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Document 'union buflib_data'

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Change-Id: Ia98fa8e7887338d6c0b7a5795a0ae5c7a13014ba
This commit is contained in:
Thomas Jarosch 2014-12-29 23:36:50 +01:00
parent 193c5df75d
commit da5a36d6d2
2 changed files with 11 additions and 8 deletions
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4
firmware/buflib.c
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@ -44,7 +44,7 @@
* the buffer. The buffer is treated as an array of union buflib_data. Blocks * the buffer. The buffer is treated as an array of union buflib_data. Blocks
* start with a length marker, which is included in their length. Free blocks * start with a length marker, which is included in their length. Free blocks
* are marked by negative length. Allocated blocks have a positiv length marker, * are marked by negative length. Allocated blocks have a positiv length marker,
* and additional metadata forllowing that: It follows a pointer * and additional metadata following that: It follows a pointer
* (union buflib_data*) to the corresponding handle table entry. so that it can * (union buflib_data*) to the corresponding handle table entry. so that it can
* be quickly found and updated during compaction. After that follows * be quickly found and updated during compaction. After that follows
* the pointer to the struct buflib_callbacks associated with this allocation * the pointer to the struct buflib_callbacks associated with this allocation
@ -62,7 +62,7 @@
* |L|H|C|cccc|L2|crc|XXXXXX|-L|YYYYYYYYYYYYYYYY|L|H|C|cc|L2|crc|XXXXXXXXXXXXX|AAA| * |L|H|C|cccc|L2|crc|XXXXXX|-L|YYYYYYYYYYYYYYYY|L|H|C|cc|L2|crc|XXXXXXXXXXXXX|AAA|
* *
* L - length marker (negative if block unallocated) * L - length marker (negative if block unallocated)
* H - handle table enry pointer * H - handle table entry pointer
* C - pointer to struct buflib_callbacks * C - pointer to struct buflib_callbacks
* c - variable sized string identifier * c - variable sized string identifier
* L2 - second length marker for string identifier * L2 - second length marker for string identifier

15
firmware/include/buflib.h
View file

@ -35,12 +35,15 @@
union buflib_data union buflib_data
{ {
intptr_t val; intptr_t val; /* length of the block in n*sizeof(union buflib_data).
char name[1]; /* actually a variable sized string */ Includes buflib metadata overhead. A negative value
struct buflib_callbacks* ops; indicates block is unallocated */
char* alloc; char name[1]; /* name, actually a variable sized string */
union buflib_data *handle; struct buflib_callbacks* ops; /* callback functions for move and shrink. Can be NULL */
uint32_t crc; char* alloc; /* start of allocated memory area */
union buflib_data *handle; /* pointer to entry in the handle table.
Used during compaction for fast lookup */
uint32_t crc; /* checksum of this data to detect corruption */
}; };
struct buflib_context struct buflib_context