Doxygen Source Code Documentation
jfdctfst.c File Reference
#include "jinclude.h"#include "jpeglib.h"#include "jdct.h"Go to the source code of this file.
Defines | |
| #define | JPEG_INTERNALS |
| #define | CONST_BITS 8 |
| #define | FIX_0_382683433 ((INT32) 98) |
| #define | FIX_0_541196100 ((INT32) 139) |
| #define | FIX_0_707106781 ((INT32) 181) |
| #define | FIX_1_306562965 ((INT32) 334) |
| #define | DESCALE(x, n) RIGHT_SHIFT(x, n) |
| #define | MULTIPLY(var, const) ((DCTELEM) DESCALE((var) * (const), CONST_BITS)) |
Functions | |
| jpeg_fdct_ifast (DCTELEM *data) | |
Define Documentation
|
|
Definition at line 68 of file jfdctfst.c. |
|
|
Definition at line 98 of file jfdctfst.c. |
|
|
Definition at line 79 of file jfdctfst.c. Referenced by jpeg_fdct_ifast(). |
|
|
Definition at line 80 of file jfdctfst.c. Referenced by jpeg_fdct_ifast(). |
|
|
Definition at line 81 of file jfdctfst.c. Referenced by jpeg_fdct_ifast(). |
|
|
Definition at line 82 of file jfdctfst.c. Referenced by jpeg_fdct_ifast(). |
|
|
Definition at line 33 of file jfdctfst.c. |
|
|
Definition at line 106 of file jfdctfst.c. Referenced by jpeg_fdct_ifast(), jpeg_fdct_islow(), jpeg_idct_2x2(), jpeg_idct_4x4(), jpeg_idct_ifast(), and jpeg_idct_islow(). |
Function Documentation
|
|
Definition at line 114 of file jfdctfst.c. References dataptr, FIX_0_382683433, FIX_0_541196100, FIX_0_707106781, FIX_1_306562965, MULTIPLY, and z1. Referenced by jinit_forward_dct().
00115 {
00116 DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
00117 DCTELEM tmp10, tmp11, tmp12, tmp13;
00118 DCTELEM z1, z2, z3, z4, z5, z11, z13;
00119 DCTELEM *dataptr;
00120 int ctr;
00121 SHIFT_TEMPS
00122
00123 /* Pass 1: process rows. */
00124
00125 dataptr = data;
00126 for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
00127 tmp0 = dataptr[0] + dataptr[7];
00128 tmp7 = dataptr[0] - dataptr[7];
00129 tmp1 = dataptr[1] + dataptr[6];
00130 tmp6 = dataptr[1] - dataptr[6];
00131 tmp2 = dataptr[2] + dataptr[5];
00132 tmp5 = dataptr[2] - dataptr[5];
00133 tmp3 = dataptr[3] + dataptr[4];
00134 tmp4 = dataptr[3] - dataptr[4];
00135
00136 /* Even part */
00137
00138 tmp10 = tmp0 + tmp3; /* phase 2 */
00139 tmp13 = tmp0 - tmp3;
00140 tmp11 = tmp1 + tmp2;
00141 tmp12 = tmp1 - tmp2;
00142
00143 dataptr[0] = tmp10 + tmp11; /* phase 3 */
00144 dataptr[4] = tmp10 - tmp11;
00145
00146 z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
00147 dataptr[2] = tmp13 + z1; /* phase 5 */
00148 dataptr[6] = tmp13 - z1;
00149
00150 /* Odd part */
00151
00152 tmp10 = tmp4 + tmp5; /* phase 2 */
00153 tmp11 = tmp5 + tmp6;
00154 tmp12 = tmp6 + tmp7;
00155
00156 /* The rotator is modified from fig 4-8 to avoid extra negations. */
00157 z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
00158 z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
00159 z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
00160 z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
00161
00162 z11 = tmp7 + z3; /* phase 5 */
00163 z13 = tmp7 - z3;
00164
00165 dataptr[5] = z13 + z2; /* phase 6 */
00166 dataptr[3] = z13 - z2;
00167 dataptr[1] = z11 + z4;
00168 dataptr[7] = z11 - z4;
00169
00170 dataptr += DCTSIZE; /* advance pointer to next row */
00171 }
00172
00173 /* Pass 2: process columns. */
00174
00175 dataptr = data;
00176 for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
00177 tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
00178 tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
00179 tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
00180 tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
00181 tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
00182 tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
00183 tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
00184 tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];
00185
00186 /* Even part */
00187
00188 tmp10 = tmp0 + tmp3; /* phase 2 */
00189 tmp13 = tmp0 - tmp3;
00190 tmp11 = tmp1 + tmp2;
00191 tmp12 = tmp1 - tmp2;
00192
00193 dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */
00194 dataptr[DCTSIZE*4] = tmp10 - tmp11;
00195
00196 z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
00197 dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */
00198 dataptr[DCTSIZE*6] = tmp13 - z1;
00199
00200 /* Odd part */
00201
00202 tmp10 = tmp4 + tmp5; /* phase 2 */
00203 tmp11 = tmp5 + tmp6;
00204 tmp12 = tmp6 + tmp7;
00205
00206 /* The rotator is modified from fig 4-8 to avoid extra negations. */
00207 z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
00208 z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
00209 z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
00210 z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
00211
00212 z11 = tmp7 + z3; /* phase 5 */
00213 z13 = tmp7 - z3;
00214
00215 dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */
00216 dataptr[DCTSIZE*3] = z13 - z2;
00217 dataptr[DCTSIZE*1] = z11 + z4;
00218 dataptr[DCTSIZE*7] = z11 - z4;
00219
00220 dataptr++; /* advance pointer to next column */
00221 }
00222 }
|
