#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdint.h>

static const  unsigned long BUFFER_SIZE = 65536;

struct  __attribute__ ((packed)) local_header {
  uint32_t signature;
  uint16_t version;
  uint16_t flags;
  uint16_t compression;
  uint16_t modtime;
  uint16_t moddate;
  uint32_t crc32;
  uint32_t compressed_size;
  uint32_t uncompressed_size;
  uint16_t filename_len;
  uint16_t extrafield_len;
};

int
main(int argc, char **argv, char **env)
{
  int fd;
  unsigned char *buffer = NULL;
  unsigned char *filename, *extra_field;
  unsigned short *p;
  struct local_header *lhp;
  unsigned char ch;

  if (argc > 1) {
    if ((buffer = calloc(1, BUFFER_SIZE))) {
      if ((fd = open(argv[1], O_RDONLY)) != -1) {
        fprintf(stderr, "info: opened %s\n", argv[1]);
        read(fd, buffer, BUFFER_SIZE);
        lhp = (struct local_header *)buffer;
        printf("%s\n", "Local Header");
        printf("Signature: \t%2s\n", (char*)&lhp->signature);
        printf("Version: \t%1.1f\n", ((float)(lhp->version))/10);
        printf("CRC32: \t%08X\n", lhp->crc32);
        printf("Compressed: \t%d\n", lhp->compressed_size);
        printf("Uncompressed: \t%d\n", lhp->uncompressed_size);
        printf("Filename length: \t%d\n", lhp->filename_len);
        printf("Extra length: \t%d\n", lhp->extrafield_len);

        filename = buffer + 0x1E;
        extra_field = filename + lhp->filename_len;
        ch = *extra_field;
        *extra_field = 0;
        printf("Filename: \t%s\n", filename);
        *extra_field = ch;
        printf("%s\n", "Extra fields");
        for (p = (unsigned short *)extra_field; p < (unsigned short *)extra_field + lhp->extrafield_len; p+=2) {
          printf("Header: \t%04X\tData:\t%04X\n", (unsigned short)*p, (unsigned short)*(p+1));
        }

        

        close(fd);
      }
      else fprintf(stderr, "error: failed to open %s\n", argv[1]);
    }
    else fprintf(stderr, "error: %s\n", "malloc failed");
  }

  return 0;
}