libmng_chunk_io.c

Linux下的基于X11的图形开发环境。

/* ************************************************************************** */
/* *             For conditions of distribution and use,                    * */
/* *                see copyright notice in libmng.h                        * */
/* ************************************************************************** */
/* *                                                                        * */
/* * project   : libmng                                                     * */
/* * file      : libmng_chunk_io.c         copyright (c) 2000 G.Juyn        * */
/* * version   : 1.0.2                                                      * */
/* *                                                                        * */
/* * purpose   : Chunk I/O routines (implementation)                        * */
/* *                                                                        * */
/* * author    : G.Juyn                                                     * */
/* * web       : http://www.3-t.com                                         * */
/* * email     : mailto:[e-mail]                                        * */
/* *                                                                        * */
/* * comment   : implementation of chunk input/output routines              * */
/* *                                                                        * */
/* * changes   : 0.5.1 - 05/01/2000 - G.Juyn                                * */
/* *             - cleaned up left-over teststuff in the BACK chunk routine * */
/* *             0.5.1 - 05/04/2000 - G.Juyn                                * */
/* *             - changed CRC initialization to use dynamic structure      * */
/* *               (wasn't thread-safe the old way !)                       * */
/* *             0.5.1 - 05/06/2000 - G.Juyn                                * */
/* *             - filled in many missing sequence&length checks            * */
/* *             - filled in many missing chunk-store snippets              * */
/* *             0.5.1 - 05/08/2000 - G.Juyn                                * */
/* *             - added checks for running animations                      * */
/* *             - filled some write routines                               * */
/* *             - changed strict-ANSI stuff                                * */
/* *             0.5.1 - 05/10/2000 - G.Juyn                                * */
/* *             - filled some more write routines                          * */
/* *             0.5.1 - 05/11/2000 - G.Juyn                                * */
/* *             - filled remaining write routines                          * */
/* *             - fixed read_pplt with regard to deltatype                 * */
/* *             - added callback error-reporting support                   * */
/* *             - added pre-draft48 support (short MHDR, frame_mode, LOOP) * */
/* *             0.5.1 - 05/12/2000 - G.Juyn                                * */
/* *             - changed trace to macro for callback error-reporting      * */
/* *             - fixed chunk-storage bit in several routines              * */
/* *             0.5.1 - 05/13/2000 - G.Juyn                                * */
/* *             - added eMNGma hack (will be removed in 1.0.0 !!!)         * */
/* *             - added TERM animation object pointer (easier reference)   * */
/* *             - supplemented the SAVE & SEEK display processing          * */
/* *                                                                        * */
/* *             0.5.2 - 05/18/2000 - G.Juyn                                * */
/* *             - B004 - fixed problem with MNG_SUPPORT_WRITE not defined  * */
/* *               also for MNG_SUPPORT_WRITE without MNG_INCLUDE_JNG       * */
/* *             0.5.2 - 05/19/2000 - G.Juyn                                * */
/* *             - cleaned up some code regarding mixed support             * */
/* *             0.5.2 - 05/20/2000 - G.Juyn                                * */
/* *             - implemented JNG support                                  * */
/* *             0.5.2 - 05/24/2000 - G.Juyn                                * */
/* *             - added support for global color-chunks in animation       * */
/* *             - added support for global PLTE,tRNS,bKGD in animation     * */
/* *             - added support for SAVE & SEEK in animation               * */
/* *             0.5.2 - 05/29/2000 - G.Juyn                                * */
/* *             - changed ani_create calls not returning object pointer    * */
/* *             - create ani objects always (not just inside TERM/LOOP)    * */
/* *             0.5.2 - 05/30/2000 - G.Juyn                                * */
/* *             - added support for delta-image processing                 * */
/* *             0.5.2 - 05/31/2000 - G.Juyn                                * */
/* *             - fixed up punctuation (contributed by Tim Rowley)         * */
/* *             0.5.2 - 06/02/2000 - G.Juyn                                * */
/* *             - changed SWAP_ENDIAN to BIGENDIAN_SUPPORTED               * */
/* *             0.5.2 - 06/03/2000 - G.Juyn                                * */
/* *             - fixed makeup for Linux gcc compile                       * */
/* *                                                                        * */
/* *             0.5.3 - 06/12/2000 - G.Juyn                                * */
/* *             - added processing of color-info on delta-image            * */
/* *             0.5.3 - 06/13/2000 - G.Juyn                                * */
/* *             - fixed handling of empty SAVE chunk                       * */
/* *             0.5.3 - 06/17/2000 - G.Juyn                                * */
/* *             - changed to support delta-images                          * */
/* *             - added extra checks for delta-images                      * */
/* *             0.5.3 - 06/20/2000 - G.Juyn                                * */
/* *             - fixed possible trouble if IEND display-process got       * */
/* *               broken up                                                * */
/* *             0.5.3 - 06/21/2000 - G.Juyn                                * */
/* *             - added processing of PLTE & tRNS for delta-images         * */
/* *             - added administration of imagelevel parameter             * */
/* *             0.5.3 - 06/22/2000 - G.Juyn                                * */
/* *             - implemented support for PPLT chunk                       * */
/* *             0.5.3 - 06/26/2000 - G.Juyn                                * */
/* *             - added precaution against faulty iCCP chunks from PS      * */
/* *             0.5.3 - 06/29/2000 - G.Juyn                                * */
/* *             - fixed some 64-bit warnings                               * */
/* *                                                                        * */
/* *             0.9.1 - 07/14/2000 - G.Juyn                                * */
/* *             - changed pre-draft48 frame_mode=3 to frame_mode=1         * */
/* *             0.9.1 - 07/16/2000 - G.Juyn                                * */
/* *             - fixed storage of images during mng_read()                * */
/* *             - fixed support for mng_display() after mng_read()         * */
/* *             0.9.1 - 07/19/2000 - G.Juyn                                * */
/* *             - fixed several chunk-writing routines                     * */
/* *             0.9.1 - 07/24/2000 - G.Juyn                                * */
/* *             - fixed reading of still-images                            * */
/* *                                                                        * */
/* *             0.9.2 - 08/05/2000 - G.Juyn                                * */
/* *             - changed file-prefixes                                    * */
/* *                                                                        * */
/* *             0.9.3 - 08/07/2000 - G.Juyn                                * */
/* *             - B111300 - fixup for improved portability                 * */
/* *             0.9.3 - 08/08/2000 - G.Juyn                                * */
/* *             - fixed compiler-warnings from Mozilla                     * */
/* *             0.9.3 - 08/09/2000 - G.Juyn                                * */
/* *             - added check for simplicity-bits in MHDR                  * */
/* *             0.9.3 - 08/12/2000 - G.Juyn                                * */
/* *             - fixed check for simplicity-bits in MHDR (JNG)            * */
/* *             0.9.3 - 08/12/2000 - G.Juyn                                * */
/* *             - added workaround for faulty PhotoShop iCCP chunk         * */
/* *             0.9.3 - 08/22/2000 - G.Juyn                                * */
/* *             - fixed write-code for zTXt & iTXt                         * */
/* *             - fixed read-code for iTXt                                 * */
/* *             0.9.3 - 08/26/2000 - G.Juyn                                * */
/* *             - added MAGN chunk                                         * */
/* *             0.9.3 - 09/07/2000 - G.Juyn                                * */
/* *             - added support for new filter_types                       * */
/* *             0.9.3 - 09/10/2000 - G.Juyn                                * */
/* *             - fixed DEFI behavior                                      * */
/* *             0.9.3 - 10/02/2000 - G.Juyn                                * */
/* *             - fixed simplicity-check in compliance with draft 81/0.98a * */
/* *             0.9.3 - 10/10/2000 - G.Juyn                                * */
/* *             - added support for alpha-depth prediction                 * */
/* *             0.9.3 - 10/11/2000 - G.Juyn                                * */
/* *             - added support for nEED                                   * */
/* *             0.9.3 - 10/16/2000 - G.Juyn                                * */
/* *             - added support for JDAA                                   * */
/* *             0.9.3 - 10/17/2000 - G.Juyn                                * */
/* *             - fixed support for MAGN                                   * */
/* *             - implemented nEED "xxxx" (where "xxxx" is a chunkid)      * */
/* *             - added callback to process non-critical unknown chunks    * */
/* *             - fixed support for bKGD                                   * */
/* *             0.9.3 - 10/23/2000 - G.Juyn                                * */
/* *             - fixed bug in empty PLTE handling                         * */
/* *                                                                        * */
/* *             0.9.4 - 11/20/2000 - G.Juyn                                * */
/* *             - changed IHDR filter_method check for PNGs                * */
/* *             0.9.4 -  1/18/2001 - G.Juyn                                * */
/* *             - added errorchecking for MAGN methods                     * */
/* *             - removed test filter-methods 1 & 65                       * */
/* *                                                                        * */
/* *             0.9.5 -  1/25/2001 - G.Juyn                                * */
/* *             - fixed some small compiler warnings (thanks Nikki)        * */
/* *                                                                        * */
/* *             1.0.2 - 05/05/2000 - G.Juyn                                * */
/* *             - B421427 - writes wrong format in bKGD and tRNS           * */
/* *             1.0.2 - 06/20/2000 - G.Juyn                                * */
/* *             - B434583 - compiler-warning if MNG_STORE_CHUNKS undefined * */
/* *                                                                        * */
/* ************************************************************************** */

#include "libmng.h"
#include "libmng_data.h"
#include "libmng_error.h"
#include "libmng_trace.h"
#ifdef __BORLANDC__
#pragma hdrstop
#endif
#include "libmng_objects.h"
#include "libmng_object_prc.h"
#include "libmng_chunks.h"
#ifdef MNG_CHECK_BAD_ICCP
#include "libmng_chunk_prc.h"
#endif
#include "libmng_memory.h"
#include "libmng_display.h"
#include "libmng_zlib.h"
#include "libmng_pixels.h"
#include "libmng_chunk_io.h"

#if defined(__BORLANDC__) && defined(MNG_STRICT_ANSI)
#pragma option -A                      /* force ANSI-C */
#endif

/* ************************************************************************** */
/* *                                                                        * */
/* * CRC - Cyclic Redundancy Check                                          * */
/* *                                                                        * */
/* * The code below is taken directly from the sample provided with the     * */
/* * PNG specification.                                                     * */
/* * (it is only adapted to the library's internal data-definitions)        * */
/* *                                                                        * */
/* ************************************************************************** */

/* Make the table for a fast CRC. */
void make_crc_table (mng_datap pData)
{
  mng_uint32 iC;
  mng_int32  iN, iK;

  for (iN = 0; iN < 256; iN++)
  {
    iC = (mng_uint32) iN;

    for (iK = 0; iK < 8; iK++)
    {
      if (iC & 1)
        iC = 0xedb88320U ^ (iC >> 1);
      else
        iC = iC >> 1;
    }

    pData->aCRCtable [iN] = iC;
  }

  pData->bCRCcomputed = MNG_TRUE;
}

/* Update a running CRC with the bytes buf[0..len-1]--the CRC
   should be initialized to all 1's, and the transmitted value
   is the 1's complement of the final running CRC (see the
   crc() routine below). */

mng_uint32 update_crc (mng_datap  pData,
                       mng_uint32 iCrc,
                       mng_uint8p pBuf,
                       mng_int32  iLen)
{
  mng_uint32 iC = iCrc;
  mng_int32 iN;

  if (!pData->bCRCcomputed)
    make_crc_table (pData);

  for (iN = 0; iN < iLen; iN++)
    iC = pData->aCRCtable [(iC ^ pBuf [iN]) & 0xff] ^ (iC >> 8);

  return iC;
}

/* Return the CRC of the bytes buf[0..len-1]. */
mng_uint32 crc (mng_datap  pData,
                mng_uint8p pBuf,
                mng_int32  iLen)
{
  return update_crc (pData, 0xffffffffU, pBuf, iLen) ^ 0xffffffffU;
}

/* ************************************************************************** */
/* *                                                                        * */
/* * Routines for swapping byte-order from and to graphic files             * */
/* * (This code is adapted from the libpng package)                         * */
/* *                                                                        * */
/* ************************************************************************** */

#ifndef MNG_BIGENDIAN_SUPPORTED

/* ************************************************************************** */

mng_uint32 mng_get_uint32 (mng_uint8p pBuf)
{
   mng_uint32 i = ((mng_uint32)(*pBuf)       << 24) +
                  ((mng_uint32)(*(pBuf + 1)) << 16) +
                  ((mng_uint32)(*(pBuf + 2)) <<  8) +
                   (mng_uint32)(*(pBuf + 3));
   return (i);
}

/* ************************************************************************** */

mng_int32 mng_get_int32 (mng_uint8p pBuf)
{
   mng_int32 i = ((mng_int32)(*pBuf)       << 24) +
                 ((mng_int32)(*(pBuf + 1)) << 16) +
                 ((mng_int32)(*(pBuf + 2)) <<  8) +
                  (mng_int32)(*(pBuf + 3));
   return (i);
}

/* ************************************************************************** */

mng_uint16 mng_get_uint16 (mng_uint8p pBuf)
{
   mng_uint16 i = (mng_uint16)(((mng_uint16)(*pBuf) << 8) +
                                (mng_uint16)(*(pBuf + 1)));
   return (i);
}

/* ************************************************************************** */

void mng_put_uint32 (mng_uint8p pBuf,
                     mng_uint32 i)
{
   *pBuf     = (mng_uint8)((i >> 24) & 0xff);
   *(pBuf+1) = (mng_uint8)((i >> 16) & 0xff);
   *(pBuf+2) = (mng_uint8)((i >> 8) & 0xff);
   *(pBuf+3) = (mng_uint8)(i & 0xff);
}

/* ************************************************************************** */

void mng_put_int32 (mng_uint8p pBuf,
                    mng_int32  i)
{
   *pBuf     = (mng_uint8)((i >> 24) & 0xff);
   *(pBuf+1) = (mng_uint8)((i >> 16) & 0xff);
   *(pBuf+2) = (mng_uint8)((i >> 8) & 0xff);
   *(pBuf+3) = (mng_uint8)(i & 0xff);
}

/* ************************************************************************** */

void mng_put_uint16 (mng_uint8p pBuf,
                     mng_uint16 i)
{
   *pBuf     = (mng_uint8)((i >> 8) & 0xff);
   *(pBuf+1) = (mng_uint8)(i & 0xff);
}

/* ************************************************************************** */

#endif /* !MNG_BIGENDIAN_SUPPORTED */

/* ************************************************************************** */
/* *                                                                        * */
/* * Helper routines to simplify chunk-data extraction                      * */
/* *                                                                        * */
/* ************************************************************************** */

#ifdef MNG_INCLUDE_READ_PROCS

/* ************************************************************************** */

mng_uint8p find_null (mng_uint8p pIn)
{
  mng_uint8p pOut = pIn;

  while (*pOut)                        /* the read_graphic routine has made sure there's */
    pOut++;                            /* always at least 1 zero-byte in the buffer */