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Diffstat (limited to 'plugins/FreeImage/Source/LibJPEG/jidctflt.c')
| -rw-r--r-- | plugins/FreeImage/Source/LibJPEG/jidctflt.c | 235 |
1 files changed, 0 insertions, 235 deletions
diff --git a/plugins/FreeImage/Source/LibJPEG/jidctflt.c b/plugins/FreeImage/Source/LibJPEG/jidctflt.c deleted file mode 100644 index 23ae9d333b..0000000000 --- a/plugins/FreeImage/Source/LibJPEG/jidctflt.c +++ /dev/null @@ -1,235 +0,0 @@ -/* - * jidctflt.c - * - * Copyright (C) 1994-1998, Thomas G. Lane. - * Modified 2010 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 - * inverse DCT (Discrete Cosine Transform). In the IJG code, this routine - * must also perform dequantization of the input coefficients. - * - * This implementation should be more accurate than either of the integer - * IDCT 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 IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT - * on each row (or vice versa, but it's more convenient to emit a row at - * a time). 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 - - -/* Dequantize a coefficient by multiplying it by the multiplier-table - * entry; produce a float result. - */ - -#define DEQUANTIZE(coef,quantval) (((FAST_FLOAT) (coef)) * (quantval)) - - -/* - * Perform dequantization and inverse DCT on one block of coefficients. - */ - -GLOBAL(void) -jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, - JSAMPARRAY output_buf, JDIMENSION output_col) -{ - FAST_FLOAT tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; - FAST_FLOAT tmp10, tmp11, tmp12, tmp13; - FAST_FLOAT z5, z10, z11, z12, z13; - JCOEFPTR inptr; - FLOAT_MULT_TYPE * quantptr; - FAST_FLOAT * wsptr; - JSAMPROW outptr; - JSAMPLE *range_limit = cinfo->sample_range_limit; - int ctr; - FAST_FLOAT workspace[DCTSIZE2]; /* buffers data between passes */ - - /* Pass 1: process columns from input, store into work array. */ - - inptr = coef_block; - quantptr = (FLOAT_MULT_TYPE *) compptr->dct_table; - wsptr = workspace; - for (ctr = DCTSIZE; ctr > 0; ctr--) { - /* Due to quantization, we will usually find that many of the input - * coefficients are zero, especially the AC terms. We can exploit this - * by short-circuiting the IDCT calculation for any column in which all - * the AC terms are zero. In that case each output is equal to the - * DC coefficient (with scale factor as needed). - * With typical images and quantization tables, half or more of the - * column DCT calculations can be simplified this way. - */ - - if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 && - inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*4] == 0 && - inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*6] == 0 && - inptr[DCTSIZE*7] == 0) { - /* AC terms all zero */ - FAST_FLOAT dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); - - wsptr[DCTSIZE*0] = dcval; - wsptr[DCTSIZE*1] = dcval; - wsptr[DCTSIZE*2] = dcval; - wsptr[DCTSIZE*3] = dcval; - wsptr[DCTSIZE*4] = dcval; - wsptr[DCTSIZE*5] = dcval; - wsptr[DCTSIZE*6] = dcval; - wsptr[DCTSIZE*7] = dcval; - - inptr++; /* advance pointers to next column */ - quantptr++; - wsptr++; - continue; - } - - /* Even part */ - - tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); - tmp1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); - tmp2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]); - tmp3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); - - tmp10 = tmp0 + tmp2; /* phase 3 */ - tmp11 = tmp0 - tmp2; - - tmp13 = tmp1 + tmp3; /* phases 5-3 */ - tmp12 = (tmp1 - tmp3) * ((FAST_FLOAT) 1.414213562) - tmp13; /* 2*c4 */ - - tmp0 = tmp10 + tmp13; /* phase 2 */ - tmp3 = tmp10 - tmp13; - tmp1 = tmp11 + tmp12; - tmp2 = tmp11 - tmp12; - - /* Odd part */ - - tmp4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); - tmp5 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); - tmp6 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); - tmp7 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); - - z13 = tmp6 + tmp5; /* phase 6 */ - z10 = tmp6 - tmp5; - z11 = tmp4 + tmp7; - z12 = tmp4 - tmp7; - - tmp7 = z11 + z13; /* phase 5 */ - tmp11 = (z11 - z13) * ((FAST_FLOAT) 1.414213562); /* 2*c4 */ - - z5 = (z10 + z12) * ((FAST_FLOAT) 1.847759065); /* 2*c2 */ - tmp10 = z5 - z12 * ((FAST_FLOAT) 1.082392200); /* 2*(c2-c6) */ - tmp12 = z5 - z10 * ((FAST_FLOAT) 2.613125930); /* 2*(c2+c6) */ - - tmp6 = tmp12 - tmp7; /* phase 2 */ - tmp5 = tmp11 - tmp6; - tmp4 = tmp10 - tmp5; - - wsptr[DCTSIZE*0] = tmp0 + tmp7; - wsptr[DCTSIZE*7] = tmp0 - tmp7; - wsptr[DCTSIZE*1] = tmp1 + tmp6; - wsptr[DCTSIZE*6] = tmp1 - tmp6; - wsptr[DCTSIZE*2] = tmp2 + tmp5; - wsptr[DCTSIZE*5] = tmp2 - tmp5; - wsptr[DCTSIZE*3] = tmp3 + tmp4; - wsptr[DCTSIZE*4] = tmp3 - tmp4; - - inptr++; /* advance pointers to next column */ - quantptr++; - wsptr++; - } - - /* Pass 2: process rows from work array, store into output array. */ - - wsptr = workspace; - for (ctr = 0; ctr < DCTSIZE; ctr++) { - outptr = output_buf[ctr] + output_col; - /* Rows of zeroes can be exploited in the same way as we did with columns. - * However, the column calculation has created many nonzero AC terms, so - * the simplification applies less often (typically 5% to 10% of the time). - * And testing floats for zero is relatively expensive, so we don't bother. - */ - - /* Even part */ - - /* Apply signed->unsigned and prepare float->int conversion */ - z5 = wsptr[0] + ((FAST_FLOAT) CENTERJSAMPLE + (FAST_FLOAT) 0.5); - tmp10 = z5 + wsptr[4]; - tmp11 = z5 - wsptr[4]; - - tmp13 = wsptr[2] + wsptr[6]; - tmp12 = (wsptr[2] - wsptr[6]) * ((FAST_FLOAT) 1.414213562) - tmp13; - - tmp0 = tmp10 + tmp13; - tmp3 = tmp10 - tmp13; - tmp1 = tmp11 + tmp12; - tmp2 = tmp11 - tmp12; - - /* Odd part */ - - z13 = wsptr[5] + wsptr[3]; - z10 = wsptr[5] - wsptr[3]; - z11 = wsptr[1] + wsptr[7]; - z12 = wsptr[1] - wsptr[7]; - - tmp7 = z11 + z13; - tmp11 = (z11 - z13) * ((FAST_FLOAT) 1.414213562); - - z5 = (z10 + z12) * ((FAST_FLOAT) 1.847759065); /* 2*c2 */ - tmp10 = z5 - z12 * ((FAST_FLOAT) 1.082392200); /* 2*(c2-c6) */ - tmp12 = z5 - z10 * ((FAST_FLOAT) 2.613125930); /* 2*(c2+c6) */ - - tmp6 = tmp12 - tmp7; - tmp5 = tmp11 - tmp6; - tmp4 = tmp10 - tmp5; - - /* Final output stage: float->int conversion and range-limit */ - - outptr[0] = range_limit[((int) (tmp0 + tmp7)) & RANGE_MASK]; - outptr[7] = range_limit[((int) (tmp0 - tmp7)) & RANGE_MASK]; - outptr[1] = range_limit[((int) (tmp1 + tmp6)) & RANGE_MASK]; - outptr[6] = range_limit[((int) (tmp1 - tmp6)) & RANGE_MASK]; - outptr[2] = range_limit[((int) (tmp2 + tmp5)) & RANGE_MASK]; - outptr[5] = range_limit[((int) (tmp2 - tmp5)) & RANGE_MASK]; - outptr[3] = range_limit[((int) (tmp3 + tmp4)) & RANGE_MASK]; - outptr[4] = range_limit[((int) (tmp3 - tmp4)) & RANGE_MASK]; - - wsptr += DCTSIZE; /* advance pointer to next row */ - } -} - -#endif /* DCT_FLOAT_SUPPORTED */ |