/** A helper function for midp_file_cache_flush(). */
static
void midp_file_cache_flush_using_buffer(char** ppszError, int handle,
char* buf, long bufsize) {
MidpFileCacheBlock *b; /* current cache block */
MidpFileCacheBlock *n; /* next cache block */
MidpFileCacheBlock *q; /* first block not (yet) copied to the buffer,
finally, the value to be stored
in mFileCache->blocks */
char *bufPos; /* first not yet used byte in the write buffer */
long startPos, endPos; /* positions in the file cached in a series
of buffers, from...upto */
long len;
*ppszError = NULL;
while ((b = mFileCache->blocks) != NULL) {
if ( NULL != buf
&& NULL != (n = b->next)
&& n->position == b->position + b->length /* adjacent? */
&& b->length + n->length < bufsize
) { /* begin merging blocks */
/* position in the buffer */
bufPos = buf;
/* position in the file */
startPos = endPos = b->position;
b = mFileCache->blocks;
/* now copy a series of adjacent blocks to the write buffer */
do {
len = b->length;
memcpy(bufPos,DATA(b),len);
endPos += len;
bufPos += len;
b = b->next;
} while ( NULL != b
&& b->position == endPos
&& endPos - startPos + b->length < bufsize
);
q = b; /* q is next to the last copied block */
/* the cache state has not been modified yet */
/* now write from the write buffer */
storagePosition(ppszError, handle, startPos);
CHECK_ERROR(*ppszError);
storageWrite(ppszError, handle, buf, endPos-startPos);
CHECK_ERROR(*ppszError);
/* write successful, now free the cache blocks */
while ( q != (b = mFileCache->blocks)) {
mFileCache->size -= b->length + sizeof(MidpFileCacheBlock);
mFileCache->blocks = b->next;
midpFree(b);
}
} else {
storagePosition(ppszError, handle, b->position);
CHECK_ERROR(*ppszError);
storageWrite(ppszError, handle, DATA(b), b->length);
CHECK_ERROR(*ppszError);
mFileCache->size -= b->length + sizeof(MidpFileCacheBlock);
mFileCache->blocks = b->next;
midpFree(b);
}
}
storageCommitWrite(ppszError, handle);
CHECK_ERROR(*ppszError);
/* ASSERT (mFileCache->size == 0) */
if (mFileCache->size != 0) {
REPORT_ERROR(LC_RMS, "File cache out of sync");
}
}
/**
* Writes integer to the file.
*
* @param data integer to be written
* @return number of bytes written
*/
static int write_int(int data) {
storageWrite(&io_error_message, table_file, (char *)&data, sizeof(int));
return sizeof(int);
}
