hexdump.cpp

#include <ctype.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>

uintptr_t HexDumpData(const uint8_t *data, size_t length, size_t width = 16,
                      uintptr_t base_address = 0, bool tail_addr_out = true) {
  const uint8_t *data_cur = data;
  if (!data || width == 0) return 0;
  while (length) {
    printf("%08" PRIxPTR "  ", data_cur - data + base_address);
    for (size_t i = 0; i < width; i++) {
      if (i < length)
        printf("%02" PRIx8 " %s", data_cur[i], i == width / 2 - 1 ? " " : "");
      else
        printf("   %s", i == width / 2 - 1 ? " " : "");
    }
    printf(" |");
    for (size_t i = 0; i < width && i < length; i++)
      printf("%c", isprint(data_cur[i]) ? data_cur[i] : '.');
    printf("|\n");
    data_cur += length < width ? length : width;
    length -= length < width ? length : width;
  }
  if (tail_addr_out) printf("%08" PRIxPTR "\n", data_cur - data + base_address);
  return data_cur - data + base_address;
}

uintptr_t HexDumpFile(FILE *file, size_t width) {
  if (!file) return 0;
  uint8_t buffer[width];
  uintptr_t cur_address = 0;
  while (size_t count = fread(buffer, 1, sizeof(buffer), file)) {
    cur_address =
        HexDumpData(buffer, count, width, cur_address, count != width);
  }
  if (width == 1) HexDumpData(buffer, 0, width, cur_address, true);
  return cur_address;
}

int main(int argc, char *argv[]) {
  char filename[FILENAME_MAX];  // C's max length of file name.
  FILE *file = nullptr;
  if (argc == 1) {
    printf(
        "Please tell me your file name(with path if not in the current "
        "dir):\n");
    scanf("%s", filename);
  } else {
    strcpy(filename, argv[1]);
  }
  file = fopen(filename, "rb");
  if (file == nullptr) {
    printf("Can't access %s!\n", filename);
    return 0;
  }
  HexDumpFile(file, 16);
  fclose(file);
}