123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225 |
- #define JPEG_INTERNALS
- #include "jinclude.h"
- #include "jpeglib.h"
- #include "jdct.h"
- #ifdef DCT_IFAST_SUPPORTED
- #if DCTSIZE != 8
- Sorry, this code only copes with 8x8 DCTs.
- #endif
- #define CONST_BITS 8
- #if CONST_BITS == 8
- #define FIX_0_382683433 ((INT32) 98)
- #define FIX_0_541196100 ((INT32) 139)
- #define FIX_0_707106781 ((INT32) 181)
- #define FIX_1_306562965 ((INT32) 334)
- #else
- #define FIX_0_382683433 FIX(0.382683433)
- #define FIX_0_541196100 FIX(0.541196100)
- #define FIX_0_707106781 FIX(0.707106781)
- #define FIX_1_306562965 FIX(1.306562965)
- #endif
- #ifndef USE_ACCURATE_ROUNDING
- #undef DESCALE
- #define DESCALE(x,n) RIGHT_SHIFT(x, n)
- #endif
- #define MULTIPLY(var,const) ((DCTELEM) DESCALE((var) * (const), CONST_BITS))
- GLOBAL void
- jpeg_fdct_ifast (DCTELEM * data)
- {
- DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
- DCTELEM tmp10, tmp11, tmp12, tmp13;
- DCTELEM z1, z2, z3, z4, z5, z11, z13;
- DCTELEM *dataptr;
- int ctr;
- SHIFT_TEMPS
-
- dataptr = data;
- for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
- tmp0 = dataptr[0] + dataptr[7];
- tmp7 = dataptr[0] - dataptr[7];
- tmp1 = dataptr[1] + dataptr[6];
- tmp6 = dataptr[1] - dataptr[6];
- tmp2 = dataptr[2] + dataptr[5];
- tmp5 = dataptr[2] - dataptr[5];
- tmp3 = dataptr[3] + dataptr[4];
- tmp4 = dataptr[3] - dataptr[4];
-
-
-
- tmp10 = tmp0 + tmp3;
- tmp13 = tmp0 - tmp3;
- tmp11 = tmp1 + tmp2;
- tmp12 = tmp1 - tmp2;
-
- dataptr[0] = tmp10 + tmp11;
- dataptr[4] = tmp10 - tmp11;
-
- z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781);
- dataptr[2] = tmp13 + z1;
- dataptr[6] = tmp13 - z1;
-
-
- tmp10 = tmp4 + tmp5;
- tmp11 = tmp5 + tmp6;
- tmp12 = tmp6 + tmp7;
-
- z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433);
- z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5;
- z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5;
- z3 = MULTIPLY(tmp11, FIX_0_707106781);
- z11 = tmp7 + z3;
- z13 = tmp7 - z3;
- dataptr[5] = z13 + z2;
- dataptr[3] = z13 - z2;
- dataptr[1] = z11 + z4;
- dataptr[7] = z11 - z4;
- dataptr += DCTSIZE;
- }
-
- dataptr = data;
- for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
- tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
- tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
- tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
- tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
- tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
- tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
- tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
- tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];
-
-
-
- tmp10 = tmp0 + tmp3;
- tmp13 = tmp0 - tmp3;
- tmp11 = tmp1 + tmp2;
- tmp12 = tmp1 - tmp2;
-
- dataptr[DCTSIZE*0] = tmp10 + tmp11;
- dataptr[DCTSIZE*4] = tmp10 - tmp11;
-
- z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781);
- dataptr[DCTSIZE*2] = tmp13 + z1;
- dataptr[DCTSIZE*6] = tmp13 - z1;
-
-
- tmp10 = tmp4 + tmp5;
- tmp11 = tmp5 + tmp6;
- tmp12 = tmp6 + tmp7;
-
- z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433);
- z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5;
- z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5;
- z3 = MULTIPLY(tmp11, FIX_0_707106781);
- z11 = tmp7 + z3;
- z13 = tmp7 - z3;
- dataptr[DCTSIZE*5] = z13 + z2;
- dataptr[DCTSIZE*3] = z13 - z2;
- dataptr[DCTSIZE*1] = z11 + z4;
- dataptr[DCTSIZE*7] = z11 - z4;
- dataptr++;
- }
- }
- #endif
|