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-rw-r--r--src/liballoc.c534
1 files changed, 534 insertions, 0 deletions
diff --git a/src/liballoc.c b/src/liballoc.c
new file mode 100644
index 0000000..f407527
--- /dev/null
+++ b/src/liballoc.c
@@ -0,0 +1,534 @@
+#include "liballoc.h"
+#include <stddef.h>
+
+/** Durand's Ridiculously Amazing Super Duper Memory functions. */
+
+//#define DEBUG
+
+#define LIBALLOC_MAGIC 0xc001c0de
+#define MAXCOMPLETE 5
+#define MAXEXP 32
+#define MINEXP 8
+
+#define MODE_BEST 0
+#define MODE_INSTANT 1
+
+#define MODE MODE_BEST
+
+#ifdef DEBUG
+#include "printf.h"
+#endif
+
+
+struct boundary_tag* l_freePages[MAXEXP]; //< Allowing for 2^MAXEXP blocks
+int l_completePages[MAXEXP]; //< Allowing for 2^MAXEXP blocks
+
+
+#ifdef DEBUG
+unsigned int l_allocated = 0; //< The real amount of memory allocated.
+unsigned int l_inuse = 0; //< The amount of memory in use (malloc'ed).
+#endif
+
+
+static int l_initialized = 0; //< Flag to indicate initialization.
+static int l_pageSize = 4096; //< Individual page size
+static int l_pageCount = 16; //< Minimum number of pages to allocate.
+
+
+// *********** HELPER FUNCTIONS *******************************
+
+/** Returns the exponent required to manage 'size' amount of memory.
+ *
+ * Returns n where 2^n <= size < 2^(n+1)
+ */
+static inline int getexp( unsigned int size )
+{
+ if ( size < (1<<MINEXP) )
+ {
+ #ifdef DEBUG
+ printf("getexp returns -1 for %i less than MINEXP\n", size );
+ #endif
+ return -1; // Smaller than the quantum.
+ }
+
+
+ int shift = MINEXP;
+
+ while ( shift < MAXEXP )
+ {
+ if ( (1<<shift) > size ) break;
+ shift += 1;
+ }
+
+ #ifdef DEBUG
+ printf("getexp returns %i (%i bytes) for %i size\n", shift - 1, (1<<(shift -1)), size );
+ #endif
+
+ return shift - 1;
+}
+
+
+static void* liballoc_memset(void* s, int c, size_t n)
+{
+ int i;
+ for ( i = 0; i < n ; i++)
+ ((char*)s)[i] = c;
+
+ return s;
+}
+
+static void* liballoc_memcpy(void* s1, const void* s2, size_t n)
+{
+ char *cdest;
+ char *csrc;
+ unsigned int *ldest = (unsigned int*)s1;
+ unsigned int *lsrc = (unsigned int*)s2;
+
+ while ( n >= sizeof(unsigned int) )
+ {
+ *ldest++ = *lsrc++;
+ n -= sizeof(unsigned int);
+ }
+
+ cdest = (char*)ldest;
+ csrc = (char*)lsrc;
+
+ while ( n > 0 )
+ {
+ *cdest++ = *csrc++;
+ n -= 1;
+ }
+
+ return s1;
+}
+
+
+
+#ifdef DEBUG
+static void dump_array()
+{
+ int i = 0;
+ struct boundary_tag *tag = NULL;
+
+ printf("------ Free pages array ---------\n");
+ printf("System memory allocated: %i\n", l_allocated );
+ printf("Memory in used (malloc'ed): %i\n", l_inuse );
+
+ for ( i = 0; i < MAXEXP; i++ )
+ {
+ printf("%.2i(%i): ",i, l_completePages[i] );
+
+ tag = l_freePages[ i ];
+ while ( tag != NULL )
+ {
+ if ( tag->split_left != NULL ) printf("*");
+ printf("%i", tag->real_size );
+ if ( tag->split_right != NULL ) printf("*");
+
+ printf(" ");
+ tag = tag->next;
+ }
+ printf("\n");
+ }
+
+ printf("'*' denotes a split to the left/right of a tag\n");
+}
+#endif
+
+
+
+static inline void insert_tag( struct boundary_tag *tag, int index )
+{
+ int realIndex;
+
+ if ( index < 0 )
+ {
+ realIndex = getexp( tag->real_size - sizeof(struct boundary_tag) );
+ if ( realIndex < MINEXP ) realIndex = MINEXP;
+ }
+ else
+ realIndex = index;
+
+ tag->index = realIndex;
+
+ if ( l_freePages[ realIndex ] != NULL )
+ {
+ l_freePages[ realIndex ]->prev = tag;
+ tag->next = l_freePages[ realIndex ];
+ }
+
+ l_freePages[ realIndex ] = tag;
+}
+
+static inline void remove_tag( struct boundary_tag *tag )
+{
+ if ( l_freePages[ tag->index ] == tag ) l_freePages[ tag->index ] = tag->next;
+
+ if ( tag->prev != NULL ) tag->prev->next = tag->next;
+ if ( tag->next != NULL ) tag->next->prev = tag->prev;
+
+ tag->next = NULL;
+ tag->prev = NULL;
+ tag->index = -1;
+}
+
+
+static inline struct boundary_tag* melt_left( struct boundary_tag *tag )
+{
+ struct boundary_tag *left = tag->split_left;
+
+ left->real_size += tag->real_size;
+ left->split_right = tag->split_right;
+
+ if ( tag->split_right != NULL ) tag->split_right->split_left = left;
+
+ return left;
+}
+
+
+static inline struct boundary_tag* absorb_right( struct boundary_tag *tag )
+{
+ struct boundary_tag *right = tag->split_right;
+
+ remove_tag( right ); // Remove right from free pages.
+
+ tag->real_size += right->real_size;
+
+ tag->split_right = right->split_right;
+ if ( right->split_right != NULL )
+ right->split_right->split_left = tag;
+
+ return tag;
+}
+
+static inline struct boundary_tag* split_tag( struct boundary_tag* tag )
+{
+ unsigned int remainder = tag->real_size - sizeof(struct boundary_tag) - tag->size;
+
+ struct boundary_tag *new_tag =
+ (struct boundary_tag*)((unsigned int)tag + sizeof(struct boundary_tag) + tag->size);
+
+ new_tag->magic = LIBALLOC_MAGIC;
+ new_tag->real_size = remainder;
+
+ new_tag->next = NULL;
+ new_tag->prev = NULL;
+
+ new_tag->split_left = tag;
+ new_tag->split_right = tag->split_right;
+
+ if (new_tag->split_right != NULL) new_tag->split_right->split_left = new_tag;
+ tag->split_right = new_tag;
+
+ tag->real_size -= new_tag->real_size;
+
+ insert_tag( new_tag, -1 );
+
+ return new_tag;
+}
+
+
+// ***************************************************************
+
+
+
+
+static struct boundary_tag* allocate_new_tag( unsigned int size )
+{
+ unsigned int pages;
+ unsigned int usage;
+ struct boundary_tag *tag;
+
+ // This is how much space is required.
+ usage = size + sizeof(struct boundary_tag);
+
+ // Perfect amount of space
+ pages = usage / l_pageSize;
+ if ( (usage % l_pageSize) != 0 ) pages += 1;
+
+ // Make sure it's >= the minimum size.
+ if ( pages < l_pageCount ) pages = l_pageCount;
+
+ tag = (struct boundary_tag*)liballoc_alloc( pages );
+
+ if ( tag == NULL ) return NULL; // uh oh, we ran out of memory.
+
+ tag->magic = LIBALLOC_MAGIC;
+ tag->size = size;
+ tag->real_size = pages * l_pageSize;
+ tag->index = -1;
+
+ tag->next = NULL;
+ tag->prev = NULL;
+ tag->split_left = NULL;
+ tag->split_right = NULL;
+
+
+ #ifdef DEBUG
+ printf("Resource allocated %x of %i pages (%i bytes) for %i size.\n", tag, pages, pages * l_pageSize, size );
+
+ l_allocated += pages * l_pageSize;
+
+ printf("Total memory usage = %i KB\n", (int)((l_allocated / (1024))) );
+ #endif
+
+ return tag;
+}
+
+
+
+void *malloc(size_t size)
+{
+ int index;
+ void *ptr;
+ struct boundary_tag *tag = NULL;
+
+ liballoc_lock();
+
+ if ( l_initialized == 0 )
+ {
+ #ifdef DEBUG
+ printf("%s\n","liballoc initializing.");
+ #endif
+ for ( index = 0; index < MAXEXP; index++ )
+ {
+ l_freePages[index] = NULL;
+ l_completePages[index] = 0;
+ }
+ l_initialized = 1;
+ }
+
+ index = getexp( size ) + MODE;
+ if ( index < MINEXP ) index = MINEXP;
+
+
+ // Find one big enough.
+ tag = l_freePages[ index ]; // Start at the front of the list.
+ while ( tag != NULL )
+ {
+ // If there's enough space in this tag.
+ if ( (tag->real_size - sizeof(struct boundary_tag))
+ >= (size + sizeof(struct boundary_tag) ) )
+ {
+ #ifdef DEBUG
+ printf("Tag search found %i >= %i\n",(tag->real_size - sizeof(struct boundary_tag)), (size + sizeof(struct boundary_tag) ) );
+ #endif
+ break;
+ }
+
+ tag = tag->next;
+ }
+
+
+ // No page found. Make one.
+ if ( tag == NULL )
+ {
+ if ( (tag = allocate_new_tag( size )) == NULL )
+ {
+ liballoc_unlock();
+ return NULL;
+ }
+
+ index = getexp( tag->real_size - sizeof(struct boundary_tag) );
+ }
+ else
+ {
+ remove_tag( tag );
+
+ if ( (tag->split_left == NULL) && (tag->split_right == NULL) )
+ l_completePages[ index ] -= 1;
+ }
+
+ // We have a free page. Remove it from the free pages list.
+
+ tag->size = size;
+
+ // Removed... see if we can re-use the excess space.
+
+ #ifdef DEBUG
+ printf("Found tag with %i bytes available (requested %i bytes, leaving %i), which has exponent: %i (%i bytes)\n", tag->real_size - sizeof(struct boundary_tag), size, tag->real_size - size - sizeof(struct boundary_tag), index, 1<<index );
+ #endif
+
+ unsigned int remainder = tag->real_size - size - sizeof( struct boundary_tag ) * 2; // Support a new tag + remainder
+
+ if ( ((int)(remainder) > 0) /*&& ( (tag->real_size - remainder) >= (1<<MINEXP))*/ )
+ {
+ int childIndex = getexp( remainder );
+
+ if ( childIndex >= 0 )
+ {
+ #ifdef DEBUG
+ printf("Seems to be splittable: %i >= 2^%i .. %i\n", remainder, childIndex, (1<<childIndex) );
+ #endif
+
+ struct boundary_tag *new_tag = split_tag( tag );
+
+ new_tag = new_tag; // Get around the compiler warning about unused variables.
+
+ #ifdef DEBUG
+ printf("Old tag has become %i bytes, new tag is now %i bytes (%i exp)\n", tag->real_size, new_tag->real_size, new_tag->index );
+ #endif
+ }
+ }
+
+
+
+ ptr = (void*)((unsigned int)tag + sizeof( struct boundary_tag ) );
+
+
+
+ #ifdef DEBUG
+ l_inuse += size;
+ printf("malloc: %x, %i, %i\n", ptr, (int)l_inuse / 1024, (int)l_allocated / 1024 );
+ dump_array();
+ #endif
+
+
+ liballoc_unlock();
+ return ptr;
+}
+
+
+
+
+
+void free(void *ptr)
+{
+ int index;
+ struct boundary_tag *tag;
+
+ if ( ptr == NULL ) return;
+
+ liballoc_lock();
+
+
+ tag = (struct boundary_tag*)((unsigned int)ptr - sizeof( struct boundary_tag ));
+
+ if ( tag->magic != LIBALLOC_MAGIC )
+ {
+ liballoc_unlock(); // release the lock
+ return;
+ }
+
+
+
+ #ifdef DEBUG
+ l_inuse -= tag->size;
+ printf("free: %x, %i, %i\n", ptr, (int)l_inuse / 1024, (int)l_allocated / 1024 );
+ #endif
+
+
+ // MELT LEFT...
+ while ( (tag->split_left != NULL) && (tag->split_left->index >= 0) )
+ {
+ #ifdef DEBUG
+ printf("Melting tag left into available memory. Left was %i, becomes %i (%i)\n", tag->split_left->real_size, tag->split_left->real_size + tag->real_size, tag->split_left->real_size );
+ #endif
+ tag = melt_left( tag );
+ remove_tag( tag );
+ }
+
+ // MELT RIGHT...
+ while ( (tag->split_right != NULL) && (tag->split_right->index >= 0) )
+ {
+ #ifdef DEBUG
+ printf("Melting tag right into available memory. This was was %i, becomes %i (%i)\n", tag->real_size, tag->split_right->real_size + tag->real_size, tag->split_right->real_size );
+ #endif
+ tag = absorb_right( tag );
+ }
+
+
+ // Where is it going back to?
+ index = getexp( tag->real_size - sizeof(struct boundary_tag) );
+ if ( index < MINEXP ) index = MINEXP;
+
+ // A whole, empty block?
+ if ( (tag->split_left == NULL) && (tag->split_right == NULL) )
+ {
+
+ if ( l_completePages[ index ] == MAXCOMPLETE )
+ {
+ // Too many standing by to keep. Free this one.
+ unsigned int pages = tag->real_size / l_pageSize;
+
+ if ( (tag->real_size % l_pageSize) != 0 ) pages += 1;
+ if ( pages < l_pageCount ) pages = l_pageCount;
+
+ liballoc_free( tag, pages );
+
+ #ifdef DEBUG
+ l_allocated -= pages * l_pageSize;
+ printf("Resource freeing %x of %i pages\n", tag, pages );
+ dump_array();
+ #endif
+
+ liballoc_unlock();
+ return;
+ }
+
+
+ l_completePages[ index ] += 1; // Increase the count of complete pages.
+ }
+
+
+ // ..........
+
+
+ insert_tag( tag, index );
+
+ #ifdef DEBUG
+ printf("Returning tag with %i bytes (requested %i bytes), which has exponent: %i\n", tag->real_size, tag->size, index );
+ dump_array();
+ #endif
+
+ liballoc_unlock();
+}
+
+
+
+
+void* calloc(size_t nobj, size_t size)
+{
+ int real_size;
+ void *p;
+
+ real_size = nobj * size;
+
+ p = malloc( real_size );
+
+ liballoc_memset( p, 0, real_size );
+
+ return p;
+}
+
+
+
+void* realloc(void *p, size_t size)
+{
+ void *ptr;
+ struct boundary_tag *tag;
+ int real_size;
+
+ if ( size == 0 )
+ {
+ free( p );
+ return NULL;
+ }
+ if ( p == NULL ) return malloc( size );
+
+ if ( liballoc_lock != NULL ) liballoc_lock(); // lockit
+ tag = (struct boundary_tag*)((unsigned int)p - sizeof( struct boundary_tag ));
+ real_size = tag->size;
+ if ( liballoc_unlock != NULL ) liballoc_unlock();
+
+ if ( real_size > size ) real_size = size;
+
+ ptr = malloc( size );
+ liballoc_memcpy( ptr, p, real_size );
+ free( p );
+
+ return ptr;
+}
+
+
+
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