/* inflate.c 
 * expands a Deflate (RFC 1951) stream */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include "ot.h"

#define PUSHBYTE(val) do { \
		is->bitbuf|=(val)<<is->bitbuf_len; \
		is->bitbuf_len+=8; /* we can only take 8-bit chars */ \
	} while(0)

#define READBITS(dest, n) do { \
	if(is->bitbuf_len < n) { \
		OT_WAIT_WHILE(&is->state, buflen<1); \
		PUSHBYTE(*p); \
		p++; buflen--; \
	} \
	(dest)=is->bitbuf&~((~0)<<n); \
	is->bitbuf>>=n; \
	is->bitbuf_len-=n; \
	} while(0)

struct inflate_state {
	char *name;
	unsigned bitbuf; /* big enough to hold a 15 bit value */
	int bitbuf_len;
	struct ot_state state;
	unsigned lit, dist, len; /* used in the dynamic huffman code section */
};

int inflate_init(struct inflate_state *is, const char *name) {
	is->name=strdup(name);
	is->bitbuf_len=0;
	OT_INITIALIZE(&is->state);
	return 1;
}

int inflate_update(struct inflate_state *is, void *buf, size_t buflen) {
	unsigned char *p=buf;
	unsigned x;
	OT_BEGIN(&is->state);

	READBITS(x, 1);
	fprintf(stderr, "Last block: %d\n", x);

	READBITS(x, 2);
	fprintf(stderr, "Type: %d\n", x);

	if(x==2) { /* dynamic huffman codes */
		READBITS(x, 5);
		is->lit=x+257; /* literal codes */
		printf("LiteralCodes: %u\n", is->lit);

		READBITS(x, 5);
		is->dist=x+1; /* dist codes */
		printf("DistCodes: %u\n", is->dist);

		READBITS(x, 4);
		is->len=4+x; /* len codes */
		printf("LenCodes: %u\n", is->len);
	} else {
		fprintf(stderr, "unknown type %d\n", x);
	}

	/* flush bitbuf */
	fprintf(stderr, "remaining: 0x%02x\n", is->bitbuf&~((~0)<<is->bitbuf_len));
	is->bitbuf_len=0;

	while(1) {
		OT_WAIT_WHILE(&is->state, buflen<=0);
		p++; buflen--;
	}
	
	OT_END(&is->state);
	return 1;
}

int inflate_final(struct inflate_state *is) {
	free(is->name);
	return 1;
}

#ifdef STAND_ALONE
int main(int argc, char **argv) {
	struct inflate_state is;
	char buf[64];
	int len;
	int total_len;

	total_len=0;
	inflate_init(&is, "stdin");
	while((len=fread(buf, 1, sizeof buf, stdin))>0) {
		total_len+=len;
		inflate_update(&is, buf, len);
	}
	if(len<0) perror("stdin");
	inflate_final(&is);
	fprintf(stderr, "%d bytes\n", total_len);
	return 0;
}
#endif

/* CRAP */
#if 0
	/* CMF */
	OT_WAIT_WHILE(&is->state, buflen<1);
	printf("CMF: %02x\n", *p);
	printf("\tCM: %u\n", *p&15);
	if((*p&15) == 8) {
		/* CINFO */
		printf("\tCINFO: %u\n", *p>>4);
	}
	p++; buflen--;
	/* FLG */
	OT_WAIT_WHILE(&is->state, buflen<1);
	printf("FLG: %02x\n", *p);
	p++; buflen--;

	while(1) {
		OT_WAIT_WHILE(&is->state, buflen<=0);
		p++; buflen--;
	}
#endif