back. This makes any function pointer type a generic function pointer type. Yet even this does not make pointers to void generic function pointers. Both GCC and Clang emit warnings for this when in pedantic mode. This commit fixes this by using a union that can hold one member of any of the required function pointer types to store the function pointer. This works even for C90. Reviewed-by: Michael Niedermayer Signed-off-by: Andreas Rheinhardt --- libswscale/vscale.c | 51 +++++++++++++++++++++++++++++---------------------- 1 file changed, 29 insertions(+), 22 deletions(-) (limited to 'libswscale') diff --git a/libswscale/vscale.c b/libswscale/vscale.c index 72352dedb3..9ed227e908 100644 --- a/libswscale/vscale.c +++ b/libswscale/vscale.c @@ -25,7 +25,14 @@ typedef struct VScalerContext int32_t *filter_pos; int filter_size; int isMMX; - void *pfn; + union { + yuv2planar1_fn yuv2planar1; + yuv2planarX_fn yuv2planarX; + yuv2interleavedX_fn yuv2interleavedX; + yuv2packed1_fn yuv2packed1; + yuv2packed2_fn yuv2packed2; + yuv2anyX_fn yuv2anyX; + } pfn; yuv2packedX_fn yuv2packedX; } VScalerContext; @@ -43,9 +50,9 @@ static int lum_planar_vscale(SwsContext *c, SwsFilterDescriptor *desc, int slice uint16_t *filter = inst->filter[0] + (inst->isMMX ? 0 : sliceY * inst->filter_size); if (inst->filter_size == 1) - ((yuv2planar1_fn)inst->pfn)((const int16_t*)src[0], dst[0], dstW, c->lumDither8, 0); + inst->pfn.yuv2planar1((const int16_t*)src[0], dst[0], dstW, c->lumDither8, 0); else - ((yuv2planarX_fn)inst->pfn)(filter, inst->filter_size, (const int16_t**)src, dst[0], dstW, c->lumDither8, 0); + inst->pfn.yuv2planarX(filter, inst->filter_size, (const int16_t**)src, dst[0], dstW, c->lumDither8, 0); if (desc->alpha) { int sp = first - desc->src->plane[3].sliceY; @@ -55,9 +62,9 @@ static int lum_planar_vscale(SwsContext *c, SwsFilterDescriptor *desc, int slice uint16_t *filter = inst->filter[1] + (inst->isMMX ? 0 : sliceY * inst->filter_size); if (inst->filter_size == 1) - ((yuv2planar1_fn)inst->pfn)((const int16_t*)src[0], dst[0], dstW, c->lumDither8, 0); + inst->pfn.yuv2planar1((const int16_t*)src[0], dst[0], dstW, c->lumDither8, 0); else - ((yuv2planarX_fn)inst->pfn)(filter, inst->filter_size, (const int16_t**)src, dst[0], dstW, c->lumDither8, 0); + inst->pfn.yuv2planarX(filter, inst->filter_size, (const int16_t**)src, dst[0], dstW, c->lumDither8, 0); } return 1; @@ -85,13 +92,13 @@ static int chr_planar_vscale(SwsContext *c, SwsFilterDescriptor *desc, int slice uint16_t *filter = inst->filter[0] + (inst->isMMX ? 0 : chrSliceY * inst->filter_size); if (c->yuv2nv12cX) { - ((yuv2interleavedX_fn)inst->pfn)(c, filter, inst->filter_size, (const int16_t**)src1, (const int16_t**)src2, dst1[0], dstW); + inst->pfn.yuv2interleavedX(c, filter, inst->filter_size, (const int16_t**)src1, (const int16_t**)src2, dst1[0], dstW); } else if (inst->filter_size == 1) { - ((yuv2planar1_fn)inst->pfn)((const int16_t*)src1[0], dst1[0], dstW, c->chrDither8, 0); - ((yuv2planar1_fn)inst->pfn)((const int16_t*)src2[0], dst2[0], dstW, c->chrDither8, 3); + inst->pfn.yuv2planar1((const int16_t*)src1[0], dst1[0], dstW, c->chrDither8, 0); + inst->pfn.yuv2planar1((const int16_t*)src2[0], dst2[0], dstW, c->chrDither8, 3); } else { - ((yuv2planarX_fn)inst->pfn)(filter, inst->filter_size, (const int16_t**)src1, dst1[0], dstW, c->chrDither8, 0); - ((yuv2planarX_fn)inst->pfn)(filter, inst->filter_size, (const int16_t**)src2, dst2[0], dstW, c->chrDither8, inst->isMMX ? (c->uv_offx2 >> 1) : 3); + inst->pfn.yuv2planarX(filter, inst->filter_size, (const int16_t**)src1, dst1[0], dstW, c->chrDither8, 0); + inst->pfn.yuv2planarX(filter, inst->filter_size, (const int16_t**)src2, dst2[0], dstW, c->chrDither8, inst->isMMX ? (c->uv_offx2 >> 1) : 3); } } @@ -125,13 +132,13 @@ static int packed_vscale(SwsContext *c, SwsFilterDescriptor *desc, int sliceY, i if (c->yuv2packed1 && lum_fsize == 1 && chr_fsize == 1) { // unscaled RGB - ((yuv2packed1_fn)inst->pfn)(c, (const int16_t*)*src0, (const int16_t**)src1, (const int16_t**)src2, + inst->pfn.yuv2packed1(c, (const int16_t*)*src0, (const int16_t**)src1, (const int16_t**)src2, (const int16_t*)(desc->alpha ? *src3 : NULL), *dst, dstW, 0, sliceY); } else if (c->yuv2packed1 && lum_fsize == 1 && chr_fsize == 2 && chr_filter[2 * chrSliceY + 1] + chr_filter[2 * chrSliceY] == 4096 && chr_filter[2 * chrSliceY + 1] <= 4096U) { // unscaled RGB int chrAlpha = chr_filter[2 * chrSliceY + 1]; - ((yuv2packed1_fn)inst->pfn)(c, (const int16_t*)*src0, (const int16_t**)src1, (const int16_t**)src2, + inst->pfn.yuv2packed1(c, (const int16_t*)*src0, (const int16_t**)src1, (const int16_t**)src2, (const int16_t*)(desc->alpha ? *src3 : NULL), *dst, dstW, chrAlpha, sliceY); } else if (c->yuv2packed2 && lum_fsize == 2 && chr_fsize == 2 && lum_filter[2 * sliceY + 1] + lum_filter[2 * sliceY] == 4096 && @@ -145,7 +152,7 @@ static int packed_vscale(SwsContext *c, SwsFilterDescriptor *desc, int sliceY, i c->lumMmxFilter[3] = lum_filter[2 * sliceY] * 0x10001; c->chrMmxFilter[2] = c->chrMmxFilter[3] = chr_filter[2 * chrSliceY] * 0x10001; - ((yuv2packed2_fn)inst->pfn)(c, (const int16_t**)src0, (const int16_t**)src1, (const int16_t**)src2, (const int16_t**)src3, + inst->pfn.yuv2packed2(c, (const int16_t**)src0, (const int16_t**)src1, (const int16_t**)src2, (const int16_t**)src3, *dst, dstW, lumAlpha, chrAlpha, sliceY); } else { // general RGB if ((c->yuv2packed1 && lum_fsize == 1 && chr_fsize == 2) || @@ -195,7 +202,7 @@ static int any_vscale(SwsContext *c, SwsFilterDescriptor *desc, int sliceY, int desc->alpha ? desc->dst->plane[3].line[dp3] : NULL }; av_assert1(!c->yuv2packed1 && !c->yuv2packed2); - ((yuv2anyX_fn)inst->pfn)(c, lum_filter + sliceY * lum_fsize, + inst->pfn.yuv2anyX(c, lum_filter + sliceY * lum_fsize, (const int16_t**)src0, lum_fsize, chr_filter + sliceY * chr_fsize, (const int16_t**)src1, (const int16_t**)src2, chr_fsize, (const int16_t**)src3, dst, dstW, sliceY); @@ -270,9 +277,9 @@ void ff_init_vscale_pfn(SwsContext *c, chrCtx->isMMX = use_mmx; --idx; - if (yuv2nv12cX) chrCtx->pfn = yuv2nv12cX; - else if (c->vChrFilterSize == 1) chrCtx->pfn = yuv2plane1; - else chrCtx->pfn = yuv2planeX; + if (yuv2nv12cX) chrCtx->pfn.yuv2interleavedX = yuv2nv12cX; + else if (c->vChrFilterSize == 1) chrCtx->pfn.yuv2planar1 = yuv2plane1; + else chrCtx->pfn.yuv2planarX = yuv2planeX; } lumCtx = c->desc[idx].instance; @@ -283,8 +290,8 @@ void ff_init_vscale_pfn(SwsContext *c, lumCtx->filter_pos = c->vLumFilterPos; lumCtx->isMMX = use_mmx; - if (c->vLumFilterSize == 1) lumCtx->pfn = yuv2plane1; - else lumCtx->pfn = yuv2planeX; + if (c->vLumFilterSize == 1) lumCtx->pfn.yuv2planar1 = yuv2plane1; + else lumCtx->pfn.yuv2planarX = yuv2planeX; } else { lumCtx = c->desc[idx].instance; @@ -303,12 +310,12 @@ void ff_init_vscale_pfn(SwsContext *c, if (yuv2packedX) { if (c->yuv2packed1 && c->vLumFilterSize == 1 && c->vChrFilterSize <= 2) - lumCtx->pfn = yuv2packed1; + lumCtx->pfn.yuv2packed1 = yuv2packed1; else if (c->yuv2packed2 && c->vLumFilterSize == 2 && c->vChrFilterSize == 2) - lumCtx->pfn = yuv2packed2; + lumCtx->pfn.yuv2packed2 = yuv2packed2; lumCtx->yuv2packedX = yuv2packedX; } else - lumCtx->pfn = yuv2anyX; + lumCtx->pfn.yuv2anyX = yuv2anyX; } } -- cgit v1.2.3