//
// Created by bruno on 6.2.2025.
//

#include "hexdump.h"
#include <stdio.h>
#include <ctype.h>
#include <malloc.h>
#include <stdint.h>
#include <string.h>

#define BYTES_PER_LINE 16  // Adjust for different widths


char *hexdump_to_string(const unsigned char *data, uint32_t start, uint32_t end) {
    if (start >= end) return NULL;  // Invalid range

    // Estimate max output size: each line is approx. 80 chars
    uint32_t estimated_size = ((end - start) / BYTES_PER_LINE + 1) * 60;

    // Allocate memory for output string
    char *output = malloc(estimated_size);
    if (!output) return NULL;

    uint32_t out_offset = 0; // Tracks position in output buffer

    for (uint32_t i = start; i < end; i += BYTES_PER_LINE) {
        // Print offset
        out_offset += snprintf(output + out_offset, estimated_size - out_offset, "%07x   ", i);

        // Print hex values
        for (uint32_t j = 0; j < BYTES_PER_LINE; j++) {
            if (i + j < end)
                out_offset += snprintf(output + out_offset, estimated_size - out_offset, "%02x ", data[i + j]);
            else
                out_offset += snprintf(output + out_offset, estimated_size - out_offset, "   "); // Padding
            if (j == 7)
                out_offset += snprintf(output + out_offset, estimated_size - out_offset, " "); // Extra space
        }

        out_offset += snprintf(output + out_offset, estimated_size - out_offset, "\n");
    }

    return output;
}