Add a9 file submissions

Before didn't write the final IEND chunk

Assignment8/code/disk.c

@@ -75,36 +75,30 @@ void destroyDiskQueue(DiskQueue *queue) {
 	free(queue);
 }
 
+int calcDistance(int position, int destination) {
+	if (position > destination) {
+		return destination + (9999 + 1 - position);
+	} else {
+		return destination - position;
+	}
+}
+
 DiskRequest* findClosest(DiskQueue *queue, int position, double time) {
 	DiskRequest *current = queue->head;
-	DiskRequest *next = NULL;
+	DiskRequest *closest = NULL;
-	DiskRequest *first = NULL;
 	while (current != NULL) {
 		if (current->time <= time) { // Filter out requests that haven't come in yet
-			if (first == NULL) {
+			if (closest == NULL) { // If there is no closest yet, set it to the current
-				first = current;
+				closest = current;
 			} else {
-				if (current->position < first->position) {
+				int closestDistance = calcDistance(position, closest->position); // Distance from the closest to the current position, negative means down (bad)
-					first = current;
+				int currentDistance = calcDistance(position, current->position); // Distance from the current to the current position, negative means down (bad
-				}
+				if (currentDistance < closestDistance) { // If the current is closer than the closest
-			}
+					closest = current;
-			int currentDistance = current->position - position; // Distance from the current to the current position, negative means down (bad)
-			if (currentDistance > 0) { // If the current is up
-				if (next == NULL) { // If there is no next yet, set it to the current
-					next = current;
-				} else {
-					int nextDistance = next->position - position; // Distance from the next to the current position, negative means down (bad)
-					if (currentDistance < nextDistance) { // If the current is closer than the next
-						next = current;
-					}
 				}
 			}
 		}
 		current = current->next;
 	}
-	// If we didn't find a request that is above the current position, return the first as a fallback
+	return closest;
-	if (next == NULL) {
+}
-		return first;
-	}
-	return next;
-}

Assignment8/code/disk.h

@@ -26,3 +26,5 @@ DiskRequest *dequeue(DiskQueue *queue);
 DiskRequest *findClosest(DiskQueue *queue, int position, double time);
 
 void destroyDiskQueue(DiskQueue *queue);
+
+int calcDistance(int position, int destination);

Assignment8/code/main.c

@@ -92,4 +92,4 @@ int main(int argc, char **argv) {
 	destroyDiskQueue(queue);
 
 	return 0;
-}
+}

Assignment9/.idea/.gitignore

@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

Assignment9/.idea/Assignment9.iml

@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module classpath="CMake" type="CPP_MODULE" version="4" />

Assignment9/.idea/cmake.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CMakeSharedSettings">
+    <configurations>
+      <configuration PROFILE_NAME="Debug" ENABLED="true" GENERATION_DIR="build" CONFIG_NAME="Debug" />
+    </configurations>
+  </component>
+</project>

Assignment9/.idea/misc.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CMakeWorkspace" PROJECT_DIR="$PROJECT_DIR$" />
+</project>

Assignment9/.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/Assignment9.iml" filepath="$PROJECT_DIR$/.idea/Assignment9.iml" />
+    </modules>
+  </component>
+</project>

Assignment9/.idea/runConfigurations/All_CTest.xml

@@ -0,0 +1,8 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All CTest" type="CTestRunConfiguration" factoryName="CTestRun" PROGRAM_PARAMS="--extra-verbose" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" WORKING_DIR="file://$CMakeCurrentLocalGenerationDir$" PASS_PARENT_ENVS_2="true" CONFIG_NAME="Debug" RUN_PATH="$CTestCurrentExecutableName$" EXPLICIT_BUILD_TARGET_NAME="all" TEST_MODE="PATTERN">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+      <option name="BeforeTestRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

Assignment9/.idea/runConfigurations/Assignment9.xml

@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Assignment9" type="CMakeRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="Assignment9" TARGET_NAME="Assignment9" CONFIG_NAME="Debug" RUN_TARGET_PROJECT_NAME="Assignment9" RUN_TARGET_NAME="Assignment9">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

Assignment9/.idea/runConfigurations/Test1.xml

@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Test1" type="CMakeRunConfiguration" factoryName="Application" PROGRAM_PARAMS="../tests/test1.png" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="Assignment9" TARGET_NAME="Assignment9" CONFIG_NAME="Debug" RUN_TARGET_PROJECT_NAME="Assignment9" RUN_TARGET_NAME="Assignment9">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

Assignment9/.idea/runConfigurations/Test2.xml

@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Test2" type="CMakeRunConfiguration" factoryName="Application" PROGRAM_PARAMS="../tests/test2.png" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="Assignment9" TARGET_NAME="Assignment9" CONFIG_NAME="Debug" RUN_TARGET_PROJECT_NAME="Assignment9" RUN_TARGET_NAME="Assignment9">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

Assignment9/.idea/runConfigurations/Test3.xml

@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Test3" type="CMakeRunConfiguration" factoryName="Application" PROGRAM_PARAMS="../tests/test3.png" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="Assignment9" TARGET_NAME="Assignment9" CONFIG_NAME="Debug" RUN_TARGET_PROJECT_NAME="Assignment9" RUN_TARGET_NAME="Assignment9">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

Assignment9/.idea/runConfigurations/Test4.xml

@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Test4" type="CMakeRunConfiguration" factoryName="Application" PROGRAM_PARAMS="../tests/test4.png" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="Assignment9" TARGET_NAME="Assignment9" CONFIG_NAME="Debug" RUN_TARGET_PROJECT_NAME="Assignment9" RUN_TARGET_NAME="Assignment9">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

Assignment9/.idea/runConfigurations/Test_All.xml

@@ -0,0 +1,10 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Test All" type="CMakeRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="Assignment9" TARGET_NAME="Assignment9" CONFIG_NAME="Debug" RUN_TARGET_PROJECT_NAME="Assignment9" RUN_TARGET_NAME="Assignment9">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+      <option name="RunConfigurationTask" enabled="false" run_configuration_name="Test1" run_configuration_type="CMakeRunConfiguration" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="Test3" run_configuration_type="CMakeRunConfiguration" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="Test4" run_configuration_type="CMakeRunConfiguration" />
+    </method>
+  </configuration>
+</component>

Assignment9/.idea/runConfigurations/images.xml

@@ -0,0 +1,8 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="images" type="CTestRunConfiguration" factoryName="CTestRun" PROGRAM_PARAMS="--extra-verbose" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" WORKING_DIR="file://$CMakeCurrentLocalGenerationDir$" PASS_PARENT_ENVS_2="true" CONFIG_NAME="Debug" RUN_PATH="$CTestCurrentExecutableName$" EXPLICIT_BUILD_TARGET_NAME="all" TEST_METHOD="images" TEST_MODE="SUITE_TEST">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+      <option name="BeforeTestRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

Assignment9/.idea/runConfigurations/output.xml

@@ -0,0 +1,8 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="output" type="CTestRunConfiguration" factoryName="CTestRun" PROGRAM_PARAMS="--extra-verbose" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" WORKING_DIR="file://$CMakeCurrentLocalGenerationDir$" PASS_PARENT_ENVS_2="true" CONFIG_NAME="Debug" RUN_PATH="$CTestCurrentExecutableName$" EXPLICIT_BUILD_TARGET_NAME="all" TEST_METHOD="output" TEST_MODE="SUITE_TEST">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+      <option name="BeforeTestRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

Assignment9/.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$/.." vcs="Git" />
+  </component>
+</project>

Assignment9/CMakeLists.txt

@@ -0,0 +1,10 @@
+cmake_minimum_required(VERSION 3.20)
+project(Assignment9 C)
+set(CMAKE_C_STANDARD 99)
+add_executable(Assignment9 src/main.c
+        src/png.c
+        src/png.h)
+
+enable_testing()
+add_test(NAME output COMMAND test_text.sh WORKING_DIRECTORY ../tests)
+add_test(NAME images COMMAND test_images.sh WORKING_DIRECTORY ../tests)

Assignment9/documentation/EndiannessAndHomework9.c

@@ -0,0 +1,68 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+// FILE format is: 'header', then 2023 skipped bytes, then the number of interest
+#define OURINT 1426915328
+#define OFFSETTODATA 2023
+
+int writeToFile(){
+
+    FILE* fp = fopen("toReadLater.txt","w+");
+	char c = 'h';
+    fwrite(&c, sizeof(char), 1, fp);
+    c = 'e';
+    fwrite(&c, sizeof(char), 1, fp);
+    c = 'a';
+    fwrite(&c, sizeof(char), 1, fp);
+    c = 'd';
+    fwrite(&c, sizeof(char), 1, fp);
+    c = 'e';
+    fwrite(&c, sizeof(char), 1, fp);
+    c = 'r';
+    fwrite(&c, sizeof(char), 1, fp);
+    unsigned int buf = OFFSETTODATA;
+    fwrite(&buf, sizeof(int), 1, fp);
+    fseek(fp, OFFSETTODATA, SEEK_CUR);
+
+    buf = OURINT;
+    fwrite(&buf, sizeof(int), 1, fp);
+    fclose(fp);
+}
+
+int readFromFile(){
+	FILE *fp = fopen("toReadLater.txt", "r+");
+	fseek(fp, 6 , SEEK_SET);
+	int skip = 0;
+	fread(&skip, sizeof(int), 1, fp);
+    // NOTE, in HW, the size of the section is a value in 
+    // Big-Endian format, it will actually need conversion
+	fseek(fp, skip, SEEK_CUR);
+	unsigned int qBe = 0;
+	unsigned int qLe = 0;
+	int i;
+	unsigned char *c = (char *)(&qBe);
+	unsigned char *d = (char *)(&qLe);
+	for (i = 0; i < 4; i++)
+	{
+		c[i] = getc(fp);
+		printf("Byte %i: %i %x\n",i, c[i], c[i]);
+	}
+
+    for (i = 0; i < 4; i++)
+	{
+		d[4-i-1] = c[i];
+	}
+
+    printf("Translated using swapping the bytes order: %i\n", qLe);
+	qLe = ntohl(qBe);
+    printf("Translated using ntohl: %i\n", qLe);
+    fclose(fp);
+}
+int main (int argc, char** argv){
+    unsigned int wantToRead;
+	writeToFile();
+	printf("Sizeof (int) is:%li\n", sizeof(unsigned int));
+	readFromFile();
+
+	return 0;
+}

Assignment9/src/main.c

@@ -0,0 +1,50 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <string.h>
+#include <stdbool.h>
+#include "png.h"
+
+int main(int argc, char *argv[]) {
+	// Error handling
+	if (argc != 2) {
+		printf("Usage: %s <png file>\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+	if (strlen(argv[1]) > PATH_MAX) {
+		printf("Path too long\n");
+		exit(EXIT_FAILURE);
+	}
+	// Read file
+	char *path = argv[1];
+	char *png_buffer = load_file(path);
+	if (!is_png(png_buffer)) {
+		printf("It's not a PNG file\n");
+		exit(EXIT_FAILURE);
+	} else {
+		printf("It's a PNG file\n");
+	}
+	png_chunk **chunks = get_png_chunks(png_buffer);
+	free(png_buffer);
+	// Done with buffer, as chunks are a structured way to access the data
+	// Iterate over chunks to display info and "decrypt" IDAT chunks
+	int size = get_number_of_chunks(chunks);
+	for (int i = 0; i < size; i++) {
+		// Check if header is IDAT or IEND
+		bool is_idat = memcmp(chunks[i]->type, "IDAT", 4) == 0;
+		bool is_iend = memcmp(chunks[i]->type, "IEND", 4) == 0;
+		if (is_idat || is_iend) {
+			printf("Found %.4s\n", chunks[i]->type);
+			if (is_idat) {
+				xor_data(chunks[i]);
+			}
+		} else {
+			printf("Found unknown: %.4s\n", chunks[i]->type);
+		}
+		printf("Chunk size is:%d\n", chunks[i]->length);
+	}
+	// Write file and free memory
+	write_png_chunks(path, chunks);
+	destroy_chunks(chunks);
+	return EXIT_SUCCESS;
+}

Assignment9/src/png.c

@@ -0,0 +1,159 @@
+/*
+ * Copyright Notice
+ * ----------------
+ * Copyright © 1998, 1999 by: Glenn Randers-Pehrson
+ * This specification is a modification of the PNG 1.0 specification. It is being
+ * provided by the copyright holder under the provisions of the 1996 MIT copyright and license:
+ * Copyright © 1996 by: Massachusetts Institute of Technology (MIT)
+ * This W3C specification is being provided by the copyright holders under
+ * the following license. By obtaining, using and/or copying this specification, you
+ * agree that you have read, understood, and will comply with the following terms
+ * and conditions:
+ * Permission to use, copy, and distribute this specification for any purpose
+ * and without fee or royalty is hereby granted, provided that the full text of
+ * this NOTICE appears on ALL copies of the specification or portions thereof,
+ * including modifications, that you make.
+ * THIS SPECIFICATION IS PROVIDED ”AS IS,” AND COPYRIGHT HOLD-ERS
+ * MAKE NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
+ * IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, COPYRIGHT
+ * HOLDERS MAKE NO REPRESENTATIONS OR WARRANTIES OF MERCHANTABILITY
+ * OR FITNESS FOR ANY PARTICULAR PURPOSE OR
+ * THAT THE USE OF THE SPECIFICATION WILL NOT INFRINGE ANY
+ * THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER
+ * RIGHTS. COPYRIGHT HOLDERS WILL BEAR NO LIABILITY FOR ANY
+ * USE OF THIS SPECIFICATION.
+ * The name and trademarks of copyright holders may NOT be used in
+ * advertising or publicity pertaining to the specification without specific, written
+ * prior permission. Title to copyright in this specification and any associated
+ * documentation will at all times remain with copyright holders.
+ */
+
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include "png.h"
+
+FILE *get_file(char *path) {
+	FILE *fp = fopen(path, "rb");
+	if (fp == NULL) {
+		perror("fopen");
+		exit(EXIT_FAILURE);
+	}
+	return fp;
+}
+
+char *load_file(char *path) {
+	FILE *fp = get_file(path);
+	fseek(fp, 0, SEEK_END);
+	long size = ftell(fp);
+	rewind(fp);
+	char *buffer = malloc(size);
+	if (buffer == NULL) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+	fread(buffer, 1, size, fp);
+	fclose(fp);
+	return buffer;
+}
+
+int is_png(char *buffer) {
+	return memcmp(buffer, PNG_SIGNATURE, PNG_SIGNATURE_SIZE) == 0;
+}
+
+png_chunk *get_png_chunk(char *buffer, unsigned int offset) {
+	png_chunk *chunk = malloc(sizeof(png_chunk));
+	if (chunk == NULL) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+	memcpy(&chunk->length, buffer + offset + 0, 4);
+	// Convert length to host byte order because PNG lengths is in network byte order/Big Endian
+	chunk->length = ntohl(chunk->length);
+	memcpy(&chunk->type, buffer + offset + 4, 4);
+	chunk->data = malloc(chunk->length);
+	if (chunk->data == NULL) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+	memcpy(chunk->data, buffer + offset + 8, chunk->length);
+	memcpy(&chunk->crc, buffer + offset + 8 + chunk->length, 4);
+	return chunk;
+}
+
+png_chunk **get_png_chunks(char *buffer) {
+	png_chunk **chunks = malloc(sizeof(png_chunk *));
+	if (chunks == NULL) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+	// Running offset of the buffer
+	unsigned int offset = PNG_SIGNATURE_SIZE;
+	// Index of the current chunk
+	int i = 0;
+	while (true) {
+		chunks[i] = get_png_chunk(buffer, offset);
+		// 12 = 4 (length) + 4 (type) + 4 (crc)
+		offset += 12 + chunks[i]->length;
+		if (memcmp(chunks[i]->type, "IEND", 4) == 0) {
+			break;
+		}
+		i++;
+		// Add one because realloc is 1-indexed when multiplying by sizeof
+		png_chunk **err_check = realloc(chunks, sizeof(png_chunk *) * (i + 1));
+		if (err_check == NULL) {
+			destroy_chunks(chunks);
+			perror("realloc");
+			exit(EXIT_FAILURE);
+		}
+		chunks = err_check;
+	}
+	return chunks;
+}
+
+int get_number_of_chunks(png_chunk **chunks) {
+	int i = 0;
+	while (memcmp(chunks[i]->type, "IEND", 4) != 0) {
+		i++;
+	}
+	// Add one for the IEND chunk
+	return ++i;
+}
+
+void xor_data(png_chunk *chunk) {
+	for (int i = 0; i < chunk->length; i++) {
+		chunk->data[i] ^= KEY;
+	}
+}
+
+void destroy_chunks(png_chunk **chunks) {
+	unsigned int size = get_number_of_chunks(chunks);
+	for (int i = 0; i < size; i++) {
+		free(chunks[i]->data);
+		free(chunks[i]);
+	}
+	free(chunks);
+}
+
+void write_png_chunks(char *path, png_chunk **chunks) {
+	FILE *fp = fopen(path, "wb");
+	if (fp == NULL) {
+		perror("fopen");
+		exit(EXIT_FAILURE);
+	}
+	fwrite(PNG_SIGNATURE, PNG_SIGNATURE_SIZE, 1, fp);
+	unsigned int size = get_number_of_chunks(chunks);
+	for (int i = 0; i < size; i++) {
+		// Convert length to network byte order for writing
+		chunks[i]->length = htonl(chunks[i]->length);
+		fwrite(&chunks[i]->length, 4, 1, fp);
+		fwrite(chunks[i]->type, 4, 1, fp);
+		// Convert back so we can accurately use it to write the length of the data
+		chunks[i]->length = ntohl(chunks[i]->length);
+		fwrite(chunks[i]->data, chunks[i]->length, 1, fp);
+		fwrite(&chunks[i]->crc, 4, 1, fp);
+	}
+	fclose(fp);
+}

Assignment9/src/png.h

@@ -0,0 +1,75 @@
+/*
+ * Copyright Notice
+ * ----------------
+ * Copyright © 1998, 1999 by: Glenn Randers-Pehrson
+ * This specification is a modification of the PNG 1.0 specification. It is being
+ * provided by the copyright holder under the provisions of the 1996 MIT copyright and license:
+ * Copyright © 1996 by: Massachusetts Institute of Technology (MIT)
+ * This W3C specification is being provided by the copyright holders under
+ * the following license. By obtaining, using and/or copying this specification, you
+ * agree that you have read, understood, and will comply with the following terms
+ * and conditions:
+ * Permission to use, copy, and distribute this specification for any purpose
+ * and without fee or royalty is hereby granted, provided that the full text of
+ * this NOTICE appears on ALL copies of the specification or portions thereof,
+ * including modifications, that you make.
+ * THIS SPECIFICATION IS PROVIDED ”AS IS,” AND COPYRIGHT HOLD-ERS
+ * MAKE NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
+ * IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, COPYRIGHT
+ * HOLDERS MAKE NO REPRESENTATIONS OR WARRANTIES OF MERCHANTABILITY
+ * OR FITNESS FOR ANY PARTICULAR PURPOSE OR
+ * THAT THE USE OF THE SPECIFICATION WILL NOT INFRINGE ANY
+ * THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER
+ * RIGHTS. COPYRIGHT HOLDERS WILL BEAR NO LIABILITY FOR ANY
+ * USE OF THIS SPECIFICATION.
+ * The name and trademarks of copyright holders may NOT be used in
+ * advertising or publicity pertaining to the specification without specific, written
+ * prior permission. Title to copyright in this specification and any associated
+ * documentation will at all times remain with copyright holders.
+ */
+
+#pragma once
+
+// Needed for uint types
+#include <arpa/inet.h>
+
+// http://www.libpng.org/pub/png/spec/1.2/PNG-Rationale.html#R.PNG-file-signature
+#define PNG_SIGNATURE "\211PNG\r\n\032\n"
+#define PNG_SIGNATURE_SIZE 8
+
+// The key used to "encrypt/decrypt" the PNG chunks
+#define KEY 42
+
+typedef struct png_chunk {
+	uint32_t length;
+	char type[4];
+	char *data;
+	uint32_t crc;
+} png_chunk;
+
+// Get FILE from path
+int get_fd(char *path);
+
+// Store file in heap memory
+char *load_file(char *path);
+
+// Check if file is a PNG
+int is_png(char *buffer);
+
+// Get PNG chunk
+png_chunk *get_png_chunk(char *buffer, unsigned int offset);
+
+// Get all PNG chunks
+png_chunk **get_png_chunks(char *buffer);
+
+// Get number of chunks
+int get_number_of_chunks(png_chunk **chunks);
+
+// XOR chunk with key
+void xor_data(png_chunk *chunk);
+
+// Destroy all chunks
+void destroy_chunks(png_chunk **chunks);
+
+// Write PNG chunks to file
+void write_png_chunks(char *path, png_chunk **chunks);

Assignment9/tests/output1.txt

@@ -0,0 +1,13 @@
+It's a PNG file
+Found unknown: IHDR
+Chunk size is:13
+Found unknown: sRGB
+Chunk size is:1
+Found unknown: gAMA
+Chunk size is:4
+Found unknown: pHYs
+Chunk size is:9
+Found IDAT
+Chunk size is:18944
+Found IEND
+Chunk size is:0

Assignment9/tests/output2.txt

@@ -0,0 +1 @@
+It's not a PNG file

Assignment9/tests/output3.txt

@@ -0,0 +1,249 @@
+It's a PNG file
+Found unknown: IHDR
+Chunk size is:13
+Found unknown: sRGB
+Chunk size is:1
+Found unknown: gAMA
+Chunk size is:4
+Found unknown: pHYs
+Chunk size is:9
+Found unknown: tEXt
+Chunk size is:15
+Found unknown: tIME
+Chunk size is:7
+Found unknown: tEXt
+Chunk size is:32
+Found unknown: tEXt
+Chunk size is:33
+Found IDAT
+Chunk size is:65310
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:17176
+Found IEND
+Chunk size is:0

Assignment9/tests/output4.txt

@@ -0,0 +1,317 @@
+It's a PNG file
+Found unknown: IHDR
+Chunk size is:13
+Found unknown: sRGB
+Chunk size is:1
+Found unknown: gAMA
+Chunk size is:4
+Found unknown: pHYs
+Chunk size is:9
+Found unknown: tEXt
+Chunk size is:15
+Found unknown: tIME
+Chunk size is:7
+Found unknown: tEXt
+Chunk size is:32
+Found unknown: tEXt
+Chunk size is:33
+Found IDAT
+Chunk size is:65310
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:65524
+Found IDAT
+Chunk size is:53390
+Found IEND
+Chunk size is:0

Assignment9/tests/test_images.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+# Executable path
+EXECUTABLE=../build/Assignment9
+
+
+test_reverse() {
+    start=$(date +%s)
+    cp "$1" in.png
+    cp in.png out.png
+    $EXECUTABLE out.png > /dev/null
+    $EXECUTABLE out.png > /dev/null
+    diff in.png out.png
+    rm in.png out.png
+    end=$(date +%s)
+    echo "Test $1 took $((end - start)) seconds"
+}
+
+test_reverse test1.png
+# test_reverse test2.png # This png is invalid, so it will fail
+test_reverse test3.png
+test_reverse test4.png

Assignment9/tests/test_text.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+EXECUTABLE=../build/Assignment9
+
+# Test the text output
+$EXECUTABLE test1.png | diff output1.txt -
+$EXECUTABLE test2.png | diff output2.txt -
+$EXECUTABLE test3.png | diff output3.txt -
+$EXECUTABLE test4.png | diff output4.txt -
+
+
+# Reverse the images
+$EXECUTABLE test1.png > /dev/null
+$EXECUTABLE test2.png > /dev/null
+$EXECUTABLE test3.png > /dev/null
+$EXECUTABLE test4.png > /dev/null
+
+echo "If there is no diff output, then the test passed."