48 lines
852 B
C
48 lines
852 B
C
//---
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// gint:image:fixed - Minimal fixed-point interface for linear transformations
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//---
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#ifndef GINT_IMAGE_FIXED
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#define GINT_IMAGE_FIXED
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/* Constants */
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#define fconst(x) ((x) * 65536)
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/* Multiplication */
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static inline int fmul(int x, int y)
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{
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return ((int64_t)x * (int64_t)y) >> 16;
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}
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/* Division */
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static inline int fdiv(int x, int y)
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{
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return ((int64_t)x << 16) / y;
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}
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/* Integer square root */
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static inline int isqrt(int n)
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{
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if(n <= 0) return 0;
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if(n < 4) return 1;
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int low_bound = isqrt(n / 4) * 2;
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int high_bound = low_bound + 1;
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return (high_bound * high_bound <= n) ? high_bound : low_bound;
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}
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/* Floor operation */
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static inline int ffloor(int x)
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{
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return (x >> 16);
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}
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/* Round operation */
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static inline int fround(int x)
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{
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return ffloor(x + fconst(0.5));
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}
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#endif /* GINT_IMAGE_FIXED */
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