cpp

// mylib2.cc

#include "mylib2.h"

#include <errno.h>

#include <unistd.h>  // isatty

#include "my_runtime.h"  // kIntBufSize

using gc_heap::gHeap;

using gc_heap::kStrHeaderSize;

using gc_heap::StackRoots;

mylib::BufWriter gBuf;

namespace mylib {

Tuple2<Str*, Str*> split_once(Str* s, Str* delim) {

  StackRoots _roots({&s, &delim});

  assert(len(delim) == 1);

  const char* start = s->data_;  // note: this pointer may move

  char c = delim->data_[0];

  int length = len(s);

  const char* p = static_cast<const char*>(memchr(start, c, length));

  if (p) {

    int len1 = p - start;

    int len2 = length - len1 - 1;  // -1 for delim

    Str* s1 = nullptr;

    Str* s2 = nullptr;

    StackRoots _roots({&s1, &s2});

    // Allocate together to avoid 's' moving in between

    s1 = AllocStr(len1);

    s2 = AllocStr(len2);

    memcpy(s1->data_, s->data_, len1);

    memcpy(s2->data_, s->data_ + len1 + 1, len2);

    return Tuple2<Str*, Str*>(s1, s2);

  } else {

    return Tuple2<Str*, Str*>(s, nullptr);

  }

}

LineReader* gStdin;

Str* CFileLineReader::readline() {

  char* line = nullptr;

  size_t allocated_size = 0;  // unused

  // Reset errno because we turn the EOF error into empty string (like Python).

  errno = 0;

  ssize_t len = getline(&line, &allocated_size, f_);

  if (len < 0) {

    if (errno != 0) {  // Unexpected error

      log("getline() error: %s", strerror(errno));

      throw new AssertionError(errno);

    }

    // Expected EOF

    return gc_heap::kEmptyString;

  }

  // TODO: Fix the leak here.

  // Note: getline() NUL terminates the buffer

  return CopyStr(line, len);

}

// Problem: most Str methods like index() and slice() COPY so they have a

// NUL terminator.

// log("%s") falls back on sprintf, so it expects a NUL terminator.

// It would be easier for us to just share.

Str* BufLineReader::readline() {

  auto self = this;

  Str* line = nullptr;

  StackRoots _roots({&self, &line});

  int buf_len = len(s_);

  if (pos_ == buf_len) {

    return gc_heap::kEmptyString;

  }

  int orig_pos = pos_;

  const char* p = strchr(s_->data_ + pos_, '\n');

  // log("pos_ = %s", pos_);

  int line_len;

  if (p) {

    int new_pos = p - self->s_->data_;

    line_len = new_pos - pos_ + 1;  // past newline char

    pos_ = new_pos + 1;

  } else {  // leftover line

    line_len = buf_len - pos_;

    pos_ = buf_len;

  }

  line = AllocStr(line_len);

  memcpy(line->data_, self->s_->data_ + orig_pos, line_len);

  assert(line->data_[line_len] == '\0');

  return line;

}

Writer* gStdout;

Writer* gStderr;

void BufWriter::write(Str* s) {

  int orig_len = len_;

  int n = len(s);

  len_ += n;

  // BUG: This is quadratic!

  // TODO:

  //

  // - add capacity_, and double it?  start at 32 bytes -> 64 -> 128

  //   - only realloc by doublings?

  // - or change this to append to a list?  and then getvalue() does a join()

  // on it?

  // - DEALLOCATE.  mylib2 doesn't leak!

  // data_ is nullptr at first

  data_ = static_cast<char*>(realloc(data_, len_ + 1));

  // Append to the end

  memcpy(data_ + orig_len, s->data_, n);

  data_[len_] = '\0';

}

void BufWriter::write_const(const char* s, int len) {

  int orig_len = len_;

  len_ += len;

  // data_ is nullptr at first

  data_ = static_cast<char*>(realloc(data_, len_ + 1));

  // Append to the end

  memcpy(data_ + orig_len, s, len);

  data_[len_] = '\0';

}

void BufWriter::format_s(Str* s) {

  this->write(s);

}

void BufWriter::format_d(int i) {

  // extend to the maximum size

  data_ = static_cast<char*>(realloc(data_, len_ + kIntBufSize));

  int len = snprintf(data_ + len_, kIntBufSize, "%d", i);

  // but record only the number of bytes written

  len_ += len;

}

// repr() calls this too

//

// TODO: This could be replaced with QSN?  The upper bound is greater there

// because of \u{}.

void BufWriter::format_r(Str* s) {

  // Worst case: \0 becomes 4 bytes as '\\x00', and then two quote bytes.

  int n = len(s);

  int upper_bound = n * 4 + 2;

  // Extend the buffer

  data_ = static_cast<char*>(realloc(data_, len_ + upper_bound + 1));

  char quote = '\'';

  if (memchr(s->data_, '\'', n) && !memchr(s->data_, '"', n)) {

    quote = '"';

  }

  char* p = data_ + len_;  // end of valid data

  // From PyString_Repr()

  *p++ = quote;

  for (int i = 0; i < n; ++i) {

    char c = s->data_[i];

    if (c == quote || c == '\\') {

      *p++ = '\\';

      *p++ = c;

    } else if (c == '\t') {

      *p++ = '\\';

      *p++ = 't';

    } else if (c == '\n') {

      *p++ = '\\';

      *p++ = 'n';

    } else if (c == '\r') {

      *p++ = '\\';

      *p++ = 'r';

    } else if (c < ' ' || c >= 0x7f) {

      sprintf(p, "\\x%02x", c & 0xff);

      p += 4;

    } else {

      *p++ = c;

    }

  }

  *p++ = quote;

  *p = '\0';

  len_ = p - data_;

  // Shrink the buffer.  This is valid usage and GNU libc says it can actually

  // release.

  data_ = static_cast<char*>(realloc(data_, len_ + 1));

}

void CFileWriter::write(Str* s) {

  // note: throwing away the return value

  fwrite(s->data_, sizeof(char), len(s), f_);

}

void CFileWriter::flush() {

  ::fflush(f_);

}

bool CFileWriter::isatty() {

  return ::isatty(fileno(f_));

}

}  // namespace mylib