bbuffer.c

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/*====================================================================*
 -  Copyright (C) 2001 Leptonica.  All rights reserved.
 -
 -  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.
 -
 -  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 ANY
 -  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.
 *====================================================================*/

#include <string.h>
#include "allheaders.h"

static const l_int32  INITIAL_BUFFER_ARRAYSIZE = 1024;   
/*--------------------------------------------------------------------------*
 *                         BBuffer create/destroy                           *
 *--------------------------------------------------------------------------*/
L_BBUFFER *
bbufferCreate(const l_uint8  *indata,
              l_int32         nalloc)
{
L_BBUFFER  *bb;

    PROCNAME("bbufferCreate");

    if (nalloc <= 0)
        nalloc = INITIAL_BUFFER_ARRAYSIZE;

    if ((bb = (L_BBUFFER *)LEPT_CALLOC(1, sizeof(L_BBUFFER))) == NULL)
        return (L_BBUFFER *)ERROR_PTR("bb not made", procName, NULL);
    if ((bb->array = (l_uint8 *)LEPT_CALLOC(nalloc, sizeof(l_uint8))) == NULL) {
        LEPT_FREE(bb);
        return (L_BBUFFER *)ERROR_PTR("byte array not made", procName, NULL);
    }
    bb->nalloc = nalloc;
    bb->nwritten = 0;

    if (indata) {
        memcpy(bb->array, indata, nalloc);
        bb->n = nalloc;
    } else {
        bb->n = 0;
    }

    return bb;
}


void
bbufferDestroy(L_BBUFFER  **pbb)
{
L_BBUFFER  *bb;

    PROCNAME("bbufferDestroy");

    if (pbb == NULL) {
        L_WARNING("ptr address is NULL\n", procName);
        return;
    }

    if ((bb = *pbb) == NULL)
        return;

    if (bb->array)
        LEPT_FREE(bb->array);
    LEPT_FREE(bb);
    *pbb = NULL;

    return;
}


l_uint8 *
bbufferDestroyAndSaveData(L_BBUFFER  **pbb,
                          size_t      *pnbytes)
{
l_uint8    *array;
size_t      nbytes;
L_BBUFFER  *bb;

    PROCNAME("bbufferDestroyAndSaveData");

    if (pbb == NULL) {
        L_WARNING("ptr address is NULL\n", procName);
        return NULL;
    }
    if (pnbytes == NULL) {
        L_WARNING("&nbytes is NULL\n", procName);
        bbufferDestroy(pbb);
        return NULL;
    }

    if ((bb = *pbb) == NULL)
        return NULL;

        /* write all unwritten bytes out to a new array */
    nbytes = bb->n - bb->nwritten;
    *pnbytes = nbytes;
    if ((array = (l_uint8 *)LEPT_CALLOC(nbytes, sizeof(l_uint8))) == NULL) {
        L_WARNING("calloc failure for array\n", procName);
        return NULL;
    }
    memcpy(array, bb->array + bb->nwritten, nbytes);

    bbufferDestroy(pbb);
    return array;
}


/*--------------------------------------------------------------------------*
 *                   Operations to read data INTO a BBuffer                 *
 *--------------------------------------------------------------------------*/
l_ok
bbufferRead(L_BBUFFER  *bb,
            l_uint8    *src,
            l_int32     nbytes)
{
l_int32  navail, nadd, nwritten;

    PROCNAME("bbufferRead");

    if (!bb)
        return ERROR_INT("bb not defined", procName, 1);
    if (!src)
        return ERROR_INT("src not defined", procName, 1);
    if (nbytes == 0)
        return ERROR_INT("no bytes to read", procName, 1);

    if ((nwritten = bb->nwritten)) {  /* move the unwritten bytes over */
        memmove(bb->array, bb->array + nwritten, bb->n - nwritten);
        bb->nwritten = 0;
        bb->n -= nwritten;
    }

        /* If necessary, expand the allocated array.  Do so by
         * by at least a factor of two. */
    navail = bb->nalloc - bb->n;
    if (nbytes > navail) {
        nadd = L_MAX(bb->nalloc, nbytes);
        bbufferExtendArray(bb, nadd);
    }

        /* Read in the new bytes */
    memcpy(bb->array + bb->n, src, nbytes);
    bb->n += nbytes;

    return 0;
}


l_ok
bbufferReadStream(L_BBUFFER  *bb,
                  FILE       *fp,
                  l_int32     nbytes)
{
l_int32  navail, nadd, nread, nwritten;

    PROCNAME("bbufferReadStream");

    if (!bb)
        return ERROR_INT("bb not defined", procName, 1);
    if (!fp)
        return ERROR_INT("fp not defined", procName, 1);
    if (nbytes == 0)
        return ERROR_INT("no bytes to read", procName, 1);

    if ((nwritten = bb->nwritten)) {  /* move any unwritten bytes over */
        memmove(bb->array, bb->array + nwritten, bb->n - nwritten);
        bb->nwritten = 0;
        bb->n -= nwritten;
    }

        /* If necessary, expand the allocated array.  Do so by
         * by at least a factor of two. */
    navail = bb->nalloc - bb->n;
    if (nbytes > navail) {
        nadd = L_MAX(bb->nalloc, nbytes);
        bbufferExtendArray(bb, nadd);
    }

        /* Read in the new bytes */
    nread = fread(bb->array + bb->n, 1, nbytes, fp);
    bb->n += nread;

    return 0;
}


l_ok
bbufferExtendArray(L_BBUFFER  *bb,
                   l_int32     nbytes)
{
    PROCNAME("bbufferExtendArray");

    if (!bb)
        return ERROR_INT("bb not defined", procName, 1);

    if ((bb->array = (l_uint8 *)reallocNew((void **)&bb->array,
                                bb->nalloc,
                                bb->nalloc + nbytes)) == NULL)
            return ERROR_INT("new ptr array not returned", procName, 1);

    bb->nalloc += nbytes;
    return 0;
}


/*--------------------------------------------------------------------------*
 *                  Operations to write data FROM a BBuffer                 *
 *--------------------------------------------------------------------------*/
l_ok
bbufferWrite(L_BBUFFER  *bb,
             l_uint8    *dest,
             size_t      nbytes,
             size_t     *pnout)
{
size_t  nleft, nout;

    PROCNAME("bbufferWrite");

    if (!bb)
        return ERROR_INT("bb not defined", procName, 1);
    if (!dest)
        return ERROR_INT("dest not defined", procName, 1);
    if (nbytes <= 0)
        return ERROR_INT("no bytes requested to write", procName, 1);
    if (!pnout)
        return ERROR_INT("&nout not defined", procName, 1);

    nleft = bb->n - bb->nwritten;
    nout = L_MIN(nleft, nbytes);
    *pnout = nout;

    if (nleft == 0) {   /* nothing to write; reinitialize the buffer */
        bb->n = 0;
        bb->nwritten = 0;
        return 0;
    }

        /* nout > 0; transfer the data out */
    memcpy(dest, bb->array + bb->nwritten, nout);
    bb->nwritten += nout;

        /* If all written; "empty" the buffer */
    if (nout == nleft) {
        bb->n = 0;
        bb->nwritten = 0;
    }

    return 0;
}


l_ok
bbufferWriteStream(L_BBUFFER  *bb,
                   FILE       *fp,
                   size_t      nbytes,
                   size_t     *pnout)
{
size_t  nleft, nout;

    PROCNAME("bbufferWriteStream");

    if (!bb)
        return ERROR_INT("bb not defined", procName, 1);
    if (!fp)
        return ERROR_INT("output stream not defined", procName, 1);
    if (nbytes <= 0)
        return ERROR_INT("no bytes requested to write", procName, 1);
    if (!pnout)
        return ERROR_INT("&nout not defined", procName, 1);

    nleft = bb->n - bb->nwritten;
    nout = L_MIN(nleft, nbytes);
    *pnout = nout;

    if (nleft == 0) {   /* nothing to write; reinitialize the buffer */
        bb->n = 0;
        bb->nwritten = 0;
        return 0;
    }

        /* nout > 0; transfer the data out */
    fwrite(bb->array + bb->nwritten, 1, nout, fp);
    bb->nwritten += nout;

        /* If all written; "empty" the buffer */
    if (nout == nleft) {
        bb->n = 0;
        bb->nwritten = 0;
    }

    return 0;
}