124 lines
3.3 KiB
C
124 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 FILE_HEADER_STRING "__info2_image_file_format__"
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#define FILE_HEADER_LENGTH (sizeof(FILE_HEADER_STRING) - 1U)
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// Reads an entire image series file and returns a heap-allocated descriptor.
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GrayScaleImageSeries *readImages(const char *path)
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{
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FILE *file = fopen(path, "rb");
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if(file == NULL)
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{
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return NULL;
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}
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if(!checkFileHeader(file))
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{
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fclose(file);
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return NULL;
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}
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unsigned int numberOfImages = readDimension(file);
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unsigned short width = readDimension(file);
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unsigned short height = readDimension(file);
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GrayScaleImageSeries *series = (GrayScaleImageSeries *)malloc(sizeof(GrayScaleImageSeries));
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if(series == NULL)
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{
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fclose(file);
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return NULL;
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}
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series->images = (GrayScaleImage *)calloc(numberOfImages, sizeof(GrayScaleImage));
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series->labels = (unsigned char *)calloc(numberOfImages, sizeof(unsigned char));
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series->count = numberOfImages;
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if(series->images == NULL || series->labels == NULL)
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{
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clearSeries(series);
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fclose(file);
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return NULL;
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}
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for(unsigned int i = 0; i < numberOfImages; i++)
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{
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series->images[i] = readImage(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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// Validates and consumes the file header tag that identifies the custom format.
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bool checkFileHeader(FILE *file)
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{
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char buffer[FILE_HEADER_LENGTH + 1] = {0};
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size_t bytesRead = fread(buffer, sizeof(char), FILE_HEADER_LENGTH, file);
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if(bytesRead != FILE_HEADER_LENGTH)
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{
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return false;
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}
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return strncmp(buffer, FILE_HEADER_STRING, FILE_HEADER_LENGTH) == 0;
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}
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// Reads a single 16-bit dimension (width, height or count of Images) from the file.
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unsigned short int readDimension(FILE *file)
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{
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unsigned short int dimension = 0;
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fread(&dimension, sizeof(unsigned short int), 1, file);
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return dimension;
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}
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// Reads a single grayscale image of the provided dimensions from the file.
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GrayScaleImage readImage(FILE *file, unsigned short width, unsigned short height)
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{
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GrayScaleImage image = {0};
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image.width = width;
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image.height = height;
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unsigned int pixelCount = (unsigned int)width * (unsigned int)height;
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image.buffer = (GrayScalePixelType *)malloc(pixelCount * sizeof(GrayScalePixelType));
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if(image.buffer != NULL)
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{
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fread(image.buffer, sizeof(GrayScalePixelType), pixelCount, file);
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}
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return image;
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}
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// Reads one byte label that belongs to the preceding image.
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unsigned char readLabel(FILE *file)
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{
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unsigned char label = 0;
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fread(&label, sizeof(unsigned char), 1, file);
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return label;
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}
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// Releases all heap allocations associated with a GrayScaleImageSeries.
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void clearSeries(GrayScaleImageSeries *series)
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{
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if (series != NULL)
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{
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if (series->images != NULL)
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{
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// Free each image's buffer
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for (unsigned int i = 0; i < series->count; i++)
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{
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if (series->images[i].buffer != NULL)
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free(series->images[i].buffer);
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}
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free(series->images);
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}
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if (series->labels != NULL)
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free(series->labels);
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free(series);
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}
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} |