/***************************************************************************
* charpool.cc -- Handles Nmap's "character pool" memory allocation *
* system. *
* *
***********************IMPORTANT NMAP LICENSE TERMS************************
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***************************************************************************/
/* $Id$ */
#include <stddef.h>
#include "nbase.h"
/* Character pool memory allocation */
#include "charpool.h"
#include "nmap_error.h"
static char *charpool[16];
static int currentcharpool;
static int currentcharpoolsz;
static char *nextchar;
/* Allocated blocks are allocated to multiples of ALIGN_ON. This is the
definition used by the malloc in Glibc 2.7, which says that it "suffices for
nearly all current machines and C compilers." */
#define ALIGN_ON (2 * sizeof(size_t))
static int cp_init(void) {
static int charpool_initialized = 0;
if (charpool_initialized) return 0;
/* Create our char pool */
currentcharpool = 0;
currentcharpoolsz = 16384;
nextchar = charpool[0] = (char *) safe_malloc(currentcharpoolsz);
charpool_initialized = 1;
return 0;
}
void cp_free(void) {
int ccp;
for(ccp=0; ccp <= currentcharpool; ccp++)
if(charpool[ccp]){
free(charpool[ccp]);
charpool[ccp] = NULL;
}
currentcharpool = 0;
}
static inline void cp_grow(void) {
/* Doh! We've got to make room */
if (++currentcharpool > 15) {
fatal("Character Pool is out of buckets!");
}
currentcharpoolsz <<= 1;
nextchar = charpool[currentcharpool] = (char *)
safe_malloc(currentcharpoolsz);
}
void *cp_alloc(int sz) {
char *p;
int modulus;
cp_init();
if ((modulus = sz % ALIGN_ON))
sz += ALIGN_ON - modulus;
if ((nextchar - charpool[currentcharpool]) + sz <= currentcharpoolsz) {
p = nextchar;
nextchar += sz;
return p;
}
/* Doh! We've got to make room */
cp_grow();
return cp_alloc(sz);
}
char *cp_strdup(const char *src) {
const char *p;
char *q;
/* end points to the first illegal char */
char *end;
int modulus;
cp_init();
end = charpool[currentcharpool] + currentcharpoolsz;
q = nextchar;
p = src;
while((nextchar < end) && *p) {
*nextchar++ = *p++;
}
if (nextchar < end) {
/* Goody, we have space */
*nextchar++ = '\0';
if ((modulus = (nextchar - q) % ALIGN_ON))
nextchar += ALIGN_ON - modulus;
return q;
}
/* Doh! We ran out -- need to allocate more */
cp_grow();
return cp_strdup(src);
}