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Diffstat (limited to 'src/jpeg-8c/jfdctflt.c')
| -rw-r--r-- | src/jpeg-8c/jfdctflt.c | 174 |
1 files changed, 0 insertions, 174 deletions
diff --git a/src/jpeg-8c/jfdctflt.c b/src/jpeg-8c/jfdctflt.c deleted file mode 100644 index 74d0d862..00000000 --- a/src/jpeg-8c/jfdctflt.c +++ /dev/null @@ -1,174 +0,0 @@ -/* - * jfdctflt.c - * - * Copyright (C) 1994-1996, Thomas G. Lane. - * Modified 2003-2009 by Guido Vollbeding. - * This file is part of the Independent JPEG Group's software. - * For conditions of distribution and use, see the accompanying README file. - * - * This file contains a floating-point implementation of the - * forward DCT (Discrete Cosine Transform). - * - * This implementation should be more accurate than either of the integer - * DCT implementations. However, it may not give the same results on all - * machines because of differences in roundoff behavior. Speed will depend - * on the hardware's floating point capacity. - * - * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT - * on each column. Direct algorithms are also available, but they are - * much more complex and seem not to be any faster when reduced to code. - * - * This implementation is based on Arai, Agui, and Nakajima's algorithm for - * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in - * Japanese, but the algorithm is described in the Pennebaker & Mitchell - * JPEG textbook (see REFERENCES section in file README). The following code - * is based directly on figure 4-8 in P&M. - * While an 8-point DCT cannot be done in less than 11 multiplies, it is - * possible to arrange the computation so that many of the multiplies are - * simple scalings of the final outputs. These multiplies can then be - * folded into the multiplications or divisions by the JPEG quantization - * table entries. The AA&N method leaves only 5 multiplies and 29 adds - * to be done in the DCT itself. - * The primary disadvantage of this method is that with a fixed-point - * implementation, accuracy is lost due to imprecise representation of the - * scaled quantization values. However, that problem does not arise if - * we use floating point arithmetic. - */ - -#define JPEG_INTERNALS -#include "jinclude.h" -#include "jpeglib.h" -#include "jdct.h" /* Private declarations for DCT subsystem */ - -#ifdef DCT_FLOAT_SUPPORTED - - -/* - * This module is specialized to the case DCTSIZE = 8. - */ - -#if DCTSIZE != 8 - Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ -#endif - - -/* - * Perform the forward DCT on one block of samples. - */ - -GLOBAL(void) -jpeg_fdct_float (FAST_FLOAT * data, JSAMPARRAY sample_data, JDIMENSION start_col) -{ - FAST_FLOAT tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; - FAST_FLOAT tmp10, tmp11, tmp12, tmp13; - FAST_FLOAT z1, z2, z3, z4, z5, z11, z13; - FAST_FLOAT *dataptr; - JSAMPROW elemptr; - int ctr; - - /* Pass 1: process rows. */ - - dataptr = data; - for (ctr = 0; ctr < DCTSIZE; ctr++) { - elemptr = sample_data[ctr] + start_col; - - /* Load data into workspace */ - tmp0 = (FAST_FLOAT) (GETJSAMPLE(elemptr[0]) + GETJSAMPLE(elemptr[7])); - tmp7 = (FAST_FLOAT) (GETJSAMPLE(elemptr[0]) - GETJSAMPLE(elemptr[7])); - tmp1 = (FAST_FLOAT) (GETJSAMPLE(elemptr[1]) + GETJSAMPLE(elemptr[6])); - tmp6 = (FAST_FLOAT) (GETJSAMPLE(elemptr[1]) - GETJSAMPLE(elemptr[6])); - tmp2 = (FAST_FLOAT) (GETJSAMPLE(elemptr[2]) + GETJSAMPLE(elemptr[5])); - tmp5 = (FAST_FLOAT) (GETJSAMPLE(elemptr[2]) - GETJSAMPLE(elemptr[5])); - tmp3 = (FAST_FLOAT) (GETJSAMPLE(elemptr[3]) + GETJSAMPLE(elemptr[4])); - tmp4 = (FAST_FLOAT) (GETJSAMPLE(elemptr[3]) - GETJSAMPLE(elemptr[4])); - - /* Even part */ - - tmp10 = tmp0 + tmp3; /* phase 2 */ - tmp13 = tmp0 - tmp3; - tmp11 = tmp1 + tmp2; - tmp12 = tmp1 - tmp2; - - /* Apply unsigned->signed conversion */ - dataptr[0] = tmp10 + tmp11 - 8 * CENTERJSAMPLE; /* phase 3 */ - dataptr[4] = tmp10 - tmp11; - - z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */ - dataptr[2] = tmp13 + z1; /* phase 5 */ - dataptr[6] = tmp13 - z1; - - /* Odd part */ - - tmp10 = tmp4 + tmp5; /* phase 2 */ - tmp11 = tmp5 + tmp6; - tmp12 = tmp6 + tmp7; - - /* The rotator is modified from fig 4-8 to avoid extra negations. */ - z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */ - z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */ - z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */ - z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */ - - z11 = tmp7 + z3; /* phase 5 */ - z13 = tmp7 - z3; - - dataptr[5] = z13 + z2; /* phase 6 */ - dataptr[3] = z13 - z2; - dataptr[1] = z11 + z4; - dataptr[7] = z11 - z4; - - dataptr += DCTSIZE; /* advance pointer to next row */ - } - - /* Pass 2: process columns. */ - - 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]; - - /* Even part */ - - tmp10 = tmp0 + tmp3; /* phase 2 */ - tmp13 = tmp0 - tmp3; - tmp11 = tmp1 + tmp2; - tmp12 = tmp1 - tmp2; - - dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */ - dataptr[DCTSIZE*4] = tmp10 - tmp11; - - z1 = (tmp12 + tmp13) * ((FAST_FLOAT) 0.707106781); /* c4 */ - dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */ - dataptr[DCTSIZE*6] = tmp13 - z1; - - /* Odd part */ - - tmp10 = tmp4 + tmp5; /* phase 2 */ - tmp11 = tmp5 + tmp6; - tmp12 = tmp6 + tmp7; - - /* The rotator is modified from fig 4-8 to avoid extra negations. */ - z5 = (tmp10 - tmp12) * ((FAST_FLOAT) 0.382683433); /* c6 */ - z2 = ((FAST_FLOAT) 0.541196100) * tmp10 + z5; /* c2-c6 */ - z4 = ((FAST_FLOAT) 1.306562965) * tmp12 + z5; /* c2+c6 */ - z3 = tmp11 * ((FAST_FLOAT) 0.707106781); /* c4 */ - - z11 = tmp7 + z3; /* phase 5 */ - z13 = tmp7 - z3; - - dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */ - dataptr[DCTSIZE*3] = z13 - z2; - dataptr[DCTSIZE*1] = z11 + z4; - dataptr[DCTSIZE*7] = z11 - z4; - - dataptr++; /* advance pointer to next column */ - } -} - -#endif /* DCT_FLOAT_SUPPORTED */ |