diff options
Diffstat (limited to 'src/libjpeg/jfdctfst.c')
| -rw-r--r-- | src/libjpeg/jfdctfst.c | 48 |
1 files changed, 27 insertions, 21 deletions
diff --git a/src/libjpeg/jfdctfst.c b/src/libjpeg/jfdctfst.c index ccb378a..8cad5f2 100644 --- a/src/libjpeg/jfdctfst.c +++ b/src/libjpeg/jfdctfst.c @@ -2,6 +2,7 @@ * jfdctfst.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. * @@ -111,42 +112,47 @@ */ GLOBAL(void) -jpeg_fdct_ifast (DCTELEM * data) +jpeg_fdct_ifast (DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col) { DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; DCTELEM tmp10, tmp11, tmp12, tmp13; DCTELEM z1, z2, z3, z4, z5, z11, z13; DCTELEM *dataptr; + JSAMPROW elemptr; int ctr; SHIFT_TEMPS /* Pass 1: process rows. */ 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]; - + for (ctr = 0; ctr < DCTSIZE; ctr++) { + elemptr = sample_data[ctr] + start_col; + + /* Load data into workspace */ + tmp0 = GETJSAMPLE(elemptr[0]) + GETJSAMPLE(elemptr[7]); + tmp7 = GETJSAMPLE(elemptr[0]) - GETJSAMPLE(elemptr[7]); + tmp1 = GETJSAMPLE(elemptr[1]) + GETJSAMPLE(elemptr[6]); + tmp6 = GETJSAMPLE(elemptr[1]) - GETJSAMPLE(elemptr[6]); + tmp2 = GETJSAMPLE(elemptr[2]) + GETJSAMPLE(elemptr[5]); + tmp5 = GETJSAMPLE(elemptr[2]) - GETJSAMPLE(elemptr[5]); + tmp3 = GETJSAMPLE(elemptr[3]) + GETJSAMPLE(elemptr[4]); + tmp4 = GETJSAMPLE(elemptr[3]) - GETJSAMPLE(elemptr[4]); + /* Even part */ - + tmp10 = tmp0 + tmp3; /* phase 2 */ tmp13 = tmp0 - tmp3; tmp11 = tmp1 + tmp2; tmp12 = tmp1 - tmp2; - - dataptr[0] = tmp10 + tmp11; /* phase 3 */ + + /* Apply unsigned->signed conversion */ + dataptr[0] = tmp10 + tmp11 - 8 * CENTERJSAMPLE; /* phase 3 */ dataptr[4] = tmp10 - tmp11; - + z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */ dataptr[2] = tmp13 + z1; /* phase 5 */ dataptr[6] = tmp13 - z1; - + /* Odd part */ tmp10 = tmp4 + tmp5; /* phase 2 */ @@ -182,21 +188,21 @@ jpeg_fdct_ifast (DCTELEM * data) 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 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */ dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */ dataptr[DCTSIZE*6] = tmp13 - z1; - + /* Odd part */ tmp10 = tmp4 + tmp5; /* phase 2 */ |