exFAT file system implementation library.
Free exFAT implementation.
- Copyright (C) 2010-2018 Andrew Nayenko
+ Copyright (C) 2010-2023 Andrew Nayenko
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
ssize_t exfat_generic_pread(const struct exfat* ef, struct exfat_node* node,
void* buffer, size_t size, off_t offset)
{
- uint64_t newsize = offset;
+ uint64_t uoffset = offset;
cluster_t cluster;
char* bufp = buffer;
off_t lsize, loffset, remainder;
if (offset < 0)
return -EINVAL;
- if (newsize >= node->size)
+ if (uoffset >= node->size)
return 0;
if (size == 0)
return 0;
- cluster = exfat_advance_cluster(ef, node, newsize / CLUSTER_SIZE(*ef->sb));
+ if (uoffset + size > node->valid_size)
+ {
+ ssize_t bytes = 0;
+
+ if (uoffset < node->valid_size)
+ {
+ bytes = exfat_generic_pread(ef, node, buffer,
+ node->valid_size - uoffset, offset);
+ if (bytes < 0 || (size_t) bytes < node->valid_size - uoffset)
+ return bytes;
+ }
+ memset(buffer + bytes, 0,
+ MIN(size - bytes, node->size - node->valid_size));
+ return MIN(size, node->size - uoffset);
+ }
+
+ cluster = exfat_advance_cluster(ef, node, uoffset / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(*ef->sb, cluster))
{
exfat_error("invalid cluster 0x%x while reading", cluster);
return -EIO;
}
- loffset = newsize % CLUSTER_SIZE(*ef->sb);
- remainder = MIN(size, node->size - newsize);
+ loffset = uoffset % CLUSTER_SIZE(*ef->sb);
+ remainder = MIN(size, node->size - uoffset);
while (remainder > 0)
{
if (CLUSTER_INVALID(*ef->sb, cluster))
}
if (!(node->attrib & EXFAT_ATTRIB_DIR) && !ef->ro && !ef->noatime)
exfat_update_atime(node);
- return MIN(size, node->size - newsize) - remainder;
+ return MIN(size, node->size - uoffset) - remainder;
}
ssize_t exfat_generic_pwrite(struct exfat* ef, struct exfat_node* node,
const void* buffer, size_t size, off_t offset)
{
- uint64_t newsize = offset;
+ uint64_t uoffset = offset;
int rc;
cluster_t cluster;
const char* bufp = buffer;
if (offset < 0)
return -EINVAL;
- if (newsize > node->size)
+ if (uoffset > node->size)
{
- rc = exfat_truncate(ef, node, newsize, true);
+ rc = exfat_truncate(ef, node, uoffset, true);
if (rc != 0)
return rc;
}
- if (newsize + size > node->size)
+ if (uoffset + size > node->size)
{
- rc = exfat_truncate(ef, node, newsize + size, false);
+ rc = exfat_truncate(ef, node, uoffset + size, false);
if (rc != 0)
return rc;
}
if (size == 0)
return 0;
- cluster = exfat_advance_cluster(ef, node, newsize / CLUSTER_SIZE(*ef->sb));
+ cluster = exfat_advance_cluster(ef, node, uoffset / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(*ef->sb, cluster))
{
exfat_error("invalid cluster 0x%x while writing", cluster);
return -EIO;
}
- loffset = newsize % CLUSTER_SIZE(*ef->sb);
+ loffset = uoffset % CLUSTER_SIZE(*ef->sb);
remainder = size;
while (remainder > 0)
{
bufp += lsize;
loffset = 0;
remainder -= lsize;
+ node->valid_size = MAX(node->valid_size, uoffset + size - remainder);
cluster = exfat_next_cluster(ef, node, cluster);
}
if (!(node->attrib & EXFAT_ATTRIB_DIR))