generated from freudenreichan/info2Praktikum-NeuronalesNetz
138 lines
3.7 KiB
C
138 lines
3.7 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "imageInput.h"
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#define BUFFER_SIZE 100
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#define FILE_HEADER_STRING "__info2_image_file_format__"
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// TODO Implementieren Sie geeignete Hilfsfunktionen für das Lesen der Bildserie aus einer Datei
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static int checkHeader (FILE *file)
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{
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char header [strlen (FILE_HEADER_STRING) +1]; //Ermittle die Länge des Strings, +1 wegen Null
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size_t gelesen = fread (header, sizeof(char), strlen(FILE_HEADER_STRING), file);
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if (gelesen != strlen (FILE_HEADER_STRING))
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return -1;
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header [strlen (FILE_HEADER_STRING)] = '\0';
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if (strcmp(header, FILE_HEADER_STRING) == 0) {
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return 1;
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} else {
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return -1;
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}
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}
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static unsigned short readShort (FILE *file)
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{
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unsigned char bytes [2];
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if (fread(bytes, sizeof(unsigned char), 2, file) != 2)
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return 0;
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return (bytes [1] << 8) | bytes [0]; //Big-Endian -> Little-Endian
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}
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static GrayScaleImage readSingleImage (FILE *file, unsigned short width, unsigned short height)
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{
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GrayScaleImage img;
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img.width = width;
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img.height = height;
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img.buffer = NULL;
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//Speicher für Pixel reservieren
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size_t pixelCount = width * height;
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img.buffer = malloc(pixelCount * sizeof(GrayScalePixelType));
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if (img.buffer == NULL){
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img.width = 0;
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img.height = 0;
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return img;
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}
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//Pixel einlesen
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size_t gelesenPixels = fread (img.buffer, sizeof(GrayScalePixelType), pixelCount, file);
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if (gelesenPixels != pixelCount) {
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img.buffer = NULL;
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img.width = 0;
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img.height = 0;
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}
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return img;
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}
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static unsigned char readLabel (FILE *file)
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{
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unsigned char label = 0;
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size_t gelesen = fread (&label, sizeof(unsigned char), 1, file);
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if (gelesen == 0)
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return 0;
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return label;
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}
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// TODO Vervollständigen Sie die Funktion readImages unter Benutzung Ihrer Hilfsfunktionen
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GrayScaleImageSeries *readImages(const char *path)
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{
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GrayScaleImageSeries *series = NULL;
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FILE *file = fopen(path, "rb");
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if (file == NULL) {
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return NULL;
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}
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if (checkHeader(file) != 1) {
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return NULL;
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}
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unsigned short count = readShort(file);
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unsigned short width = readShort(file);
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unsigned short height = readShort(file);
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series = malloc (sizeof(GrayScaleImageSeries));
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if (series == NULL)
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return NULL;
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series->count = count;
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series->images = malloc (count * sizeof(GrayScaleImage));
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series->labels = malloc (count * sizeof(unsigned char));
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if (series->images == NULL || series->labels == NULL)
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return NULL;
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for (unsigned int i = 0; i < count; i++)
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{
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series->images[i] = readSingleImage(file, width, height);
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series->labels[i] = readLabel(file);
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}
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fclose (file);
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return series;
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}
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// TODO Vervollständigen Sie die Funktion clearSeries, welche eine Bildserie vollständig aus dem Speicher freigibt
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void clearSeries(GrayScaleImageSeries *series)
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{
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if (series == NULL) {
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return;
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}
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// Alle Bilder durchgehen und deren Buffer freigeben
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for (int i = 0; i < series->count; i++) {
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if (series->images[i].buffer != NULL) {
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free(series->images[i].buffer);
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series->images[i].buffer = NULL;
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}
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}
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// Arrays freigeben
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if (series->images != NULL) {
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free(series->images);
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series->images = NULL;
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}
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if (series->labels != NULL) {
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free(series->labels);
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series->labels = NULL;
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}
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// Schließlich die gesamte Serie freigeben
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free(series);
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} |