www.pudn.com > xiaobo.zip.zip > spt.c

 
/**************** 
 
I unrolled some if's on 7-2 : did it slow this down? !? 
 
----- 
 
todos for speed : 
 
	1. don't do the "S" and "P" in separate steps : inline them and 
		thereby eliminate the need for a temp workspace as well 
	2. don't actually transpose; include a "step" in the _tdec_ call 
 
******************/ 
 
#include  
#include  
#include  
#include  
 
/** line is just a temp workspace **/ 
 
static void do_tdec_line(int *data,int *line,int len) 
{ 
int x,a,b,E,W,ND,pred; 
int *high; 
 
//  if ( len <= 2 ) errexit("special-cased to len > 2 , scumbag"); 
//	if ( len&1 ) errexit("len shouldn't be odd"); 
 
	for(x=0;x>1; 
		line[x+1] = a-b; 
	} 
 
	line[1] += (( line[2] - line[0] + line[3] ) >> 1); 
 
	for(x=2;x<=(len-4);x += 2) { 
		E = line[x + 2] - line[x - 2]; 
		W = line[x + 2] - line[x]; 
		ND = line[x + 3]; 
		pred = ( E + E + W + ND + ND ) >> 3; 
		line[x+1] += pred; 
	} 
 
	// x = len-2; 
	line[len-1] += line[len-2] - line[len-4]; 
 
	/** line is now interleaved LHLHLH ; reshuffle to LLLLHHHH **/ 
 
	high = data + (len>>1); 
	for(x=0;x<(len>>1);x++) { 
		data[x] = line[x+x]; 
		high[x] = line[x+x+1]; 
	} 
} 
 
static void un_tdec_line(int *data,int *line,int len) 
{ 
int x,a,A,D; 
int E,W,ND,pred; 
int *high; 
 
	/** data is in LLLHHHH order ; we must deshuffle it into line ***/ 
 
	high = data + (len>>1); 
	for(x=0;x<(len>>1);x++) { 
		line[x+x] = data[x]; 
		line[x+x+1] = high[x]; 
	}	 
 
	//** run backwards cuz of ND 
 
	// x = len-2; 
	line[len-1] -= line[len-2] - line[len-4]; 
 
	for(x=len-4;x>=2;x -= 2) { 
		E = line[x + 2] - line[x - 2]; 
		W = line[x + 2] - line[x]; 
		ND = line[x + 3]; 
		pred = ( E + E + W + ND + ND ) >> 3; 
		line[x+1] -= pred; 
	} 
 
	line[1] -= ( line[2] - line[0] + line[3] ) >> 1; 
 
	for(x=0;x>1); 
		data[x+1] = a - D; 
	} 
 
} 
 
 
static void un_tdec_zeros(int *data,int *line,int len) 
{ 
int x,a,A,D; 
int E,W,ND,pred; 
//int *high; 
 
	/** data is in LLLHHHH order ; we must deshuffle it into line ***/ 
	/** the HHHH are all zeros, the LLL are goods ***/ 
 
	for(x=0;x<(len>>1);x++) { 
		line[x+x] = data[x]; 
	}	 
 
	for(x=len - 2;x>=0;x -= 2) { //** run backwards cuz of ND 
		if ( x > 0 ) E = line[x] - line[x - 2]; 
		else E = 0; 
		if ( (x+2)> 3; 
 
		line[x+1] = -pred; //** sign difference with encoder 
	} 
 
	for(x=0;x>1); 
		data[x+1] = a - D; 
	} 
 
} 
 
void sp_Transform2D(int **rows, int width, int height, int levels,bool inverse) 
{ 
int x, y, w, h, l; 
int *buffer,*tempbuf; 
 
    /* Check the dimensions for compatability. */ 
 
    if (width%(1 << (levels+1)) || height%(1 << (levels+1))) { 
		errputs("width and height must be divisible by 2^(levels+1)"); 
		exit(10); 
	} 
   
    /* Allocate a work array (for transposing columns) */ 
     
   	if ( (buffer = newarray(int,height+max(width,height))) == NULL ) { 
		errputs("malloc failed"); exit(10); 
	} 
	tempbuf = buffer+height; 
 
    /* do it */ 
   
	if ( !inverse ) { /* forward transform. */ 
 
		for (l = 0; l < levels; l++) { 
			w = width >> l; 
			h = height >> l; 
       
			/* Rows. */ 
	 
			for (y = 0; y < h; y++) { 
				do_tdec_line(rows[y],tempbuf,w); 
			} 
     
			/* Columns. */ 
	 
			for (x = 0; x < w; x++) { 
					for (y = 0; y < h; y++) buffer[y] = rows[y][x]; 
				do_tdec_line(buffer,tempbuf,h); 
					for (y = 0; y < h; y++) rows[y][x] = buffer[y]; 
			} 
		} 
 
    } else { 
 
		for (l = levels-1; l >= 0; l--) { /** backwards in scale **/ 
			w = width >> l; 
			h = height >> l; 
 
			/* Columns. */ 
	 
			for (x = 0; x < w; x++) { 
					for (y = 0; y < h; y++) buffer[y] = rows[y][x]; 
				un_tdec_line(buffer,tempbuf,h); 
					for (y = 0; y < h; y++) rows[y][x] = buffer[y]; 
			} 
 
			/* Rows. */ 
	 
			for (y = 0; y < h; y++) { 
				un_tdec_line(rows[y],tempbuf,w); 
			}     
		} 
	} 
 
	free(buffer); 
} 
 
 
void spQuad(int *band,int w,int h,int fullw,bool inverse) 
{ 
int x, y; 
int *buffer,*tempbuf,*bptr; 
 
   	if ( (buffer = newarray(int,h+max(w,h))) == NULL ) { 
		errputs("malloc failed"); exit(10); 
	} 
	tempbuf = buffer+h; 
   
	if ( !inverse ) { /* forward transform. */ 
	 
		bptr = band; 
		for (y = 0; y < h; y++) { 
			do_tdec_line(bptr,tempbuf,w); 
			bptr += fullw; 
		} 
     
		for (x = 0; x < w; x++) { 
			bptr = band + x; 
			for (y = 0; y < h; y++) { buffer[y] = *bptr; bptr += fullw; } 
			do_tdec_line(buffer,tempbuf,h); 
			bptr = band + x; 
			for (y = 0; y < h; y++) { *bptr = buffer[y]; bptr += fullw; } 
		} 
 
    } else { 
 
		for (x = 0; x < w; x++) { 
			bptr = band + x; 
			for (y = 0; y < h; y++) { buffer[y] = *bptr; bptr += fullw; } 
			un_tdec_line(buffer,tempbuf,h); 
			bptr = band + x; 
			for (y = 0; y < h; y++) { *bptr = buffer[y]; bptr += fullw; } 
		} 
 
		bptr = band; 
		for (y = 0; y < h; y++) { 
			un_tdec_line(bptr,tempbuf,w); 
			bptr += fullw; 
		} 
 
	} 
 
	free(buffer); 
}