// emitcode.cc            see license.txt for copyright and terms of use
// code for emitcode.h

#include "emitcode.h"           // this module
#include "syserr.h"             // xsyserror
#include "SourceLocation.h"     // SourceLocation
using ellcc::SourceLocation;
#include "SourceManager.h"      // SourceManager
#include "trace.h"              // tracingSys
#include <string.h>             // memcpy

using namespace ellcc;

EmitCode::EmitCode(rostring f)
  : stringBuilder(),
    os(f.c_str()),
    fname(f),
    line(1)
{
  if (!os) {
    xsyserror("open", fname);
  }
}

EmitCode::~EmitCode()
{
  flush();
}


int EmitCode::getLine()
{
  flush();
  return line;
}


void EmitCode::flush()
{
  // count newlines
  char const *p = c_str();
  while (*p) {
    if (*p == '\n') {
      line++;
    }
    p++;
  }

  #if 0
    // this is the original code
    os << *this;
  #else
    // 2005-06-28: There is a bug in the cygwin implementation of
    // ofstream::operator<< that causes a stack overflow segfault
    // when writing strings longer than about 2MB.  So, I will
    // manually break up the string into little chunks to write it.

    // how long is the string?
    int len = p - c_str();

    enum { SZ = 0x1000 };       // write in 4k chunks
    p = c_str();

    while (len >= SZ) {
      char buf[SZ+1];
      memcpy(buf, p, SZ);
      buf[SZ] = 0;

      os << buf;

      p += SZ;
      len -= SZ;
    }

    os << p;
  #endif

  setlength(0);
}


char const *hashLine()
{                   
  if (tracingSys("nolines")) {
    // emit with comment to disable its effect
    return "// #line ";
  }
  else {
    return "#line "; 
  }
}


// note that #line must be preceeded by a newline
sm::string lineDirective(SourceLocation loc)
{
  SourceManager SM;
  PresumedLoc ploc = SM.getPresumedLoc(loc);
  return stringc << hashLine() << ploc.getLine() << " \"" << ploc.getFilename() << "\"\n";
}

stringBuilder &restoreLine(stringBuilder &sb)
{
  // little hack..
  EmitCode &os = (EmitCode&)sb;

  // +1 because we specify what line will be *next*
  int line = os.getLine()+1;
  return os << hashLine() << line
            << " \"" << os.getFname() << "\"\n";
}