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buflib: omit CRC field if CRC paranoia is not enabled

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If we don't check or generate CRCs then the CRC field can be left
out of the header, which reduces buflib overhead slightly.

Change-Id: I08b4cf77a701d8f6da453e019a0373d858a79ae4
This commit is contained in:
Aidan MacDonald 2022-03-30 18:18:55 +01:00
parent dcc4e54b77
commit 59edcc57a2
1 changed files with 31 additions and 1 deletions
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32
firmware/buflib.c
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@ -105,6 +105,10 @@
/* Bitmask of enabled paranoia checks */ /* Bitmask of enabled paranoia checks */
#define BUFLIB_PARANOIA 0 #define BUFLIB_PARANOIA 0
#if BUFLIB_PARANOIA & PARANOIA_CHECK_CRC
# define BUFLIB_HAS_CRC
#endif
/* Forward indices, used to index a block start pointer as block[fidx_XXX] */ /* Forward indices, used to index a block start pointer as block[fidx_XXX] */
enum { enum {
fidx_LEN, /* length of the block, must come first */ fidx_LEN, /* length of the block, must come first */
@ -116,14 +120,20 @@ enum {
/* Backward indices, used to index a block end pointer as block[-bidx_XXX] */ /* Backward indices, used to index a block end pointer as block[-bidx_XXX] */
enum { enum {
bidx_USER, /* dummy to get below fields to be 1-based */ bidx_USER, /* dummy to get below fields to be 1-based */
#ifdef BUFLIB_HAS_CRC
bidx_CRC, /* CRC, protects all metadata behind it */ bidx_CRC, /* CRC, protects all metadata behind it */
#endif
bidx_BSIZE, /* total size of the block header */ bidx_BSIZE, /* total size of the block header */
}; };
/* Number of fields in the block header, excluding the name, which is /* Number of fields in the block header, excluding the name, which is
* accounted for using the BSIZE field. Note that bidx_USER is not an * accounted for using the BSIZE field. Note that bidx_USER is not an
* actual field so it is not included in the count. */ * actual field so it is not included in the count. */
#define BUFLIB_NUM_FIELDS 5 #ifdef BUFLIB_HAS_CRC
# define BUFLIB_NUM_FIELDS 5
#else
# define BUFLIB_NUM_FIELDS 4
#endif
struct buflib_callbacks buflib_ops_locked = { struct buflib_callbacks buflib_ops_locked = {
.move_callback = NULL, .move_callback = NULL,
@ -1211,6 +1221,7 @@ static void check_block_handle(struct buflib_context *ctx,
} }
} }
#ifdef BUFLIB_HAS_CRC
static uint32_t calc_block_crc(union buflib_data *block, static uint32_t calc_block_crc(union buflib_data *block,
union buflib_data *block_end) union buflib_data *block_end)
{ {
@ -1247,3 +1258,22 @@ static void check_block_crc(struct buflib_context *ctx,
} }
} }
} }
#else
static void update_block_crc(struct buflib_context *ctx,
union buflib_data *block,
union buflib_data *block_end)
{
(void)ctx;
(void)block;
(void)block_end;
}
static void check_block_crc(struct buflib_context *ctx,
union buflib_data *block,
union buflib_data *block_end)
{
(void)ctx;
(void)block;
(void)block_end;
}
#endif