comic_cbt.c

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#include <stddef.h>
#include <stdint.h>
 
#include "comic.h"
#include "comic_internal.h"
#include "ra8_attributes.h"
#include "ra8_check.h"
#include "unarch_tar.h"

static const char* const s_tag_cbt = "comic_cbt";

typedef enum : uint32_t {
  k_cbt_name_max    = 256U,    
  k_cbt_max_members = 100000U, 
} cbt_limits_t;

RA8_INTERNAL static ra8_err_t
internal_add_member(comic_t* c, const unarch_tar_entry_t* ent, const char* name, uint16_t nlen)
{
  if (ent->is_file == 0U) {
    return k_ra8_ok;
  }
  if (!priv_comic_is_page_name(name, nlen)) {
    return k_ra8_ok;
  }
  return priv_comic_page_add(c,
                             name,
                             nlen,
                             ent->size,
                             1U,
                             (uint8_t)k_ra8_rar_method_store, /* stored verbatim */
                             0U,
                             ent->data_off,
                             ent->size);
}
 
RA8_PRIV ra8_err_t priv_comic_cbt_open(comic_t* c)
{
  RA8_CHECK_NULL_PTR(c, s_tag_cbt, "cbt open: null c");
  if (!c->tar.live) {
    return k_ra8_err_invalid_state;
  }
  uint64_t off = 0U;
  for (uint32_t n = 0U; n < (uint32_t)k_cbt_max_members; ++n) { /* bound: static member cap */
    char               nb[k_cbt_name_max] = {};
    unarch_tar_entry_t ent                = {};
    const ra8_err_t    nerr = unarch_tar_next(&c->tar, off, nb, (uint16_t)sizeof(nb), &ent);
    if (nerr == k_ra8_err_not_found) {
      return k_ra8_ok; /* clean end of archive */
    }
    if (nerr != k_ra8_ok) {
      return nerr; /* malformed / lying / over-policy member: reject */
    }
    const ra8_err_t ae = internal_add_member(c, &ent, nb, ent.name_len);
    if (ae != k_ra8_ok) {
      return ae; /* index / arena full -- a real capacity error, propagate */
    }
    off = ent.next_off;
  }
  return k_ra8_err_validation_failed; /* GCOVR_EXCL_LINE -- the walker's policy
                                       * entry cap (4096) fires inside tar_next
                                       * far below the static member cap */
}
 
RA8_PRIV ra8_err_t
priv_comic_cbt_extract(comic_t* c, const comic_page_t* p, uint8_t* buf, size_t cap, size_t* got)
{
  RA8_CHECK_NULL_PTR(c, s_tag_cbt, "cbt extract: null c");
  RA8_CHECK_NULL_PTR(p, s_tag_cbt, "cbt extract: null p");
  RA8_CHECK_NULL_PTR(buf, s_tag_cbt, "cbt extract: null buf");
  RA8_CHECK_NULL_PTR(got, s_tag_cbt, "cbt extract: null got");
  *got = 0U;
  if (!c->tar.live) {
    return k_ra8_err_invalid_state;
  }
  unarch_tar_entry_t ent = {};
  ent.is_file            = 1U;
  ent.data_off           = p->data_off;
  ent.size               = p->raw_size;
  return unarch_tar_read(&c->tar, &ent, buf, cap, got);
}