samp-re/bitstream.c

/* vim: set filetype=c ts=8 noexpandtab: */

#include "common.h"
#include "bitstream.h"
#include "packet.h"
#include <stdio.h>

__declspec(naked)
void __stdcall BitStream__ctor(
	struct CBitStream *this,
	char *buffer,
	int lengthInBytes,
	char copyData)
{
	_asm {
		pop eax
		pop ecx
		push eax
		mov eax, 0x44D930
		jmp eax
	}
}

__declspec(naked)
void __stdcall BitStream__dtor(struct CBitStream *this)
{
	_asm {
		pop eax
		pop ecx
		push eax
		mov eax, 0x44D9B0
		jmp eax
	}
}

__declspec(naked)
int __stdcall BitStream__Read(struct CBitStream *this, char *out)
{
	_asm {
		pop eax
		pop ecx
		push eax
		mov eax, 0x44D840
		jmp eax
	}
}

int __stdcall Hooked_BitStream__ReadCompressed(
	char *out,
	unsigned char a,
	unsigned char unsignedData)
{
	struct CBitStream *this;
	unsigned char tmpa, tmpread;
	int myReadOffset;

	_asm mov this, ecx

	tmpa = (a >> 3) - 1;
	if (unsignedData) {
		unsignedData = 0;
		a = 0;
	} else {
		unsignedData = 0xFF;
		a = 0xF0;
	}

	while (tmpa > 0) {
		myReadOffset = this->readOffset + 1;
		if (myReadOffset > this->numberOfBitsUsed) {
			return 0;
		}
		if ((0x80 >> this->readOffset) == this->ptrData[myReadOffset]) {
			this->readOffset = myReadOffset;
			return (int) thiscall3(
				(void*) 0x44DA70, this, (int) out, tmpa, 1);
		}

		this->readOffset = myReadOffset;
		out[tmpa] = unsignedData;
		tmpa--;
	}

	if (this->readOffset + 1 > this->numberOfBitsUsed) {
		return 0;
	}

	if (!thiscall1((void*) 0x44D840, this, (int) &tmpread)) { /*readBit*/
		return 0;
	}

	out += 0; /*? esi + ebx but esi should be always 0?*/
	if (tmpread) {
		if (!thiscall3((void*) 0x44DA70, this, (int) out, 4, 1)) {
			return 0;
		}
		*out |= a;
	} else {
		if (!thiscall3((void*) 0x44DA70, this, (int) out, 8, 1)) {
			return 0;
		}
	}
	return 1;
}