#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "zlib.h"

#define MAX_IMAGE_SIZE 20000000

#define HEADER_BRANCH_INSTRUCTION 0xEA00003E
#define HEADER_IMAGE_ID ""
#define HEADER_PLATFORM_ID "nBk2"
#define HEADER_LOAD_OFFSET 0x00408000
#define HEADER_FLAGS 0x00010003
#define HEADER_TARGET_FILENAME "nBkProOs.img"
#define HEADER_IMAGE_NAME "NETBOOKPRO Linux26"
#define HEADER_IMAGE_VERSION "K123m"
#define HEADER_VALUE_AT_256 0x90a9a600


static unsigned cksum(const char * buf, int len)
{
	static unsigned const crctab[]={
		0x00000000,0x04C11DB7,0x09823B6E,0x0D4326D9,
		0x130476DC,0x17C56B6B,0x1A864DB2,0x1E475005,
		0x2608EDB8,0x22C9F00F,0x2F8AD6D6,0x2B4BCB61,
		0x350C9B64,0x31CD86D3,0x3C8EA00A,0x384FBDBD,
		0x4C11DB70,0x48D0C6C7,0x4593E01E,0x4152FDA9,
		0x5F15ADAC,0x5BD4B01B,0x569796C2,0x52568B75,
		0x6A1936C8,0x6ED82B7F,0x639B0DA6,0x675A1011,
		0x791D4014,0x7DDC5DA3,0x709F7B7A,0x745E66CD,
		0x9823B6E0,0x9CE2AB57,0x91A18D8E,0x95609039,
		0x8B27C03C,0x8FE6DD8B,0x82A5FB52,0x8664E6E5,
		0xBE2B5B58,0xBAEA46EF,0xB7A96036,0xB3687D81,
		0xAD2F2D84,0xA9EE3033,0xA4AD16EA,0xA06C0B5D,
		0xD4326D90,0xD0F37027,0xDDB056FE,0xD9714B49,
		0xC7361B4C,0xC3F706FB,0xCEB42022,0xCA753D95,
		0xF23A8028,0xF6FB9D9F,0xFBB8BB46,0xFF79A6F1,
		0xE13EF6F4,0xE5FFEB43,0xE8BCCD9A,0xEC7DD02D,
		0x34867077,0x30476DC0,0x3D044B19,0x39C556AE,
		0x278206AB,0x23431B1C,0x2E003DC5,0x2AC12072,
		0x128E9DCF,0x164F8078,0x1B0CA6A1,0x1FCDBB16,
		0x018AEB13,0x054BF6A4,0x0808D07D,0x0CC9CDCA,
		0x7897AB07,0x7C56B6B0,0x71159069,0x75D48DDE,
		0x6B93DDDB,0x6F52C06C,0x6211E6B5,0x66D0FB02,
		0x5E9F46BF,0x5A5E5B08,0x571D7DD1,0x53DC6066,
		0x4D9B3063,0x495A2DD4,0x44190B0D,0x40D816BA,
		0xACA5C697,0xA864DB20,0xA527FDF9,0xA1E6E04E,
		0xBFA1B04B,0xBB60ADFC,0xB6238B25,0xB2E29692,
		0x8AAD2B2F,0x8E6C3698,0x832F1041,0x87EE0DF6,
		0x99A95DF3,0x9D684044,0x902B669D,0x94EA7B2A,
		0xE0B41DE7,0xE4750050,0xE9362689,0xEDF73B3E,
		0xF3B06B3B,0xF771768C,0xFA325055,0xFEF34DE2,
		0xC6BCF05F,0xC27DEDE8,0xCF3ECB31,0xCBFFD686,
		0xD5B88683,0xD1799B34,0xDC3ABDED,0xD8FBA05A,
		0x690CE0EE,0x6DCDFD59,0x608EDB80,0x644FC637,
		0x7A089632,0x7EC98B85,0x738AAD5C,0x774BB0EB,
		0x4F040D56,0x4BC510E1,0x46863638,0x42472B8F,
		0x5C007B8A,0x58C1663D,0x558240E4,0x51435D53,
		0x251D3B9E,0x21DC2629,0x2C9F00F0,0x285E1D47,
		0x36194D42,0x32D850F5,0x3F9B762C,0x3B5A6B9B,
		0x0315D626,0x07D4CB91,0x0A97ED48,0x0E56F0FF,
		0x1011A0FA,0x14D0BD4D,0x19939B94,0x1D528623,
		0xF12F560E,0xF5EE4BB9,0xF8AD6D60,0xFC6C70D7,
		0xE22B20D2,0xE6EA3D65,0xEBA91BBC,0xEF68060B,
		0xD727BBB6,0xD3E6A601,0xDEA580D8,0xDA649D6F,
		0xC423CD6A,0xC0E2D0DD,0xCDA1F604,0xC960EBB3,
		0xBD3E8D7E,0xB9FF90C9,0xB4BCB610,0xB07DABA7,
		0xAE3AFBA2,0xAAFBE615,0xA7B8C0CC,0xA379DD7B,
		0x9B3660C6,0x9FF77D71,0x92B45BA8,0x9675461F,
		0x8832161A,0x8CF30BAD,0x81B02D74,0x857130C3,
		0x5D8A9099,0x594B8D2E,0x5408ABF7,0x50C9B640,
		0x4E8EE645,0x4A4FFBF2,0x470CDD2B,0x43CDC09C,
		0x7B827D21,0x7F436096,0x7200464F,0x76C15BF8,
		0x68860BFD,0x6C47164A,0x61043093,0x65C52D24,
		0x119B4BE9,0x155A565E,0x18197087,0x1CD86D30,
		0x029F3D35,0x065E2082,0x0B1D065B,0x0FDC1BEC,
		0x3793A651,0x3352BBE6,0x3E119D3F,0x3AD08088,
		0x2497D08D,0x2056CD3A,0x2D15EBE3,0x29D4F654,
		0xC5A92679,0xC1683BCE,0xCC2B1D17,0xC8EA00A0,
		0xD6AD50A5,0xD26C4D12,0xDF2F6BCB,0xDBEE767C,
		0xE3A1CBC1,0xE760D676,0xEA23F0AF,0xEEE2ED18,
		0xF0A5BD1D,0xF464A0AA,0xF9278673,0xFDE69BC4,
		0x89B8FD09,0x8D79E0BE,0x803AC667,0x84FBDBD0,
		0x9ABC8BD5,0x9E7D9662,0x933EB0BB,0x97FFAD0C,
		0xAFB010B1,0xAB710D06,0xA6322BDF,0xA2F33668,
		0xBCB4666D,0xB8757BDA,0xB5365D03,0xB1F740B4
	};
	unsigned crc;
	int i;

	for (crc=0,i=0; i<len; i++) {
		crc=(crc<<8)^crctab[((unsigned char)buf[i])^(crc>>24)];
	}
	for (; len; len>>=8) {
		crc=(crc<<8)^crctab[((unsigned char)len)^(crc>>24)];
	}
	return crc^0xFFFFFFFF;
}


static void store32(char * ptr, unsigned val)
{
	ptr[0]=(char)val;
	ptr[1]=(char)(val>>8);
	ptr[2]=(char)(val>>16);
	ptr[3]=(char)(val>>24);
}


int main(int argc, char * argv[])
{
	z_stream zs;
	char * buf, * buf2;
	int l,len,len2;


	buf=(char*)malloc(MAX_IMAGE_SIZE);
	for (len=0; !feof(stdin); len+=l) {
		if (len>=MAX_IMAGE_SIZE) {
			fprintf(stderr,"image too large\n");
			exit(1);
		}
		l=fread(buf+len,1,MAX_IMAGE_SIZE-len,stdin);
		if (l<=0) {
			if (ferror(stdin)) {
				fprintf(stderr,"failed to read stdin: %s\n",strerror(errno));
				exit(1);
			}
			break;
		}
	}

	buf2=(char*)malloc(MAX_IMAGE_SIZE);
	memset(&zs,0,sizeof(zs));
	if (deflateInit(&zs,Z_BEST_COMPRESSION)!=Z_OK) {
		fprintf(stderr,"deflateInit failed\n");
		exit(1);
	}
	zs.next_in=buf;
	zs.avail_in=len;
	zs.next_out=buf2;
	zs.avail_out=MAX_IMAGE_SIZE;
	if (deflate(&zs,Z_FINISH)!=Z_STREAM_END) {
		fprintf(stderr,"deflate failed\n");
		exit(1);
	}
	len2=MAX_IMAGE_SIZE-zs.avail_out;
	deflateEnd(&zs);

	if (len2+260>MAX_IMAGE_SIZE) {
		fprintf(stderr,"image too large\n");
		exit(1);
	}
	len=260+len2;
	memset(buf,0,260);
	memcpy(buf+260,buf2,len2);
	store32(buf+256,HEADER_VALUE_AT_256);
	store32(buf,HEADER_BRANCH_INSTRUCTION);
	strcpy(buf+8,HEADER_IMAGE_ID);
	strcpy(buf+12,HEADER_PLATFORM_ID);
	store32(buf+16,len-256);
	store32(buf+20,cksum(buf+256,len-256));
	store32(buf+24,HEADER_LOAD_OFFSET);
	store32(buf+28,HEADER_FLAGS);
	strcpy(buf+32,HEADER_TARGET_FILENAME);
	strcpy(buf+64,HEADER_IMAGE_NAME);
	strcpy(buf+128,HEADER_IMAGE_VERSION);
	store32(buf+252,cksum(buf,252));

	if (fwrite(buf,1,len,stdout)!=len) {
		fprintf(stderr,"failed to write stdout: %s\n",strerror(errno));
		exit(1);
	}

	return 0;
}
 