From c2e52566ed53b53227a6fe577a05170766a1ae4c Mon Sep 17 00:00:00 2001
From: Christian Cunningham <cc@localhost>
Date: Thu, 20 Jan 2022 20:52:25 -0700
Subject: Added realloc
Added NULL ptr return
---
include/lib/mem.h | 3 +++
src/lib/mem.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 47 insertions(+), 6 deletions(-)
diff --git a/include/lib/mem.h b/include/lib/mem.h
index 646a170..529ecea 100644
--- a/include/lib/mem.h
+++ b/include/lib/mem.h
@@ -5,6 +5,7 @@
#define MEM_USE_OFFSET 1
#define MEM_BASE_SIZE 2
#define MEM_META_SIZE 3
+#define NULL 0
struct MemTab {
unsigned char size;
@@ -29,8 +30,10 @@ void memset32(unsigned long* dest, unsigned long value, unsigned int n);
void memcpy32(unsigned long* src, unsigned long* dest, unsigned int n);
unsigned char memcmp32(unsigned long* a, unsigned long* b, unsigned int n);
+void* realloc(void* old, unsigned char size);
void* malloc(unsigned char size);
void* calloc(unsigned char size);
+void* realloca(void* old, unsigned char size, unsigned char amnt);
void* malloca(unsigned char size, unsigned char amnt);
void* calloca(unsigned char size, unsigned char amnt);
void free(void* memloc);
diff --git a/src/lib/mem.c b/src/lib/mem.c
index e51ec32..bc5f23c 100644
--- a/src/lib/mem.c
+++ b/src/lib/mem.c
@@ -76,7 +76,7 @@ unsigned char memcmp32(unsigned long* a, unsigned long* b, unsigned int n)
static unsigned char rpi_heap[MAX_MM] = {0,};
static void* rpi_heap_top = &rpi_heap;
-// TODO: Put size at end and cleanup from tail
+
void* malloc(unsigned char size)
{
unsigned char* mem = (unsigned char*)rpi_heap;
@@ -85,6 +85,8 @@ void* malloc(unsigned char size)
while (((void*)(mem + i) < rpi_heap_top) && !(mem[i + MEM_SIZE_OFFSET] == size && mem[i + MEM_USE_OFFSET]==0)) {
i += mem[i] + MEM_META_SIZE;
}
+ if (mem + i >= (unsigned char*)(rpi_heap_top + MAX_MM))
+ return NULL;
// Update top of heap
if (mem[i] == 0)
rpi_heap_top = (void*)&mem[i + MEM_META_SIZE + size];
@@ -98,8 +100,23 @@ void* malloc(unsigned char size)
void* calloc(unsigned char size)
{
void* addr = malloc(size);
- memset(addr, 0, size);
- return addr;
+ if (addr != NULL) {
+ memset(addr, 0, size);
+ return addr;
+ }
+ return NULL;
+}
+void* realloc(void* old, unsigned char size)
+{
+ unsigned char osize = *(unsigned char*)(old - MEM_BASE_SIZE);
+ if (size <= osize)
+ return old;
+ void* new = malloc(size);
+ if (new != NULL) {
+ free(old);
+ return new;
+ }
+ return NULL;
}
void* malloca(unsigned char size, unsigned char amnt)
@@ -110,7 +127,7 @@ void* malloca(unsigned char size, unsigned char amnt)
unsigned char* mem = (unsigned char*)rpi_heap;
unsigned long i = 0;
// TODO: Use Null PID
- while(1) {
+ while(mem + i < rpi_heap + MAX_MM) {
unsigned long diff = (unsigned long)mem + i + MEM_BASE_SIZE;
diff %= amnt;
diff = amnt - diff;
@@ -134,6 +151,10 @@ void* malloca(unsigned char size, unsigned char amnt)
diff += amnt;
}
unsigned long empty_size = diff - MEM_META_SIZE;
+ if(empty_size == 0) {
+ empty_size += amnt;
+ diff += amnt;
+ }
mem[i + MEM_SIZE_OFFSET] = empty_size;
mem[i + MEM_BASE_SIZE + empty_size] = empty_size;
i += diff;
@@ -147,13 +168,30 @@ void* malloca(unsigned char size, unsigned char amnt)
i += mem[i] + MEM_META_SIZE;
}
+ return NULL;
}
void* calloca(unsigned char size, unsigned char amnt)
{
void* addr = malloca(size, amnt);
- memset(addr, 0, size);
- return addr;
+ if (addr != NULL) {
+ memset(addr, 0, size);
+ return addr;
+ }
+ return NULL;
+}
+
+void* realloca(void* old, unsigned char size, unsigned char amnt)
+{
+ unsigned char osize = *(unsigned char*)(old - MEM_BASE_SIZE);
+ if (size <= osize)
+ return old;
+ void* new = malloca(size, amnt);
+ if (new != NULL) {
+ free(old);
+ return new;
+ }
+ return NULL;
}
void free(void* memloc)
--
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