6:22 p.m.
The `alloc` field is the maximum number of items you can append to a
vector before it need to be resized. This may confuse users with the
size of the `ptr` array which is `alloc * itemsize`. Rename to "cap",
common term for this property in many languages (e.g C++, Rust, Go).
Tested with "make check". Tests requiring root or external libraries
(vddk) not tested.
Ported from libnbd:
https://listman.redhat.com/archives/libguestfs/2021-October/msg00307.html
---
common/allocators/malloc.c | 24 ++++++++++++------------
common/utils/vector.c | 16 ++++++++--------
common/utils/vector.h | 12 ++++++------
plugins/vddk/reexec.c | 2 +-
4 files changed, 27 insertions(+), 27 deletions(-)
diff --git a/common/allocators/malloc.c b/common/allocators/malloc.c
index 59409c24..f7474465 100644
--- a/common/allocators/malloc.c
+++ b/common/allocators/malloc.c
@@ -88,16 +88,16 @@ extend (struct m_alloc *ma, uint64_t new_size)
ACQUIRE_WRLOCK_FOR_CURRENT_SCOPE (&ma->lock);
size_t old_size, n;
- if (ma->ba.alloc < new_size) {
- old_size = ma->ba.alloc;
- n = new_size - ma->ba.alloc;
+ if (ma->ba.cap < new_size) {
+ old_size = ma->ba.cap;
+ n = new_size - ma->ba.cap;
#ifdef HAVE_MUNLOCK
/* Since the memory might be moved by realloc, we must unlock the
* original array.
*/
if (ma->use_mlock)
- munlock (ma->ba.ptr, ma->ba.alloc);
+ munlock (ma->ba.ptr, ma->ba.cap);
#endif
if (bytearray_reserve (&ma->ba, n) == -1) {
@@ -110,7 +110,7 @@ extend (struct m_alloc *ma, uint64_t new_size)
#ifdef HAVE_MLOCK
if (ma->use_mlock) {
- if (mlock (ma->ba.ptr, ma->ba.alloc) == -1) {
+ if (mlock (ma->ba.ptr, ma->ba.cap) == -1) {
nbdkit_error ("allocator=malloc: mlock: %m");
return -1;
}
@@ -138,11 +138,11 @@ m_alloc_read (struct allocator *a, void *buf,
/* Avoid reading beyond the end of the allocated array. Return
* zeroes for that part.
*/
- if (offset >= ma->ba.alloc)
+ if (offset >= ma->ba.cap)
memset (buf, 0, count);
- else if (offset + count > ma->ba.alloc) {
- memcpy (buf, ma->ba.ptr + offset, ma->ba.alloc - offset);
- memset (buf + ma->ba.alloc - offset, 0, offset + count - ma->ba.alloc);
+ else if (offset + count > ma->ba.cap) {
+ memcpy (buf, ma->ba.ptr + offset, ma->ba.cap - offset);
+ memset (buf + ma->ba.cap - offset, 0, offset + count - ma->ba.cap);
}
else
memcpy (buf, ma->ba.ptr + offset, count);
@@ -191,9 +191,9 @@ m_alloc_zero (struct allocator *a, uint64_t count, uint64_t offset)
/* Try to avoid extending the array, since the unallocated part
* always reads as zero.
*/
- if (offset < ma->ba.alloc) {
- if (offset + count > ma->ba.alloc)
- memset (ma->ba.ptr + offset, 0, ma->ba.alloc - offset);
+ if (offset < ma->ba.cap) {
+ if (offset + count > ma->ba.cap)
+ memset (ma->ba.ptr + offset, 0, ma->ba.cap - offset);
else
memset (ma->ba.ptr + offset, 0, count);
}
diff --git a/common/utils/vector.c b/common/utils/vector.c
index 7df17e1b..a4b43ce7 100644
--- a/common/utils/vector.c
+++ b/common/utils/vector.c
@@ -41,21 +41,21 @@ int
generic_vector_reserve (struct generic_vector *v, size_t n, size_t itemsize)
{
void *newptr;
- size_t reqalloc, newalloc;
+ size_t reqcap, newcap;
- reqalloc = v->alloc + n;
- if (reqalloc < v->alloc)
+ reqcap = v->cap + n;
+ if (reqcap < v->cap)
return -1; /* overflow */
- newalloc = (v->alloc * 3 + 1) / 2;
+ newcap = (v->cap * 3 + 1) / 2;
- if (newalloc < reqalloc)
- newalloc = reqalloc;
+ if (newcap < reqcap)
+ newcap = reqcap;
- newptr = realloc (v->ptr, newalloc * itemsize);
+ newptr = realloc (v->ptr, newcap * itemsize);
if (newptr == NULL)
return -1;
v->ptr = newptr;
- v->alloc = newalloc;
+ v->cap = newcap;
return 0;
}
diff --git a/common/utils/vector.h b/common/utils/vector.h
index f6a0af78..782dcba6 100644
--- a/common/utils/vector.h
+++ b/common/utils/vector.h
@@ -86,7 +86,7 @@
struct name { \
type *ptr; /* Pointer to array of items. */ \
size_t size; /* Number of valid items in the array. */ \
- size_t alloc; /* Number of items allocated. */ \
+ size_t cap; /* Maximum number of items. */ \
}; \
typedef struct name name; \
\
@@ -106,7 +106,7 @@
name##_insert (name *v, type elem, size_t i) \
{ \
assert (i <= v->size); \
- if (v->size >= v->alloc) { \
+ if (v->size >= v->cap) { \
if (name##_reserve (v, 1) == -1) return -1; \
} \
memmove (&v->ptr[i+1], &v->ptr[i], (v->size-i) * sizeof (elem));
\
@@ -137,7 +137,7 @@
{ \
free (v->ptr); \
v->ptr = NULL; \
- v->size = v->alloc = 0; \
+ v->size = v->cap = 0; \
} \
\
/* Iterate over the vector, calling f() on each element. */ \
@@ -181,17 +181,17 @@
if (newptr == NULL) return -1; \
memcpy (newptr, vptr, len); \
copy->ptr = newptr; \
- copy->size = copy->alloc = v->size; \
+ copy->size = copy->cap = v->size; \
return 0; \
} \
\
-#define empty_vector { .ptr = NULL, .size = 0, .alloc = 0 }
+#define empty_vector { .ptr = NULL, .size = 0, .cap = 0 }
struct generic_vector {
void *ptr;
size_t size;
- size_t alloc;
+ size_t cap;
};
extern int generic_vector_reserve (struct generic_vector *v,
diff --git a/plugins/vddk/reexec.c b/plugins/vddk/reexec.c
index 46acdb62..9e87025e 100644
--- a/plugins/vddk/reexec.c
+++ b/plugins/vddk/reexec.c
@@ -116,7 +116,7 @@ perform_reexec (const char *env, const char *prepend)
nbdkit_error ("realloc: %m");
exit (EXIT_FAILURE);
}
- r = read (fd, buf.ptr + buf.size, buf.alloc - buf.size);
+ r = read (fd, buf.ptr + buf.size, buf.cap - buf.size);
if (r == -1) {
nbdkit_error ("read: %s: %m", cmdline_file);
exit (EXIT_FAILURE);
--
2.31.1