Merge changes

lab3/Makefile

@@ -0,0 +1,27 @@
+CC = gcc
+CFLAGS = -Wall -std=gnu99 -g # "curl-config --cflags" output is empty  
+LD = gcc
+LDFLAGS = -std=gnu99 -g
+LDLIBS = -lz -lcurl -pthread       # "curl-config --libs" output 
+
+SRCS   = paster2.c zutil.c crc.c
+OBJS   = paster2.o zutil.o crc.o
+TARGETS= paster2
+
+all: ${TARGETS}
+
+paster2: $(OBJS)
+    $(LD) -o $@ $^ $(LDLIBS) $(LDFLAGS)  
+
+%.o: %.c
+    $(CC) $(CFLAGS) -c $< 
+
+%.d: %.c
+    gcc -MM -MF $@ $<
+
+-include $(SRCS:.c=.d)
+
+.PHONY: clean
+clean:
+    rm -f *~ *.d *.o *~ $(TARGETS) *.png
+~                     

lab3/crc.c

@@ -0,0 +1,54 @@
+/********************************************************************
+ * @file: crc.c
+ * @brief: PNG crc calculation
+ * Reference: https://www.w3.org/TR/PNG-CRCAppendix.html
+ */
+
+/* Table of CRCs of all 8-bit messages. */
+unsigned long crc_table[256];
+
+/* Flag: has the table been computed? Initially false. */
+int crc_table_computed = 0;
+
+/* Make the table for a fast CRC. */
+void make_crc_table(void)
+{
+    unsigned long c;
+    int n, k;
+
+    for (n = 0; n < 256; n++) {
+        c = (unsigned long) n;
+        for (k = 0; k < 8; k++) {
+            if (c & 1)
+                c = 0xedb88320L ^ (c >> 1);
+            else
+                c = c >> 1;
+        }
+        crc_table[n] = c;
+    }
+    crc_table_computed = 1;
+}
+
+/* Update a running CRC with the bytes buf[0..len-1]--the CRC
+   should be initialized to all 1's, and the transmitted value
+   is the 1's complement of the final running CRC (see the
+   crc() routine below)). */
+
+unsigned long update_crc(unsigned long crc, unsigned char *buf, int len)
+{
+    unsigned long c = crc;
+    int n;
+
+    if (!crc_table_computed)
+        make_crc_table();
+    for (n = 0; n < len; n++) {
+        c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
+    }
+    return c;
+}
+
+/* Return the CRC of the bytes buf[0..len-1]. */
+unsigned long crc(unsigned char *buf, int len)
+{
+    return update_crc(0xffffffffL, buf, len) ^ 0xffffffffL;
+}

lab3/crc.h

@@ -0,0 +1,10 @@
+/**
+ * @file: crc.h
+ * @brief: crc calculation functions for PNG file
+ */
+
+#pragma once
+
+void make_crc_table(void);
+unsigned long update_crc(unsigned long crc, unsigned char *buf, int len);
+unsigned long crc(unsigned char *buf, int len);

lab3/lab3_eceubuntu1.csv

@@ -0,0 +1,40 @@
+B,P,C,X,N,Time
+5,1,1,0,1,11.031589
+5,1,5,0,1,16.740917
+5,5,1,0,1,2.379882
+5,5,5,0,1,3.559238
+10,1,1,0,1,10.849649
+10,1,5,0,1,14.668302
+10,1,10,0,1,18.287099
+10,5,1,0,1,2.185177
+10,5,5,0,1,3.189513
+10,5,10,0,1,4.437578
+10,10,1,0,1,1.179276
+10,10,5,0,1,1.513533
+10,10,10,0,1,1.901437
+5,1,1,200,1,10.478608
+5,1,5,200,1,10.845563
+5,5,1,200,1,
+5,5,5,200,1,2.95628
+10,1,1,200,1,10.488353
+10,1,5,200,1,10.824044
+10,1,10,200,1,10.901582
+10,5,1,200,1,
+10,5,5,200,1,2.508308
+10,5,10,200,1,2.5136
+10,10,1,200,1,
+10,10,5,200,1,
+10,10,10,200,1,1.720996
+5,1,1,400,1,20.07438
+5,1,5,400,1,10.747398
+5,5,1,400,1,
+5,5,5,400,1,4.502687
+10,1,1,400,1,20.104304
+10,1,5,400,1,10.760721
+10,1,10,400,1,10.815564
+10,5,1,400,1,
+10,5,5,400,1,4.515022
+10,5,10,400,1,2.949063
+10,10,1,400,1,
+10,10,5,400,1,
+10,10,10,400,1,2.562455