usr/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, 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 lint
static char sccsid[] = "@(#)buf.c       5.5 (Berkeley) 12/28/90";
#endif /* not lint */

/*-
 * buf.c --
 *      Functions for automatically-expanded buffers.
 */

#include    "sprite.h"
#include    "buf.h"

#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->left < (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;\
            (bp)->left = newSize - ((bp)->inPtr - (bp)->buffer);\
        }

#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_OvAddByte --
 *      Add a single byte to the buffer.  left is zero or negative.
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      The buffer may be expanded.
 *
 *-----------------------------------------------------------------------
 */
void
Buf_OvAddByte (bp, byte)
    register Buffer bp;
    Byte    byte;
{

    bp->left = 0;
    BufExpand (bp, 1);

    *bp->inPtr++ = byte;
    bp->left--;

    /*
     * Null-terminate
     */
    *bp->inPtr = 0;
}
\f
/*-
 *-----------------------------------------------------------------------
 * Buf_AddBytes --
 *      Add a number of bytes to the buffer.
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      Guess what?
 *
 *-----------------------------------------------------------------------
 */
void
Buf_AddBytes (bp, numBytes, bytesPtr)
    register Buffer bp;
    int     numBytes;
    Byte    *bytesPtr;
{

    BufExpand (bp, numBytes);

    bcopy (bytesPtr, bp->inPtr, numBytes);
    bp->inPtr += numBytes;
    bp->left -= numBytes;

    /*
     * Null-terminate
     */
    *bp->inPtr = 0;
}
\f
/*-
 *-----------------------------------------------------------------------
 * 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 (bp, byte)
    register Buffer bp;
    Byte    byte;
{

    if (bp->outPtr != bp->buffer) {
        bp->outPtr--;
        *bp->outPtr = byte;
    } else if (bp->outPtr == bp->inPtr) {
        *bp->inPtr = byte;
        bp->inPtr++;
        bp->left--;
        *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 ((char *)bp->outPtr,
                        (char *)(newBuf+BUF_UNGET_INC), numBytes+1);
        bp->outPtr = newBuf + BUF_UNGET_INC;
        bp->inPtr = bp->outPtr + numBytes;
        free ((char *)bp->buffer);
        bp->buffer = newBuf;
        bp->size += BUF_UNGET_INC;
        bp->left = bp->size - (bp->inPtr - bp->buffer);
        bp->outPtr -= 1;
        *bp->outPtr = byte;
    }
}
\f
/*-
 *-----------------------------------------------------------------------
 * 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 (bp, numBytes, bytesPtr)
    register Buffer bp;
    int     numBytes;
    Byte    *bytesPtr;
{

    if (bp->outPtr - bp->buffer >= numBytes) {
        bp->outPtr -= numBytes;
        bcopy (bytesPtr, bp->outPtr, numBytes);
    } else if (bp->outPtr == bp->inPtr) {
        Buf_AddBytes (bp, 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((char *)bp->outPtr, (char *)(newBuf+newBytes), curNumBytes+1);
        bp->outPtr = newBuf + newBytes;
        bp->inPtr = bp->outPtr + curNumBytes;
        free ((char *)bp->buffer);
        bp->buffer = newBuf;
        bp->size += newBytes;
        bp->left = bp->size - (bp->inPtr - bp->buffer);
        bp->outPtr -= numBytes;
        bcopy ((char *)bytesPtr, (char *)bp->outPtr, numBytes);
    }
}
\f
/*-
 *-----------------------------------------------------------------------
 * 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 (bp)
    register Buffer bp;
{
    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->left = bp->size;
            *bp->inPtr = 0;
        }
        return (res);
    }
}
\f
/*-
 *-----------------------------------------------------------------------
 * 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 (bp, numBytes, bytesPtr)
    register Buffer bp;
    int     numBytes;
    Byte    *bytesPtr;
{

    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->left = bp->size;
        *bp->inPtr = 0;
    }
    return (numBytes);
}
\f
/*-
 *-----------------------------------------------------------------------
 * 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 (bp, numBytesPtr)
    register Buffer bp;
    int     *numBytesPtr;
{

    if (numBytesPtr != (int *)NULL) {
        *numBytesPtr = bp->inPtr - bp->outPtr;
    }

    return (bp->outPtr);
}
\f
/*-
 *-----------------------------------------------------------------------
 * Buf_Discard --
 *      Throw away bytes in a buffer.
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      The bytes are discarded.
 *
 *-----------------------------------------------------------------------
 */
void
Buf_Discard (bp, numBytes)
    register Buffer bp;
    int     numBytes;
{

    if (bp->inPtr - bp->outPtr <= numBytes) {
        bp->inPtr = bp->outPtr = bp->buffer;
        bp->left = bp->size;
        *bp->inPtr = 0;
    } else {
        bp->outPtr += numBytes;
    }
}
\f
/*-
 *-----------------------------------------------------------------------
 * 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 (buf->inPtr - buf->outPtr);
}
\f
/*-
 *-----------------------------------------------------------------------
 * 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 */
{
    Buffer bp;          /* New Buffer */

    bp = (Buffer)emalloc(sizeof(*bp));

    if (size <= 0) {
        size = BUF_DEF_SIZE;
    }
    bp->left = bp->size = size;
    bp->buffer = (Byte *)emalloc(size);
    bp->inPtr = bp->outPtr = bp->buffer;
    *bp->inPtr = 0;

    return (bp);
}
\f
/*-
 *-----------------------------------------------------------------------
 * 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 */
{

    if (freeData) {
        free ((char *)buf->buffer);
    }
    free ((char *)buf);
}