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authorMattias Andrée <maandree@operamail.com>2015-11-17 01:55:25 +0100
committerMattias Andrée <maandree@operamail.com>2015-11-17 01:55:25 +0100
commita6636056fd26a5c08fac33e1a25c6b15d5727770 (patch)
treea08acdca60630e44a16c12d51b25dd5a1747768e /src
parentincrease readability of unescape (diff)
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increase readability of falloc
Signed-off-by: Mattias Andrée <maandree@operamail.com>
Diffstat (limited to '')
-rw-r--r--src/slibc-alloc.c114
1 files changed, 72 insertions, 42 deletions
diff --git a/src/slibc-alloc.c b/src/slibc-alloc.c
index a7ae30a..5ae9cbd 100644
--- a/src/slibc-alloc.c
+++ b/src/slibc-alloc.c
@@ -403,6 +403,51 @@ void* naive_extalloc(void* ptr, size_t size)
}
+/**
+ * Reallocation procedure for `falloc`.
+ *
+ * @param ptr The old pointer.
+ * @param ptrshift Pointer that is used to keep track of the pointer's
+ * shift for alignment.
+ * @param alignment The aligment of both the new and old pointer.
+ * @param old_size The old allocation size.
+ * @param new_size The new allocation size.
+ * @param mode `FALLOC_CLEAR`, `FALLOC_INIT`, or `FALLOC_MEMCPY`, or
+ * both or neither.
+ * @return The new pointer, or the old pointer if it was reallocated
+ * without creating a new allocation. `NULL` is returned
+ * on error (errno is set to describe the error.)
+ *
+ * @throws ENOMEM The process cannot allocate more memory.
+ */
+__GCC_ONLY(__attribute__((nonnull)))
+static inline void* falloc_realloc(void* ptr, size_t* ptrshift, size_t alignment,
+ size_t old_size, size_t new_size, enum falloc_mode mode)
+{
+ void* new_ptr = NULL;
+ size_t shift = *ptrshift;
+
+ if ((mode & FALLOC_CLEAR) && (old_size > new_size))
+ explicit_bzero(ptr + new_size, old_size - new_size);
+
+ new_ptr = falloc_extalloc(ptr - shift, old_size + shift, new_size + shift);
+ if ((new_ptr == NULL) && (errno == 0))
+ {
+ new_ptr = falloc_malloc(new_size + alignment - 1);
+ if (new_ptr != NULL)
+ {
+ if ((size_t)new_ptr % alignment)
+ shift = alignment - ((size_t)new_ptr % alignment);
+ *ptrshift = shift;
+ new_ptr = (void*)((char*)new_ptr + shift);
+ if (mode & FALLOC_MEMCPY)
+ memcpy(new_ptr, ptr, old_size);
+ }
+ }
+
+ return new_ptr;
+}
+
/**
* Allocates, deallocates, or reallocates memory without
@@ -460,55 +505,27 @@ void* naive_extalloc(void* ptr, size_t size)
void* falloc(void* ptr, size_t* ptrshift, size_t alignment,
size_t old_size, size_t new_size, enum falloc_mode mode)
{
+ /* TODO implement falloc_malloc, falloc_free, and falloc_extalloc */
+
+ size_t shift = 0, _ptrshift = 0;
void* new_ptr = NULL;
- size_t shift = 0;
if (mode & (enum falloc_mode)~(FALLOC_CLEAR | FALLOC_INIT | FALLOC_MEMCPY))
- return errno = EINVAL, NULL;
-
- alignment = alignment ? alignment : 1;
+ goto invalid;
if (new_size && old_size && ptr)
{
- shift = ptrshift == NULL ? *ptrshift : 0;
- if ((alignment > 1) && (ptrshift == NULL))
- return errno = EINVAL, NULL;
- if ((mode & FALLOC_CLEAR) && (old_size > new_size))
- explicit_bzero(ptr + new_size, old_size - new_size);
- new_ptr = falloc_extalloc(ptr - shift, old_size + shift, new_size + shift);
- if ((new_ptr == NULL) && (errno == 0))
- {
- new_ptr = falloc_malloc(new_size + alignment - 1);
- if (new_ptr != NULL)
- {
- if ((size_t)new_ptr % alignment)
- shift = alignment - ((size_t)new_ptr % alignment);
- if (ptrshift != NULL)
- *ptrshift = shift;
- new_ptr = (void*)((char*)new_ptr + shift);
- if (mode & FALLOC_MEMCPY)
- memcpy(new_ptr, ptr, old_size);
- }
- }
- }
- else if (new_size && (old_size || ptr))
- return errno = EINVAL, NULL;
- else if (new_size)
- new_ptr = falloc_malloc(new_size);
- else if (old_size && ptr)
- {
- shift = ptrshift == NULL ? *ptrshift : 0;
- if ((alignment > 1) && (ptrshift == NULL))
- return errno = EINVAL, NULL;
- if (mode & FALLOC_CLEAR)
- explicit_bzero(ptr, old_size);
- falloc_free(ptr - shift);
- return errno = 0, NULL;
+ if ((alignment > 1) && !ptrshift) goto invalid;
+ new_ptr = falloc_realloc(ptr, ptrshift ? ptrshift : &_ptrshift,
+ alignment ? alignment : 1,
+ old_size, new_size, mode, &shift);
+ shift = ptrshift ? *ptrshift : _ptrshift;
}
- else if (old_size || !ptr)
- return errno = 0, NULL;
- else
- return errno = EINVAL, NULL;
+ else if (new_size && (old_size || ptr)) goto invalid;
+ else if (new_size) new_ptr = falloc_malloc(new_size);
+ else if (old_size && ptr) goto deallocate;
+ else if (old_size || !ptr) goto return_null;
+ else goto invalid;
if (new_ptr != NULL)
{
@@ -528,5 +545,18 @@ void* falloc(void* ptr, size_t* ptrshift, size_t alignment,
}
return errno = 0, new_ptr;
+
+ deallocate:
+ shift = ptrshift == NULL ? *ptrshift : 0;
+ if ((alignment > 1) && (ptrshift == NULL))
+ goto invalid;
+ if (mode & FALLOC_CLEAR)
+ explicit_bzero(ptr, old_size);
+ falloc_free(ptr - shift);
+ return_null:
+ return errno = 0, NULL;
+
+ invalid:
+ return errno = EINVAL, NULL;
}