summaryrefslogtreecommitdiff
path: root/src/libjpeg/jfdctflt.c
diff options
context:
space:
mode:
authorscuri <scuri>2009-08-20 01:10:27 +0000
committerscuri <scuri>2009-08-20 01:10:27 +0000
commit83b3c8b629d96f5fdf754d35d5f4f5369dbfef1d (patch)
tree81242227fb731da262139283c301e58f861e9727 /src/libjpeg/jfdctflt.c
parentb014c9fa4544c111796aed1406e704338bacf456 (diff)
*** empty log message ***
Diffstat (limited to 'src/libjpeg/jfdctflt.c')
-rw-r--r--src/libjpeg/jfdctflt.c48
1 files changed, 27 insertions, 21 deletions
diff --git a/src/libjpeg/jfdctflt.c b/src/libjpeg/jfdctflt.c
index 79d7a00..74d0d86 100644
--- a/src/libjpeg/jfdctflt.c
+++ b/src/libjpeg/jfdctflt.c
@@ -2,6 +2,7 @@
* 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.
*
@@ -56,41 +57,46 @@
*/
GLOBAL(void)
-jpeg_fdct_float (FAST_FLOAT * data)
+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 = 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 = (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;
-
- dataptr[0] = tmp10 + tmp11; /* phase 3 */
+
+ /* 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 */
@@ -126,21 +132,21 @@ jpeg_fdct_float (FAST_FLOAT * 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 = (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 */