1 // Copyright 2012 Google Inc. All Rights Reserved.
2 //
3 // Use of this source code is governed by a BSD-style license
4 // that can be found in the COPYING file in the root of the source
5 // tree. An additional intellectual property rights grant can be found
6 // in the file PATENTS. All contributing project authors may
7 // be found in the AUTHORS file in the root of the source tree.
8 // -----------------------------------------------------------------------------
9 //
10 // Rescaling functions
11 //
12 // Author: Skal (pascal.massimino@gmail.com)
13
14 #include <assert.h>
15 #include <stdlib.h>
16 #include "./rescaler.h"
17 #include "../dsp/dsp.h"
18
19 //------------------------------------------------------------------------------
20 // Implementations of critical functions ImportRow / ExportRow
21
22 void (*WebPRescalerImportRow)(WebPRescaler* const wrk,
23 const uint8_t* const src, int channel) = NULL;
24 void (*WebPRescalerExportRow)(WebPRescaler* const wrk, int x_out) = NULL;
25
26 #define RFIX 30
27 #define MULT_FIX(x, y) (((int64_t)(x) * (y) + (1 << (RFIX - 1))) >> RFIX)
28
ImportRowC(WebPRescaler * const wrk,const uint8_t * const src,int channel)29 static void ImportRowC(WebPRescaler* const wrk,
30 const uint8_t* const src, int channel) {
31 const int x_stride = wrk->num_channels;
32 const int x_out_max = wrk->dst_width * wrk->num_channels;
33 int x_in = channel;
34 int x_out;
35 int accum = 0;
36 if (!wrk->x_expand) {
37 int sum = 0;
38 for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
39 accum += wrk->x_add;
40 for (; accum > 0; accum -= wrk->x_sub) {
41 sum += src[x_in];
42 x_in += x_stride;
43 }
44 { // Emit next horizontal pixel.
45 const int32_t base = src[x_in];
46 const int32_t frac = base * (-accum);
47 x_in += x_stride;
48 wrk->frow[x_out] = (sum + base) * wrk->x_sub - frac;
49 // fresh fractional start for next pixel
50 sum = (int)MULT_FIX(frac, wrk->fx_scale);
51 }
52 }
53 } else { // simple bilinear interpolation
54 int left = src[channel], right = src[channel];
55 for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
56 if (accum < 0) {
57 left = right;
58 x_in += x_stride;
59 right = src[x_in];
60 accum += wrk->x_add;
61 }
62 wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum;
63 accum -= wrk->x_sub;
64 }
65 }
66 // Accumulate the contribution of the new row.
67 for (x_out = channel; x_out < x_out_max; x_out += x_stride) {
68 wrk->irow[x_out] += wrk->frow[x_out];
69 }
70 }
71
ExportRowC(WebPRescaler * const wrk,int x_out)72 static void ExportRowC(WebPRescaler* const wrk, int x_out) {
73 if (wrk->y_accum <= 0) {
74 uint8_t* const dst = wrk->dst;
75 int32_t* const irow = wrk->irow;
76 const int32_t* const frow = wrk->frow;
77 const int yscale = wrk->fy_scale * (-wrk->y_accum);
78 const int x_out_max = wrk->dst_width * wrk->num_channels;
79 for (; x_out < x_out_max; ++x_out) {
80 const int frac = (int)MULT_FIX(frow[x_out], yscale);
81 const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
82 dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
83 irow[x_out] = frac; // new fractional start
84 }
85 wrk->y_accum += wrk->y_add;
86 wrk->dst += wrk->dst_stride;
87 }
88 }
89
90 //------------------------------------------------------------------------------
91 // MIPS version
92
93 #if defined(WEBP_USE_MIPS32)
94
ImportRowMIPS(WebPRescaler * const wrk,const uint8_t * const src,int channel)95 static void ImportRowMIPS(WebPRescaler* const wrk,
96 const uint8_t* const src, int channel) {
97 const int x_stride = wrk->num_channels;
98 const int x_out_max = wrk->dst_width * wrk->num_channels;
99 const int fx_scale = wrk->fx_scale;
100 const int x_add = wrk->x_add;
101 const int x_sub = wrk->x_sub;
102 int* frow = wrk->frow + channel;
103 int* irow = wrk->irow + channel;
104 const uint8_t* src1 = src + channel;
105 int temp1, temp2, temp3;
106 int base, frac, sum;
107 int accum, accum1;
108 const int x_stride1 = x_stride << 2;
109 int loop_c = x_out_max - channel;
110
111 if (!wrk->x_expand) {
112 __asm__ volatile (
113 "li %[temp1], 0x8000 \n\t"
114 "li %[temp2], 0x10000 \n\t"
115 "li %[sum], 0 \n\t"
116 "li %[accum], 0 \n\t"
117 "1: \n\t"
118 "addu %[accum], %[accum], %[x_add] \n\t"
119 "blez %[accum], 3f \n\t"
120 "2: \n\t"
121 "lbu %[temp3], 0(%[src1]) \n\t"
122 "subu %[accum], %[accum], %[x_sub] \n\t"
123 "addu %[src1], %[src1], %[x_stride] \n\t"
124 "addu %[sum], %[sum], %[temp3] \n\t"
125 "bgtz %[accum], 2b \n\t"
126 "3: \n\t"
127 "lbu %[base], 0(%[src1]) \n\t"
128 "addu %[src1], %[src1], %[x_stride] \n\t"
129 "negu %[accum1], %[accum] \n\t"
130 "mul %[frac], %[base], %[accum1] \n\t"
131 "addu %[temp3], %[sum], %[base] \n\t"
132 "mul %[temp3], %[temp3], %[x_sub] \n\t"
133 "lw %[base], 0(%[irow]) \n\t"
134 "subu %[loop_c], %[loop_c], %[x_stride] \n\t"
135 "sll %[accum1], %[frac], 2 \n\t"
136 "mult %[temp1], %[temp2] \n\t"
137 "madd %[accum1], %[fx_scale] \n\t"
138 "mfhi %[sum] \n\t"
139 "subu %[temp3], %[temp3], %[frac] \n\t"
140 "sw %[temp3], 0(%[frow]) \n\t"
141 "add %[base], %[base], %[temp3] \n\t"
142 "sw %[base], 0(%[irow]) \n\t"
143 "addu %[irow], %[irow], %[x_stride1] \n\t"
144 "addu %[frow], %[frow], %[x_stride1] \n\t"
145 "bgtz %[loop_c], 1b \n\t"
146
147 : [accum] "=&r" (accum), [src1] "+r" (src1), [temp3] "=&r" (temp3),
148 [sum] "=&r" (sum), [base] "=&r" (base), [frac] "=&r" (frac),
149 [frow] "+r" (frow), [irow] "+r" (irow), [accum1] "=&r" (accum1),
150 [temp2] "=&r" (temp2), [temp1] "=&r" (temp1)
151 : [x_stride] "r" (x_stride), [fx_scale] "r" (fx_scale),
152 [x_sub] "r" (x_sub), [x_add] "r" (x_add),
153 [loop_c] "r" (loop_c), [x_stride1] "r" (x_stride1)
154 : "memory", "hi", "lo"
155 );
156 } else {
157 __asm__ volatile (
158 "lbu %[temp1], 0(%[src1]) \n\t"
159 "move %[temp2], %[temp1] \n\t"
160 "li %[accum], 0 \n\t"
161 "1: \n\t"
162 "bgez %[accum], 2f \n\t"
163 "move %[temp2], %[temp1] \n\t"
164 "addu %[src1], %[x_stride] \n\t"
165 "lbu %[temp1], 0(%[src1]) \n\t"
166 "addu %[accum], %[x_add] \n\t"
167 "2: \n\t"
168 "subu %[temp3], %[temp2], %[temp1] \n\t"
169 "mul %[temp3], %[temp3], %[accum] \n\t"
170 "mul %[base], %[temp1], %[x_add] \n\t"
171 "subu %[accum], %[accum], %[x_sub] \n\t"
172 "lw %[frac], 0(%[irow]) \n\t"
173 "subu %[loop_c], %[loop_c], %[x_stride] \n\t"
174 "addu %[temp3], %[base], %[temp3] \n\t"
175 "sw %[temp3], 0(%[frow]) \n\t"
176 "addu %[frow], %[x_stride1] \n\t"
177 "addu %[frac], %[temp3] \n\t"
178 "sw %[frac], 0(%[irow]) \n\t"
179 "addu %[irow], %[x_stride1] \n\t"
180 "bgtz %[loop_c], 1b \n\t"
181
182 : [src1] "+r" (src1), [accum] "=&r" (accum), [temp1] "=&r" (temp1),
183 [temp2] "=&r" (temp2), [temp3] "=&r" (temp3), [base] "=&r" (base),
184 [frac] "=&r" (frac), [frow] "+r" (frow), [irow] "+r" (irow)
185 : [x_stride] "r" (x_stride), [x_add] "r" (x_add), [x_sub] "r" (x_sub),
186 [x_stride1] "r" (x_stride1), [loop_c] "r" (loop_c)
187 : "memory", "hi", "lo"
188 );
189 }
190 }
191
ExportRowMIPS(WebPRescaler * const wrk,int x_out)192 static void ExportRowMIPS(WebPRescaler* const wrk, int x_out) {
193 if (wrk->y_accum <= 0) {
194 uint8_t* const dst = wrk->dst;
195 int32_t* const irow = wrk->irow;
196 const int32_t* const frow = wrk->frow;
197 const int yscale = wrk->fy_scale * (-wrk->y_accum);
198 const int x_out_max = wrk->dst_width * wrk->num_channels;
199 // if wrk->fxy_scale can fit into 32 bits use optimized code,
200 // otherwise use C code
201 if ((wrk->fxy_scale >> 32) == 0) {
202 int temp0, temp1, temp3, temp4, temp5, temp6, temp7, loop_end;
203 const int temp2 = (int)(wrk->fxy_scale);
204 const int temp8 = x_out_max << 2;
205 uint8_t* dst_t = (uint8_t*)dst;
206 int32_t* irow_t = (int32_t*)irow;
207 const int32_t* frow_t = (const int32_t*)frow;
208
209 __asm__ volatile(
210 "addiu %[temp6], $zero, -256 \n\t"
211 "addiu %[temp7], $zero, 255 \n\t"
212 "li %[temp3], 0x10000 \n\t"
213 "li %[temp4], 0x8000 \n\t"
214 "addu %[loop_end], %[frow_t], %[temp8] \n\t"
215 "1: \n\t"
216 "lw %[temp0], 0(%[frow_t]) \n\t"
217 "mult %[temp3], %[temp4] \n\t"
218 "addiu %[frow_t], %[frow_t], 4 \n\t"
219 "sll %[temp0], %[temp0], 2 \n\t"
220 "madd %[temp0], %[yscale] \n\t"
221 "mfhi %[temp1] \n\t"
222 "lw %[temp0], 0(%[irow_t]) \n\t"
223 "addiu %[dst_t], %[dst_t], 1 \n\t"
224 "addiu %[irow_t], %[irow_t], 4 \n\t"
225 "subu %[temp0], %[temp0], %[temp1] \n\t"
226 "mult %[temp3], %[temp4] \n\t"
227 "sll %[temp0], %[temp0], 2 \n\t"
228 "madd %[temp0], %[temp2] \n\t"
229 "mfhi %[temp5] \n\t"
230 "sw %[temp1], -4(%[irow_t]) \n\t"
231 "and %[temp0], %[temp5], %[temp6] \n\t"
232 "slti %[temp1], %[temp5], 0 \n\t"
233 "beqz %[temp0], 2f \n\t"
234 "xor %[temp5], %[temp5], %[temp5] \n\t"
235 "movz %[temp5], %[temp7], %[temp1] \n\t"
236 "2: \n\t"
237 "sb %[temp5], -1(%[dst_t]) \n\t"
238 "bne %[frow_t], %[loop_end], 1b \n\t"
239
240 : [temp0]"=&r"(temp0), [temp1]"=&r"(temp1), [temp3]"=&r"(temp3),
241 [temp4]"=&r"(temp4), [temp5]"=&r"(temp5), [temp6]"=&r"(temp6),
242 [temp7]"=&r"(temp7), [frow_t]"+r"(frow_t), [irow_t]"+r"(irow_t),
243 [dst_t]"+r"(dst_t), [loop_end]"=&r"(loop_end)
244 : [temp2]"r"(temp2), [yscale]"r"(yscale), [temp8]"r"(temp8)
245 : "memory", "hi", "lo"
246 );
247 wrk->y_accum += wrk->y_add;
248 wrk->dst += wrk->dst_stride;
249 } else {
250 ExportRowC(wrk, x_out);
251 }
252 }
253 }
254 #endif // WEBP_USE_MIPS32
255
256 //------------------------------------------------------------------------------
257
WebPRescalerInit(WebPRescaler * const wrk,int src_width,int src_height,uint8_t * const dst,int dst_width,int dst_height,int dst_stride,int num_channels,int x_add,int x_sub,int y_add,int y_sub,int32_t * const work)258 void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
259 uint8_t* const dst, int dst_width, int dst_height,
260 int dst_stride, int num_channels, int x_add, int x_sub,
261 int y_add, int y_sub, int32_t* const work) {
262 wrk->x_expand = (src_width < dst_width);
263 wrk->src_width = src_width;
264 wrk->src_height = src_height;
265 wrk->dst_width = dst_width;
266 wrk->dst_height = dst_height;
267 wrk->dst = dst;
268 wrk->dst_stride = dst_stride;
269 wrk->num_channels = num_channels;
270 // for 'x_expand', we use bilinear interpolation
271 wrk->x_add = wrk->x_expand ? (x_sub - 1) : x_add - x_sub;
272 wrk->x_sub = wrk->x_expand ? (x_add - 1) : x_sub;
273 wrk->y_accum = y_add;
274 wrk->y_add = y_add;
275 wrk->y_sub = y_sub;
276 wrk->fx_scale = (1 << RFIX) / x_sub;
277 wrk->fy_scale = (1 << RFIX) / y_sub;
278 wrk->fxy_scale = wrk->x_expand ?
279 ((int64_t)dst_height << RFIX) / (x_sub * src_height) :
280 ((int64_t)dst_height << RFIX) / (x_add * src_height);
281 wrk->irow = work;
282 wrk->frow = work + num_channels * dst_width;
283
284 if (WebPRescalerImportRow == NULL) {
285 WebPRescalerImportRow = ImportRowC;
286 WebPRescalerExportRow = ExportRowC;
287 if (VP8GetCPUInfo != NULL) {
288 #if defined(WEBP_USE_MIPS32)
289 if (VP8GetCPUInfo(kMIPS32)) {
290 WebPRescalerImportRow = ImportRowMIPS;
291 WebPRescalerExportRow = ExportRowMIPS;
292 }
293 #endif
294 }
295 }
296 }
297
298 #undef MULT_FIX
299 #undef RFIX
300
301 //------------------------------------------------------------------------------
302 // all-in-one calls
303
WebPRescaleNeededLines(const WebPRescaler * const wrk,int max_num_lines)304 int WebPRescaleNeededLines(const WebPRescaler* const wrk, int max_num_lines) {
305 const int num_lines = (wrk->y_accum + wrk->y_sub - 1) / wrk->y_sub;
306 return (num_lines > max_num_lines) ? max_num_lines : num_lines;
307 }
308
WebPRescalerImport(WebPRescaler * const wrk,int num_lines,const uint8_t * src,int src_stride)309 int WebPRescalerImport(WebPRescaler* const wrk, int num_lines,
310 const uint8_t* src, int src_stride) {
311 int total_imported = 0;
312 while (total_imported < num_lines && wrk->y_accum > 0) {
313 int channel;
314 for (channel = 0; channel < wrk->num_channels; ++channel) {
315 WebPRescalerImportRow(wrk, src, channel);
316 }
317 src += src_stride;
318 ++total_imported;
319 wrk->y_accum -= wrk->y_sub;
320 }
321 return total_imported;
322 }
323
WebPRescalerExport(WebPRescaler * const rescaler)324 int WebPRescalerExport(WebPRescaler* const rescaler) {
325 int total_exported = 0;
326 while (WebPRescalerHasPendingOutput(rescaler)) {
327 WebPRescalerExportRow(rescaler, 0);
328 ++total_exported;
329 }
330 return total_exported;
331 }
332
333 //------------------------------------------------------------------------------
334