From aa380d4323bcc4dae0f8bafdd074466f8bc5bcf5 Mon Sep 17 00:00:00 2001

From: Vladimir 'phcoder' Serbinenko <phcoder@gmail.com>

Date: Sat, 5 Jan 2013 17:36:04 +0100

Subject: [PATCH 086/364] 	* grub-core/fs/ntfs.c: Eliminate useless

 divisions in favor of shifts. 	* grub-core/fs/ntfscomp.c: Likewise. 	*

 include/grub/ntfs.h (grub_ntfs_data): Replace spc with log_spc. 

 (grub_ntfs_comp): Likewise.

---

 ChangeLog               |  7 +++++++

 grub-core/fs/ntfs.c     | 47 ++++++++++++++++++++++++-----------------------

 grub-core/fs/ntfscomp.c | 39 ++++++++++++++++++++-------------------

 include/grub/ntfs.h     |  6 ++++--

 4 files changed, 55 insertions(+), 44 deletions(-)

diff --git a/ChangeLog b/ChangeLog

index ea191b3..88fd763 100644

--- a/ChangeLog

+++ b/ChangeLog

@@ -1,5 +1,12 @@

 2013-01-05  Vladimir Serbinenko  <phcoder@gmail.com>

+	* grub-core/fs/ntfs.c: Eliminate useless divisions in favor of shifts.

+	* grub-core/fs/ntfscomp.c: Likewise.

+	* include/grub/ntfs.h (grub_ntfs_data): Replace spc with log_spc.

+	(grub_ntfs_comp): Likewise.

+

+2013-01-05  Vladimir Serbinenko  <phcoder@gmail.com>

+

 	* grub-core/fs/nilfs2.c (-grub_nilfs2_palloc_groups_per_desc_block):

 	Rename to ...

 	(grub_nilfs2_palloc_log_groups_per_desc_block): ... this. Return log

diff --git a/grub-core/fs/ntfs.c b/grub-core/fs/ntfs.c

index b9762b6..6004e1f 100644

--- a/grub-core/fs/ntfs.c

+++ b/grub-core/fs/ntfs.c

@@ -391,7 +391,7 @@ read_data (struct grub_ntfs_attr *at, char *pa, char *dest,

   grub_memset (&cc, 0, sizeof (cc));

   ctx = &cc;

   ctx->attr = at;

-  ctx->comp.spc = at->mft->data->spc;

+  ctx->comp.log_spc = at->mft->data->log_spc;

   ctx->comp.disk = at->mft->data->disk;

   if (pa[8] == 0)

@@ -440,11 +440,11 @@ read_data (struct grub_ntfs_attr *at, char *pa, char *dest,

 	  at->save_pos = 1;

 	}

-      vcn = ctx->target_vcn = (ofs >> GRUB_NTFS_COM_LOG_LEN) * (GRUB_NTFS_COM_SEC / ctx->comp.spc);

+      vcn = ctx->target_vcn = (ofs >> GRUB_NTFS_COM_LOG_LEN) * (GRUB_NTFS_COM_SEC >> ctx->comp.log_spc);

       ctx->target_vcn &= ~0xFULL;

     }

   else

-    vcn = ctx->target_vcn = grub_divmod64 (ofs >> GRUB_NTFS_BLK_SHR, ctx->comp.spc, 0);

+    vcn = ctx->target_vcn = ofs >> (GRUB_NTFS_BLK_SHR + ctx->comp.log_spc);

   ctx->next_vcn = u32at (pa, 0x10);

   ctx->curr_lcn = 0;

@@ -459,17 +459,17 @@ read_data (struct grub_ntfs_attr *at, char *pa, char *dest,

       grub_disk_addr_t st0, st1;

       grub_uint64_t m;

-      grub_divmod64 (ofs >> GRUB_NTFS_BLK_SHR, ctx->comp.spc, &m);

+      m = (ofs >> GRUB_NTFS_BLK_SHR) & ((1 << ctx->comp.log_spc) - 1);

       st0 =

-	(ctx->target_vcn - ctx->curr_vcn + ctx->curr_lcn) * ctx->comp.spc + m;

+	((ctx->target_vcn - ctx->curr_vcn + ctx->curr_lcn) << ctx->comp.log_spc) + m;

       st1 = st0 + 1;

       if (st1 ==

-	  (ctx->next_vcn - ctx->curr_vcn + ctx->curr_lcn) * ctx->comp.spc)

+	  (ctx->next_vcn - ctx->curr_vcn + ctx->curr_lcn) << ctx->comp.log_spc)

 	{

 	  if (grub_ntfs_read_run_list (ctx))

 	    return grub_errno;

-	  st1 = ctx->curr_lcn * ctx->comp.spc;

+	  st1 = ctx->curr_lcn << ctx->comp.log_spc;

 	}

       grub_set_unaligned32 (dest, grub_cpu_to_le32 (st0));

       grub_set_unaligned32 (dest + 4, grub_cpu_to_le32 (st1));

@@ -478,12 +478,10 @@ read_data (struct grub_ntfs_attr *at, char *pa, char *dest,

   if (!(ctx->flags & GRUB_NTFS_RF_COMP))

     {

-      unsigned int pow;

-

-      if (!grub_fshelp_log2blksize (ctx->comp.spc, &pow))

-	grub_fshelp_read_file (ctx->comp.disk, (grub_fshelp_node_t) ctx,

-			       read_hook, ofs, len, dest,

-			       grub_ntfs_read_block, ofs + len, pow, 0);

+      grub_fshelp_read_file (ctx->comp.disk, (grub_fshelp_node_t) ctx,

+			     read_hook, ofs, len, dest,

+			     grub_ntfs_read_block, ofs + len,

+			     ctx->comp.log_spc, 0);

       return grub_errno;

     }

@@ -515,11 +513,11 @@ read_attr (struct grub_ntfs_attr *at, char *dest, grub_disk_addr_t ofs,

       /* If compression is possible make sure that we include possible

 	 compressed block size.  */

-      if (GRUB_NTFS_COM_SEC >= at->mft->data->spc)

+      if (GRUB_NTFS_LOG_COM_SEC >= at->mft->data->log_spc)

 	vcn = ((ofs >> GRUB_NTFS_COM_LOG_LEN)

-	       * (GRUB_NTFS_COM_SEC / at->mft->data->spc)) & ~0xFULL;

+	       << (GRUB_NTFS_LOG_COM_SEC - at->mft->data->log_spc)) & ~0xFULL;

       else

-	vcn = grub_divmod64 (ofs, at->mft->data->spc << GRUB_NTFS_BLK_SHR, 0);

+	vcn = ofs >> (at->mft->data->log_spc + GRUB_NTFS_BLK_SHR);

       pa = at->attr_nxt + u16at (at->attr_nxt, 4);

       while (pa < at->attr_end)

 	{

@@ -934,6 +932,7 @@ grub_ntfs_mount (grub_disk_t disk)

 {

   struct grub_ntfs_bpb bpb;

   struct grub_ntfs_data *data = 0;

+  grub_uint32_t spc;

   if (!disk)

     goto fail;

@@ -955,23 +954,25 @@ grub_ntfs_mount (grub_disk_t disk)

       || (bpb.bytes_per_sector & (bpb.bytes_per_sector - 1)) != 0)

     goto fail;

-  data->spc = (((grub_uint32_t) bpb.sectors_per_cluster

-		* (grub_uint32_t) grub_le_to_cpu16 (bpb.bytes_per_sector))

-	       >> GRUB_NTFS_BLK_SHR);

-  if (!data->spc)

+  spc = (((grub_uint32_t) bpb.sectors_per_cluster

+	  * (grub_uint32_t) grub_le_to_cpu16 (bpb.bytes_per_sector))

+	 >> GRUB_NTFS_BLK_SHR);

+  if (spc == 0 || (spc & (spc - 1)))

     goto fail;

+  for (data->log_spc = 0; (1U << data->log_spc) < spc; data->log_spc++);

+

   if (bpb.clusters_per_mft > 0)

-    data->mft_size = data->spc * bpb.clusters_per_mft;

+    data->mft_size = bpb.clusters_per_mft << data->log_spc;

   else

     data->mft_size = 1 << (-bpb.clusters_per_mft - GRUB_NTFS_BLK_SHR);

   if (bpb.clusters_per_index > 0)

-    data->idx_size = data->spc * bpb.clusters_per_index;

+    data->idx_size = bpb.clusters_per_index << data->log_spc;

   else

     data->idx_size = 1 << (-bpb.clusters_per_index - GRUB_NTFS_BLK_SHR);

-  data->mft_start = grub_le_to_cpu64 (bpb.mft_lcn) * data->spc;

+  data->mft_start = grub_le_to_cpu64 (bpb.mft_lcn) << data->log_spc;

   if ((data->mft_size > GRUB_NTFS_MAX_MFT) || (data->idx_size > GRUB_NTFS_MAX_IDX))

     goto fail;

diff --git a/grub-core/fs/ntfscomp.c b/grub-core/fs/ntfscomp.c

index ec359fa..9b3b75d 100644

--- a/grub-core/fs/ntfscomp.c

+++ b/grub-core/fs/ntfscomp.c

@@ -33,8 +33,9 @@ decomp_nextvcn (struct grub_ntfs_comp *cc)

   if (grub_disk_read

       (cc->disk,

        (cc->comp_table[cc->comp_head].next_lcn -

-	(cc->comp_table[cc->comp_head].next_vcn - cc->cbuf_vcn)) * cc->spc, 0,

-       cc->spc << GRUB_NTFS_BLK_SHR, cc->cbuf))

+	(cc->comp_table[cc->comp_head].next_vcn - cc->cbuf_vcn)) << cc->log_spc,

+       0,

+       1 << (cc->log_spc + GRUB_NTFS_BLK_SHR), cc->cbuf))

     return grub_errno;

   cc->cbuf_vcn++;

   if ((cc->cbuf_vcn >= cc->comp_table[cc->comp_head].next_vcn))

@@ -46,7 +47,7 @@ decomp_nextvcn (struct grub_ntfs_comp *cc)

 static grub_err_t

 decomp_getch (struct grub_ntfs_comp *cc, unsigned char *res)

 {

-  if (cc->cbuf_ofs >= (cc->spc << GRUB_NTFS_BLK_SHR))

+  if (cc->cbuf_ofs >= (1U << (cc->log_spc + GRUB_NTFS_BLK_SHR)))

     {

       if (decomp_nextvcn (cc))

 	return grub_errno;

@@ -159,7 +160,7 @@ decomp_block (struct grub_ntfs_comp *cc, char *dest)

     {

       int n;

-      n = (cc->spc << GRUB_NTFS_BLK_SHR) - cc->cbuf_ofs;

+      n = (1 << (cc->log_spc + GRUB_NTFS_BLK_SHR)) - cc->cbuf_ofs;

       if (n > cnt)

 	n = cnt;

       if ((dest) && (n))

@@ -178,7 +179,7 @@ decomp_block (struct grub_ntfs_comp *cc, char *dest)

 static grub_err_t

 read_block (struct grub_ntfs_rlst *ctx, char *buf, grub_size_t num)

 {

-  int cpb = GRUB_NTFS_COM_SEC / ctx->comp.spc;

+  int log_cpb = GRUB_NTFS_LOG_COM_SEC - ctx->comp.log_spc;

   while (num)

     {

@@ -192,7 +193,7 @@ read_block (struct grub_ntfs_rlst *ctx, char *buf, grub_size_t num)

 	    return grub_error (GRUB_ERR_BAD_FS, "invalid compression block");

 	  ctx->comp.comp_head = ctx->comp.comp_tail = 0;

 	  ctx->comp.cbuf_vcn = ctx->target_vcn;

-	  ctx->comp.cbuf_ofs = (ctx->comp.spc << GRUB_NTFS_BLK_SHR);

+	  ctx->comp.cbuf_ofs = (1 << (ctx->comp.log_spc + GRUB_NTFS_BLK_SHR));

 	  if (ctx->target_vcn >= ctx->next_vcn)

 	    {

 	      if (grub_ntfs_read_run_list (ctx))

@@ -211,14 +212,14 @@ read_block (struct grub_ntfs_rlst *ctx, char *buf, grub_size_t num)

 	    }

 	}

-      nn = (16 - (unsigned) (ctx->target_vcn & 0xF)) / cpb;

+      nn = (16 - (unsigned) (ctx->target_vcn & 0xF)) >> log_cpb;

       if (nn > num)

 	nn = num;

       num -= nn;

       if (ctx->flags & GRUB_NTFS_RF_BLNK)

 	{

-	  ctx->target_vcn += nn * cpb;

+	  ctx->target_vcn += nn << log_cpb;

 	  if (ctx->comp.comp_tail == 0)

 	    {

 	      if (buf)

@@ -241,7 +242,7 @@ read_block (struct grub_ntfs_rlst *ctx, char *buf, grub_size_t num)

 	}

       else

 	{

-	  nn *= cpb;

+	  nn <<= log_cpb;

 	  while ((ctx->comp.comp_head < ctx->comp.comp_tail) && (nn))

 	    {

 	      grub_disk_addr_t tt;

@@ -258,10 +259,10 @@ read_block (struct grub_ntfs_rlst *ctx, char *buf, grub_size_t num)

 		      (ctx->comp.disk,

 		       (ctx->comp.comp_table[ctx->comp.comp_head].next_lcn -

 			(ctx->comp.comp_table[ctx->comp.comp_head].next_vcn -

-			 ctx->target_vcn)) * ctx->comp.spc, 0,

-		       tt * (ctx->comp.spc << GRUB_NTFS_BLK_SHR), buf))

+			 ctx->target_vcn)) << ctx->comp.log_spc, 0,

+		       tt << (ctx->comp.log_spc + GRUB_NTFS_BLK_SHR), buf))

 		    return grub_errno;

-		  buf += tt * (ctx->comp.spc << GRUB_NTFS_BLK_SHR);

+		  buf += tt << (ctx->comp.log_spc + GRUB_NTFS_BLK_SHR);

 		}

 	      nn -= tt;

 	      if (ctx->target_vcn >=

@@ -275,10 +276,10 @@ read_block (struct grub_ntfs_rlst *ctx, char *buf, grub_size_t num)

 		  if (grub_disk_read

 		      (ctx->comp.disk,

 		       (ctx->target_vcn - ctx->curr_vcn +

-			ctx->curr_lcn) * ctx->comp.spc, 0,

-		       nn * (ctx->comp.spc << GRUB_NTFS_BLK_SHR), buf))

+			ctx->curr_lcn) << ctx->comp.log_spc, 0,

+		       nn << (ctx->comp.log_spc + GRUB_NTFS_BLK_SHR), buf))

 		    return grub_errno;

-		  buf += nn * (ctx->comp.spc << GRUB_NTFS_BLK_SHR);

+		  buf += nn << (ctx->comp.log_spc + GRUB_NTFS_BLK_SHR);

 		}

 	      ctx->target_vcn += nn;

 	    }

@@ -294,7 +295,7 @@ ntfscomp (struct grub_ntfs_attr *at, char *dest, grub_disk_addr_t ofs,

   grub_err_t ret;

   ctx->comp.comp_head = ctx->comp.comp_tail = 0;

-  ctx->comp.cbuf = grub_malloc ((ctx->comp.spc) << GRUB_NTFS_BLK_SHR);

+  ctx->comp.cbuf = grub_malloc (1 << (ctx->comp.log_spc + GRUB_NTFS_BLK_SHR));

   if (!ctx->comp.cbuf)

     return 0;

@@ -304,7 +305,7 @@ ntfscomp (struct grub_ntfs_attr *at, char *dest, grub_disk_addr_t ofs,

   if ((vcn > ctx->target_vcn) &&

       (read_block

-       (ctx, NULL, ((vcn - ctx->target_vcn) * ctx->comp.spc) / GRUB_NTFS_COM_SEC)))

+       (ctx, NULL, (vcn - ctx->target_vcn) >> (GRUB_NTFS_LOG_COM_SEC - ctx->comp.log_spc))))

     {

       ret = grub_errno;

       goto quit;

@@ -314,7 +315,7 @@ ntfscomp (struct grub_ntfs_attr *at, char *dest, grub_disk_addr_t ofs,

     {

       grub_uint32_t t, n, o;

-      t = ctx->target_vcn * (ctx->comp.spc << GRUB_NTFS_BLK_SHR);

+      t = ctx->target_vcn << (ctx->comp.log_spc + GRUB_NTFS_BLK_SHR);

       if (read_block (ctx, at->sbuf, 1))

 	{

 	  ret = grub_errno;

@@ -346,7 +347,7 @@ ntfscomp (struct grub_ntfs_attr *at, char *dest, grub_disk_addr_t ofs,

     {

       grub_uint32_t t;

-      t = ctx->target_vcn * (ctx->comp.spc << GRUB_NTFS_BLK_SHR);

+      t = ctx->target_vcn << (ctx->comp.log_spc + GRUB_NTFS_BLK_SHR);

       if (read_block (ctx, at->sbuf, 1))

 	{

 	  ret = grub_errno;

diff --git a/include/grub/ntfs.h b/include/grub/ntfs.h

index 0935342..cc28a01 100644

--- a/include/grub/ntfs.h

+++ b/include/grub/ntfs.h

@@ -87,6 +87,7 @@ enum

 #define GRUB_NTFS_COM_LEN		4096

 #define GRUB_NTFS_COM_LOG_LEN	12

 #define GRUB_NTFS_COM_SEC		(GRUB_NTFS_COM_LEN >> GRUB_NTFS_BLK_SHR)

+#define GRUB_NTFS_LOG_COM_SEC		(GRUB_NTFS_COM_LOG_LEN - GRUB_NTFS_BLK_SHR)

 enum

   {

@@ -156,7 +157,7 @@ struct grub_ntfs_data

   grub_disk_t disk;

   grub_uint32_t mft_size;

   grub_uint32_t idx_size;

-  grub_uint32_t spc;

+  int log_spc;

   grub_uint32_t mft_start;

   grub_uint64_t uuid;

 };

@@ -172,7 +173,8 @@ struct grub_ntfs_comp

   grub_disk_t disk;

   int comp_head, comp_tail;

   struct grub_ntfs_comp_table_element comp_table[16];

-  grub_uint32_t cbuf_ofs, cbuf_vcn, spc;

+  grub_uint32_t cbuf_ofs, cbuf_vcn;

+  int log_spc;

   char *cbuf;

 };

-- 

1.8.1.4