I was referring to memory usage, ie not freeing of temporary strings, strings used in eg any single instance of a Scriptclip frame
are not released until Avisynth closure, despite them never being used again. We should be able to automatically release local strings that are
created in any script function and are not returned as the function result. I dont know if memory used for other non string local variables
additionally are not released until closure.
EDIT: Plugin writers can rely upon strings returned via SaveString() to be still available later on, so to be able to release strings
allocated via plugins, there must be another function akin to SaveString() that hands over total ownership to Avisynth and such
memory cannot be later accessed by the plugin. The original SaveString(), copies the string into Avisnth allocated memory.
How to return Strings (I'm guessin that you dont need this, perhaps some do):- http://forum.doom9.org/showthread.php?p=1633936&highlight=SaveString#post1633936
Creating an expanded system environment string + file is not I think such a big problem, (does not need to be implemented in core,
although GetSystemEnv() could be a good idea).
AVSValue __cdecl RT_GetSystemEnv(AVSValue args, void* user_data, IScriptEnvironment* env) {
// char * myName="RT_GetSystemEnv: ";
const char *s=args[0].AsString();
char * sysenv = getenv(s);
if(sysenv==NULL)
sysenv="";
return env->SaveString(sysenv);
}
fn=RT_GetSystemEnv("HOMEPATH") + "\MyFile.xyz" although that aint exactly bullet proof.
this is string formatting as implemented in RT_Stats RT_string
AVSValue __cdecl RT_String(AVSValue args, void* user_data, IScriptEnvironment* env) {
char *myName="RT_String: ";
const char *s = args[0].AsString(); // text
int arrsz = args[1].ArraySize();
int esc = args[2].AsInt(1);
if(esc < 0 || esc > 2)
env->ThrowError("%sEsc range 0 -> 2 only",myName);
enum {
CHICKEN=64
};
// what size buffer we need ?
int i,mem=strlen(s) + 1 + CHICKEN;
for(i=0;i<arrsz;++i) {
if(args[1][i].IsString()) {
const char *st=args[1][i].AsString();
mem += strlen(st) + 1 + CHICKEN;
} else {
mem += 8 + CHICKEN; // no particular reason why so big, just chicken factor.
}
}
char *pbuf = new char[(mem+1)*2];
if(pbuf==NULL)
env->ThrowError("%sCannot allocate memory",myName);
char *ptem=pbuf+(mem+1); // temp buffer
const unsigned char * r= (const unsigned char *)s;
char *p=pbuf;
int c,ix=0;
int t=0;
// Parse text and insert variables
while(c=*r) {
if(c=='%') {
++r;
if(*r=='\0') {
*p++ ='%';
} else if(*r=='%') {
*p++=*r++; // replace escaped double % with single
} else {
if(ix>=arrsz) {
delete [] pbuf;
env->ThrowError("%sExpecting data arg (%d)",myName,ix+1);
}
char *tp=ptem;
*tp++='%';
if(*r=='-' || *r=='+' || *r=='0' || *r==' ' || *r=='#') // flags
*tp++=*r++;
if(*r=='*') { // int holds length
t=args[1][ix].IsBool() ?1: \
args[1][ix].IsString() ?2: \
args[1][ix].IsInt() ?3: \
args[1][ix].IsFloat() ?4: \
0;
if(t!=3) {
delete [] pbuf;
env->ThrowError("%sUnsupported data type, Expecting Width as Int (%d)",myName,ix+1);
}
tp+=sprintf(tp,"%d",args[1][ix].IsInt());
++r; // skip '*'
++ix; // next data
} else {
while(*r>='0' && *r<='9') {
*tp++ = *r++;
}
}
if(*r=='.') {
*tp++ = *r++; // precision prefix
if(*r=='*') { // int holds length
t=args[1][ix].IsBool() ?1: \
args[1][ix].IsString() ?2: \
args[1][ix].IsInt() ?3: \
args[1][ix].IsFloat() ?4: \
0;
if(t!=3) {
delete [] pbuf;
env->ThrowError("%sUnsupported data type, Expecting Precision as Int (%d)",myName,ix+1);
}
tp+=sprintf(tp,"%d",args[1][ix].AsInt());
++r; // skip '*'
++ix; // next data
} else {
while(*r>='0' && *r<='9') {
*tp++ = *r++;
}
}
}
t=args[1][ix].IsBool() ?1: \
args[1][ix].IsString() ?2: \
args[1][ix].IsInt() ?3: \
args[1][ix].IsFloat() ?4: \
0;
// type
if( (*r=='c' ) || (*r=='C' ) || // char as int
(*r=='d' || *r=='i') || // int
(*r=='o' || *r=='u' || *r=='x' || *r=='X')) { // unsigned int
if(t!=3) {
delete [] pbuf;
env->ThrowError("%sType='%c', Expecting Int data (%d)",myName,*r,ix+1);
}
*tp++=*r++;
*tp='\0';
p+=sprintf(p,ptem,args[1][ix].AsInt());
++ix; // next data
} else if(*r=='e' || *r=='E' || *r=='f' || *r=='g' || *r=='G') { // double
if(t!=4&&t!=3) {
delete [] pbuf;
env->ThrowError("%sType='%c', Expecting Float (%d)",myName,*r,ix+1);
}
*tp++=*r++;
*tp='\0';
p+=sprintf(p,ptem,args[1][ix].AsFloat());
++ix; // next data
} else if((*r=='s')||(*r=='S')) { // string
if(t!=2&&t!=1) {
delete [] pbuf;
env->ThrowError("%sType='s', Expecting String (%d)",myName,ix+1);
}
*tp++=*r++;
*tp='\0';
if(t==1) { // Bool
p+=sprintf(p,ptem,args[1][ix].AsBool()?"True":"False");
} else { // String
p+=sprintf(p,ptem,args[1][ix].AsString());
}
++ix; // next data
} else {
delete [] pbuf;
env->ThrowError("%sUnknown format type '%c' (%d)",myName,*r,ix+1);
}
}
} else if(c == '\\' && esc == 1) {
++r;
c=*r;
// abfnrtv
switch (c) {
case '\0' : *p++='\\'; break; // copy single backslash at end of string
case '\\' : *p++=*r++; break; // replace double backslash with single backslash
case 'n' : ++r; *p++='\n'; break;
case 'r' : ++r; *p++='\r'; break;
case 't' : ++r; *p++='\t'; break;
case 'v' : ++r; *p++='\v'; break;
case 'f' : ++r; *p++='\f'; break;
case 'b' : ++r; *p++='\b'; break;
case 'a' : ++r; *p++='\a'; break;
default : *p++='\\'; *p++=*r++; break; // anything else we copy backslash and whatever follows
}
} else {
*p++=*r++;
}
}
*p=0; // nul term
if(ix<arrsz) {
delete [] pbuf;
env->ThrowError("%sUnexpected data arg (%d)",myName,ix+1);
}
// dprintf("RT_String: MEM Estimate=%d : Actual=%d\n",mem+1,strlen(pbuf));
if(esc==2) {
p=pbuf;
r=(const unsigned char*)p;
while(c=*r) {
if(c=='\\') {
++r;
c=*r;
// abfnrtv
switch (c) {
case '\0' : *p++='\\'; break; // copy single backslash at end of string
case '\\' : *p++=*r++; break; // replace double backslash with single backslash
case 'n' : ++r; *p++='\n'; break;
case 'r' : ++r; *p++='\r'; break;
case 't' : ++r; *p++='\t'; break;
case 'v' : ++r; *p++='\v'; break;
case 'f' : ++r; *p++='\f'; break;
case 'b' : ++r; *p++='\b'; break;
case 'a' : ++r; *p++='\a'; break;
default : *p++='\\'; *p++=*r++; break; // anything else we copy backslash and whatever follows
}
} else {
*p++=*r++;
}
}
*p=0; // nul term
}
AVSValue ret = env->SaveString(pbuf,p-pbuf);
delete [] pbuf;
return ret;
Much better than the basic Avisynth String() function.