diff options
Diffstat (limited to 'src/3rdparty/libjpeg/jidctflt.c')
| -rw-r--r-- | src/3rdparty/libjpeg/jidctflt.c | 57 |
1 files changed, 25 insertions, 32 deletions
diff --git a/src/3rdparty/libjpeg/jidctflt.c b/src/3rdparty/libjpeg/jidctflt.c index 0188ce3..23ae9d3 100644 --- a/src/3rdparty/libjpeg/jidctflt.c +++ b/src/3rdparty/libjpeg/jidctflt.c @@ -2,6 +2,7 @@ * 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. * @@ -76,10 +77,9 @@ jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr, FLOAT_MULT_TYPE * quantptr; FAST_FLOAT * wsptr; JSAMPROW outptr; - JSAMPLE *range_limit = IDCT_range_limit(cinfo); + JSAMPLE *range_limit = cinfo->sample_range_limit; int ctr; FAST_FLOAT workspace[DCTSIZE2]; /* buffers data between passes */ - SHIFT_TEMPS /* Pass 1: process columns from input, store into work array. */ @@ -152,12 +152,12 @@ jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr, tmp11 = (z11 - z13) * ((FAST_FLOAT) 1.414213562); /* 2*c4 */ z5 = (z10 + z12) * ((FAST_FLOAT) 1.847759065); /* 2*c2 */ - tmp10 = ((FAST_FLOAT) 1.082392200) * z12 - z5; /* 2*(c2-c6) */ - tmp12 = ((FAST_FLOAT) -2.613125930) * z10 + z5; /* -2*(c2+c6) */ + 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; + tmp4 = tmp10 - tmp5; wsptr[DCTSIZE*0] = tmp0 + tmp7; wsptr[DCTSIZE*7] = tmp0 - tmp7; @@ -165,8 +165,8 @@ jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr, wsptr[DCTSIZE*6] = tmp1 - tmp6; wsptr[DCTSIZE*2] = tmp2 + tmp5; wsptr[DCTSIZE*5] = tmp2 - tmp5; - wsptr[DCTSIZE*4] = tmp3 + tmp4; - wsptr[DCTSIZE*3] = tmp3 - tmp4; + wsptr[DCTSIZE*3] = tmp3 + tmp4; + wsptr[DCTSIZE*4] = tmp3 - tmp4; inptr++; /* advance pointers to next column */ quantptr++; @@ -174,7 +174,6 @@ jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr, } /* 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. */ wsptr = workspace; for (ctr = 0; ctr < DCTSIZE; ctr++) { @@ -187,8 +186,10 @@ jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr, /* Even part */ - tmp10 = wsptr[0] + wsptr[4]; - tmp11 = wsptr[0] - wsptr[4]; + /* 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; @@ -209,31 +210,23 @@ jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr, tmp11 = (z11 - z13) * ((FAST_FLOAT) 1.414213562); z5 = (z10 + z12) * ((FAST_FLOAT) 1.847759065); /* 2*c2 */ - tmp10 = ((FAST_FLOAT) 1.082392200) * z12 - z5; /* 2*(c2-c6) */ - tmp12 = ((FAST_FLOAT) -2.613125930) * z10 + z5; /* -2*(c2+c6) */ + 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: scale down by a factor of 8 and range-limit */ - - outptr[0] = range_limit[(int) DESCALE((INT32) (tmp0 + tmp7), 3) - & RANGE_MASK]; - outptr[7] = range_limit[(int) DESCALE((INT32) (tmp0 - tmp7), 3) - & RANGE_MASK]; - outptr[1] = range_limit[(int) DESCALE((INT32) (tmp1 + tmp6), 3) - & RANGE_MASK]; - outptr[6] = range_limit[(int) DESCALE((INT32) (tmp1 - tmp6), 3) - & RANGE_MASK]; - outptr[2] = range_limit[(int) DESCALE((INT32) (tmp2 + tmp5), 3) - & RANGE_MASK]; - outptr[5] = range_limit[(int) DESCALE((INT32) (tmp2 - tmp5), 3) - & RANGE_MASK]; - outptr[4] = range_limit[(int) DESCALE((INT32) (tmp3 + tmp4), 3) - & RANGE_MASK]; - outptr[3] = range_limit[(int) DESCALE((INT32) (tmp3 - tmp4), 3) - & RANGE_MASK]; + 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 */ } |