4.3BSD-Reno/src/usr.bin/make/buf.c
/*
* Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
* 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 are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement: ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifndef lint
static char sccsid[] = "@(#)buf.c 5.4 (Berkeley) 6/1/90";
#endif /* not lint */
/*-
* buf.c --
* Functions for automatically-expanded buffers.
*/
#include "sprite.h"
#include "buf.h"
typedef struct {
int size; /* Current size of the buffer */
Byte *buffer; /* The buffer itself */
Byte *inPtr; /* Place to write to */
Byte *outPtr; /* Place to read from */
} Buf, *BufPtr;
#ifndef max
#define max(a,b) ((a) > (b) ? (a) : (b))
#endif
/*
* BufExpand --
* Expand the given buffer to hold the given number of additional
* bytes.
* Makes sure there's room for an extra NULL byte at the end of the
* buffer in case it holds a string.
*/
#define BufExpand(bp,nb) \
if (((bp)->size - ((bp)->inPtr - (bp)->buffer)) < (nb)+1) {\
int newSize = (bp)->size + max((nb)+1,BUF_ADD_INC); \
Byte *newBuf = (Byte *) realloc((bp)->buffer, newSize); \
\
(bp)->inPtr = newBuf + ((bp)->inPtr - (bp)->buffer); \
(bp)->outPtr = newBuf + ((bp)->outPtr - (bp)->buffer);\
(bp)->buffer = newBuf;\
(bp)->size = newSize;\
}
#define BUF_DEF_SIZE 256 /* Default buffer size */
#define BUF_ADD_INC 256 /* Expansion increment when Adding */
#define BUF_UNGET_INC 16 /* Expansion increment when Ungetting */
/*-
*-----------------------------------------------------------------------
* Buf_AddByte --
* Add a single byte to the buffer.
*
* Results:
* None.
*
* Side Effects:
* The buffer may be expanded.
*
*-----------------------------------------------------------------------
*/
void
Buf_AddByte (buf, byte)
Buffer buf;
Byte byte;
{
register BufPtr bp = (BufPtr) buf;
BufExpand (bp, 1);
*bp->inPtr = byte;
bp->inPtr += 1;
/*
* Null-terminate
*/
*bp->inPtr = 0;
}
/*-
*-----------------------------------------------------------------------
* Buf_AddBytes --
* Add a number of bytes to the buffer.
*
* Results:
* None.
*
* Side Effects:
* Guess what?
*
*-----------------------------------------------------------------------
*/
void
Buf_AddBytes (buf, numBytes, bytesPtr)
Buffer buf;
int numBytes;
Byte *bytesPtr;
{
register BufPtr bp = (BufPtr) buf;
BufExpand (bp, numBytes);
bcopy (bytesPtr, bp->inPtr, numBytes);
bp->inPtr += numBytes;
/*
* Null-terminate
*/
*bp->inPtr = 0;
}
/*-
*-----------------------------------------------------------------------
* Buf_UngetByte --
* Place the byte back at the beginning of the buffer.
*
* Results:
* SUCCESS if the byte was added ok. FAILURE if not.
*
* Side Effects:
* The byte is stuffed in the buffer and outPtr is decremented.
*
*-----------------------------------------------------------------------
*/
void
Buf_UngetByte (buf, byte)
Buffer buf;
Byte byte;
{
register BufPtr bp = (BufPtr) buf;
if (bp->outPtr != bp->buffer) {
bp->outPtr -= 1;
*bp->outPtr = byte;
} else if (bp->outPtr == bp->inPtr) {
*bp->inPtr = byte;
bp->inPtr += 1;
*bp->inPtr = 0;
} else {
/*
* Yech. have to expand the buffer to stuff this thing in.
* We use a different expansion constant because people don't
* usually push back many bytes when they're doing it a byte at
* a time...
*/
int numBytes = bp->inPtr - bp->outPtr;
Byte *newBuf;
newBuf = (Byte *)emalloc(bp->size + BUF_UNGET_INC);
bcopy ((Address)bp->outPtr,
(Address)(newBuf+BUF_UNGET_INC), numBytes+1);
bp->outPtr = newBuf + BUF_UNGET_INC;
bp->inPtr = bp->outPtr + numBytes;
free ((Address)bp->buffer);
bp->buffer = newBuf;
bp->size += BUF_UNGET_INC;
bp->outPtr -= 1;
*bp->outPtr = byte;
}
}
/*-
*-----------------------------------------------------------------------
* Buf_UngetBytes --
* Push back a series of bytes at the beginning of the buffer.
*
* Results:
* None.
*
* Side Effects:
* outPtr is decremented and the bytes copied into the buffer.
*
*-----------------------------------------------------------------------
*/
void
Buf_UngetBytes (buf, numBytes, bytesPtr)
Buffer buf;
int numBytes;
Byte *bytesPtr;
{
register BufPtr bp = (BufPtr) buf;
if (bp->outPtr - bp->buffer >= numBytes) {
bp->outPtr -= numBytes;
bcopy (bytesPtr, bp->outPtr, numBytes);
} else if (bp->outPtr == bp->inPtr) {
Buf_AddBytes (buf, numBytes, bytesPtr);
} else {
int curNumBytes = bp->inPtr - bp->outPtr;
Byte *newBuf;
int newBytes = max(numBytes,BUF_UNGET_INC);
newBuf = (Byte *)emalloc (bp->size + newBytes);
bcopy((Address)bp->outPtr, (Address)(newBuf+newBytes), curNumBytes+1);
bp->outPtr = newBuf + newBytes;
bp->inPtr = bp->outPtr + curNumBytes;
free ((Address)bp->buffer);
bp->buffer = newBuf;
bp->size += newBytes;
bp->outPtr -= numBytes;
bcopy ((Address)bytesPtr, (Address)bp->outPtr, numBytes);
}
}
/*-
*-----------------------------------------------------------------------
* Buf_GetByte --
* Return the next byte from the buffer. Actually returns an integer.
*
* Results:
* Returns BUF_ERROR if there's no byte in the buffer, or the byte
* itself if there is one.
*
* Side Effects:
* outPtr is incremented and both outPtr and inPtr will be reset if
* the buffer is emptied.
*
*-----------------------------------------------------------------------
*/
int
Buf_GetByte (buf)
Buffer buf;
{
BufPtr bp = (BufPtr) buf;
int res;
if (bp->inPtr == bp->outPtr) {
return (BUF_ERROR);
} else {
res = (int) *bp->outPtr;
bp->outPtr += 1;
if (bp->outPtr == bp->inPtr) {
bp->outPtr = bp->inPtr = bp->buffer;
bp->inPtr = 0;
}
return (res);
}
}
/*-
*-----------------------------------------------------------------------
* Buf_GetBytes --
* Extract a number of bytes from the buffer.
*
* Results:
* The number of bytes gotten.
*
* Side Effects:
* The passed array is overwritten.
*
*-----------------------------------------------------------------------
*/
int
Buf_GetBytes (buf, numBytes, bytesPtr)
Buffer buf;
int numBytes;
Byte *bytesPtr;
{
BufPtr bp = (BufPtr) buf;
if (bp->inPtr - bp->outPtr < numBytes) {
numBytes = bp->inPtr - bp->outPtr;
}
bcopy (bp->outPtr, bytesPtr, numBytes);
bp->outPtr += numBytes;
if (bp->outPtr == bp->inPtr) {
bp->outPtr = bp->inPtr = bp->buffer;
*bp->inPtr = 0;
}
return (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 (buf, numBytesPtr)
Buffer buf;
int *numBytesPtr;
{
BufPtr bp = (BufPtr)buf;
if (numBytesPtr != (int *)NULL) {
*numBytesPtr = bp->inPtr - bp->outPtr;
}
return (bp->outPtr);
}
/*-
*-----------------------------------------------------------------------
* Buf_Discard --
* Throw away bytes in a buffer.
*
* Results:
* None.
*
* Side Effects:
* The bytes are discarded.
*
*-----------------------------------------------------------------------
*/
void
Buf_Discard (buf, numBytes)
Buffer buf;
int numBytes;
{
register BufPtr bp = (BufPtr) buf;
if (bp->inPtr - bp->outPtr <= numBytes) {
bp->inPtr = bp->outPtr = bp->buffer;
*bp->inPtr = 0;
} else {
bp->outPtr += numBytes;
}
}
/*-
*-----------------------------------------------------------------------
* Buf_Size --
* Returns the number of bytes in the given buffer. Doesn't include
* the null-terminating byte.
*
* Results:
* The number of bytes.
*
* Side Effects:
* None.
*
*-----------------------------------------------------------------------
*/
int
Buf_Size (buf)
Buffer buf;
{
return (((BufPtr)buf)->inPtr - ((BufPtr)buf)->outPtr);
}
/*-
*-----------------------------------------------------------------------
* Buf_Init --
* Initialize a buffer. If no initial size is given, a reasonable
* default is used.
*
* Results:
* A buffer to be given to other functions in this library.
*
* Side Effects:
* The buffer is created, the space allocated and pointers
* initialized.
*
*-----------------------------------------------------------------------
*/
Buffer
Buf_Init (size)
int size; /* Initial size for the buffer */
{
BufPtr bp; /* New Buffer */
bp = (Buf *)emalloc(sizeof(Buf));
if (size <= 0) {
size = BUF_DEF_SIZE;
}
bp->size = size;
bp->buffer = (Byte *)emalloc (size);
bp->inPtr = bp->outPtr = bp->buffer;
*bp->inPtr = 0;
return ((Buffer) bp);
}
/*-
*-----------------------------------------------------------------------
* Buf_Destroy --
* Nuke a buffer and all its resources.
*
* Results:
* None.
*
* Side Effects:
* The buffer is freed.
*
*-----------------------------------------------------------------------
*/
void
Buf_Destroy (buf, freeData)
Buffer buf; /* Buffer to destroy */
Boolean freeData; /* TRUE if the data should be destroyed as well */
{
BufPtr bp = (BufPtr) buf;
if (freeData) {
free ((Address)bp->buffer);
}
free ((Address)bp);
}