vcbuffer.c revision 3f54fd611f536639ec30dd53c48e5ec1897cc7d9
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 2003-2011 AT&T Intellectual Property *
* and is licensed under the *
* Eclipse Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.eclipse.org/org/documents/epl-v10.html *
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#include "vchdr.h"
/* Managing buffered data for a handle.
**
** Written by Kiem-Phong Vo (kpv@research.att.com)
*/
#if __STD_C
Vcchar_t* _vcbuffer(Vcodex_t* vc, Vcchar_t* trunc, ssize_t size, ssize_t head)
#else
Vcchar_t* _vcbuffer(vc, trunc, size, head)
Vcodex_t* vc;
Vcchar_t* trunc; /* if != NULL, a buffer to be truncated */
ssize_t size; /* the size needed for buffered data */
ssize_t head; /* head room in front of buffer */
#endif
{
Vcbuffer_t *b, *n;
/**/DEBUG_DECLARE(static ssize_t, Busy=0);
#ifdef VMFL
/**/DEBUG_DECLARE(Vmstat_t, statb); DEBUG_ASSERT(vmstat(Vmregion, &statb) >= 0);
#endif
if(!vc)
return NIL(Vcchar_t*);
if(trunc) /* truncating a buffer */
{ /* find the buffer */
for(; vc; vc = vc->coder)
{ for(n = NIL(Vcbuffer_t*), b = vc->list; b; n = b, b = b->next)
if(trunc >= b->buf && trunc < b->buf+b->size)
break;
if(!b) /* not in this handle */
continue;
if(n) /* isolate b from buffer pool */
n->next = b->next;
else vc->list = b->next;
if(size < 0 ) /* just free the buffer */
{ /**/DEBUG_SET(Busy, Busy - b->size);
/**/DEBUG_PRINT(2,"free: file=%s ", b->file);
/**/DEBUG_PRINT(2,"line=%d ",b->line);
/**/DEBUG_PRINT(2,"size=%d\n",b->size);
vc->busy -= b->size;
vc->nbuf -= 1;
free(b);
return NIL(Vcchar_t*);
}
if(trunc+size > b->buf+b->size) /* no extension */
{ b->next = vc->list;
vc->list = b;
return NIL(Vcchar_t*);
}
size += (head = trunc - (Vcchar_t*)b->buf);
if(size < 3*b->size/4 )
{ if(!(n = (Vcbuffer_t*)realloc(b, sizeof(Vcbuffer_t)+size)) )
RETURN(NIL(Vcchar_t*));
/**/DEBUG_SET(Busy, Busy - b->size + size);
/**/DEBUG_PRINT(2,"realloc: file=%s ", b->file);
/**/DEBUG_PRINT(2,"line=%d ",b->line);
/**/DEBUG_PRINT(2,"oldsize=%d ",b->size);
/**/DEBUG_PRINT(2,"newsize=%d\n",size);
vc->busy -= n->size - size; /* n->size is old b->size */
n->size = size;
if(n != b)
b = n;
}
b->next = vc->list;
vc->list = b;
return (Vcchar_t*)(&b->buf[head]);
}
return NIL(Vcchar_t*);
}
else if(size < 0) /* free all buffers */
{ for(; vc; vc = vc->coder)
{ if(vc->meth->eventf) /* tell vc to free its internal buffers */
(*vc->meth->eventf)(vc, VC_FREEBUFFER, 0);
for(b = vc->list; b; b = n)
{ n = b->next;
/**/DEBUG_SET(Busy, Busy - b->size);
/**/DEBUG_PRINT(2,"free: file=%s ", b->file);
/**/DEBUG_PRINT(2,"line=%d ",b->line);
/**/DEBUG_PRINT(2,"size=%d\n",b->size);
free(b);
}
vc->list = NIL(Vcbuffer_t*);
vc->busy = 0;
vc->nbuf = 0;
}
return NIL(Vcchar_t*);
}
else
{ head = (head <= 0 ? 0 : head) + vc->head; /* required head room */
if(!(b = (Vcbuffer_t*)malloc(sizeof(Vcbuffer_t)+head+size)) )
RETURN(NIL(Vcchar_t*));
b->size = head+size;
b->next = vc->list;
b->file = vc->file; vc->file = NIL(char*);
b->line = vc->line; vc->line = 0;
/**/DEBUG_SET(Busy, Busy + b->size);
/**/DEBUG_PRINT(2,"alloc: file=%s ", b->file);
/**/DEBUG_PRINT(2,"line=%d ",b->line);
/**/DEBUG_PRINT(2,"size=%d\n",b->size);
vc->list = b;
vc->busy += b->size;
vc->nbuf += 1;
return (Vcchar_t*)(&b->buf[head]);
}
}