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

#define BLOCKROWS 3

#define NEXT2(x) (((x) + 1) & -2) // uguale o successivo (pad)
#define NEXT4(x) (((x) + 3) & -4) // uguale o successivo multiplo di 4	(pad)
#define FIXDPI(x) ((x) / 65536.)  // fixedpt

typedef long psdByte;
typedef unsigned short psdUint16;
typedef long psdPixel;

enum { RAWDATA,
	   RLECOMP,
	   ZIPWITHOUTPREDICTION,
	   ZIPWITHPREDICTION };

struct TPSDChannelInfo {
	int id;						   // channel id
	int comptype;				   // channel's compression type
	psdPixel rows, cols, rowbytes; // computed by dochannel()
	// FIXME: need depth??
	psdByte length;			  // channel byte count in file
	psdByte filepos;		  // file offset of channel data (AFTER compression type)
	psdByte *rowpos;		  // row data file positions (RLE ONLY)
	unsigned char *unzipdata; // uncompressed data (ZIP ONLY)
};

int unpackrow(unsigned char *out, unsigned char *in, psdPixel outlen, psdPixel inlen);

void readrow(FILE *psd,
			 TPSDChannelInfo *chan,
			 psdPixel rowIndex,
			 unsigned char *inbuffer,
			 unsigned char *outbuffer);

void skipBlock(FILE *f);

void *mymalloc(long n);
unsigned read2UBytes(FILE *f);
int read2Bytes(FILE *f);
long read4Bytes(FILE *f);

int psdUnzipWithoutPrediction(unsigned char *src_buf, int src_len,
							  unsigned char *dst_buf, int dst_len);
int psdUnzipWithPrediction(unsigned char *src_buf, int src_len,
						   unsigned char *dst_buf, int dst_len,
						   int row_size, int color_depth);