unarch_xz_pool.c

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#include "unarch_xz_pool.h"
 
#include "ra8_check.h"

static uint8_t* s_pool_base = nullptr;

static uint32_t s_pool_len = 0U;

static uint32_t s_pool_off = 0U;
 
ra8_err_t unarch_xz_pool_install(void* base, uint32_t len)
{
  static const char* const tag = "ra8_xz_pool";
  RA8_CHECK_NULL_PTR(base, tag, "install: null base");
  if (len == 0U) {
    return k_ra8_err_invalid_size;
  }
  const uintptr_t base_address = (uintptr_t)base;
  if ((base_address % (uintptr_t)k_unarch_xz_pool_align) != 0U) {
    return k_ra8_err_invalid_size;
  }
  if (s_pool_base != nullptr) {
    return k_ra8_err_busy;
  }
  s_pool_base = (uint8_t*)base;
  s_pool_len  = len;
  s_pool_off  = 0U;
  return k_ra8_ok;
}
 
void unarch_xz_pool_reset(void)
{
  s_pool_base = nullptr;
  s_pool_len  = 0U;
  s_pool_off  = 0U;
}
 
void* unarch_xz_pool_alloc(uint32_t size)
{
  if (s_pool_base == nullptr) {
    return nullptr;
  }
  if (size == 0U) {
    return nullptr;
  }
  const uint32_t align = (uint32_t)k_unarch_xz_pool_align;
  if (size > (UINT32_MAX - (align - 1U))) {
    return nullptr; /* rounding would wrap: refuse */
  }
  const uint32_t need = (size + (align - 1U)) & ~(align - 1U);
  if (need > (s_pool_len - s_pool_off)) {
    return nullptr; /* arena exhausted: xz-embedded aborts init cleanly */
  }
  void* const p = &s_pool_base[s_pool_off];
  s_pool_off += need;
  return p;
}
 
uint32_t unarch_xz_pool_used(void)
{
  if (s_pool_base == nullptr) {
    return 0U;
  }
  return s_pool_off;
}