NetBSD/usr.bin/make/buf.c
sjg 26aa697a51 Var* are generally very liberal with memory, with the expectation
that none of it persists for long.
This isn't always true - for example a long running .for loop.

Buf_DestroyCompact() is used by Var_Subst(), rather than Buf_Destroy().
If it looks like we can save BUF_COMPACT_LIMIT (128) or more bytes,
call realloc.  This can reduce memory consumption by about 20%
Setting BUF_COMPACT_LIMIT to 0 dissables this.
2012-04-24 20:26:58 +00:00

292 lines
8.0 KiB
C

/* $NetBSD: buf.c,v 1.25 2012/04/24 20:26:58 sjg Exp $ */
/*
* Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Adam de Boor.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Copyright (c) 1988, 1989 by Adam de Boor
* Copyright (c) 1989 by Berkeley Softworks
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Adam de Boor.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef MAKE_NATIVE
static char rcsid[] = "$NetBSD: buf.c,v 1.25 2012/04/24 20:26:58 sjg Exp $";
#else
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)buf.c 8.1 (Berkeley) 6/6/93";
#else
__RCSID("$NetBSD: buf.c,v 1.25 2012/04/24 20:26:58 sjg Exp $");
#endif
#endif /* not lint */
#endif
/*-
* buf.c --
* Functions for automatically-expanded buffers.
*/
#include "make.h"
#include "buf.h"
#ifndef max
#define max(a,b) ((a) > (b) ? (a) : (b))
#endif
#define BUF_DEF_SIZE 256 /* Default buffer size */
/*-
*-----------------------------------------------------------------------
* Buf_Expand_1 --
* Extend buffer for single byte add.
*
*-----------------------------------------------------------------------
*/
void
Buf_Expand_1(Buffer *bp)
{
bp->size += max(bp->size, 16);
bp->buffer = bmake_realloc(bp->buffer, bp->size);
}
/*-
*-----------------------------------------------------------------------
* Buf_AddBytes --
* Add a number of bytes to the buffer.
*
* Results:
* None.
*
* Side Effects:
* Guess what?
*
*-----------------------------------------------------------------------
*/
void
Buf_AddBytes(Buffer *bp, int numBytes, const Byte *bytesPtr)
{
int count = bp->count;
Byte *ptr;
if (__predict_false(count + numBytes >= bp->size)) {
bp->size += max(bp->size, numBytes + 16);
bp->buffer = bmake_realloc(bp->buffer, bp->size);
}
ptr = bp->buffer + count;
bp->count = count + numBytes;
ptr[numBytes] = 0;
memcpy(ptr, bytesPtr, numBytes);
}
/*-
*-----------------------------------------------------------------------
* Buf_GetAll --
* Get all the available data at once.
*
* Results:
* A pointer to the data and the number of bytes available.
*
* Side Effects:
* None.
*
*-----------------------------------------------------------------------
*/
Byte *
Buf_GetAll(Buffer *bp, int *numBytesPtr)
{
if (numBytesPtr != NULL)
*numBytesPtr = bp->count;
return (bp->buffer);
}
/*-
*-----------------------------------------------------------------------
* Buf_Empty --
* Throw away bytes in a buffer.
*
* Results:
* None.
*
* Side Effects:
* The bytes are discarded.
*
*-----------------------------------------------------------------------
*/
void
Buf_Empty(Buffer *bp)
{
bp->count = 0;
*bp->buffer = 0;
}
/*-
*-----------------------------------------------------------------------
* Buf_Init --
* Initialize a buffer. If no initial size is given, a reasonable
* default is used.
*
* Input:
* size Initial size for the buffer
*
* Results:
* A buffer to be given to other functions in this library.
*
* Side Effects:
* The buffer is created, the space allocated and pointers
* initialized.
*
*-----------------------------------------------------------------------
*/
void
Buf_Init(Buffer *bp, int size)
{
if (size <= 0) {
size = BUF_DEF_SIZE;
}
bp->size = size;
bp->count = 0;
bp->buffer = bmake_malloc(size);
*bp->buffer = 0;
}
/*-
*-----------------------------------------------------------------------
* Buf_Destroy --
* Nuke a buffer and all its resources.
*
* Input:
* buf Buffer to destroy
* freeData TRUE if the data should be destroyed
*
* Results:
* Data buffer, NULL if freed
*
* Side Effects:
* The buffer is freed.
*
*-----------------------------------------------------------------------
*/
Byte *
Buf_Destroy(Buffer *buf, Boolean freeData)
{
Byte *data;
data = buf->buffer;
if (freeData) {
free(data);
data = NULL;
}
buf->size = 0;
buf->count = 0;
buf->buffer = NULL;
return data;
}
/*-
*-----------------------------------------------------------------------
* Buf_DestroyCompact --
* Nuke a buffer and return its data.
*
* Input:
* buf Buffer to destroy
*
* Results:
* Data buffer
*
* Side Effects:
* If the buffer size is much greater than its content,
* a new buffer will be allocated and the old one freed.
*
*-----------------------------------------------------------------------
*/
#ifndef BUF_COMPACT_LIMIT
# define BUF_COMPACT_LIMIT 128 /* worthwhile saving */
#endif
Byte *
Buf_DestroyCompact(Buffer *buf)
{
#if BUF_COMPACT_LIMIT > 0
Byte *data;
if (buf->size - buf->count >= BUF_COMPACT_LIMIT) {
/* We trust realloc to be smart */
data = bmake_realloc(buf->buffer, buf->count + 1);
if (data) {
data[buf->count] = 0;
Buf_Destroy(buf, FALSE);
return data;
}
}
#endif
return Buf_Destroy(buf, FALSE);
}