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/*****
* ImBuffer.c : imageBuffer routines.
*
* This file Version $Revision: 1.2 $
*
* Creation date: Thu May 8 05:52:16 GMT+0100 1997
* Last modification: $Date: 1997/10/23 00:30:35 $
* By: $Author: newt $
* Current State: $State: Exp $
*
* Author: Koen D'Hondt <ripley@xs4all.nl>
*
* Copyright (C) 1994-1997 by Ripley Software Development
* All Rights Reserved
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose and without fee is hereby granted, provided
* that the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. This software is provided "as is" without express or
* implied warranty.
*
*****/
/*****
* ChangeLog
* $Log: ImBuffer.c,v $
* Revision 1.2 1997/10/23 00:30:35 newt
* XmHTML Beta 1.1.0 release
*
* Revision 1.1 1997/05/28 13:14:08 newt
* Initial Revision
*
*****/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include "ImBuffer.h"
/*** External Function Prototype Declarations ***/
/*** Public Variable Declarations ***/
/*** Private Datatype Declarations ****/
/*** Private Function Prototype Declarations ****/
/*** Private Variable Declarations ***/
/*****
* Name: ImageFileToBuffer
* Return Type: ImageBuffer*
* Description: loads a file into a memory buffer
* In:
* file: file to load
* Returns:
* filled ImageBuffer.
*****/
ImageBuffer*
ImageFileToBuffer(char *file)
{
FILE *fp;
static ImageBuffer *ib;
int size;
ib = NULL;
if((fp = fopen(file, "r")) == NULL)
{
perror(file);
return(NULL);
}
fseek(fp, 0L, SEEK_END);
size = ftell(fp);
/* sanity check */
if(size == 0)
return(NULL);
rewind(fp);
ib = (ImageBuffer*)malloc(sizeof(ImageBuffer));
ib->buffer = (Byte*)malloc(size*sizeof(Byte));
ib->size = size;
if((fread(ib->buffer, ib->size, 1, fp)) != 1)
{
perror(file);
fclose(fp);
free(ib->buffer);
free(ib);
return(NULL);
}
fclose(fp);
ib->file = strdup(file);
ib->next = 0;
ib->may_free = 1;
return(ib);
}
/*****
* Name: ReadOK
* Return Type: size_t
* Description: copy len bytes to buf from an ImageBuffer
* In:
* *bp: data source
* buf: data destination
* len: no of bytes to copy
* Returns:
* actual no of bytes read or 0 on failure or end of buffer.
*****/
size_t
ReadOK(ImageBuffer *ib, Byte *buf, int len)
{
if(ib->size > ib->next)
{
if(ib->next + len > ib->size)
len = ib->size - ib->next;
memcpy(buf, ib->buffer + ib->next, len);
ib->next += len;
return(len);
}
return(0);
}
/*****
* Name: GifGetDataBlock
* Return Type: int
* Description: gets the next amount of data from the input buffer
* In:
* ib: current ImageBuffer
* buf: storage buffer, filled upon return.
* Returns:
* no of bytes copied into buf or 0 when no more data.
*****/
size_t
GifGetDataBlock(ImageBuffer *ib, Byte *buf)
{
Byte count = 0;
if(!ReadOK(ib, &count, 1))
return(0);
if(((int)count != 0) && (!ReadOK(ib, buf, (int)count)))
return(0);
return((size_t)count);
}
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