examples

#include "mycpp/gc_mylib.h"

#include <errno.h>

#include <stdio.h>

#include <unistd.h>  // isatty

#include "mycpp/gc_iolib.h"

namespace mylib {

void InitCppOnly() {

  // We don't seem need this now that we have ctx_FlushStdout().

  // setvbuf(stdout, 0, _IONBF, 0);

  // Arbitrary threshold of 50K objects based on eyeballing

  // benchmarks/osh-runtime 10K or 100K aren't too bad either.

  gHeap.Init(50000);

}

void print_stderr(BigStr* s) {

  fputs(s->data_, stderr);  // prints until first NUL

  fputc('\n', stderr);

}

#if 0

void writeln(BigStr* s, int fd) {

  // TODO: handle errors and write in a loop, like posix::write().  If possible,

  // use posix::write directly, but that introduces some dependency problems.

  if (write(fd, s->data_, len(s)) < 0) {

    assert(0);

  }

  if (write(fd, "\n", 1) < 0) {

    assert(0);

  }

}

#endif

BigStr* JoinBytes(List<int>* byte_list) {

  int n = len(byte_list);

  BigStr* result = NewStr(n);

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

    result->data_[i] = byte_list->at(i);

  }

  return result;

}

// For BashArray

void BigIntSort(List<mops::BigInt>* keys) {

  keys->sort();

}

class MutableStr : public BigStr {};

MutableStr* NewMutableStr(int n) {

  // In order for everything to work, MutableStr must be identical in layout to

  // BigStr. One easy way to achieve this is for MutableStr to have no members

  // and to inherit from BigStr.

  static_assert(sizeof(MutableStr) == sizeof(BigStr),

                "BigStr and MutableStr must have same size");

  return reinterpret_cast<MutableStr*>(NewStr(n));

}

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

  DCHECK(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

    BigStr* s1 = nullptr;

    BigStr* s2 = nullptr;

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

    s1 = NewStr(len1);

    s2 = NewStr(len2);

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

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

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

  } else {

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

  }

}

LineReader* gStdin;

LineReader* open(BigStr* path) {

  // TODO: Don't use C I/O; use POSIX I/O!

  FILE* f = fopen(path->data_, "r");

  if (f == nullptr) {

    throw Alloc<IOError>(errno);

  }

  return reinterpret_cast<LineReader*>(Alloc<CFile>(f));

}

BigStr* CFile::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_);

  // log("getline = %d", len);

  if (len < 0) {

    // Reset EOF flag so the next readline() will get a line.

    clearerr(f_);

    // man page says the buffer should be freed even if getline fails

    free(line);

    // Raise KeyboardInterrupt like mylib.Stdin().readline() does in Python!

    // This affects _PlainPromptInput() in frontend/reader.py.

    if (errno == EINTR && iolib::gSignalSafe->PollUntrappedSigInt()) {

      throw Alloc<KeyboardInterrupt>();

    }

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

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

      throw Alloc<IOError>(errno);

    }

    return kEmptyString;  // Indicate EOF with empty string, like Python

  }

  // Note: getline() NUL-terminates the buffer

  BigStr* result = ::StrFromC(line, len);

  free(line);

  return result;

}

bool CFile::isatty() {

  return ::isatty(fileno(f_));

}

// Problem: most BigStr 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.

BigStr* BufLineReader::readline() {

  BigStr* line = nullptr;

  int str_len = len(s_);

  if (pos_ == str_len) {

    return 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 - s_->data_;

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

    pos_ = new_pos + 1;

  } else {             // leftover line

    if (pos_ == 0) {   // The string has no newlines at all -- just return it

      pos_ = str_len;  // advance to the end

      return s_;

    } else {

      line_len = str_len - pos_;

      pos_ = str_len;  // advance to the end

    }

  }

  line = NewStr(line_len);

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

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

  return line;

}

Writer* gStdout;

Writer* gStderr;

//

// CFileWriter

//

void CFile::write(BigStr* s) {

  // Writes can be short!

  int n = len(s);

  int num_written = ::fwrite(s->data_, sizeof(char), n, f_);

  // Similar to CPython fileobject.c

  if (num_written != n) {

    throw Alloc<IOError>(errno);

  }

}

void CFile::flush() {

  if (::fflush(f_) != 0) {

    throw Alloc<IOError>(errno);

  }

}

void CFile::close() {

  if (::fclose(f_) != 0) {

    throw Alloc<IOError>(errno);

  }

}

//

// BufWriter

//

void BufWriter::EnsureMoreSpace(int n) {

  if (str_ == nullptr) {

    // TODO: we could make the default capacity big enough for a line, e.g. 128

    // capacity: 128 -> 256 -> 512

    str_ = NewMutableStr(n);

    return;

  }

  int current_cap = len(str_);

  DCHECK(current_cap >= len_);

  int new_cap = len_ + n;

  if (current_cap < new_cap) {

    auto* s = NewMutableStr(std::max(current_cap * 2, new_cap));

    memcpy(s->data_, str_->data_, len_);

    s->data_[len_] = '\0';

    str_ = s;

  }

}

uint8_t* BufWriter::LengthPointer() {

  // start + len

  return reinterpret_cast<uint8_t*>(str_->data_) + len_;

}

uint8_t* BufWriter::CapacityPointer() {

  // start + capacity

  return reinterpret_cast<uint8_t*>(str_->data_) + str_->len_;

}

void BufWriter::SetLengthFrom(uint8_t* length_ptr) {

  uint8_t* begin = reinterpret_cast<uint8_t*>(str_->data_);

  DCHECK(length_ptr >= begin);  // we should have written some data

  // Set the length, e.g. so we know where to resume writing from

  len_ = length_ptr - begin;

  // printf("SET LEN to %d\n", len_);

}

void BufWriter::Truncate(int length) {

  len_ = length;

}

void BufWriter::WriteRaw(char* s, int n) {

  DCHECK(is_valid_);  // Can't write() after getvalue()

  // write('') is a no-op, so don't create Buf if we don't need to

  if (n == 0) {

    return;

  }

  EnsureMoreSpace(n);

  // Append the contents to the buffer

  memcpy(str_->data_ + len_, s, n);

  len_ += n;

  str_->data_[len_] = '\0';

}

void BufWriter::WriteConst(const char* c_string) {

  // meant for short strings like '"'

  WriteRaw(const_cast<char*>(c_string), strlen(c_string));

}

void BufWriter::write(BigStr* s) {

  WriteRaw(s->data_, len(s));

}

void BufWriter::write_spaces(int n) {

  DCHECK(n >= 0);

  if (n == 0) {

    return;

  }

  EnsureMoreSpace(n);

  char* dest = str_->data_ + len_;

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

    dest[i] = ' ';

  }

  len_ += n;

  str_->data_[len_] = '\0';

}

BigStr* BufWriter::getvalue() {

  DCHECK(is_valid_);  // Check for two INVALID getvalue() in a row

  is_valid_ = false;

  if (str_ == nullptr) {  // if no write() methods are called, the result is ""

    return kEmptyString;

  } else {

    BigStr* s = str_;

    s->MaybeShrink(len_);

    str_ = nullptr;

    len_ = -1;

    return s;

  }

}

}  // namespace mylib