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ntfs-3g
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Move some run list related functions out of attrib.[hc] into runlist.[hc]. 

(Logical change 1.60)
edge.strict_endians
cantab.net!aia21 2002-12-27 16:35:17 +00:00
parent e5d59f00f1
commit 928eff2891
4 changed files with 141 additions and 141 deletions
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8
include/attrib.h
View File

@ -254,14 +254,6 @@ extern int ntfs_attr_map_runlist(ntfs_attr *na, VCN vcn);
extern LCN ntfs_attr_vcn_to_lcn(ntfs_attr *na, const VCN vcn);
extern runlist_element *ntfs_attr_find_vcn(ntfs_attr *na, const VCN vcn);
extern int ntfs_get_nr_significant_bytes(const s64 n);
extern int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
const runlist_element *rl);
extern int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max,
const s64 n);
extern int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a,
const u32 newsize);

8
include/runlist.h
View File

@ -60,6 +60,14 @@ extern runlist_element *ntfs_runlists_merge(runlist_element *drl,
extern runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
const ATTR_RECORD *attr, runlist_element *old_rl);
extern int ntfs_get_nr_significant_bytes(const s64 n);
extern int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
const runlist_element *rl);
extern int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max,
const s64 n);
extern int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
const int dst_len, const runlist_element *rl);

133
libntfs/attrib.c
View File

@ -1905,139 +1905,6 @@ void ntfs_attr_put_search_ctx(ntfs_attr_search_ctx *ctx)
return;
}
/**
* ntfs_get_nr_significant_bytes - get number of bytes needed to store a number
* @n: number for which to get the number of bytes for
*
* Return the number of bytes required to store @n unambiguously as
* a signed number.
*
* This is used in the context of the mapping pairs array to determine how
* many bytes will be needed in the array to store a given logical cluster
* number (lcn) or a specific run length.
*
* Return the number of bytes written. This function cannot fail.
*/
__inline__ int ntfs_get_nr_significant_bytes(const s64 n)
{
s64 l = n;
int i;
s8 j;
i = 0;
do {
l >>= 8;
i++;
} while (l != 0LL && l != -1LL);
j = (n >> 8 * (i - 1)) & 0xff;
/* If the sign bit is wrong, we need an extra byte. */
if ((n < 0LL && j >= 0) || (n > 0LL && j < 0))
i++;
return i;
}
/**
* ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
* @vol: ntfs volume (needed for the ntfs version)
* @rl: runlist for which to determine the size of the mapping pairs
*
* Walk the runlist @rl and calculate the size in bytes of the mapping pairs
* array corresponding to the runlist @rl. This for example allows us to
* allocate a buffer of the right size when building the mapping pairs array.
*
* Return the calculated size in bytes on success. If @rl is NULL return 0.
* On error, return -1 with errno set to the error code. The following error
* codes are defined:
* EINVAL - Run list contains unmapped elements. Make sure to only pass
* fully mapped runlists to this function.
* EIO - The runlist is corrupt.
*/
int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
const runlist_element *rl)
{
LCN prev_lcn;
int i, rls;
if (!rl)
return 0;
/* Always need the termining zero byte. */
rls = 1;
for (prev_lcn = i = 0; rl[i].length; prev_lcn = rl[++i].lcn) {
if (rl[i].length < 0 || rl[i].lcn < LCN_HOLE)
goto err_out;
/* Header byte + length. */
rls += 1 + ntfs_get_nr_significant_bytes(rl[i].length);
/*
* If the logical cluster number (lcn) denotes a hole and we
* are on NTFS 3.0+, we don't store it at all, i.e. we need
* zero space. On earlier NTFS versions we just store the lcn.
*/
if (rl[i].lcn == LCN_HOLE && vol->major_ver >= 3)
continue;
/* Change in lcn. */
rls += ntfs_get_nr_significant_bytes(rl[i].lcn - prev_lcn);
}
return rls;
err_out:
if (rl[i].lcn == LCN_RL_NOT_MAPPED)
errno = EINVAL;
else
errno = EIO;
return -1;
}
/**
* ntfs_write_significant_bytes - write the significant bytes of a number
* @dst: destination buffer to write to
* @dst_max: pointer to last byte of destination buffer for bounds checking
* @n: number whose significant bytes to write
*
* Store in @dst, the minimum bytes of the number @n which are required to
* identify @n unambiguously as a signed number, taking care not to exceed
* @dest_max, the maximum position within @dst to which we are allowed to
* write.
*
* This is used when building the mapping pairs array of a runlist to compress
* a given logical cluster number (lcn) or a specific run length to the minumum
* size possible.
*
* Return the number of bytes written on success. On error, i.e. the
* destination buffer @dst is too small, return -1 with errno set ENOSPC.
*/
__inline__ int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max,
const s64 n)
{
s64 l = n;
int i;
s8 j;
i = 0;
do {
if (dst > dst_max)
goto err_out;
*dst++ = l & 0xffLL;
l >>= 8;
i++;
} while (l != 0LL && l != -1LL);
j = (n >> 8 * (i - 1)) & 0xff;
/* If the sign bit is wrong, we need an extra byte. */
if (n < 0LL && j >= 0) {
if (dst > dst_max)
goto err_out;
i++;
*dst = (s8)-1;
} else if (n > 0LL && j < 0) {
if (dst > dst_max)
goto err_out;
i++;
*dst = (s8)0;
}
return i;
err_out:
errno = ENOSPC;
return -1;
}
/**
* ntfs_resident_attr_value_resize - resize the value of a resident attribute
* @m: mft record containing attribute record

133
libntfs/runlist.c
View File

@ -1097,6 +1097,139 @@ rl_err_out:
return -1;
}
/**
* ntfs_get_nr_significant_bytes - get number of bytes needed to store a number
* @n: number for which to get the number of bytes for
*
* Return the number of bytes required to store @n unambiguously as
* a signed number.
*
* This is used in the context of the mapping pairs array to determine how
* many bytes will be needed in the array to store a given logical cluster
* number (lcn) or a specific run length.
*
* Return the number of bytes written. This function cannot fail.
*/
__inline__ int ntfs_get_nr_significant_bytes(const s64 n)
{
s64 l = n;
int i;
s8 j;
i = 0;
do {
l >>= 8;
i++;
} while (l != 0LL && l != -1LL);
j = (n >> 8 * (i - 1)) & 0xff;
/* If the sign bit is wrong, we need an extra byte. */
if ((n < 0LL && j >= 0) || (n > 0LL && j < 0))
i++;
return i;
}
/**
* ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
* @vol: ntfs volume (needed for the ntfs version)
* @rl: runlist for which to determine the size of the mapping pairs
*
* Walk the runlist @rl and calculate the size in bytes of the mapping pairs
* array corresponding to the runlist @rl. This for example allows us to
* allocate a buffer of the right size when building the mapping pairs array.
*
* Return the calculated size in bytes on success. If @rl is NULL return 0.
* On error, return -1 with errno set to the error code. The following error
* codes are defined:
* EINVAL - Run list contains unmapped elements. Make sure to only pass
* fully mapped runlists to this function.
* EIO - The runlist is corrupt.
*/
int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
const runlist_element *rl)
{
LCN prev_lcn;
int i, rls;
if (!rl)
return 0;
/* Always need the termining zero byte. */
rls = 1;
for (prev_lcn = i = 0; rl[i].length; prev_lcn = rl[++i].lcn) {
if (rl[i].length < 0 || rl[i].lcn < LCN_HOLE)
goto err_out;
/* Header byte + length. */
rls += 1 + ntfs_get_nr_significant_bytes(rl[i].length);
/*
* If the logical cluster number (lcn) denotes a hole and we
* are on NTFS 3.0+, we don't store it at all, i.e. we need
* zero space. On earlier NTFS versions we just store the lcn.
*/
if (rl[i].lcn == LCN_HOLE && vol->major_ver >= 3)
continue;
/* Change in lcn. */
rls += ntfs_get_nr_significant_bytes(rl[i].lcn - prev_lcn);
}
return rls;
err_out:
if (rl[i].lcn == LCN_RL_NOT_MAPPED)
errno = EINVAL;
else
errno = EIO;
return -1;
}
/**
* ntfs_write_significant_bytes - write the significant bytes of a number
* @dst: destination buffer to write to
* @dst_max: pointer to last byte of destination buffer for bounds checking
* @n: number whose significant bytes to write
*
* Store in @dst, the minimum bytes of the number @n which are required to
* identify @n unambiguously as a signed number, taking care not to exceed
* @dest_max, the maximum position within @dst to which we are allowed to
* write.
*
* This is used when building the mapping pairs array of a runlist to compress
* a given logical cluster number (lcn) or a specific run length to the minumum
* size possible.
*
* Return the number of bytes written on success. On error, i.e. the
* destination buffer @dst is too small, return -1 with errno set ENOSPC.
*/
__inline__ int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max,
const s64 n)
{
s64 l = n;
int i;
s8 j;
i = 0;
do {
if (dst > dst_max)
goto err_out;
*dst++ = l & 0xffLL;
l >>= 8;
i++;
} while (l != 0LL && l != -1LL);
j = (n >> 8 * (i - 1)) & 0xff;
/* If the sign bit is wrong, we need an extra byte. */
if (n < 0LL && j >= 0) {
if (dst > dst_max)
goto err_out;
i++;
*dst = (s8)-1;
} else if (n > 0LL && j < 0) {
if (dst > dst_max)
goto err_out;
i++;
*dst = (s8)0;
}
return i;
err_out:
errno = ENOSPC;
return -1;
}
/**
* ntfs_mapping_pairs_build - build the mapping pairs array from a runlist
* @vol: ntfs volume (needed for the ntfs version)