From: sgunderson@bigfoot.com <>
Date: Sun, 31 May 2009 00:26:38 +0000 (+0200)
Subject: Try to dequantize and IDCT data in the driver.
X-Git-Url: https://git.sesse.net/?p=fjl;a=commitdiff_plain;h=f96984c3f6474f2d85750351fd249b01245b5ec3

Try to dequantize and IDCT data in the driver.
---

diff --git a/driver.c b/driver.c
index bbc569e..1411b51 100644
--- a/driver.c
+++ b/driver.c
@@ -1,9 +1,11 @@
 #include <stdio.h>
+#include <string.h>
 #include <stdlib.h>
 
 #include "bytesource.h"
 #include "choice.h"
 #include "dehuff.h"
+#include "idct.h"
 #include "input.h"
 #include "zigzag.h"
 
@@ -13,6 +15,7 @@ struct jpeg_image {
 	unsigned num_components;
 	unsigned hsample[256], vsample[256], qtable[256];
 	uint32_t qvalues[256][DCTSIZE2];
+	void* idct_data[256];
 };
 
 ssize_t stdio_read(void* userdata, uint8_t* buf, size_t count) 
@@ -28,6 +31,10 @@ void read_dqt(struct byte_source* source, struct jpeg_image* image)
 	int precision = precision_table >> 4;  // 0 = 8 bits, otherwise 16 bits.
 	int table = precision_table & 0x0f;
 
+	if (image->idct_data[table] != NULL) {
+		idct_choice_free(image->idct_data[table]);
+	}
+
 	if (precision != 0) {
 		assert(len == 131);
 		fprintf(stderr, "Quantization table %u: 16 bits/entry\n", table);
@@ -45,6 +52,8 @@ void read_dqt(struct byte_source* source, struct jpeg_image* image)
 				read_uint8(byte_source_input_func, source);
 		}	
 	}
+
+	image->idct_data[table] = idct_choice_alloc(image->qvalues[table]);
 }
 
 void read_sof(struct byte_source* source, struct jpeg_image* image)
@@ -113,51 +122,72 @@ void read_scan(struct byte_source* source, struct jpeg_image* image, huffman_tab
 
 	struct bit_source bits;
 	init_bit_source(&bits, byte_source_input_func, source);
+		
+	// Some debugging code.
+	assert(image->width % 8 == 0);
+	int y_stride = image->width;
+	uint8_t* y_row_data = (uint8_t*)malloc(y_stride * DCTSIZE * image->vsample[1]);
+	assert(y_row_data != NULL);
+	int xb = 0;
 
 	for ( ;; ) {
 		for (unsigned c = 0; c < num_components; ++c) {
 			unsigned cn = component_num[c];
-			unsigned nc = image->vsample[cn] * image->hsample[cn];
-			for (unsigned n = 0; n < nc; ++n) {
-				const struct huffman_table* dc_table = &((*tables)[DC_CLASS][dc_huffman_table[c]]);
-				const struct huffman_table* ac_table = &((*tables)[AC_CLASS][ac_huffman_table[c]]);
-
-				// decode DC component
-				unsigned dc_category = read_huffman_symbol(dc_table, &bits);
-				possibly_refill(&bits, dc_category);
-				last_dc[c] += extend(read_bits(&bits, dc_category), dc_category);
-
-		//		printf("dc=%d ac=", last_dc[c]);
-				putchar(last_dc[c]);
-
-				// decode AC components
-				int zz[63] = { 0 };
-				for (unsigned i = 0; i < 63; ++i) {
-					unsigned rs = read_huffman_symbol(ac_table, &bits);
-					unsigned r = rs >> 4;
-					unsigned s = rs & 0xf;
-
-					if (rs == 0x00) {
-						/* end of block */
-						break;
+			assert(image->idct_data[image->qtable[cn]] != NULL);
+			
+			for (unsigned local_yb = 0; local_yb < image->vsample[cn]; ++local_yb) {
+				for (unsigned local_xb = 0; local_xb < image->hsample[cn]; ++local_xb) {
+					const struct huffman_table* dc_table = &((*tables)[DC_CLASS][dc_huffman_table[c]]);
+					const struct huffman_table* ac_table = &((*tables)[AC_CLASS][ac_huffman_table[c]]);
+
+					// decode DC component
+					unsigned dc_category = read_huffman_symbol(dc_table, &bits);
+					possibly_refill(&bits, dc_category);
+					last_dc[c] += extend(read_bits(&bits, dc_category), dc_category);
+					
+					int16_t coeff[DCTSIZE2] = { 0 };
+					coeff[0] = last_dc[c];
+
+					// decode AC components
+					for (unsigned i = 1; i < DCTSIZE2; ++i) {
+						unsigned rs = read_huffman_symbol(ac_table, &bits);
+						unsigned r = rs >> 4;
+						unsigned s = rs & 0xf;
+
+						if (rs == 0x00) {
+							/* end of block */
+							break;
+						}
+						if (rs == 0xf0) {
+							/* 16 zero coefficients */
+							i += 15;
+							continue;
+						}
+
+						possibly_refill(&bits, s);
+
+						i += r;
+						coeff[unzigzag[i]] = extend(read_bits(&bits, s), s);
 					}
-					if (rs == 0xf0) {
-						/* 16 zero coefficients */
-						i += 15;
+			
+					uint8_t pixdata[DCTSIZE2];	
+					idct_choice(coeff, image->idct_data[image->qtable[cn]], pixdata);
+
+					if (cn != 1) {
 						continue;
 					}
 
-					possibly_refill(&bits, s);
-
-					i += r;
-					zz[unzigzag[i]] = extend(read_bits(&bits, s), s);
-				}
-				
-				for (unsigned i = 0; i < 63; ++i) {
-					putchar(zz[i]);
-					//printf("%d ", zz[i]);
+					for (int y = 0; y < DCTSIZE; ++y) {
+						memcpy(y_row_data + (local_yb * DCTSIZE + y) * y_stride + (xb + local_xb) * DCTSIZE,
+						       pixdata + y * DCTSIZE,
+						       DCTSIZE);
+					}
 				}
-				//printf("\n");
+			}
+
+			if (cn == 1 && ++xb * DCTSIZE == y_stride) {
+				fwrite(y_row_data, y_stride * DCTSIZE * image->vsample[1], 1, stdout);
+				xb = 0;
 			}
 		}
 	}
@@ -184,6 +214,7 @@ void skip_segment(struct byte_source* source)
 int main(void)
 {
 	struct jpeg_image jpeg;
+	memset(&jpeg, 0, sizeof(jpeg));
 	init_choices();
 
 	struct byte_source source;