/**
* Contracts the size of the file containing the product-index map and
* memory-maps it.
*
* @param[in] newSize New size for the file in bytes. Must be less than
* the current size of the file.
* @retval 0 Success.
* @retval LDM7_SYSTEM System error. `log_add()` called. The state of the
* file is unspecified.
*/
static Ldm7Status
contractMapAndMap(
const size_t newSize)
{
/*
* The file must be memory-mapped before it can be consolidated; thus, the
* steps are: map, consolidate, shift, unmap, decrease size, and (re)map.
*/
int status;
(status = mapMap()) ||
(status = consolidateMap(maxSigs)) ||
(status = shiftMapDown(maxSigsFromFileSize(newSize))) ||
(status = unmapMap()) ||
(status = truncateMap(newSize)) ||
(status = mapMap());
return status;
}
/**
* Adjusts, if necessary, the size of the previously-existing file containing
* the file-identifier map and memory-maps it.
*
* @param[in] maxSigs Maximum number of data-product signatures.
* @retval 0 Success.
* @retval LDM7_SYSTEM System error. `log_add()` called. The state of the
* file is unspecified.
*/
static Ldm7Status
vetMapSizeAndMap(
const size_t maxSigs)
{
const size_t newSize = fileSizeFromNumSigs(maxSigs);
int status = (newSize > fileSize)
? expandMapAndMap(newSize)
: (newSize < fileSize)
? contractMapAndMap(newSize)
: mapMap();
return status;
}
/**
* Expands the size of the file containing the product-index map and
* memory-maps it.
*
* @param[in] newSize New size for the file in bytes. Must be greater than
* the current size of the file.
* @retval 0 Success.
* @retval LDM7_SYSTEM System error. `log_add()` called. The state of the
* file is unspecified.
*/
static Ldm7Status
expandMapAndMap(
const size_t newSize)
{
const size_t oldSize = fileSize;
int status = truncateMap(newSize);
if (0 == status) {
if (0 == (status = mapMap())) {
consolidateMap(maxSigsFromFileSize(oldSize));
} // file is memory-mapped
} // file size was increased
return status;
}
/**
* Initializes and memory-maps the newly-created file that will contain the
* product-index map for reading and writing.
*
* @param[in] max Maximum number of data-product signatures for the
* map.
* @retval 0 Success.
* @retval LDM7_SYSTEM System error. `log_add()` called.
*/
static Ldm7Status
initNewMapAndMap(
const size_t max)
{
const size_t size = fileSizeFromNumSigs(max);
int status = truncateMap(size);
if (0 == status) {
fileSize = size;
status = mapMap();
if (0 == status) {
clearMap();
maxSigs = max;
}
}
return status;
}
