/*
THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
*/

/*
 *
 * Routines to do run length encoding/decoding
 * on bitmaps.
 *
 */


#ifdef HAVE_CONFIG_H
#include <conf.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "pstypes.h"
#include "u_mem.h"
#include "gr.h"
#include "grdef.h"
#include "error.h"
#include "rle.h"
#include "byteswap.h"

#define RLE_CODE        0xE0
#define NOT_RLE_CODE    31

#define IS_RLE_CODE(x) (((x) & RLE_CODE) == RLE_CODE)

#if !defined(NO_ASM) && defined(__WATCOMC__)
#define RLE_DECODE_ASM

ubyte *gr_rle_decode_asm( ubyte * src, ubyte * dest );
#pragma aux gr_rle_decode_asm parm [esi] [edi] value [edi] modify exact [eax ebx ecx edx esi edi] = \
"  cld              " \
"   xor ecx, ecx    " \
"   cld             " \
"   jmp NextByte    " \
"                   " \
"Unique:            " \
"   mov [edi],al    " \
"   inc edi         " \
"                   " \
"NextByte:          " \
"   mov al,[esi]    " \
"   inc esi         " \
"                   " \
"   mov ah, al      " \
"   and ah, 0xE0    " \
"  cmp  ah, 0xE0    " \
"   jne   Unique    " \
"                   " \
"   mov cl, al      " \
"   and cl, 31      " \
"   je      done    " \
"                   " \
"   mov al,[esi]    " \
"   inc esi         " \
"   mov ah, al      " \
"   shr ecx,1       " \
"   rep stosw       " \
"   jnc NextByte    " \
"   mov [edi],al    " \
"   inc edi         " \
"                   " \
"   jmp NextByte    " \
"                   " \
"done:              ";

#elif !defined(NO_ASM) && defined(__GNUC__)
#define RLE_DECODE_ASM

static inline int gr_rle_decode_asm( ubyte * src, ubyte * dest ) {
   register int __ret;
   int dummy;
   __asm__ __volatile__ (
"   cld;"
"   xorl %%ecx, %%ecx;"
"   jmp 1f;"
"0:;"
"   movb %%al,(%%edi);"
"   incl %%edi;"
"1:;"
"   movb (%%esi), %%al;"
"   incl %%esi;"
"   movb %%al, %%ah;"
"   andb $0xE0, %%ah;"
"   cmpb $0xE0, %%ah;"
"   jne 0b;"
"   movb %%al, %%cl;"
"   andb $31, %%cl;"
"   je 2f;"
"   movb (%%esi), %%al;"
"   incl %%esi;"
"   movb %%al, %%ah;"
"   shrl $1, %%ecx;"
"   rep; stosw;"
"   jnc 1b;"
"   movb %%al, (%%edi);"
"   incl %%edi;"
"   jmp 1b;"
"2:"
: "=D" (__ret), "=S" (dummy) : "1" (src), "D" (dest) : "%eax", "%ecx");
  return __ret;
}

#elif !defined(NO_ASM) && defined(_MSC_VER)
#define RLE_DECODE_ASM

__inline int gr_rle_decode_asm( ubyte * src, ubyte * dest )
{
	 int retval;
	__asm {
		mov esi,[src]
		mov edi,[dest]
        xor ecx, ecx
		cld
		jmp NextByte
Unique:
		mov [edi], al
		inc edi
NextByte:
		mov al,[esi]
		inc esi
		mov ah, al
		and ah,0xE0
		cmp ah,0xE0
		jne Unique

		mov cl, al
		and cl, 31
		je done

		mov al, [esi]
		inc esi
		mov ah, al
		shr ecx, 1
		rep stosw
		jnc NextByte
		mov [edi], al
		inc edi
		jmp NextByte
done:
		mov [retval],edi
	}
	return retval;
}

#endif

#ifdef RLE_DECODE_ASM

void gr_rle_decode( ubyte * src, ubyte * dest )
{
    gr_rle_decode_asm( src, dest );
}

#else // NO_ASM or unknown compiler

void gr_rle_decode( ubyte * src, ubyte * dest )
{
	int i;
	ubyte data, count = 0;

	while(1) {
		data = *src++;
		if ( ! IS_RLE_CODE(data) ) {
			*dest++ = data;
		} else {
			count = data & NOT_RLE_CODE;
			if (count == 0)
				return;
			data = *src++;
			for (i = 0; i < count; i++)
				*dest++ = data;
		}
	}
}

#endif

void rle_stosb (unsigned char *dest, int len, int color);

#if !defined(NO_ASM) && defined(__WATCOMC__)

#pragma aux rle_stosb = "cld rep    stosb" parm [edi] [ecx] [eax] modify exact [edi ecx];

#elif !defined(NO_ASM) && defined(__GNUC__)

inline void rle_stosb (unsigned char *dest, int len, int color) {
	int dummy[2];
   __asm__ __volatile__ (
    "cld; rep; stosb"
    : "=D" (dummy[0]), "=c" (dummy[1])
	: "0" (dest), "1" (len), "a" (color) );
}

#elif !defined(NO_ASM) && defined(_MSC_VER)

__inline void rle_stosb (unsigned char *dest, int len, int color)
{
  __asm {
	mov edi,[dest]
	mov ecx,[len]
	mov eax,[color]
	cld
	rep stosb
  }
}

#else // NO_ASM or unknown compiler

#define rle_stosb(_dest, _len, _color)	memset(_dest,_color,_len)
#endif

// Given pointer to start of one scanline of rle data, uncompress it to
// dest, from source pixels x1 to x2.
void gr_rle_expand_scanline_masked( ubyte *dest, ubyte *src, int x1, int x2  )
{
	int i = 0;
	ubyte count;
	ubyte color=0;

	if ( x2 < x1 ) return;

	count = 0;
	while ( i < x1 )	{
		color = *src++;
		if ( color == RLE_CODE ) return;
		if ( IS_RLE_CODE(color) )	{
			count = color & (~RLE_CODE);
			color = *src++;
		} else {
			// unique
			count = 1;
		}
		i += count;
	}
	count = i - x1;
	i = x1;
	// we know have '*count' pixels of 'color'.
	
	if ( x1+count > x2 )	{
		count = x2-x1+1;
		if ( color != TRANSPARENCY_COLOR )	rle_stosb( dest, count, color );
		return;
	}

	if ( color != TRANSPARENCY_COLOR )	rle_stosb( dest, count, color );
	dest += count;
	i += count;

	while( i <= x2 )
	{
		color = *src++;
		if ( color == RLE_CODE ) return;
		if ( IS_RLE_CODE(color) )	{
			count = color & (~RLE_CODE);
			color = *src++;
		} else {
			// unique
			count = 1;
		}
		// we know have '*count' pixels of 'color'.
		if ( i+count <= x2 )	{
			if ( color != 255 )rle_stosb( dest, count, color );
			i += count;
			dest += count;
		} else {
			count = x2-i+1;
			if ( color != 255 )rle_stosb( dest, count, color );
			i += count;
			dest += count;
		}
	}
}

void gr_rle_expand_scanline( ubyte *dest, ubyte *src, int x1, int x2  )
{
	int i = 0;
	ubyte count;
	ubyte color=0;

	if ( x2 < x1 ) return;

	count = 0;
	while ( i < x1 )	{
		color = *src++;
		if ( color == RLE_CODE ) return;
		if ( IS_RLE_CODE(color) )	{
			count = color & (~RLE_CODE);
			color = *src++;
		} else {
			// unique
			count = 1;
		}
		i += count;
	}
	count = i - x1;
	i = x1;
	// we know have '*count' pixels of 'color'.
	
	if ( x1+count > x2 )	{
		count = x2-x1+1;
		rle_stosb( dest, count, color );
		return;
	}

	rle_stosb( dest, count, color );
	dest += count;
	i += count;

	while( i <= x2 )		{
		color = *src++;
		if ( color == RLE_CODE ) return;
		if ( IS_RLE_CODE(color) )	{
			count = color & (~RLE_CODE);
			color = *src++;
		} else {
			// unique
			count = 1;
		}
		// we know have '*count' pixels of 'color'.
		if ( i+count <= x2 )	{
			rle_stosb( dest, count, color );
			i += count;
			dest += count;
		} else {
			count = x2-i+1;
			rle_stosb( dest, count, color );
			i += count;
			dest += count;
		}
	}
}


int gr_rle_encode( int org_size, ubyte *src, ubyte *dest )
{
	int i;
	ubyte c, oc;
	ubyte count;
	ubyte *dest_start;

	dest_start = dest;
	oc = *src++;
	count = 1;

	for (i=1; i<org_size; i++ )	{
		c = *src++;
		if ( c!=oc )	{
			if ( count )	{
				if ( (count==1) && (! IS_RLE_CODE(oc)) )	{
					*dest++ = oc;
					Assert( oc != RLE_CODE );
				} else {
					count |= RLE_CODE;
					*dest++ = count;
					*dest++ = oc;
				}
			}
			oc = c;
			count = 0;
		}
		count++;
		if ( count == NOT_RLE_CODE )	{
			count |= RLE_CODE;
			*dest++=count;
			*dest++=oc;
			count = 0;
		}
	}
	if (count)	{
		if ( (count==1) && (! IS_RLE_CODE(oc)) )	{
			*dest++ = oc;
			Assert( oc != RLE_CODE );
		} else {
			count |= RLE_CODE;
			*dest++ = count;
			*dest++ = oc;
		}
	}
	*dest++ = RLE_CODE;

	return dest-dest_start;
}


int gr_rle_getsize( int org_size, ubyte *src )
{
	int i;
	ubyte c, oc;
	ubyte count;
	int dest_size=0;

	oc = *src++;
	count = 1;

	for (i=1; i<org_size; i++ )	{
		c = *src++;
		if ( c!=oc )	{
			if ( count )	{
				if ( (count==1) && (! IS_RLE_CODE(oc)) )	{
					dest_size++;
				} else {
					dest_size++;
					dest_size++;
				}
			}
			oc = c;
			count = 0;
		}
		count++;
		if ( count == NOT_RLE_CODE )	{
			dest_size++;
			dest_size++;
			count = 0;
		}
	}
	if (count)	{
		if ( (count==1) && (! IS_RLE_CODE(oc)) )	{
			dest_size++;
		} else {
			dest_size++;
			dest_size++;
		}
	}
	dest_size++;

	return dest_size;
}

int gr_bitmap_rle_compress( grs_bitmap * bmp )
{
	int y, d1, d;
	int doffset;
	ubyte *rle_data;
	int large_rle = 0;

	// first must check to see if this is large bitmap.

	for (y=0; y<bmp->bm_h; y++ )	{
		d1= gr_rle_getsize( bmp->bm_w, &bmp->bm_data[bmp->bm_w*y] );
		if (d1 > 255) {
			large_rle = 1;
			break;
		}
	}

	rle_data=d_malloc( MAX_BMP_SIZE(bmp->bm_w, bmp->bm_h) );
	if (rle_data==NULL) return 0;
	if (!large_rle)
		doffset = 4 + bmp->bm_h;
	else
		doffset = 4 + (2 * bmp->bm_h);		// each row of rle'd bitmap has short instead of byte offset now

	for (y=0; y<bmp->bm_h; y++ )	{
		d1= gr_rle_getsize( bmp->bm_w, &bmp->bm_data[bmp->bm_w*y] );
		if ( ((doffset+d1) > bmp->bm_w*bmp->bm_h) || (d1 > (large_rle?32767:255) ) ) {
			d_free(rle_data);
			return 0;
		}
		d = gr_rle_encode( bmp->bm_w, &bmp->bm_data[bmp->bm_w*y], &rle_data[doffset] );
		Assert( d==d1 );
		doffset	+= d;
		if (large_rle)
			*((short *)&(rle_data[(y*2)+4])) = (short)d;
		else
			rle_data[y+4] = d;
	}
	memcpy( 	rle_data, &doffset, 4 );
	memcpy( 	bmp->bm_data, rle_data, doffset );
	d_free(rle_data);
	bmp->bm_flags |= BM_FLAG_RLE;
	if (large_rle)
		bmp->bm_flags |= BM_FLAG_RLE_BIG;
	return 1;
}

#define MAX_CACHE_BITMAPS 32

typedef struct rle_cache_element {
	grs_bitmap * rle_bitmap;
	ubyte * rle_data;
	grs_bitmap * expanded_bitmap;
	int last_used;
} rle_cache_element;

int rle_cache_initialized = 0;
int rle_counter = 0;
int rle_next = 0;
rle_cache_element rle_cache[MAX_CACHE_BITMAPS];

int rle_hits = 0;
int rle_misses = 0;

void rle_cache_close(void)
{
	if (rle_cache_initialized)	{
		int i;
		rle_cache_initialized = 0;
		for (i=0; i<MAX_CACHE_BITMAPS; i++ )	{
			gr_free_bitmap(rle_cache[i].expanded_bitmap);
		}
	}
}

void rle_cache_init()
{
	int i;
	for (i=0; i<MAX_CACHE_BITMAPS; i++ )	{
		rle_cache[i].rle_bitmap = NULL;
		rle_cache[i].expanded_bitmap = gr_create_bitmap( 64, 64 );
		rle_cache[i].last_used = 0;
		Assert( rle_cache[i].expanded_bitmap != NULL );
	}
	rle_cache_initialized = 1;
	atexit( rle_cache_close );
}

void rle_cache_flush()
{
	int i;
	for (i=0; i<MAX_CACHE_BITMAPS; i++ )	{
		rle_cache[i].rle_bitmap = NULL;
		rle_cache[i].last_used = 0;
	}
}

void rle_expand_texture_sub( grs_bitmap * bmp, grs_bitmap * rle_temp_bitmap_1 )
{
	unsigned char * dbits;
	unsigned char * sbits;
	int i;
#ifdef RLE_DECODE_ASM
	unsigned char * dbits1;
#endif

	sbits = &bmp->bm_data[4 + bmp->bm_h];
	dbits = rle_temp_bitmap_1->bm_data;

	rle_temp_bitmap_1->bm_flags = bmp->bm_flags & (~BM_FLAG_RLE);

	for (i=0; i < bmp->bm_h; i++ )    {
#ifdef RLE_DECODE_ASM
		dbits1=(unsigned char *)gr_rle_decode_asm( sbits, dbits );
#else
		gr_rle_decode( sbits, dbits );
#endif
		sbits += (int)bmp->bm_data[4+i];
		dbits += bmp->bm_w;
#ifdef RLE_DECODE_ASM
		Assert( dbits == dbits1 );		// Get John, bogus rle data!
#endif
	}
}


grs_bitmap * rle_expand_texture( grs_bitmap * bmp )
{
	int i;
	int lowest_count, lc;
	int least_recently_used;

	if (!rle_cache_initialized) rle_cache_init();

	Assert( !(bmp->bm_flags & BM_FLAG_PAGED_OUT) );

	lc = rle_counter;
	rle_counter++;
	if ( rle_counter < lc )	{
		for (i=0; i<MAX_CACHE_BITMAPS; i++ )	{
			rle_cache[i].rle_bitmap = NULL;
			rle_cache[i].last_used = 0;
		}
	}

	lowest_count = rle_cache[rle_next].last_used;
	least_recently_used = rle_next;
	rle_next++;
	if ( rle_next >= MAX_CACHE_BITMAPS )
		rle_next = 0;

	for (i=0; i<MAX_CACHE_BITMAPS; i++ )	{
		if (rle_cache[i].rle_bitmap == bmp) 	{
			rle_hits++;
			rle_cache[i].last_used = rle_counter;
			return rle_cache[i].expanded_bitmap;
		}
		if ( rle_cache[i].last_used < lowest_count )	{
			lowest_count = rle_cache[i].last_used;
			least_recently_used = i;
		}
	}

	Assert(bmp->bm_w<=64 && bmp->bm_h<=64); //dest buffer is 64x64
	rle_misses++;
	rle_expand_texture_sub( bmp, rle_cache[least_recently_used].expanded_bitmap );
	rle_cache[least_recently_used].rle_bitmap = bmp;
	rle_cache[least_recently_used].last_used = rle_counter;
	return rle_cache[least_recently_used].expanded_bitmap;
}


void gr_rle_expand_scanline_generic( grs_bitmap * dest, int dx, int dy, ubyte *src, int x1, int x2 )
{
	int i = 0, j;
	int count;
	ubyte color=0;

	if ( x2 < x1 ) return;

	count = 0;
	while ( i < x1 )	{
		color = *src++;
		if ( color == RLE_CODE ) return;
		if ( IS_RLE_CODE(color) )	{
			count = color & NOT_RLE_CODE;
			color = *src++;
		} else {
			// unique
			count = 1;
		}
		i += count;
	}
	count = i - x1;
	i = x1;
	// we know have '*count' pixels of 'color'.

	if ( x1+count > x2 )	{
		count = x2-x1+1;
		for ( j=0; j<count; j++ )
			gr_bm_pixel( dest, dx++, dy, color );
		return;
	}

	for ( j=0; j<count; j++ )
		gr_bm_pixel( dest, dx++, dy, color );
	i += count;

	while( i <= x2 )		{
		color = *src++;
		if ( color == RLE_CODE ) return;
		if ( IS_RLE_CODE(color) )	{
			count = color & NOT_RLE_CODE;
			color = *src++;
		} else {
			// unique
			count = 1;
		}
		// we know have '*count' pixels of 'color'.
		if ( i+count <= x2 )	{
			for ( j=0; j<count; j++ )
				gr_bm_pixel( dest, dx++, dy, color );
			i += count;
		} else {
			count = x2-i+1;
			for ( j=0; j<count; j++ )
				gr_bm_pixel( dest, dx++, dy, color );
			i += count;
		}
	}
}

void gr_rle_expand_scanline_generic_masked( grs_bitmap * dest, int dx, int dy, ubyte *src, int x1, int x2  )
{
	int i = 0, j;
	int count;
	ubyte color = 0;

	if ( x2 < x1 ) return;

	count = 0;
	while ( i < x1 )	{
		color = *src++;
		if ( color == RLE_CODE ) return;
		if ( IS_RLE_CODE(color) )	{
			count = color & NOT_RLE_CODE;
			color = *src++;
		} else {
			// unique
			count = 1;
		}
		i += count;
	}
	count = i - x1;
	i = x1;
	// we know have '*count' pixels of 'color'.

	if ( x1+count > x2 )	{
		count = x2-x1+1;
		if (color != TRANSPARENCY_COLOR) {
			for ( j=0; j<count; j++ )
				gr_bm_pixel( dest, dx++, dy, color );
		}
		return;
	}

	if ( color != TRANSPARENCY_COLOR ) {
		for ( j=0; j<count; j++ )
			gr_bm_pixel( dest, dx++, dy, color );
	} else
		dx += count;
	i += count;

	while( i <= x2 )		{
		color = *src++;
		if ( color == RLE_CODE ) return;
		if ( IS_RLE_CODE(color) )	{
			count = color & NOT_RLE_CODE;
			color = *src++;
		} else {
			// unique
			count = 1;
		}
		// we know have '*count' pixels of 'color'.
		if ( i+count <= x2 )	{
			if ( color != TRANSPARENCY_COLOR ) {
				for ( j=0; j<count; j++ )
					gr_bm_pixel( dest, dx++, dy, color );
			} else
				dx += count;
			i += count;
		} else {
			count = x2-i+1;
			if ( color != TRANSPARENCY_COLOR ) {
				for ( j=0; j<count; j++ )
					gr_bm_pixel( dest, dx++, dy, color );
			} else
				dx += count;
			i += count;
		}
	}
}

/*
 * swaps entries 0 and 255 in an RLE bitmap without uncompressing it
 */
void rle_swap_0_255(grs_bitmap *bmp)
{
	int i, j, len, rle_big;
	unsigned char *ptr, *ptr2, *temp, *start;
	unsigned short line_size;

	rle_big = bmp->bm_flags & BM_FLAG_RLE_BIG;

	temp = d_malloc( MAX_BMP_SIZE(bmp->bm_w, bmp->bm_h) );

	if (rle_big) {                  // set ptrs to first lines
		ptr = bmp->bm_data + 4 + 2 * bmp->bm_h;
		ptr2 = temp + 4 + 2 * bmp->bm_h;
	} else {
		ptr = bmp->bm_data + 4 + bmp->bm_h;
		ptr2 = temp + 4 + bmp->bm_h;
	}
	for (i = 0; i < bmp->bm_h; i++) {
		start = ptr2;
		if (rle_big)
			line_size = INTEL_SHORT(*((unsigned short *)&bmp->bm_data[4 + 2 * i]));
		else
			line_size = bmp->bm_data[4 + i];
		for (j = 0; j < line_size; j++) {
			if ( ! IS_RLE_CODE(ptr[j]) ) {
				if (ptr[j] == 0) {
					*ptr2++ = RLE_CODE | 1;
					*ptr2++ = 255;
				} else
					*ptr2++ = ptr[j];
			} else {
				*ptr2++ = ptr[j];
				if ((ptr[j] & NOT_RLE_CODE) == 0)
					break;
				j++;
				if (ptr[j] == 0)
					*ptr2++ = 255;
				else if (ptr[j] == 255)
					*ptr2++ = 0;
				else
					*ptr2++ = ptr[j];
			}
		}
		if (rle_big)                // set line size
			*((unsigned short *)&temp[4 + 2 * i]) = INTEL_SHORT(ptr2 - start);
		else
			temp[4 + i] = ptr2 - start;
		ptr += line_size;           // go to next line
	}
	len = ptr2 - temp;
	*((int *)temp) = len;           // set total size
	memcpy(bmp->bm_data, temp, len);
	d_free(temp);
}

/*
 * remaps all entries using colormap in an RLE bitmap without uncompressing it
 */
void rle_remap(grs_bitmap *bmp, ubyte *colormap)
{
	int i, j, len, rle_big;
	unsigned char *ptr, *ptr2, *temp, *start;
	unsigned short line_size;

	rle_big = bmp->bm_flags & BM_FLAG_RLE_BIG;

	temp = d_malloc( MAX_BMP_SIZE(bmp->bm_w, bmp->bm_h) + 30000 );

	if (rle_big) {                  // set ptrs to first lines
		ptr = bmp->bm_data + 4 + 2 * bmp->bm_h;
		ptr2 = temp + 4 + 2 * bmp->bm_h;
	} else {
		ptr = bmp->bm_data + 4 + bmp->bm_h;
		ptr2 = temp + 4 + bmp->bm_h;
	}
	for (i = 0; i < bmp->bm_h; i++) {
		start = ptr2;
		if (rle_big)
			line_size = INTEL_SHORT(*((unsigned short *)&bmp->bm_data[4 + 2 * i]));
		else
			line_size = bmp->bm_data[4 + i];
		for (j = 0; j < line_size; j++) {
			if ( ! IS_RLE_CODE(ptr[j])) {
				if (IS_RLE_CODE(colormap[ptr[j]])) 
					*ptr2++ = RLE_CODE | 1; // add "escape sequence"
				*ptr2++ = colormap[ptr[j]]; // translate
			} else {
				*ptr2++ = ptr[j]; // just copy current rle code
				if ((ptr[j] & NOT_RLE_CODE) == 0)
					break;
				j++;
				*ptr2++ = colormap[ptr[j]]; // translate
			}
		}
		if (rle_big)                // set line size
			*((unsigned short *)&temp[4 + 2 * i]) = INTEL_SHORT(ptr2 - start);
		else
			temp[4 + i] = ptr2 - start;
		ptr += line_size;           // go to next line
	}
	len = ptr2 - temp;
	*((int *)temp) = len;           // set total size
	memcpy(bmp->bm_data, temp, len);
	d_free(temp);
}