Add parsing cross-reference table

#ifndef PDF_SIGIL_AUXILIARY_H

#define PDF_SIGIL_AUXILIARY_H

#include <stdlib.h>

#include <stdio.h>

#ifndef CHAR_T

#define CHAR_T

void sigil_zeroize(void *a, size_t bytes);

int is_digit(const char_t c);

int is_whitespace(const char_t c);

int parse_number(FILE *in, size_t *number);

int parse_free_indicator(FILE *in, char_t *result);

void print_module_name(const char *module_name, int verbosity);

void print_module_result(int result, int verbosity);

void print_test_item(const char *test_name, int verbosity);

// maximum bytes to read from the end of file to look for the "startxref"

#define XREF_SEARCH_OFFSET      1024

// capacity to choose for the first xref allocation

#define XREF_PREALLOCATION      10

// validate values

int sigil_config_self_test(int verbosity);

#define ERR_PARAM        0x0002 // [_|_|_|x] 0000 0010

#define ERR_IO           0x0004 // [_|_|_|x] 0000 0100

#define ERR_PDF_CONT     0x0008 // [_|_|_|x] 0000 1000

#define ERR_5            0x0010 // [_|_|_|x] 0001 0000

#define ERR_NOT_IMPL     0x0010 // [_|_|_|x] 0001 0000

#define ERR_6            0x0020 // [_|_|_|x] 0010 0000

#define ERR_7            0x0040 // [_|_|_|x] 0100 0000

#define ERR_8            0x0080 // [_|_|_|x] 1000 0000

    typedef char char_t;

#endif /* CHAR_T */

#ifndef XREF_T

#define XREF_T

    typedef struct {

        size_t byte_offset;

        size_t generation_num;

    } xref_entry_t;

    typedef struct {

        xref_entry_t **entry;

        size_t capacity;

    } xref_t;

#endif /* XREF_T */

#define XREF_TYPE_UNSET    0

#define XREF_TYPE_TABLE    1

#define XREF_TYPE_STREAM   2

#define MODE_SIGN      2

typedef uint32_t mode_t;

struct xref_t;

typedef struct {

    FILE   *file;

    short   pdf_x,             /* numbers from PDF header */

            pdf_y;             /*   %PDF-<pdf_x>.<pdf_y>  */

    short   xref_type;

    xref_t *xref;

    size_t  file_size;

    size_t  pdf_start_offset;  /* offset of %PDF-x.y      */

    size_t  startxref;

#include "error.h"

sigil_err_t process_trailer(sigil_t *sgl);

int sigil_trailer_self_test(int verbosity);