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Unified Diff: jidctflt.c

Issue 1953443002: Update to libjpeg_turbo 1.4.90 (Closed) Base URL: https://chromium.googlesource.com/chromium/deps/libjpeg_turbo.git@master
Patch Set: Created 4 years, 7 months ago
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Index: jidctflt.c
diff --git a/jidctflt.c b/jidctflt.c
index 0188ce3dfcd2ce2ebaa57c17da22101de01b6f2a..68c521ed7eebe5aa3b65b6216705b12942be341d 100644
--- a/jidctflt.c
+++ b/jidctflt.c
@@ -1,9 +1,13 @@
/*
* jidctflt.c
*
+ * This file was part of the Independent JPEG Group's software:
* Copyright (C) 1994-1998, Thomas G. Lane.
- * This file is part of the Independent JPEG Group's software.
- * For conditions of distribution and use, see the accompanying README file.
+ * Modified 2010 by Guido Vollbeding.
+ * libjpeg-turbo Modifications:
+ * Copyright (C) 2014, D. R. Commander.
+ * For conditions of distribution and use, see the accompanying README.ijg
+ * file.
*
* This file contains a floating-point implementation of the
* inverse DCT (Discrete Cosine Transform). In the IJG code, this routine
@@ -22,8 +26,8 @@
* 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.
+ * JPEG textbook (see REFERENCES section in file README.ijg). 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
@@ -39,7 +43,7 @@
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
-#include "jdct.h" /* Private declarations for DCT subsystem */
+#include "jdct.h" /* Private declarations for DCT subsystem */
#ifdef DCT_FLOAT_SUPPORTED
@@ -65,21 +69,21 @@
*/
GLOBAL(void)
-jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
+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;
+ 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
+ #define _0_125 ((FLOAT_MULT_TYPE)0.125)
/* Pass 1: process columns from input, store into work array. */
@@ -95,14 +99,15 @@ jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr,
* 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) {
+ 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]);
-
+ FAST_FLOAT dcval = DEQUANTIZE(inptr[DCTSIZE*0],
+ quantptr[DCTSIZE*0] * _0_125);
+
wsptr[DCTSIZE*0] = dcval;
wsptr[DCTSIZE*1] = dcval;
wsptr[DCTSIZE*2] = dcval;
@@ -111,53 +116,53 @@ jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr,
wsptr[DCTSIZE*5] = dcval;
wsptr[DCTSIZE*6] = dcval;
wsptr[DCTSIZE*7] = dcval;
-
- inptr++; /* advance pointers to next column */
+
+ 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]);
+ tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0] * _0_125);
+ tmp1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2] * _0_125);
+ tmp2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4] * _0_125);
+ tmp3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6] * _0_125);
- tmp10 = tmp0 + tmp2; /* phase 3 */
+ tmp10 = tmp0 + tmp2; /* phase 3 */
tmp11 = tmp0 - tmp2;
- tmp13 = tmp1 + tmp3; /* phases 5-3 */
+ tmp13 = tmp1 + tmp3; /* phases 5-3 */
tmp12 = (tmp1 - tmp3) * ((FAST_FLOAT) 1.414213562) - tmp13; /* 2*c4 */
- tmp0 = tmp10 + tmp13; /* phase 2 */
+ 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]);
+ tmp4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1] * _0_125);
+ tmp5 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3] * _0_125);
+ tmp6 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5] * _0_125);
+ tmp7 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7] * _0_125);
- z13 = tmp6 + tmp5; /* phase 6 */
+ z13 = tmp6 + tmp5; /* phase 6 */
z10 = tmp6 - tmp5;
z11 = tmp4 + tmp7;
z12 = tmp4 - tmp7;
- tmp7 = z11 + z13; /* phase 5 */
+ tmp7 = z11 + z13; /* phase 5 */
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 */
+ tmp6 = tmp12 - tmp7; /* phase 2 */
tmp5 = tmp11 - tmp6;
- tmp4 = tmp10 + tmp5;
+ tmp4 = tmp10 - tmp5;
wsptr[DCTSIZE*0] = tmp0 + tmp7;
wsptr[DCTSIZE*7] = tmp0 - tmp7;
@@ -165,16 +170,15 @@ 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 */
+ 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. */
wsptr = workspace;
for (ctr = 0; ctr < DCTSIZE; ctr++) {
@@ -184,11 +188,13 @@ jpeg_idct_float (j_decompress_ptr cinfo, jpeg_component_info * compptr,
* 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 */
- 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;
@@ -209,33 +215,25 @@ 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];
-
- wsptr += DCTSIZE; /* advance pointer to next row */
+ 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 */
}
}
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