exif_harness.c

#include <stdio.h>
#include <stdlib.h>
#include "libexif/exif-data.h"

// Function to log messages
void log_message(const char *msg) {
    printf("%s\n", msg);
}

// Function to print an Exif entry
void print_exif_entry(ExifEntry *entry, ExifIfd ifd) {
    char value[1024];
    exif_entry_get_value(entry, value, sizeof(value));
    printf("    Tag: %s\n", exif_tag_get_name_in_ifd(entry->tag, ifd));
    printf("    Value: %s\n", value);
}

// Function to print the Exif content
void print_exif_content(ExifContent *content, ExifIfd ifd) {
    for (unsigned int i = 0; i < content->count; i++) {
        print_exif_entry(content->entries[i], ifd);
    }
}

// Function to read EXIF data from a file and print it
void read_exif_data(const char *filename) {
    ExifData *ed;
    ExifByteOrder byte_order;

    // Load the EXIF data from the file
    ed = exif_data_new_from_file(filename);
    if (!ed) {
        log_message("Could not read EXIF data.");
        return;
    }

    // Get the byte order of the EXIF data
    byte_order = exif_data_get_byte_order(ed);
    log_message("EXIF data byte order:");
    if (byte_order == EXIF_BYTE_ORDER_INTEL) {
        log_message("Intel (Little endian)");
    } else {
        log_message("Motorola (Big endian)");
    }

    // Loop through and print out the tags
    for (int i = 0; i < EXIF_IFD_COUNT; i++) {
        ExifIfd ifd = (ExifIfd)i;
        ExifContent *content = ed->ifd[ifd];

        if (!content || content->count == 0) {
            continue;
        }

        log_message("EXIF content:");
        print_exif_content(content, ifd);
    }

    // Free the EXIF data
    exif_data_unref(ed);
}

int main(int argc, char **argv) {
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <JPEG file>\n", argv[0]);
        return 1;
    }

    const char *filename = argv[1];
    read_exif_data(filename);

    return 0;
}