forked from freudenreichan/info2Praktikum-NeuronalesNetz
112 lines
3.3 KiB
C
112 lines
3.3 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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/* Liest den Dateitag sowie Anzahl und Abmessungen der Bilder. */
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static int readFileHeader(FILE *file, unsigned short *count, unsigned short *width, unsigned short *height)
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{
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char tag[sizeof(FILE_HEADER_STRING) - 1];
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return fread(tag, sizeof(tag), 1, file) == 1 &&
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memcmp(tag, FILE_HEADER_STRING, sizeof(tag)) == 0 &&
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fread(count, sizeof(*count), 1, file) == 1 &&
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fread(width, sizeof(*width), 1, file) == 1 &&
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fread(height, sizeof(*height), 1, file) == 1 &&
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*count > 0 && *width > 0 && *height > 0;
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}
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/* Liest die Pixel und das unmittelbar folgende Label eines Bildes. */
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static int readImage(FILE *file, GrayScaleImage *image, unsigned char *label, size_t pixelCount)
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{
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image->buffer = (GrayScalePixelType *)malloc(pixelCount);
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if (image->buffer == NULL || fread(image->buffer, sizeof(*image->buffer), pixelCount, file) != pixelCount ||
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fread(label, sizeof(*label), 1, file) != 1)
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{
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free(image->buffer);
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image->buffer = NULL;
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return 0;
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}
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return 1;
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}
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/* Gibt auch bereits teilweise geladene Serien und deren Pixelpuffer frei. */
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static void freeImages(GrayScaleImageSeries *series)
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{
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if (series == NULL)
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return;
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if (series->images != NULL)
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{
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for (unsigned int i = 0; i < series->count; ++i)
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free(series->images[i].buffer);
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}
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free(series->images);
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free(series->labels);
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free(series);
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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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unsigned short count, width, height;
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size_t pixelCount;
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FILE *file;
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if (path == NULL || (file = fopen(path, "rb")) == NULL)
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return 0;
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/* Zuerst den Header validieren, bevor Speicher reserviert wird */
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if (!readFileHeader(file, &count, &width, &height))
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{
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fclose(file);
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freeImages(series);
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return 0;
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}
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pixelCount = (size_t)width * height;
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series = (GrayScaleImageSeries *)calloc(1, sizeof(*series));
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if (series == NULL)
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{
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fclose(file);
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freeImages(series);
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return 0;
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}
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series->count = count;
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series->images = (GrayScaleImage *)calloc(count, sizeof(*series->images));
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series->labels = (unsigned char *)malloc(count * sizeof(*series->labels));
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if (series->images == NULL || series->labels == NULL)
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{
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fclose(file);
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freeImages(series);
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return 0;
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}
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/* Ein Datensatz besteht jeweils aus Pixeln, gefolgt von einem Labelbyte. */
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for (unsigned int i = 0; i < count; ++i)
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{
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series->images[i].width = width;
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series->images[i].height = height;
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if (!readImage(file, &series->images[i], &series->labels[i], pixelCount))
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{
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fclose(file);
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freeImages(series);
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return 0;
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}
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}
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fclose(file);
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return series;
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}
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void clearSeries(GrayScaleImageSeries *series)
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{
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freeImages(series);
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}
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