isle-portable/LEGO1/legostream.cpp

#include "legostream.h"

#include <cstdio>
#include <string>

#include "mxvariabletable.h"

// This is a pointer to the end of the global variable name table, which has
// the text "END_OF_VARIABLES" in it.
// TODO: make s_endOfVariables reference the actual end of the variable array.
// GLOBAL OFFSET: LEGO1 0x100f3e50
const char *s_endOfVariables = "END_OF_VARIABLES";

// Very likely but not certain sizes.
// The classes are only used on the stack in functions we have not 100% matched
// yet, we can confirm the size once we have.
DECOMP_SIZE_ASSERT(LegoStream, 0x8);
DECOMP_SIZE_ASSERT(LegoFileStream, 0xC);
DECOMP_SIZE_ASSERT(LegoMemoryStream, 0x10);

// OFFSET: LEGO1 0x10045ae0
MxBool LegoStream::IsWriteMode()
{
  return m_mode == LEGOSTREAM_MODE_WRITE;
}

// OFFSET: LEGO1 0x10045af0
MxBool LegoStream::IsReadMode()
{
  return m_mode == LEGOSTREAM_MODE_READ;
}

// OFFSET: LEGO1 0x100991c0
LegoFileStream::LegoFileStream()
  : LegoStream()
{
  m_hFile = NULL;
}

// OFFSET: LEGO1 0x10099250
LegoFileStream::~LegoFileStream()
{
  if (m_hFile != NULL)
    fclose(m_hFile);
}

// OFFSET: LEGO1 0x100992c0
MxResult LegoFileStream::Read(void* p_buffer, MxU32 p_size)
{
  if (m_hFile == NULL)
    return FAILURE;

  return (fread(p_buffer, 1, p_size, m_hFile) == p_size) ? SUCCESS : FAILURE;
}

// OFFSET: LEGO1 0x10099300
MxResult LegoFileStream::Write(const void* p_buffer, MxU32 p_size)
{
  if (m_hFile == NULL)
    return FAILURE;

  return (fwrite(p_buffer, 1, p_size, m_hFile) == p_size) ? SUCCESS : FAILURE;
}

// OFFSET: LEGO1 0x10099340
MxResult LegoFileStream::Tell(MxU32* p_offset)
{
  if (m_hFile == NULL)
    return FAILURE;

  int got = ftell(m_hFile);
  if (got == -1)
    return FAILURE;

  *p_offset = got;
  return SUCCESS;
}

// OFFSET: LEGO1 0x10099370
MxResult LegoFileStream::Seek(MxU32 p_offset)
{
  if (m_hFile == NULL)
    return FAILURE;

  return (fseek(m_hFile, p_offset, 0) == 0) ? SUCCESS : FAILURE;
}

// OFFSET: LEGO1 0x100993a0
MxResult LegoFileStream::Open(const char* p_filename, OpenFlags p_mode)
{
  char modeString[4];

  if (m_hFile != NULL)
    fclose(m_hFile);
  
  modeString[0] = '\0';
  if (p_mode & ReadBit)
  {
    m_mode = LEGOSTREAM_MODE_READ;
    strcat(modeString, "r");
  }

  if (p_mode & WriteBit)
  {
    if (m_mode != LEGOSTREAM_MODE_READ)
      m_mode = LEGOSTREAM_MODE_WRITE;
    strcat(modeString, "w");
  }

  if ((p_mode & 4) != 0)
    strcat(modeString, "b");
  else
    strcat(modeString, "t");

  return (m_hFile = fopen(p_filename, modeString)) ? SUCCESS : FAILURE;
}

// OFFSET: LEGO1 0x10099080
LegoMemoryStream::LegoMemoryStream(char* p_buffer)
  : LegoStream()
{
  m_buffer = p_buffer;
  m_offset = 0;
}

// OFFSET: LEGO1 0x10099160
MxResult LegoMemoryStream::Read(void* p_buffer, MxU32 p_size)
{
  memcpy(p_buffer, m_buffer + m_offset, p_size);
  m_offset += p_size;
  return SUCCESS;
}

// OFFSET: LEGO1 0x10099190
MxResult LegoMemoryStream::Write(const void* p_buffer, MxU32 p_size)
{
  memcpy(m_buffer + m_offset, p_buffer, p_size);
  m_offset += p_size;
  return SUCCESS;
}

// OFFSET: LEGO1 0x100994a0
MxResult LegoMemoryStream::Tell(MxU32* p_offset)
{
  *p_offset = m_offset;
  return SUCCESS;
}

// OFFSET: LEGO1 0x100994b0
MxResult LegoMemoryStream::Seek(MxU32 p_offset)
{
  m_offset = p_offset;
  return SUCCESS;
}

// OFFSET: LEGO1 0x10039f70
MxResult LegoStream::WriteVariable(LegoStream* p_stream, MxVariableTable* p_from, const char* p_variableName)
{
  MxResult result = FAILURE;
  const char *variableValue = p_from->GetVariable(p_variableName);

  if (variableValue) {
    MxU8 length = strlen(p_variableName);
    if (p_stream->Write((char*)&length, 1) == SUCCESS) {
      if (p_stream->Write(p_variableName, length) == SUCCESS) {
        length = strlen(variableValue);
        if (p_stream->Write((char*)&length, 1) == SUCCESS)
          result = p_stream->Write((char *)variableValue, length);
      }
    }
  }
  return result;
}

// 95% match, just some instruction ordering differences on the call to
// MxVariableTable::SetVariable at the end.
// OFFSET: LEGO1 0x1003a080
MxS32 LegoStream::ReadVariable(LegoStream* p_stream, MxVariableTable* p_to)
{
  MxS32 result = 1;
  MxU8 length;

  if (p_stream->Read((char*)&length, 1) == SUCCESS) {
    char nameBuffer[256];
    if (p_stream->Read(nameBuffer, length) == SUCCESS) {
      nameBuffer[length] = '\0';
      if (strcmp(nameBuffer, s_endOfVariables) == 0)
        // 2 -> "This was the last entry, done reading."
        result = 2;
      else {
        if (p_stream->Read((char*)&length, 1) == SUCCESS) {
          char valueBuffer[256];
          if (p_stream->Read(valueBuffer, length) == SUCCESS) {
            result = 0;
            valueBuffer[length] = '\0';
            p_to->SetVariable(nameBuffer, valueBuffer);
          }
        }
      }
    }
  }
  return result;
}