Complete pa07

Author: ErikSwan

pa07/Makefile

@@ -0,0 +1,7 @@
+GCCFLAGS=-Wall -Wshadow -g
+
+all: diff-plus
+	gcc $(GCCFLAGS) answer07.c main.c image-bmp.c -o main
+
+diff-plus:
+	gcc $(GCCFLAGS) diff-plus.c -o diff-plus

pa07/answer07.c

@@ -22,6 +22,10 @@
 #include "answer07.h"
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
+
+#define TRUE 1
+#define FALSE 0
 
 /**
  * Loads an ECE264 image file, returning an Image structure.
@@ -30,57 +34,91 @@
  * Hint: Please see the README for extensive hints
  */
 Image * Image_load(const char * filename) {
-    FILE * fp;
+    FILE * fp = NULL;
     ImageHeader header;
-    Image image;
+    Image * image = NULL;
+
+    void _teardown() {
+        if(image) {
+            Image_free(image);
+            image = NULL;
+        }
+        fclose(fp);
+    }
 
     // Open file for reading
-    fp = fopen(filename, "r");
+    fp = fopen(filename, "rb");
     if(!fp) {
-        fprintf(stderr, "Cannot open file '%s' for reading.", filename);
-        return NULL;
+        fprintf(stderr, "Cannot open file '%s' for reading.\n", filename);
+        return image;
     }
 
     // Read the header
     if(fread(&header, sizeof(ImageHeader), 1, fp) != 1) {
-        fprintf(stderr, "Unable to read header.");
-        return NULL;
+        fprintf(stderr, "Unable to read header.\n");
+        _teardown();
+        return image;
     }
 
     // Check the header's validity
     if(header.magic_number != ECE264_IMAGE_MAGIC_NUMBER) {
-        fprintf(stderr, "Magic number in header does not match.");
-        return NULL;
+        fprintf(stderr, "Magic number in header does not match.\n");
+        _teardown();
+        return image;
     }
 
     // Check width and height
     if(header.width <= 0 || header.height <= 0) {
-        fprintf(stderr, "Image file is not of valid width or height.");
-        return NULL;
+        fprintf(stderr, "Image file is not of valid width or height.\n");
+        _teardown();
+        return image;
     }
 
     // Validate comment
-    if(header.comment_len < 1) {
-        fprintf(stderr, "Comment length in header is invalid.");
-        return NULL;
+    if(header.comment_len < 1 || header.comment_len > 1024) {
+        fprintf(stderr, "Comment length in header is invalid.\n");
+        _teardown();
+        return image;
+    }
+
+    // Allocate space for image
+    if(!((image = malloc(sizeof(Image)))
+        && (image->comment = malloc(header.comment_len * sizeof(char)))
+        && (image->data = malloc(header.width * header.height * sizeof(uint8_t)))
+    )) {
+        fprintf(stderr, "Cannot allocate space for image.\n");
+        _teardown();
+        return image;
     }
 
+    // Set width and height
+    image->width = header.width;
+    image->height = header.height;
+
     // Read the comment
-    image.comment = malloc(header.comment_len * sizeof(char));
-    if(fread(image.comment, header.comment_len, 1, fp) != 1) {
-        fprintf(stderr, "Cannot read comment.");
-        free(image.comment);
-        return NULL;
+    if((fread(image->comment, header.comment_len, 1, fp) != 1) || image->comment[header.comment_len - 1] != '\0') {
+        fprintf(stderr, "Cannot read comment.\n");
+        _teardown();
+        return image;
     }
 
     // Read the image data
-    image.data = malloc(header.width * header.height * sizeof(uint8_t));
-    if(fread(image.data, header.width * header.height, 1, fp) != 1) {
-        fprintf(stderr, "Cannot read pixel data.");
-        free(image.data);
-    // NOT DONE
+    if(fread(image->data, header.width * header.height, 1, fp) != 1) {
+        fprintf(stderr, "Cannot read pixel data.\n");
+        _teardown();
+        return image;
+    }
 
-    return NULL;
+    // Check if there are trailing bytes
+    uint8_t byte;
+    if((fread(&byte, sizeof(uint8_t), 1, fp) != 0) || !feof(fp)) {
+        fprintf(stderr, "File has trailing bytes. Not continuing.\n");
+        _teardown();
+        return image;
+    }
+
+    fclose(fp);
+    return image;
 }
 
 /**
@@ -90,7 +128,44 @@ Image * Image_load(const char * filename) {
  * Hint: Please see the README for extensive hints
  */
 int Image_save(const char * filename, Image * image) {
-    return 0;
+    FILE * fp = NULL;
+    ImageHeader header;
+
+    fp = fopen(filename, "wb");
+    if(!fp) {
+        fprintf(stderr, "Cannot open file '%s' for writing.\n", filename);
+        return FALSE;
+    }
+
+    // Build header
+    header.magic_number = ECE264_IMAGE_MAGIC_NUMBER;
+    header.width = image->width;
+    header.height = image->height;
+    header.comment_len = strlen(image->comment) + 1;
+
+    // Write to file
+    if(fwrite(&header, sizeof(ImageHeader), 1, fp) != 1) {
+        fprintf(stderr, "Unable to write header.\n");
+        fclose(fp);
+        return FALSE;
+    }
+
+    // Write comment
+    if(fwrite(image->comment, header.comment_len * sizeof(char), 1, fp) != 1) {
+        fprintf(stderr, "Unable to write comment.\n");
+        fclose(fp);
+        return FALSE;
+    }
+
+    // Image data
+    if(fwrite(image->data, header.height * header.width * sizeof(uint8_t), 1, fp) != 1) {
+        fprintf(stderr, "Unable to write image data.\n");
+        fclose(fp);
+        return FALSE;
+    }
+
+    fclose(fp);
+    return TRUE;
 }
 
 /**
@@ -103,13 +178,35 @@ int Image_save(const char * filename, Image * image) {
  * report an error.
  */
 void Image_free(Image * image) {
-    return;
+    if(image) {
+        if(image->data) {
+            free(image->data);
+        }
+        if(image->comment) {
+            free(image->comment);
+        }
+        free(image);
+    }
 }
 
 /**
  * Performs linear normalization, see README
  */
 void linearNormalization(int width, int height, uint8_t * intensity) {
-    return;
-}
+    int i;
+    uint8_t min = 255, max = 0;
+
+    // Find max and min
+    for(i = 0; i < width * height; i++) {
+        if(intensity[i] > max) {
+            max = intensity[i];
+        } else if(intensity[i] < min) {
+            min = intensity[i];
+        }
+    }
 
+    // Normalize image
+    for(i = 0; i < width * height; i++) {
+        intensity[i] = (intensity[i] - min) * 255.0 / (max - min);
+    }
+}