diff options
author | 2017-01-25 17:49:53 +0100 | |
---|---|---|
committer | 2017-01-25 17:49:53 +0100 | |
commit | 78a7342750182687a08060c5e060cb897800e9f6 (patch) | |
tree | 73ab5b3a3b09c56a73a74950a71701adf7a22cc7 /3rdparty/libjpeg/jidctfst.c | |
parent | 93c92be81517a982ef9b47eed610a3e42ed244bc (diff) |
updated libjpeg to 9c (nw)
Diffstat (limited to '3rdparty/libjpeg/jidctfst.c')
-rw-r--r-- | 3rdparty/libjpeg/jidctfst.c | 89 |
1 files changed, 36 insertions, 53 deletions
diff --git a/3rdparty/libjpeg/jidctfst.c b/3rdparty/libjpeg/jidctfst.c index dba4216fb95..474cc45fd7f 100644 --- a/3rdparty/libjpeg/jidctfst.c +++ b/3rdparty/libjpeg/jidctfst.c @@ -2,6 +2,7 @@ * jidctfst.c * * Copyright (C) 1994-1998, Thomas G. Lane. + * Modified 2015 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. * @@ -133,35 +134,10 @@ #endif -/* Like DESCALE, but applies to a DCTELEM and produces an int. - * We assume that int right shift is unsigned if INT32 right shift is. - */ - -#ifdef RIGHT_SHIFT_IS_UNSIGNED -#define ISHIFT_TEMPS DCTELEM ishift_temp; -#if BITS_IN_JSAMPLE == 8 -#define DCTELEMBITS 16 /* DCTELEM may be 16 or 32 bits */ -#else -#define DCTELEMBITS 32 /* DCTELEM must be 32 bits */ -#endif -#define IRIGHT_SHIFT(x,shft) \ - ((ishift_temp = (x)) < 0 ? \ - (ishift_temp >> (shft)) | ((~((DCTELEM) 0)) << (DCTELEMBITS-(shft))) : \ - (ishift_temp >> (shft))) -#else -#define ISHIFT_TEMPS -#define IRIGHT_SHIFT(x,shft) ((x) >> (shft)) -#endif - -#ifdef USE_ACCURATE_ROUNDING -#define IDESCALE(x,n) ((int) IRIGHT_SHIFT((x) + (1 << ((n)-1)), n)) -#else -#define IDESCALE(x,n) ((int) IRIGHT_SHIFT(x, n)) -#endif - - /* * Perform dequantization and inverse DCT on one block of coefficients. + * + * cK represents cos(K*pi/16). */ GLOBAL(void) @@ -180,7 +156,7 @@ jpeg_idct_ifast (j_decompress_ptr cinfo, jpeg_component_info * compptr, int ctr; int workspace[DCTSIZE2]; /* buffers data between passes */ SHIFT_TEMPS /* for DESCALE */ - ISHIFT_TEMPS /* for IDESCALE */ + ISHIFT_TEMPS /* for IRIGHT_SHIFT */ /* Pass 1: process columns from input, store into work array. */ @@ -253,12 +229,12 @@ jpeg_idct_ifast (j_decompress_ptr cinfo, jpeg_component_info * compptr, tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562); /* 2*c4 */ z5 = MULTIPLY(z10 + z12, FIX_1_847759065); /* 2*c2 */ - tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5; /* 2*(c2-c6) */ - tmp12 = MULTIPLY(z10, - FIX_2_613125930) + z5; /* -2*(c2+c6) */ + tmp10 = z5 - MULTIPLY(z12, FIX_1_082392200); /* 2*(c2-c6) */ + tmp12 = z5 - MULTIPLY(z10, FIX_2_613125930); /* 2*(c2+c6) */ tmp6 = tmp12 - tmp7; /* phase 2 */ tmp5 = tmp11 - tmp6; - tmp4 = tmp10 + tmp5; + tmp4 = tmp10 - tmp5; wsptr[DCTSIZE*0] = (int) (tmp0 + tmp7); wsptr[DCTSIZE*7] = (int) (tmp0 - tmp7); @@ -266,21 +242,28 @@ jpeg_idct_ifast (j_decompress_ptr cinfo, jpeg_component_info * compptr, wsptr[DCTSIZE*6] = (int) (tmp1 - tmp6); wsptr[DCTSIZE*2] = (int) (tmp2 + tmp5); wsptr[DCTSIZE*5] = (int) (tmp2 - tmp5); - wsptr[DCTSIZE*4] = (int) (tmp3 + tmp4); - wsptr[DCTSIZE*3] = (int) (tmp3 - tmp4); + wsptr[DCTSIZE*3] = (int) (tmp3 + tmp4); + wsptr[DCTSIZE*4] = (int) (tmp3 - tmp4); inptr++; /* advance pointers to next column */ quantptr++; wsptr++; } - /* Pass 2: process rows from work array, store into output array. */ - /* Note that we must descale the results by a factor of 8 == 2**3, */ - /* and also undo the PASS1_BITS scaling. */ + /* Pass 2: process rows from work array, store into output array. + * Note that we must descale the results by a factor of 8 == 2**3, + * and also undo the PASS1_BITS scaling. + */ wsptr = workspace; for (ctr = 0; ctr < DCTSIZE; ctr++) { outptr = output_buf[ctr] + output_col; + + /* Add range center and fudge factor for final descale and range-limit. */ + z5 = (DCTELEM) wsptr[0] + + ((((DCTELEM) RANGE_CENTER) << (PASS1_BITS+3)) + + (1 << (PASS1_BITS+2))); + /* 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). @@ -293,7 +276,7 @@ jpeg_idct_ifast (j_decompress_ptr cinfo, jpeg_component_info * compptr, if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && wsptr[4] == 0 && wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) { /* AC terms all zero */ - JSAMPLE dcval = range_limit[IDESCALE(wsptr[0], PASS1_BITS+3) + JSAMPLE dcval = range_limit[(int) IRIGHT_SHIFT(z5, PASS1_BITS+3) & RANGE_MASK]; outptr[0] = dcval; @@ -312,12 +295,12 @@ jpeg_idct_ifast (j_decompress_ptr cinfo, jpeg_component_info * compptr, /* Even part */ - tmp10 = ((DCTELEM) wsptr[0] + (DCTELEM) wsptr[4]); - tmp11 = ((DCTELEM) wsptr[0] - (DCTELEM) wsptr[4]); + tmp10 = z5 + (DCTELEM) wsptr[4]; + tmp11 = z5 - (DCTELEM) wsptr[4]; - tmp13 = ((DCTELEM) wsptr[2] + (DCTELEM) wsptr[6]); - tmp12 = MULTIPLY((DCTELEM) wsptr[2] - (DCTELEM) wsptr[6], FIX_1_414213562) - - tmp13; + tmp13 = (DCTELEM) wsptr[2] + (DCTELEM) wsptr[6]; + tmp12 = MULTIPLY((DCTELEM) wsptr[2] - (DCTELEM) wsptr[6], + FIX_1_414213562) - tmp13; /* 2*c4 */ tmp0 = tmp10 + tmp13; tmp3 = tmp10 - tmp13; @@ -335,30 +318,30 @@ jpeg_idct_ifast (j_decompress_ptr cinfo, jpeg_component_info * compptr, tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562); /* 2*c4 */ z5 = MULTIPLY(z10 + z12, FIX_1_847759065); /* 2*c2 */ - tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5; /* 2*(c2-c6) */ - tmp12 = MULTIPLY(z10, - FIX_2_613125930) + z5; /* -2*(c2+c6) */ + tmp10 = z5 - MULTIPLY(z12, FIX_1_082392200); /* 2*(c2-c6) */ + tmp12 = z5 - MULTIPLY(z10, FIX_2_613125930); /* 2*(c2+c6) */ tmp6 = tmp12 - tmp7; /* phase 2 */ tmp5 = tmp11 - tmp6; - tmp4 = tmp10 + tmp5; + tmp4 = tmp10 - tmp5; /* Final output stage: scale down by a factor of 8 and range-limit */ - outptr[0] = range_limit[IDESCALE(tmp0 + tmp7, PASS1_BITS+3) + outptr[0] = range_limit[(int) IRIGHT_SHIFT(tmp0 + tmp7, PASS1_BITS+3) & RANGE_MASK]; - outptr[7] = range_limit[IDESCALE(tmp0 - tmp7, PASS1_BITS+3) + outptr[7] = range_limit[(int) IRIGHT_SHIFT(tmp0 - tmp7, PASS1_BITS+3) & RANGE_MASK]; - outptr[1] = range_limit[IDESCALE(tmp1 + tmp6, PASS1_BITS+3) + outptr[1] = range_limit[(int) IRIGHT_SHIFT(tmp1 + tmp6, PASS1_BITS+3) & RANGE_MASK]; - outptr[6] = range_limit[IDESCALE(tmp1 - tmp6, PASS1_BITS+3) + outptr[6] = range_limit[(int) IRIGHT_SHIFT(tmp1 - tmp6, PASS1_BITS+3) & RANGE_MASK]; - outptr[2] = range_limit[IDESCALE(tmp2 + tmp5, PASS1_BITS+3) + outptr[2] = range_limit[(int) IRIGHT_SHIFT(tmp2 + tmp5, PASS1_BITS+3) & RANGE_MASK]; - outptr[5] = range_limit[IDESCALE(tmp2 - tmp5, PASS1_BITS+3) + outptr[5] = range_limit[(int) IRIGHT_SHIFT(tmp2 - tmp5, PASS1_BITS+3) & RANGE_MASK]; - outptr[4] = range_limit[IDESCALE(tmp3 + tmp4, PASS1_BITS+3) + outptr[3] = range_limit[(int) IRIGHT_SHIFT(tmp3 + tmp4, PASS1_BITS+3) & RANGE_MASK]; - outptr[3] = range_limit[IDESCALE(tmp3 - tmp4, PASS1_BITS+3) + outptr[4] = range_limit[(int) IRIGHT_SHIFT(tmp3 - tmp4, PASS1_BITS+3) & RANGE_MASK]; wsptr += DCTSIZE; /* advance pointer to next row */ |