turbojpegl.c

/*
 * Copyright (C)2009-2011 D. R. Commander.  All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - 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.
 * - Neither the name of the libjpeg-turbo Project 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 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 THE COPYRIGHT HOLDERS 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.
 */

/* TurboJPEG/OSS:  this implements the TurboJPEG API using libjpeg-turbo */

#include <stdio.h>
#include <stdlib.h>
#define JPEG_INTERNALS
#include <jpeglib.h>
#include <jerror.h>
#include <setjmp.h>
#include <jinclude.h>
#include "./turbojpeg.h"
#include "./rrutil.h"
#include "transupp.h"

extern void jpeg_mem_dest_tj(j_compress_ptr, unsigned char **,
	unsigned long *, boolean);
extern void jpeg_mem_src_tj(j_decompress_ptr, unsigned char *, unsigned long);

#ifndef min
 #define min(a,b) ((a)<(b)?(a):(b))
#endif

#define PAD(v, p) ((v+(p)-1)&(~((p)-1)))


/* Error handling (based on example in example.c) */

static char errStr[JMSG_LENGTH_MAX]="No error";

struct my_error_mgr
{
	struct jpeg_error_mgr pub;
	jmp_buf setjmp_buffer;
};
typedef struct my_error_mgr *my_error_ptr;

static void my_error_exit(j_common_ptr cinfo)
{
	my_error_ptr myerr=(my_error_ptr)cinfo->err;
	(*cinfo->err->output_message)(cinfo);
	longjmp(myerr->setjmp_buffer, 1);
}

/* Based on output_message() in jerror.c */

static void my_output_message(j_common_ptr cinfo)
{
	(*cinfo->err->format_message)(cinfo, errStr);
}


/* Global structures, macros, etc. */

enum {COMPRESS=1, DECOMPRESS=2};

typedef struct _tjinstance
{
	struct jpeg_compress_struct cinfo;
	struct jpeg_decompress_struct dinfo;
	struct my_error_mgr jerr;
	int init;
} tjinstance;

static const int pixelsize[TJ_NUMSAMP]={3, 3, 3, 1, 3};

static const JXFORM_CODE xformtypes[TJ_NUMXOP]=
{
	JXFORM_NONE, JXFORM_FLIP_H, JXFORM_FLIP_V, JXFORM_TRANSPOSE,
	JXFORM_TRANSVERSE, JXFORM_ROT_90, JXFORM_ROT_180, JXFORM_ROT_270
};

#define NUMSF 4
static const tjscalingfactor sf[NUMSF]={
	{1, 1},
	{1, 2},
	{1, 4},
	{1, 8}
};

#define _throw(c) {snprintf(errStr, JMSG_LENGTH_MAX, "%s", c);  \
	retval=-1;  goto bailout;}
#define getinstance(handle) tjinstance *this=(tjinstance *)handle;  \
	j_compress_ptr cinfo=NULL;  j_decompress_ptr dinfo=NULL;  \
	if(!this) {snprintf(errStr, JMSG_LENGTH_MAX, "Invalid handle");  \
		return -1;}  \
	cinfo=&this->cinfo;  dinfo=&this->dinfo;

static int getPixelFormat(int pixelSize, int flags)
{
	if(pixelSize==1) return TJPF_GRAY;
	if(pixelSize==3)
	{
		if(flags&TJ_BGR) return TJPF_BGR;
		else return TJPF_RGB;
	}
	if(pixelSize==4)
	{
		if(flags&TJ_ALPHAFIRST)
		{
			if(flags&TJ_BGR) return TJPF_XBGR;
			else return TJPF_XRGB;
		}
		else
		{
			if(flags&TJ_BGR) return TJPF_BGRX;
			else return TJPF_RGBX;
		}
	}
	return -1;
}

static void setCompDefaults(struct jpeg_compress_struct *cinfo,
	int pixelFormat, int subsamp, int jpegQual)
{
	switch(pixelFormat)
	{
		case TJPF_GRAY:
			cinfo->in_color_space=JCS_GRAYSCALE;  break;
		#if JCS_EXTENSIONS==1
		case TJPF_RGB:
			cinfo->in_color_space=JCS_EXT_RGB;  break;
		case TJPF_BGR:
			cinfo->in_color_space=JCS_EXT_BGR;  break;
		case TJPF_RGBX:
			cinfo->in_color_space=JCS_EXT_RGBX;  break;
		case TJPF_BGRX:
			cinfo->in_color_space=JCS_EXT_BGRX;  break;
		case TJPF_XRGB:
			cinfo->in_color_space=JCS_EXT_XRGB;  break;
		case TJPF_XBGR:
			cinfo->in_color_space=JCS_EXT_XBGR;  break;
		#else
		case TJPF_RGB:
			if(RGB_RED==0 && RGB_GREEN==1 && RGB_BLUE==2 && RGB_PIXELSIZE==3)
			{
				cinfo->in_color_space=JCS_RGB;  break;
			}
		default:
			_throw("Unsupported pixel format");
		#endif
	}

	cinfo->input_components=tjPixelSize[pixelFormat];
	jpeg_set_defaults(cinfo);
	if(jpegQual>=0)
	{
		jpeg_set_quality(cinfo, jpegQual, TRUE);
		if(jpegQual>=96) cinfo->dct_method=JDCT_ISLOW;
		else cinfo->dct_method=JDCT_FASTEST;
	}
	if(subsamp==TJSAMP_GRAY)
		jpeg_set_colorspace(cinfo, JCS_GRAYSCALE);
	else
		jpeg_set_colorspace(cinfo, JCS_YCbCr);

	cinfo->comp_info[0].h_samp_factor=tjMCUWidth[subsamp]/8;
	cinfo->comp_info[1].h_samp_factor=1;
	cinfo->comp_info[2].h_samp_factor=1;
	cinfo->comp_info[0].v_samp_factor=tjMCUHeight[subsamp]/8;
	cinfo->comp_info[1].v_samp_factor=1;
	cinfo->comp_info[2].v_samp_factor=1;
}

static void setDecompDefaults(struct jpeg_decompress_struct *dinfo,
	int pixelFormat)
{
	switch(pixelFormat)
	{
		case TJPF_GRAY:
			dinfo->out_color_space=JCS_GRAYSCALE;  break;
		#if JCS_EXTENSIONS==1
		case TJPF_RGB:
			dinfo->out_color_space=JCS_EXT_RGB;  break;
		case TJPF_BGR:
			dinfo->out_color_space=JCS_EXT_BGR;  break;
		case TJPF_RGBX:
			dinfo->out_color_space=JCS_EXT_RGBX;  break;
		case TJPF_BGRX:
			dinfo->out_color_space=JCS_EXT_BGRX;  break;
		case TJPF_XRGB:
			dinfo->out_color_space=JCS_EXT_XRGB;  break;
		case TJPF_XBGR:
			dinfo->out_color_space=JCS_EXT_XBGR;  break;
		#else
		case TJPF_RGB:
			if(RGB_RED==0 && RGB_GREEN==1 && RGB_BLUE==2 && RGB_PIXELSIZE==3)
			{
				dinfo->out_color_space=JCS_RGB;  break;
			}
		default:
			_throw("Unsupported pixel format");
		#endif
	}
}


/* General API functions */

DLLEXPORT char* DLLCALL tjGetErrorStr(void)
{
	return errStr;
}


DLLEXPORT int DLLCALL tjDestroy(tjhandle handle)
{
	getinstance(handle);
	if(setjmp(this->jerr.setjmp_buffer)) return -1;
	if(this->init&COMPRESS) jpeg_destroy_compress(cinfo);
	if(this->init&DECOMPRESS) jpeg_destroy_decompress(dinfo);
	free(this);
	return 0;
}


/* Compressor  */

static tjhandle _tjInitCompress(tjinstance *this)
{
	unsigned char buffer[1], *buf=buffer;  unsigned long size=1;

	/* This is also straight out of example.c */
	this->cinfo.err=jpeg_std_error(&this->jerr.pub);
	this->jerr.pub.error_exit=my_error_exit;
	this->jerr.pub.output_message=my_output_message;

	if(setjmp(this->jerr.setjmp_buffer))
	{
		/* If we get here, the JPEG code has signaled an error. */
		if(this) free(this);  return NULL;
	}

	jpeg_create_compress(&this->cinfo);
	/* Make an initial call so it will create the destination manager */
	jpeg_mem_dest_tj(&this->cinfo, &buf, &size, 0);

	this->init|=COMPRESS;
	return (tjhandle)this;
}

DLLEXPORT tjhandle DLLCALL tjInitCompress(void)
{
	tjinstance *this=NULL;
	if((this=(tjinstance *)malloc(sizeof(tjinstance)))==NULL)
	{
		snprintf(errStr, JMSG_LENGTH_MAX,
			"tjInitCompress(): Memory allocation failure");
		return NULL;
	}
	MEMZERO(this, sizeof(tjinstance));
	return _tjInitCompress(this);
}


DLLEXPORT unsigned long DLLCALL TJBUFSIZE(int width, int height)
{
	unsigned long retval=0;
	if(width<1 || height<1)
		_throw("TJBUFSIZE(): Invalid argument");

	// This allows for rare corner cases in which a JPEG image can actually be
	// larger than the uncompressed input (we wouldn't mention it if it hadn't
	// happened before.)
	retval=PAD(width, 16) * PAD(height, 16) * 6 + 2048;

	bailout:
	return retval;
}


DLLEXPORT unsigned long DLLCALL TJBUFSIZEYUV(int width, int height,
	int subsamp)
{
	unsigned long retval=0;
	int pw, ph, cw, ch;
	if(width<1 || height<1 || subsamp<0 || subsamp>=NUMSUBOPT)
		_throw("TJBUFSIZEYUV(): Invalid argument");
	pw=PAD(width, tjMCUWidth[subsamp]/8);
	ph=PAD(height, tjMCUHeight[subsamp]/8);
	cw=pw*8/tjMCUWidth[subsamp];  ch=ph*8/tjMCUHeight[subsamp];
	retval=PAD(pw, 4)*ph + (subsamp==TJSAMP_GRAY? 0:PAD(cw, 4)*ch*2);

	bailout:
	return retval;
}


DLLEXPORT int DLLCALL tjCompress2(tjhandle handle, unsigned char *srcBuf,
	int width, int pitch, int height, int pixelFormat, unsigned char **jpegBuf,
	unsigned long *jpegSize, int jpegSubsamp, int jpegQual, int flags)
{
	int i, retval=0;  JSAMPROW *row_pointer=NULL;

	getinstance(handle)
	if((this->init&COMPRESS)==0)
		_throw("tjCompress2(): Instance has not been initialized for compression");

	if(srcBuf==NULL || width<=0 || pitch<0 || height<=0 || pixelFormat<0
		|| pixelFormat>=TJ_NUMPF || jpegBuf==NULL || jpegSize==NULL
		|| jpegSubsamp<0 || jpegSubsamp>=NUMSUBOPT || jpegQual<0 || jpegQual>100)
		_throw("tjCompress2(): Invalid argument");

	if(setjmp(this->jerr.setjmp_buffer))
	{
		/* If we get here, the JPEG code has signaled an error. */
		retval=-1;
		goto bailout;
	}

	if(pitch==0) pitch=width*tjPixelSize[pixelFormat];

	cinfo->image_width=width;
	cinfo->image_height=height;

	if(flags&TJFLAG_FORCEMMX) putenv("JSIMD_FORCEMMX=1");
	else if(flags&TJFLAG_FORCESSE) putenv("JSIMD_FORCESSE=1");
	else if(flags&TJFLAG_FORCESSE2) putenv("JSIMD_FORCESSE2=1");

	jpeg_mem_dest_tj(cinfo, jpegBuf, jpegSize, (flags&TJFLAG_NOREALLOC)==0);
	setCompDefaults(cinfo, pixelFormat, jpegSubsamp, jpegQual);

	jpeg_start_compress(cinfo, TRUE);
	if((row_pointer=(JSAMPROW *)malloc(sizeof(JSAMPROW)*height))==NULL)
		_throw("tjCompress2(): Memory allocation failure");
	for(i=0; i<height; i++)
	{
		if(flags&TJFLAG_BOTTOMUP) row_pointer[i]=&srcBuf[(height-i-1)*pitch];
		else row_pointer[i]=&srcBuf[i*pitch];
	}
	while(cinfo->next_scanline<cinfo->image_height)
	{
		jpeg_write_scanlines(cinfo, &row_pointer[cinfo->next_scanline],
			cinfo->image_height-cinfo->next_scanline);
	}
	jpeg_finish_compress(cinfo);

	bailout:
	if(cinfo->global_state>CSTATE_START) jpeg_abort_compress(cinfo);
	if(row_pointer) free(row_pointer);
	return retval;
}

DLLEXPORT int DLLCALL tjCompress(tjhandle handle, unsigned char *srcBuf,
	int width, int pitch, int height, int pixelSize, unsigned char *jpegBuf,
	unsigned long *jpegSize, int jpegSubsamp, int jpegQual, int flags)
{
	int retval=0;  unsigned long size;
	if(flags&TJ_YUV)
	{
		size=TJBUFSIZEYUV(width, height, jpegSubsamp);
		retval=tjEncodeYUV2(handle, srcBuf, width, pitch, height,
			getPixelFormat(pixelSize, flags), jpegBuf, jpegSubsamp, flags);
	}
	else
	{
		size=TJBUFSIZE(width, height);
		retval=tjCompress2(handle, srcBuf, width, pitch, height,
			getPixelFormat(pixelSize, flags), &jpegBuf, &size, jpegSubsamp, jpegQual,
			flags|TJFLAG_NOREALLOC);
	}
	*jpegSize=size;
	return retval;
}


DLLEXPORT int DLLCALL tjEncodeYUV2(tjhandle handle, unsigned char *srcBuf,
	int width, int pitch, int height, int pixelFormat, unsigned char *dstBuf,
	int subsamp, int flags)
{
	int i, retval=0;  JSAMPROW *row_pointer=NULL;
	JSAMPLE *_tmpbuf[MAX_COMPONENTS], *_tmpbuf2[MAX_COMPONENTS];
	JSAMPROW *tmpbuf[MAX_COMPONENTS], *tmpbuf2[MAX_COMPONENTS];
	JSAMPROW *outbuf[MAX_COMPONENTS];
	int row, pw, ph, cw[MAX_COMPONENTS], ch[MAX_COMPONENTS];
	JSAMPLE *ptr=dstBuf;
  unsigned long yuvsize=0;
	jpeg_component_info *compptr;

	getinstance(handle);
	if((this->init&COMPRESS)==0)
		_throw("tjEncodeYUV2(): Instance has not been initialized for compression");

	for(i=0; i<MAX_COMPONENTS; i++)
	{
		tmpbuf[i]=NULL;  _tmpbuf[i]=NULL;
		tmpbuf2[i]=NULL;  _tmpbuf2[i]=NULL;  outbuf[i]=NULL;
	}

	if(srcBuf==NULL || width<=0 || pitch<0 || height<=0 || pixelFormat<0
		|| pixelFormat>=TJ_NUMPF || dstBuf==NULL || subsamp<0
		|| subsamp>=NUMSUBOPT)
		_throw("tjEncodeYUV2(): Invalid argument");

	if(setjmp(this->jerr.setjmp_buffer))
	{
		/* If we get here, the JPEG code has signaled an error. */
		retval=-1;
		goto bailout;
	}

	if(pitch==0) pitch=width*tjPixelSize[pixelFormat];

	cinfo->image_width=width;
	cinfo->image_height=height;

	if(flags&TJFLAG_FORCEMMX) putenv("JSIMD_FORCEMMX=1");
	else if(flags&TJFLAG_FORCESSE) putenv("JSIMD_FORCESSE=1");
	else if(flags&TJFLAG_FORCESSE2) putenv("JSIMD_FORCESSE2=1");

	yuvsize=TJBUFSIZEYUV(width, height, subsamp);
	jpeg_mem_dest_tj(cinfo, &dstBuf, &yuvsize, 0);
	setCompDefaults(cinfo, pixelFormat, subsamp, -1);

	jpeg_start_compress(cinfo, TRUE);
	pw=PAD(width, cinfo->max_h_samp_factor);
	ph=PAD(height, cinfo->max_v_samp_factor);

	if((row_pointer=(JSAMPROW *)malloc(sizeof(JSAMPROW)*ph))==NULL)
		_throw("tjEncodeYUV2(): Memory allocation failure");
	for(i=0; i<height; i++)
	{
		if(flags&TJFLAG_BOTTOMUP) row_pointer[i]=&srcBuf[(height-i-1)*pitch];
		else row_pointer[i]=&srcBuf[i*pitch];
	}
	if(height<ph)
		for(i=height; i<ph; i++) row_pointer[i]=row_pointer[height-1];

	for(i=0; i<cinfo->num_components; i++)
	{
		compptr=&cinfo->comp_info[i];
		_tmpbuf[i]=(JSAMPLE *)malloc(
			PAD((compptr->width_in_blocks*cinfo->max_h_samp_factor*DCTSIZE)
				/compptr->h_samp_factor, 16) * cinfo->max_v_samp_factor + 16);
		if(!_tmpbuf[i]) _throw("tjEncodeYUV2(): Memory allocation failure");
		tmpbuf[i]=(JSAMPROW *)malloc(sizeof(JSAMPROW)*cinfo->max_v_samp_factor);
		if(!tmpbuf[i]) _throw("tjEncodeYUV2(): Memory allocation failure");
		for(row=0; row<cinfo->max_v_samp_factor; row++)
		{
			unsigned char *_tmpbuf_aligned=
				(unsigned char *)PAD((size_t)_tmpbuf[i], 16);
			tmpbuf[i][row]=&_tmpbuf_aligned[
				PAD((compptr->width_in_blocks*cinfo->max_h_samp_factor*DCTSIZE)
					/compptr->h_samp_factor, 16) * row];
		}
		_tmpbuf2[i]=(JSAMPLE *)malloc(PAD(compptr->width_in_blocks*DCTSIZE, 16)
			* compptr->v_samp_factor + 16);
		if(!_tmpbuf2[i]) _throw("tjEncodeYUV2(): Memory allocation failure");
		tmpbuf2[i]=(JSAMPROW *)malloc(sizeof(JSAMPROW)*compptr->v_samp_factor);
		if(!tmpbuf2[i]) _throw("tjEncodeYUV2(): Memory allocation failure");
		for(row=0; row<compptr->v_samp_factor; row++)
		{
			unsigned char *_tmpbuf2_aligned=
				(unsigned char *)PAD((size_t)_tmpbuf2[i], 16);
			tmpbuf2[i][row]=&_tmpbuf2_aligned[
				PAD(compptr->width_in_blocks*DCTSIZE, 16) * row];
		}
		cw[i]=pw*compptr->h_samp_factor/cinfo->max_h_samp_factor;
		ch[i]=ph*compptr->v_samp_factor/cinfo->max_v_samp_factor;
		outbuf[i]=(JSAMPROW *)malloc(sizeof(JSAMPROW)*ch[i]);
		if(!outbuf[i]) _throw("tjEncodeYUV2(): Memory allocation failure");
		for(row=0; row<ch[i]; row++)
		{
			outbuf[i][row]=ptr;
			ptr+=PAD(cw[i], 4);
		}
	}
	if(yuvsize!=(unsigned long)(ptr-dstBuf))
		_throw("tjEncodeYUV2(): Generated image is not the correct size");

	for(row=0; row<ph; row+=cinfo->max_v_samp_factor)
	{
		(*cinfo->cconvert->color_convert)(cinfo, &row_pointer[row], tmpbuf, 0,
			cinfo->max_v_samp_factor);
		(cinfo->downsample->downsample)(cinfo, tmpbuf, 0, tmpbuf2, 0);
		for(i=0, compptr=cinfo->comp_info; i<cinfo->num_components; i++, compptr++)
			jcopy_sample_rows(tmpbuf2[i], 0, outbuf[i],
				row*compptr->v_samp_factor/cinfo->max_v_samp_factor,
				compptr->v_samp_factor, cw[i]);
	}
	cinfo->next_scanline+=height;
	jpeg_abort_compress(cinfo);

	bailout:
	if(cinfo->global_state>CSTATE_START) jpeg_abort_compress(cinfo);
	if(row_pointer) free(row_pointer);
	for(i=0; i<MAX_COMPONENTS; i++)
	{
		if(tmpbuf[i]!=NULL) free(tmpbuf[i]);
		if(_tmpbuf[i]!=NULL) free(_tmpbuf[i]);
		if(tmpbuf2[i]!=NULL) free(tmpbuf2[i]);
		if(_tmpbuf2[i]!=NULL) free(_tmpbuf2[i]);
		if(outbuf[i]!=NULL) free(outbuf[i]);
	}
	return retval;
}

DLLEXPORT int DLLCALL tjEncodeYUV(tjhandle handle, unsigned char *srcBuf,
	int width, int pitch, int height, int pixelSize, unsigned char *dstBuf,
	int subsamp, int flags)
{
	return tjEncodeYUV2(handle, srcBuf, width, pitch, height,
		getPixelFormat(pixelSize, flags), dstBuf, subsamp, flags);
}


/* Decompressor */

static tjhandle _tjInitDecompress(tjinstance *this)
{
	unsigned char buffer[1];

	/* This is also straight out of example.c */
	this->dinfo.err=jpeg_std_error(&this->jerr.pub);
	this->jerr.pub.error_exit=my_error_exit;
	this->jerr.pub.output_message=my_output_message;

	if(setjmp(this->jerr.setjmp_buffer))
	{
		/* If we get here, the JPEG code has signaled an error. */
		if(this) free(this);  return NULL;
	}

	jpeg_create_decompress(&this->dinfo);
	/* Make an initial call so it will create the source manager */
	jpeg_mem_src_tj(&this->dinfo, buffer, 1);

	this->init|=DECOMPRESS;
	return (tjhandle)this;
}

DLLEXPORT tjhandle DLLCALL tjInitDecompress(void)
{
	tjinstance *this;
	if((this=(tjinstance *)malloc(sizeof(tjinstance)))==NULL)
	{
		snprintf(errStr, JMSG_LENGTH_MAX,
			"tjInitDecompress(): Memory allocation failure");
		return NULL;
	}
	MEMZERO(this, sizeof(tjinstance));
	return _tjInitDecompress(this);
}


DLLEXPORT int DLLCALL tjDecompressHeader2(tjhandle handle,
	unsigned char *jpegBuf, unsigned long jpegSize, int *width, int *height,
	int *jpegSubsamp)
{
	int i, k, retval=0;

	getinstance(handle);
	if((this->init&DECOMPRESS)==0)
		_throw("tjDecompressHeader2(): Instance has not been initialized for decompression");

	if(jpegBuf==NULL || jpegSize<=0 || width==NULL || height==NULL
		|| jpegSubsamp==NULL)
		_throw("tjDecompressHeader2(): Invalid argument");

	if(setjmp(this->jerr.setjmp_buffer))
	{
		/* If we get here, the JPEG code has signaled an error. */
		return -1;
	}

	jpeg_mem_src_tj(dinfo, jpegBuf, jpegSize);
	jpeg_read_header(dinfo, TRUE);

	*width=dinfo->image_width;
	*height=dinfo->image_height;
	*jpegSubsamp=-1;
	for(i=0; i<NUMSUBOPT; i++)
	{
		if(dinfo->num_components==pixelsize[i])
		{
			if(dinfo->comp_info[0].h_samp_factor==tjMCUWidth[i]/8
				&& dinfo->comp_info[0].v_samp_factor==tjMCUHeight[i]/8)
			{
				int match=0;
				for(k=1; k<dinfo->num_components; k++)
				{
					if(dinfo->comp_info[k].h_samp_factor==1
						&& dinfo->comp_info[k].v_samp_factor==1)
						match++;
				}
				if(match==dinfo->num_components-1)
				{
					*jpegSubsamp=i;  break;
				}
			}
		}
	}

	jpeg_abort_decompress(dinfo);

	if(*jpegSubsamp<0)
		_throw("tjDecompressHeader2(): Could not determine subsampling type for JPEG image");
	if(*width<1 || *height<1)
		_throw("tjDecompressHeader2(): Invalid data returned in header");

	bailout:
	return retval;
}

DLLEXPORT int DLLCALL tjDecompressHeader(tjhandle handle,
	unsigned char *jpegBuf, unsigned long jpegSize, int *width, int *height)
{
	int jpegSubsamp;
	return tjDecompressHeader2(handle, jpegBuf, jpegSize, width, height,
		&jpegSubsamp);
}


DLLEXPORT tjscalingfactor* DLLCALL tjGetScalingFactors(int *numscalingfactors)
{
	if(numscalingfactors==NULL)
	{
		snprintf(errStr, JMSG_LENGTH_MAX,
			"tjGetScalingFactors(): Invalid argument");
		return NULL;
	}

	*numscalingfactors=NUMSF;
	return (tjscalingfactor *)sf;
}


DLLEXPORT int DLLCALL tjDecompress2(tjhandle handle, unsigned char *jpegBuf,
	unsigned long jpegSize, unsigned char *dstBuf, int width, int pitch,
	int height, int pixelFormat, int flags)
{
	int i, retval=0;  JSAMPROW *row_pointer=NULL;
	int jpegwidth, jpegheight, scaledw, scaledh;

	getinstance(handle);
	if((this->init&DECOMPRESS)==0)
		_throw("tjDecompress2(): Instance has not been initialized for decompression");

	if(jpegBuf==NULL || jpegSize<=0 || dstBuf==NULL || width<0 || pitch<0
		|| height<0 || pixelFormat<0 || pixelFormat>=TJ_NUMPF)
		_throw("tjDecompress2(): Invalid argument");

	if(flags&TJFLAG_FORCEMMX) putenv("JSIMD_FORCEMMX=1");
	else if(flags&TJFLAG_FORCESSE) putenv("JSIMD_FORCESSE=1");
	else if(flags&TJFLAG_FORCESSE2) putenv("JSIMD_FORCESSE2=1");

	if(setjmp(this->jerr.setjmp_buffer))
	{
		/* If we get here, the JPEG code has signaled an error. */
		retval=-1;
		goto bailout;
	}

	jpeg_mem_src_tj(dinfo, jpegBuf, jpegSize);
	jpeg_read_header(dinfo, TRUE);
	setDecompDefaults(dinfo, pixelFormat);

	if(flags&TJFLAG_FASTUPSAMPLE) dinfo->do_fancy_upsampling=FALSE;

	jpegwidth=dinfo->image_width;  jpegheight=dinfo->image_height;
	if(width==0) width=jpegwidth;
	if(height==0) height=jpegheight;
	for(i=0; i<NUMSF; i++)
	{
		scaledw=TJSCALED(jpegwidth, sf[i]);
		scaledh=TJSCALED(jpegheight, sf[i]);
		if(scaledw<=width && scaledh<=height)
				break;
	}
	if(scaledw>width || scaledh>height)
		_throw("tjDecompress2(): Could not scale down to desired image dimensions");
	width=scaledw;  height=scaledh;
	dinfo->scale_num=sf[i].num;
	dinfo->scale_denom=sf[i].denom;

	jpeg_start_decompress(dinfo);
	if(pitch==0) pitch=dinfo->output_width*tjPixelSize[pixelFormat];
	if((row_pointer=(JSAMPROW *)malloc(sizeof(JSAMPROW)
		*dinfo->output_height))==NULL)
		_throw("tjDecompress2(): Memory allocation failure");
	for(i=0; i<(int)dinfo->output_height; i++)
	{
		if(flags&TJFLAG_BOTTOMUP)
			row_pointer[i]=&dstBuf[(dinfo->output_height-i-1)*pitch];
		else row_pointer[i]=&dstBuf[i*pitch];
	}
	while(dinfo->output_scanline<dinfo->output_height)
	{
		jpeg_read_scanlines(dinfo, &row_pointer[dinfo->output_scanline],
			dinfo->output_height-dinfo->output_scanline);
	}
	jpeg_finish_decompress(dinfo);

	bailout:
	if(dinfo->global_state>DSTATE_START) jpeg_abort_decompress(dinfo);
	if(row_pointer) free(row_pointer);
	return retval;
}

DLLEXPORT int DLLCALL tjDecompress(tjhandle handle, unsigned char *jpegBuf,
	unsigned long jpegSize, unsigned char *dstBuf, int width, int pitch,
	int height, int pixelSize, int flags)
{
	if(flags&TJ_YUV)
		return tjDecompressToYUV(handle, jpegBuf, jpegSize, dstBuf, flags);
	else
		return tjDecompress2(handle, jpegBuf, jpegSize, dstBuf, width, pitch,
			height, getPixelFormat(pixelSize, flags), flags);
}


DLLEXPORT int DLLCALL tjDecompressToYUV(tjhandle handle,
	unsigned char *jpegBuf, unsigned long jpegSize, unsigned char *dstBuf,
	int flags)
{
	int i, row, retval=0;  JSAMPROW *outbuf[MAX_COMPONENTS];
	int cw[MAX_COMPONENTS], ch[MAX_COMPONENTS], iw[MAX_COMPONENTS],
		tmpbufsize=0, usetmpbuf=0, th[MAX_COMPONENTS];
	JSAMPLE *_tmpbuf=NULL, *ptr=dstBuf;  JSAMPROW *tmpbuf[MAX_COMPONENTS];

	getinstance(handle);
	if((this->init&DECOMPRESS)==0)
		_throw("tjDecompressToYUV(): Instance has not been initialized for decompression");

	for(i=0; i<MAX_COMPONENTS; i++)
	{
		tmpbuf[i]=NULL;  outbuf[i]=NULL;
	}

	if(jpegBuf==NULL || jpegSize<=0 || dstBuf==NULL)
		_throw("tjDecompressToYUV(): Invalid argument");

	if(flags&TJFLAG_FORCEMMX) putenv("JSIMD_FORCEMMX=1");
	else if(flags&TJFLAG_FORCESSE) putenv("JSIMD_FORCESSE=1");
	else if(flags&TJFLAG_FORCESSE2) putenv("JSIMD_FORCESSE2=1");

	if(setjmp(this->jerr.setjmp_buffer))
	{
		/* If we get here, the JPEG code has signaled an error. */
		retval=-1;
		goto bailout;
	}

	jpeg_mem_src_tj(dinfo, jpegBuf, jpegSize);
	jpeg_read_header(dinfo, TRUE);

	for(i=0; i<dinfo->num_components; i++)
	{
		jpeg_component_info *compptr=&dinfo->comp_info[i];
		int ih;
		iw[i]=compptr->width_in_blocks*DCTSIZE;
		ih=compptr->height_in_blocks*DCTSIZE;
		cw[i]=PAD(dinfo->image_width, dinfo->max_h_samp_factor)
			*compptr->h_samp_factor/dinfo->max_h_samp_factor;
		ch[i]=PAD(dinfo->image_height, dinfo->max_v_samp_factor)
			*compptr->v_samp_factor/dinfo->max_v_samp_factor;
		if(iw[i]!=cw[i] || ih!=ch[i]) usetmpbuf=1;
		th[i]=compptr->v_samp_factor*DCTSIZE;
		tmpbufsize+=iw[i]*th[i];
		if((outbuf[i]=(JSAMPROW *)malloc(sizeof(JSAMPROW)*ch[i]))==NULL)
			_throw("tjDecompressToYUV(): Memory allocation failure");
		for(row=0; row<ch[i]; row++)
		{
			outbuf[i][row]=ptr;
			ptr+=PAD(cw[i], 4);
		}
	}
	if(usetmpbuf)
	{
		if((_tmpbuf=(JSAMPLE *)malloc(sizeof(JSAMPLE)*tmpbufsize))==NULL)
			_throw("tjDecompressToYUV(): Memory allocation failure");
		ptr=_tmpbuf;
		for(i=0; i<dinfo->num_components; i++)
		{
			if((tmpbuf[i]=(JSAMPROW *)malloc(sizeof(JSAMPROW)*th[i]))==NULL)
				_throw("tjDecompressToYUV(): Memory allocation failure");
			for(row=0; row<th[i]; row++)
			{
				tmpbuf[i][row]=ptr;
				ptr+=iw[i];
			}
		}
	}

	if(flags&TJFLAG_FASTUPSAMPLE) dinfo->do_fancy_upsampling=FALSE;
	dinfo->raw_data_out=TRUE;

	jpeg_start_decompress(dinfo);
	for(row=0; row<(int)dinfo->output_height;
		row+=dinfo->max_v_samp_factor*DCTSIZE)
	{
		JSAMPARRAY yuvptr[MAX_COMPONENTS];
		int crow[MAX_COMPONENTS];
		for(i=0; i<dinfo->num_components; i++)
		{
			jpeg_component_info *compptr=&dinfo->comp_info[i];
			crow[i]=row*compptr->v_samp_factor/dinfo->max_v_samp_factor;
			if(usetmpbuf) yuvptr[i]=tmpbuf[i];
			else yuvptr[i]=&outbuf[i][crow[i]];
		}
		jpeg_read_raw_data(dinfo, yuvptr, dinfo->max_v_samp_factor*DCTSIZE);
		if(usetmpbuf)
		{
			int j;
			for(i=0; i<dinfo->num_components; i++)
			{
				for(j=0; j<min(th[i], ch[i]-crow[i]); j++)
				{
					memcpy(outbuf[i][crow[i]+j], tmpbuf[i][j], cw[i]);
				}
			}
		}
	}
	jpeg_finish_decompress(dinfo);

	bailout:
	if(dinfo->global_state>DSTATE_START) jpeg_abort_decompress(dinfo);
	for(i=0; i<MAX_COMPONENTS; i++)
	{
		if(tmpbuf[i]) free(tmpbuf[i]);
		if(outbuf[i]) free(outbuf[i]);
	}
	if(_tmpbuf) free(_tmpbuf);
	return retval;
}


/* Transformer */

DLLEXPORT tjhandle DLLCALL tjInitTransform(void)
{
	tjinstance *this=NULL;  tjhandle handle=NULL;
	if((this=(tjinstance *)malloc(sizeof(tjinstance)))==NULL)
	{
		snprintf(errStr, JMSG_LENGTH_MAX,
			"tjInitTransform(): Memory allocation failure");
		return NULL;
	}
	MEMZERO(this, sizeof(tjinstance));
	handle=_tjInitCompress(this);
	if(!handle) return NULL;
	handle=_tjInitDecompress(this);
	return handle;
}


DLLEXPORT int DLLCALL tjTransform(tjhandle handle, unsigned char *jpegBuf,
	unsigned long jpegSize, int n, unsigned char **dstBufs,
	unsigned long *dstSizes, tjtransform *t, int flags)
{
	jpeg_transform_info *xinfo=NULL;
	jvirt_barray_ptr *srccoefs, *dstcoefs;
	int retval=0, i;

	getinstance(handle);
	if((this->init&COMPRESS)==0 || (this->init&DECOMPRESS)==0)
		_throw("tjTransform(): Instance has not been initialized for transformation");

	if(jpegBuf==NULL || jpegSize<=0 || n<1 || dstBufs==NULL || dstSizes==NULL
		|| t==NULL || flags<0)
		_throw("tjTransform(): Invalid argument");

	if(flags&TJFLAG_FORCEMMX) putenv("JSIMD_FORCEMMX=1");
	else if(flags&TJFLAG_FORCESSE) putenv("JSIMD_FORCESSE=1");
	else if(flags&TJFLAG_FORCESSE2) putenv("JSIMD_FORCESSE2=1");

	if(setjmp(this->jerr.setjmp_buffer))
	{
		/* If we get here, the JPEG code has signaled an error. */
		retval=-1;
		goto bailout;
	}

	jpeg_mem_src_tj(dinfo, jpegBuf, jpegSize);

	if((xinfo=(jpeg_transform_info *)malloc(sizeof(jpeg_transform_info)*n))
		==NULL)
		_throw("tjTransform(): Memory allocation failure");
	MEMZERO(xinfo, sizeof(jpeg_transform_info)*n);

	for(i=0; i<n; i++)
	{
		xinfo[i].transform=xformtypes[t[i].op];
		xinfo[i].perfect=(t[i].options&TJXOPT_PERFECT)? 1:0;
		xinfo[i].trim=(t[i].options&TJXOPT_TRIM)? 1:0;
		xinfo[i].force_grayscale=(t[i].options&TJXOPT_GRAY)? 1:0;
		xinfo[i].crop=(t[i].options&TJXOPT_CROP)? 1:0;
		if(n!=1 && t[i].op==TJXOP_HFLIP) xinfo[i].slow_hflip=1;
		else xinfo[i].slow_hflip=0;

		if(xinfo[i].crop)
		{
			xinfo[i].crop_xoffset=t[i].r.x;  xinfo[i].crop_xoffset_set=JCROP_POS;
			xinfo[i].crop_yoffset=t[i].r.y;  xinfo[i].crop_yoffset_set=JCROP_POS;
			if(t[i].r.w!=0)
			{
				xinfo[i].crop_width=t[i].r.w;  xinfo[i].crop_width_set=JCROP_POS;
			}
			else xinfo[i].crop_width=JCROP_UNSET;
			if(t[i].r.h!=0)
			{
				xinfo[i].crop_height=t[i].r.h;  xinfo[i].crop_height_set=JCROP_POS;
			}
			else xinfo[i].crop_height=JCROP_UNSET;
		}
	}

	jcopy_markers_setup(dinfo, JCOPYOPT_ALL);
	jpeg_read_header(dinfo, TRUE);

	for(i=0; i<n; i++)
	{
		if(!jtransform_request_workspace(dinfo, &xinfo[i]))
			_throw("tjTransform(): Transform is not perfect");

		if(xinfo[i].crop)
		{
			if((t[i].r.x%xinfo[i].iMCU_sample_width)!=0
				|| (t[i].r.y%xinfo[i].iMCU_sample_height)!=0)
			{
				snprintf(errStr, JMSG_LENGTH_MAX,
					"To crop this JPEG image, x must be a multiple of %d\n"
					"and y must be a multiple of %d.\n",
					xinfo[i].iMCU_sample_width, xinfo[i].iMCU_sample_height);
				retval=-1;  goto bailout;
			}
		}
	}

	srccoefs=jpeg_read_coefficients(dinfo);

	for(i=0; i<n; i++)
	{
		int w, h;
		jpeg_mem_dest_tj(cinfo, &dstBufs[i], &dstSizes[i],
			(flags&TJFLAG_NOREALLOC)==0);
		if(!xinfo[i].crop)
		{
			w=dinfo->image_width;  h=dinfo->image_height;
		}
		else
		{
			w=xinfo[i].crop_width;  h=xinfo[i].crop_height;
		}
		jpeg_copy_critical_parameters(dinfo, cinfo);
		dstcoefs=jtransform_adjust_parameters(dinfo, cinfo, srccoefs,
			&xinfo[i]);
		jpeg_write_coefficients(cinfo, dstcoefs);
		jcopy_markers_execute(dinfo, cinfo, JCOPYOPT_ALL);
		jtransform_execute_transformation(dinfo, cinfo, srccoefs,
			&xinfo[i]);
		jpeg_finish_compress(cinfo);
	}

	jpeg_finish_decompress(dinfo);

	bailout:
	if(cinfo->global_state>CSTATE_START) jpeg_abort_compress(cinfo);
	if(dinfo->global_state>DSTATE_START) jpeg_abort_decompress(dinfo);
	if(xinfo) free(xinfo);
	return retval;
}