align variable names with T.81 standard

xbarin02 · Nov 29, 2020 · fb8709a · fb8709a
1 parent f7105ad
commit fb8709a
Show file tree

Hide file tree

Showing 4 changed files with 26 additions and 20 deletions.
diff --git a/common.c b/common.c
@@ -6,10 +6,10 @@ int init_qtable(struct qtable *qtable)
 {
 	assert(qtable != NULL);
 
-	qtable->precision = 0;
+	qtable->Pq = 0;
 
 	for (int i = 0; i < 64; ++i) {
-		qtable->element[i] = 0;
+		qtable->Q[i] = 0;
 	}
 
 	return RET_SUCCESS;
@@ -63,12 +63,12 @@ int init_context(struct context *context)
 		init_qtable(&context->qtable[i]);
 	}
 
-	context->precision = 0;
+	context->P = 0;
 
 	context->Y = 0;
 	context->X = 0;
 
-	context->components = 0;
+	context->Nf = 0;
 
 	for (int i = 0; i < 256; ++i) {
 		init_component(&context->component[i]);

diff --git a/common.h b/common.h
@@ -52,10 +52,10 @@ static const uint8_t zigzag[64] = {
 	} while (0)
 
 struct qtable {
-	/* Value 0 indicates 8-bit Qk values; value 1 indicates 16-bit Qk values. */
-	uint8_t precision;
-	/* in zig-zag scan order */
-	uint16_t element[64];
+	/* precision: Value 0 indicates 8-bit Qk values; value 1 indicates 16-bit Qk values. */
+	uint8_t Pq;
+	/* elements: in raster scan order */
+	uint16_t Q[64];
 };
 
 struct component {
@@ -120,13 +120,13 @@ struct context {
 	struct qtable qtable[4];
 
 	/*  Sample precision */
-	uint8_t precision;
+	uint8_t P;
 
 	/* Number of lines, Number of samples per line */
 	uint16_t Y, X;
 
 	/* Number of image components in frame */
-	uint8_t components;
+	uint8_t Nf;
 
 	struct component component[256];
 

diff --git a/imgproc.c b/imgproc.c
@@ -25,7 +25,7 @@ int dequantize(struct context *context)
 				struct int_block *int_block = &context->component[i].int_buffer[b];
 
 				for (int j = 0; j < 64; ++j) {
-					int_block->c[j] *= (int32_t)qtable->element[j];
+					int_block->c[j] *= (int32_t)qtable->Q[j];
 				}
 			}
 		}
@@ -108,7 +108,8 @@ int invert_dct(struct context *context)
 
 				idct(flt_block);
 
-				uint8_t P = context->precision;
+				/* precision */
+				uint8_t P = context->P;
 				int shift = 1 << (P - 1);
 
 				// level shift
@@ -191,10 +192,10 @@ int frame_create(struct context *context, struct frame *frame)
 	assert(context != NULL);
 	assert(frame != NULL);
 
-	frame->components = context->components;
+	frame->components = context->Nf;
 	frame->Y = context->Y;
 	frame->X = context->X;
-	frame->precision = context->precision;
+	frame->precision = context->P;
 
 	size_t size_x = ceil_div(frame->X, 8 * context->max_H) * 8 * context->max_H;
 	size_t size_y = ceil_div(frame->Y, 8 * context->max_V) * 8 * context->max_V;

diff --git a/parser.c b/parser.c
@@ -35,25 +35,26 @@ int parse_qtable(FILE *stream, struct context *context)
 
 	qtable = &context->qtable[Tq];
 
-	qtable->precision = Pq;
+	/* precision */
+	qtable->Pq = Pq;
 
 	for (int i = 0; i < 64; ++i) {
 		if (Pq == 0) {
 			uint8_t byte;
 			err = read_byte(stream, &byte);
 			RETURN_IF(err);
-			qtable->element[zigzag[i]] = (uint16_t)byte;
+			qtable->Q[zigzag[i]] = (uint16_t)byte;
 		} else {
 			uint16_t word;
 			err = read_word(stream, &word);
 			RETURN_IF(err);
-			qtable->element[zigzag[i]] = word;
+			qtable->Q[zigzag[i]] = word;
 		}
 	}
 
 	for (int y = 0; y < 8; ++y) {
 		for (int x = 0; x < 8; ++x) {
-			printf("%3" PRIu16 " ", qtable->element[y * 8 + x]);
+			printf("%3" PRIu16 " ", qtable->Q[y * 8 + x]);
 		}
 		printf("\n");
 	}
@@ -116,10 +117,14 @@ int parse_frame_header(FILE *stream, struct context *context)
 
 	printf("P = %" PRIu8 " (Sample precision), Y = %" PRIu16 ", X = %" PRIu16 ", Nf = %" PRIu8 " (Number of image components)\n", P, Y, X, Nf);
 
-	context->precision = P;
+	/* precision */
+	context->P = P;
+
 	context->Y = Y;
 	context->X = X;
-	context->components = Nf;
+
+	/* components */
+	context->Nf = Nf;
 
 	uint8_t max_H = 0, max_V = 0;