Class: StringIO

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, Enumerable, `::IO::generic_readable`, `::IO::generic_writable`
Inherits:	Object
Defined in:	ext/stringio/stringio.c

Overview

IO streams for strings, with access similar to IO; see IO.

About the Examples

Examples on this page assume that StringIO has been required:

require 'stringio'

Constant Summary

MAX_LENGTH =

Maximum length that a StringIO instance can hold

# File 'ext/stringio/stringio.c', line 1914
```
LONG2NUM(LONG_MAX)
```
VERSION =

The version string

# File 'ext/stringio/stringio.c', line 1908
```
rb_str_new_cstr(STRINGIO_VERSION)
```

Class Method Summary

.open(string = '', mode = 'r+') {|strio| ... }

Note that mode defaults to 'r' if #string is frozen.
.new(*args) constructor Internal use only

Instance Attribute Summary

#closed? ⇒ Boolean readonly

Returns true if self is closed for both reading and writing, false otherwise.
#closed_read? ⇒ Boolean readonly

Returns true if self is closed for reading, false otherwise.
#closed_write? ⇒ Boolean readonly

Returns true if self is closed for writing, false otherwise.
#eof? ⇒ Boolean (also: #eof?) readonly

Returns true if positioned at end-of-stream, false otherwise; see Position.
#eof? ⇒ Boolean readonly

Alias for #eof.
#lineno ⇒ current_line_number rw

Returns the current line number in self; see Line Number.
#lineno=(new_line_number) ⇒ new_line_number rw

Sets the current line number in self to the given new_line_number; see Line Number.
#pos ⇒ stream_position rw

Returns the current position (in bytes); see Position.
#pos=(new_position) ⇒ new_position rw

Sets the current position (in bytes); see Position.
#string ⇒ String rw

Returns underlying string:
#string=(other_string) ⇒ other_string rw

Assigns the underlying string as other_string, and sets position to zero; returns other_string:
#tty? ⇒ Boolean readonly

Instance Method Summary

#binmode ⇒ self

Sets the data mode in self to binary mode; see Data Mode.
#close ⇒ nil

Closes self for both reading and writing.
#close_read ⇒ nil

Closes self for reading; closed-write setting remains unchanged.
#close_write ⇒ nil

Closes self for writing; closed-read setting remains unchanged.
#each_line(sep = $/, chomp: false) {|line| ... } ⇒ self (also: #each_line)

Calls the block with each remaining line read from the stream; does nothing if already at end-of-file; returns self.
#each_byte {|byte| ... } ⇒ self

With a block given, calls the block with each remaining byte in the stream; see Byte IO.
#each_char {|c| ... } ⇒ self

With a block given, calls the block with each remaining character in the stream; see Character IO.
#each_codepoint {|codepoint| ... } ⇒ self

With a block given, calls the block with each remaining codepoint in the stream; see Codepoint IO.
#each_line(sep = $/, chomp: false) {|line| ... } ⇒ self

Alias for #each.
#external_encoding ⇒ Encoding

Returns the Encoding object that represents the encoding of the file.
#fcntl
#fileno
#flush
#fsync
#getbyte ⇒ byte^?

Reads and returns the next 8-bit byte from the stream; see Byte IO.
#getc ⇒ character^?

Reads and returns the next character from the stream; see Character IO.
#gets(sep = $/, chomp: false) ⇒ String^?

Reads and returns a line from the stream; assigns the return value to $_; see Line IO.
#new(string = '', mode = 'r+') ⇒ StringIO constructor

Note that mode defaults to 'r' if #string is frozen.
#internal_encoding ⇒ Encoding

Returns the Encoding of the internal string if conversion is specified.
#isatty
#length ⇒ Integer (also: #size)

Returns the size of the buffer string.
#pid
#pread(maxlen, offset) ⇒ String

See IO#pread.
#putc(obj) ⇒ Object

See IO#putc.
#read([length [, outbuf]]) ⇒ String, ...

See IO#read.
#readlines(sep = $/, chomp: false) ⇒ Array

See IO#readlines.
#reopen(other, mode = 'r+') ⇒ self

Reinitializes the stream with the given other (string or StringIO) and mode; see IO.new:
#rewind ⇒ 0

Sets the current position and line number to zero; see Position and Line Number.
#seek(offset, whence = SEEK_SET) ⇒ 0

Sets the current position to the given integer offset (in bytes), with respect to a given constant whence; see Position.
#set_encoding(ext_enc, [int_enc[, opt]]) ⇒ strio

Specify the encoding of the StringIO as ext_enc.
#set_encoding_by_bom ⇒ strio^?

Sets the encoding according to the BOM (Byte Order Mark) in the string.
#size ⇒ Integer

Alias for #length.
#sync ⇒ true

Returns true; implemented only for compatibility with other stream classes.
#sync=
#tell
#truncate(integer) ⇒ 0

Truncates the buffer string to at most integer bytes.
#ungetbyte(byte) ⇒ nil

Pushes back (“unshifts”) an 8-bit byte onto the stream; see Byte IO.
#ungetc(character) ⇒ nil

Pushes back (“unshifts”) a character or integer onto the stream; see Character IO.
#write(string, ...) ⇒ Integer

Appends the given string to the underlying buffer string.
#initialize_copy(orig) Internal use only

`::IO::generic_readable` - Included

#read_nonblock	Similar to #read, but raises `EOFError` at end of string unless the `exception: false` option is passed in.
#readbyte	Like #getbyte, but raises an exception if already at end-of-stream; see Byte IO.
#readchar	Like #getc, but raises an exception if already at end-of-stream; see Character IO.
#readline	Reads a line as with `IO#gets`, but raises EOFError if already at end-of-file; see Line IO.
#readpartial	Alias for IO::generic_readable#sysread.
#sysread	Similar to #read, but raises `EOFError` at end of string instead of returning `nil`, as well as `IO#sysread` does.

`::IO::generic_writable` - Included

#<<, #print, #printf, #puts, #syswrite,
#write_nonblock	See `IO#write_nonblock`

Constructor Details

.new(*args)

This method is for internal use only.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 369


static VALUE
strio_s_new(int argc, VALUE *argv, VALUE klass)
{
    if (rb_block_given_p()) {
	VALUE cname = rb_obj_as_string(klass);

	rb_warn("%"PRIsVALUE"::new() does not take block; use %"PRIsVALUE"::open() instead",
		cname, cname);
    }
    return rb_class_new_instance_kw(argc, argv, klass, RB_PASS_CALLED_KEYWORDS);
}

#new(string = '', mode = 'r+') ⇒ `StringIO`

Note that mode defaults to 'r' if #string is frozen.

Returns a new StringIO instance formed from #string and mode; see Access Modes:

strio = StringIO.new # => #<StringIO>
strio.close

The instance should be closed when no longer needed.

Related: .open (accepts block; closes automatically).

[ GitHub ]

# File 'ext/stringio/stringio.c', line 207


static VALUE
strio_initialize(int argc, VALUE *argv, VALUE self)
{
    struct StringIO *ptr = check_strio(self);

    if (!ptr) {
	DATA_PTR(self) = ptr = strio_alloc();
    }
    rb_call_super(0, 0);
    return strio_init(argc, argv, ptr, self);
}

Class Method Details

.open(string = '', mode = 'r+') {|strio| ... }

Note that mode defaults to 'r' if #string is frozen.

Creates a new StringIO instance formed from #string and mode; see Access Modes.

With no block, returns the new instance:

strio = StringIO.open # => #<StringIO>

With a block, calls the block with the new instance and returns the block’s value; closes the instance on block exit.

StringIO.open {|strio| p strio }
# => #<StringIO>

Related: .new.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 360


static VALUE
strio_s_open(int argc, VALUE *argv, VALUE klass)
{
    VALUE obj = rb_class_new_instance_kw(argc, argv, klass, RB_PASS_CALLED_KEYWORDS);
    if (!rb_block_given_p()) return obj;
    return rb_ensure(rb_yield, obj, strio_finalize, obj);
}

Instance Attribute Details

#closed? ⇒ `Boolean` (readonly)

Returns true if self is closed for both reading and writing, false otherwise.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 570


static VALUE
strio_closed(VALUE self)
{
    StringIO(self);
    if (!CLOSED(self)) return Qfalse;
    return Qtrue;
}

#closed_read? ⇒ `Boolean` (readonly)

Returns true if self is closed for reading, false otherwise.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 584


static VALUE
strio_closed_read(VALUE self)
{
    StringIO(self);
    if (READABLE(self)) return Qfalse;
    return Qtrue;
}

#closed_write? ⇒ `Boolean` (readonly)

Returns true if self is closed for writing, false otherwise.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 598


static VALUE
strio_closed_write(VALUE self)
{
    StringIO(self);
    if (WRITABLE(self)) return Qfalse;
    return Qtrue;
}

#eof? ⇒ `Boolean` (readonly) Also known as: #eof?

Returns true if positioned at end-of-stream, false otherwise; see Position.

Raises IOError if the stream is not opened for reading.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 624


static VALUE
strio_eof(VALUE self)
{
    if (strio_to_read(self)) return Qfalse;
    return Qtrue;
}

#eof? ⇒ `Boolean` (readonly) #eof? ⇒ `Boolean`

Alias for #eof.

#lineno ⇒ `current_line_number` (rw)

Returns the current line number in self; see Line Number.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 661


static VALUE
strio_get_lineno(VALUE self)
{
    return LONG2NUM(StringIO(self)->lineno);
}

#lineno=(new_line_number) ⇒ `new_line_number` (rw)

Sets the current line number in self to the given new_line_number; see Line Number.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 674


static VALUE
strio_set_lineno(VALUE self, VALUE lineno)
{
    StringIO(self)->lineno = NUM2LONG(lineno);
    return lineno;
}

#pos ⇒ `stream_position` (rw)

Returns the current position (in bytes); see Position.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 749


static VALUE
strio_get_pos(VALUE self)
{
    return LONG2NUM(StringIO(self)->pos);
}

#pos=(new_position) ⇒ `new_position` (rw)

Sets the current position (in bytes); see Position.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 762


static VALUE
strio_set_pos(VALUE self, VALUE pos)
{
    struct StringIO *ptr = StringIO(self);
    long p = NUM2LONG(pos);
    if (p < 0) {
	error_inval(0);
    }
    ptr->pos = p;
    return pos;
}

#string ⇒ `String` (rw)

Returns underlying string:

StringIO.open('foo') do |strio|
  p strio.string
  strio.string = 'bar'
  p strio.string
end

Output:

"foo"
"bar"

Related: #string= (assigns the underlying string).

[ GitHub ]

# File 'ext/stringio/stringio.c', line 462


static VALUE
strio_get_string(VALUE self)
{
    return StringIO(self)->string;
}

#string=(other_string) ⇒ `other_string` (rw)

Assigns the underlying string as other_string, and sets position to zero; returns other_string:

StringIO.open('foo') do |strio|
  p strio.string
  strio.string = 'bar'
  p strio.string
end

Output:

"foo"
"bar"

Related: #string (returns the underlying string).

[ GitHub ]

# File 'ext/stringio/stringio.c', line 488


static VALUE
strio_set_string(VALUE self, VALUE string)
{
    struct StringIO *ptr = StringIO(self);

    rb_io_taint_check(self);
    ptr->flags &= ~FMODE_READWRITE;
    StringValue(string);
    ptr->flags = readonly_string_p(string) ? FMODE_READABLE : FMODE_READWRITE;
    ptr->pos = 0;
    ptr->lineno = 0;
    RB_OBJ_WRITE(self, &ptr->string, string);
    return string;
}

#tty? ⇒ `Boolean` (readonly)

[ GitHub ]

Instance Method Details

#binmode ⇒ `self`

Sets the data mode in self to binary mode; see Data Mode.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 689


static VALUE
strio_binmode(VALUE self)
{
    struct StringIO *ptr = StringIO(self);
    rb_encoding *enc = rb_ascii8bit_encoding();

    ptr->enc = enc;
    if (WRITABLE(self)) {
	rb_enc_associate(ptr->string, enc);
    }
    return self;
}

#close ⇒ `nil`

Closes self for both reading and writing.

Raises IOError if reading or writing is attempted.

Related: #close_read, #close_write.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 513


static VALUE
strio_close(VALUE self)
{
    StringIO(self);
    RBASIC(self)->flags &= ~STRIO_READWRITE;
    return Qnil;
}

#close_read ⇒ `nil`

Closes self for reading; closed-write setting remains unchanged.

Raises IOError if reading is attempted.

Related: #close, #close_write.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 531


static VALUE
strio_close_read(VALUE self)
{
    struct StringIO *ptr = StringIO(self);
    if (!(ptr->flags & FMODE_READABLE)) {
	rb_raise(rb_eIOError, "closing non-duplex IO for reading");
    }
    RBASIC(self)->flags &= ~STRIO_READABLE;
    return Qnil;
}

#close_write ⇒ `nil`

Closes self for writing; closed-read setting remains unchanged.

Raises IOError if writing is attempted.

Related: #close, #close_read.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 552


static VALUE
strio_close_write(VALUE self)
{
    struct StringIO *ptr = StringIO(self);
    if (!(ptr->flags & FMODE_WRITABLE)) {
	rb_raise(rb_eIOError, "closing non-duplex IO for writing");
    }
    RBASIC(self)->flags &= ~STRIO_WRITABLE;
    return Qnil;
}

#each_line(sep = $/, chomp: false) {|line| ... } ⇒ `self` #each_line(limit, chomp: false) {|line| ... } ⇒ `self` #each_line(sep, limit, chomp: false) {|line| ... } ⇒ `self`
Also known as: #each_line

Calls the block with each remaining line read from the stream; does nothing if already at end-of-file; returns self. See Line IO.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1388


static VALUE
strio_each(int argc, VALUE *argv, VALUE self)
{
    VALUE line;
    struct StringIO *ptr = readable(self);
    struct getline_arg arg;

    RETURN_ENUMERATOR(self, argc, argv);

    if (prepare_getline_args(ptr, &arg, argc, argv)->limit == 0) {
	rb_raise(rb_eArgError, "invalid limit: 0 for each_line");
    }

    while (!NIL_P(line = strio_getline(&arg, ptr))) {
	rb_yield(line);
    }
    return self;
}

#each_byte {|byte| ... } ⇒ `self`

With a block given, calls the block with each remaining byte in the stream; see Byte IO.

With no block given, returns an enumerator.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 857


static VALUE
strio_each_byte(VALUE self)
{
    struct StringIO *ptr;

    RETURN_ENUMERATOR(self, 0, 0);

    while ((ptr = strio_to_read(self)) != NULL) {
	char c = RSTRING_PTR(ptr->string)[ptr->pos++];
	rb_yield(CHR2FIX(c));
    }
    return self;
}

#each_char {|c| ... } ⇒ `self`

With a block given, calls the block with each remaining character in the stream; see Character IO.

With no block given, returns an enumerator.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1085


static VALUE
strio_each_char(VALUE self)
{
    VALUE c;

    RETURN_ENUMERATOR(self, 0, 0);

    while (!NIL_P(c = strio_getc(self))) {
	rb_yield(c);
    }
    return self;
}

#each_codepoint {|codepoint| ... } ⇒ `self`

With a block given, calls the block with each remaining codepoint in the stream; see Codepoint IO.

With no block given, returns an enumerator.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1107


static VALUE
strio_each_codepoint(VALUE self)
{
    struct StringIO *ptr;
    rb_encoding *enc;
    unsigned int c;
    int n;

    RETURN_ENUMERATOR(self, 0, 0);

    ptr = readable(self);
    enc = get_enc(ptr);
    while ((ptr = strio_to_read(self)) != NULL) {
	c = rb_enc_codepoint_len(RSTRING_PTR(ptr->string)+ptr->pos,
				 RSTRING_END(ptr->string), &n, enc);
	ptr->pos += n;
	rb_yield(UINT2NUM(c));
    }
    return self;
}

#each_line(sep = $/, chomp: false) {|line| ... } ⇒ `self` #each_line(limit, chomp: false) {|line| ... } ⇒ `self` #each_line(sep, limit, chomp: false) {|line| ... } ⇒ `self`

Alias for #each.

#external_encoding ⇒ `Encoding`

Returns the Encoding object that represents the encoding of the file. If the stream is write mode and no encoding is specified, returns nil.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1805


static VALUE
strio_external_encoding(VALUE self)
{
    struct StringIO *ptr = StringIO(self);
    return rb_enc_from_encoding(get_enc(ptr));
}

#fcntl

[ GitHub ]

#fileno

[ GitHub ]

#flush

[ GitHub ]

#fsync

[ GitHub ]

#getbyte ⇒ `byte`^?

Reads and returns the next 8-bit byte from the stream; see Byte IO.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 904


static VALUE
strio_getbyte(VALUE self)
{
    struct StringIO *ptr = readable(self);
    int c;
    if (NIL_P(ptr->string) || ptr->pos >= RSTRING_LEN(ptr->string)) {
	return Qnil;
    }
    c = RSTRING_PTR(ptr->string)[ptr->pos++];
    return CHR2FIX(c);
}

#getc ⇒ `character`^?

Reads and returns the next character from the stream; see Character IO.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 878


static VALUE
strio_getc(VALUE self)
{
    struct StringIO *ptr = readable(self);
    rb_encoding *enc = get_enc(ptr);
    VALUE str = ptr->string;
    long pos = ptr->pos;
    int len;
    char *p;

    if (NIL_P(str) || pos >= RSTRING_LEN(str)) {
	return Qnil;
    }
    p = RSTRING_PTR(str)+pos;
    len = rb_enc_mbclen(p, RSTRING_END(str), enc);
    ptr->pos += len;
    return enc_subseq(str, pos, len, enc);
}

#gets(sep = $/, chomp: false) ⇒ `String`^? #gets(limit, chomp: false) ⇒ `String`^? #gets(sep, limit, chomp: false) ⇒ `String`^?

Reads and returns a line from the stream; assigns the return value to $_; see Line IO.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1343


static VALUE
strio_gets(int argc, VALUE *argv, VALUE self)
{
    struct StringIO *ptr = readable(self);
    struct getline_arg arg;
    VALUE str;

    if (prepare_getline_args(ptr, &arg, argc, argv)->limit == 0) {
	if (NIL_P(ptr->string)) return Qnil;
	return rb_enc_str_new(0, 0, get_enc(ptr));
    }

    str = strio_getline(&arg, ptr);
    rb_lastline_set(str);
    return str;
}

#initialize_copy(orig)

This method is for internal use only.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 632


static VALUE
strio_copy(VALUE copy, VALUE orig)
{
    struct StringIO *ptr, *old_ptr;
    VALUE old_string = Qundef;

    orig = rb_convert_type(orig, T_DATA, "StringIO", "to_strio");
    if (copy == orig) return copy;
    ptr = StringIO(orig);
    old_ptr = check_strio(copy);
    if (old_ptr) {
	old_string = old_ptr->string;
	strio_free(old_ptr);
    }
    DATA_PTR(copy) = ptr;
    RB_OBJ_WRITTEN(copy, old_string, ptr->string);
    RBASIC(copy)->flags &= ~STRIO_READWRITE;
    RBASIC(copy)->flags |= RBASIC(orig)->flags & STRIO_READWRITE;
    ++ptr->count;
    return copy;
}

#internal_encoding ⇒ `Encoding`

Returns the Encoding of the internal string if conversion is specified. Otherwise returns nil.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1820


static VALUE
strio_internal_encoding(VALUE self)
{
    return Qnil;
}

#isatty

[ GitHub ]

#length ⇒ `Integer` #size ⇒ `Integer`
Also known as: #size

Returns the size of the buffer string.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1761


static VALUE
strio_size(VALUE self)
{
    VALUE string = StringIO(self)->string;
    if (NIL_P(string)) {
	return INT2FIX(0);
    }
    return ULONG2NUM(RSTRING_LEN(string));
}

#pid

[ GitHub ]

#pread(maxlen, offset) ⇒ `String` #pread(maxlen, offset, out_string) ⇒ `String`

See IO#pread.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1641


static VALUE
strio_pread(int argc, VALUE *argv, VALUE self)
{
    VALUE rb_len, rb_offset, rb_buf;
    rb_scan_args(argc, argv, "21", &rb_len, &rb_offset, &rb_buf);
    long len = NUM2LONG(rb_len);
    long offset = NUM2LONG(rb_offset);

    if (len < 0) {
	rb_raise(rb_eArgError, "negative string size (or size too big): %" PRIsVALUE, rb_len);
    }

    if (len == 0) {
	if (NIL_P(rb_buf)) {
	    return rb_str_new("", 0);
	}
	return rb_buf;
    }

    if (offset < 0) {
	rb_syserr_fail_str(EINVAL, rb_sprintf("pread: Invalid offset argument: %" PRIsVALUE, rb_offset));
    }

    struct StringIO *ptr = readable(self);

    if (offset >= RSTRING_LEN(ptr->string)) {
	rb_eof_error();
    }

    if (NIL_P(rb_buf)) {
	return strio_substr(ptr, offset, len, rb_ascii8bit_encoding());
    }

    long rest = RSTRING_LEN(ptr->string) - offset;
    if (len > rest) len = rest;
    rb_str_resize(rb_buf, len);
    rb_enc_associate(rb_buf, rb_ascii8bit_encoding());
    MEMCPY(RSTRING_PTR(rb_buf), RSTRING_PTR(ptr->string) + offset, char, len);
    return rb_buf;
}

#putc(obj) ⇒ Object

See IO#putc.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1531


static VALUE
strio_putc(VALUE self, VALUE ch)
{
    struct StringIO *ptr = writable(self);
    VALUE str;

    check_modifiable(ptr);
    if (RB_TYPE_P(ch, T_STRING)) {
	if (NIL_P(ptr->string)) return ch;
	str = rb_str_substr(ch, 0, 1);
    }
    else {
	char c = NUM2CHR(ch);
	if (NIL_P(ptr->string)) return ch;
	str = rb_str_new(&c, 1);
    }
    strio_write(self, str);
    return ch;
}

#read([length [, outbuf]]) ⇒ `String`, ...

See IO#read.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1565


static VALUE
strio_read(int argc, VALUE *argv, VALUE self)
{
    struct StringIO *ptr = readable(self);
    VALUE str = Qnil;
    long len;
    int binary = 0;

    switch (argc) {
      case 2:
	str = argv[1];
	if (!NIL_P(str)) {
	    StringValue(str);
	    rb_str_modify(str);
	}
	/* fall through */
      case 1:
	if (!NIL_P(argv[0])) {
	    len = NUM2LONG(argv[0]);
	    if (len < 0) {
		rb_raise(rb_eArgError, "negative length %ld given", len);
	    }
	    if (len > 0 &&
		(NIL_P(ptr->string) || ptr->pos >= RSTRING_LEN(ptr->string))) {
		if (!NIL_P(str)) rb_str_resize(str, 0);
		return Qnil;
	    }
	    binary = 1;
	    break;
	}
	/* fall through */
      case 0:
	if (NIL_P(ptr->string)) return Qnil;
	len = RSTRING_LEN(ptr->string);
	if (len <= ptr->pos) {
	    rb_encoding *enc = get_enc(ptr);
	    if (NIL_P(str)) {
		str = rb_str_new(0, 0);
	    }
	    else {
		rb_str_resize(str, 0);
	    }
	    rb_enc_associate(str, enc);
	    return str;
	}
	else {
	    len -= ptr->pos;
	}
	break;
      default:
	rb_error_arity(argc, 0, 2);
    }
    if (NIL_P(str)) {
	rb_encoding *enc = binary ? rb_ascii8bit_encoding() : get_enc(ptr);
	str = strio_substr(ptr, ptr->pos, len, enc);
    }
    else {
	long rest = RSTRING_LEN(ptr->string) - ptr->pos;
	if (len > rest) len = rest;
	rb_str_resize(str, len);
	MEMCPY(RSTRING_PTR(str), RSTRING_PTR(ptr->string) + ptr->pos, char, len);
	if (!binary) {
	    rb_enc_copy(str, ptr->string);
	}
    }
    ptr->pos += RSTRING_LEN(str);
    return str;
}

#readlines(sep = $/, chomp: false) ⇒ `Array` #readlines(limit, chomp: false) ⇒ `Array` #readlines(sep, limit, chomp: false) ⇒ `Array`

See IO#readlines.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1415


static VALUE
strio_readlines(int argc, VALUE *argv, VALUE self)
{
    VALUE ary, line;
    struct StringIO *ptr = readable(self);
    struct getline_arg arg;

    if (prepare_getline_args(ptr, &arg, argc, argv)->limit == 0) {
	rb_raise(rb_eArgError, "invalid limit: 0 for readlines");
    }

    ary = rb_ary_new();
    while (!NIL_P(line = strio_getline(&arg, ptr))) {
	rb_ary_push(ary, line);
    }
    return ary;
}

#reopen(other, mode = 'r+') ⇒ `self`

Reinitializes the stream with the given other (string or StringIO) and mode; see IO.new:

StringIO.open('foo') do |strio|
  p strio.string
  strio.reopen('bar')
  p strio.string
  other_strio = StringIO.new('baz')
  strio.reopen(other_strio)
  p strio.string
  other_strio.close
end

Output:

"foo"
"bar"
"baz"

[ GitHub ]

# File 'ext/stringio/stringio.c', line 732


static VALUE
strio_reopen(int argc, VALUE *argv, VALUE self)
{
    rb_io_taint_check(self);
    if (argc == 1 && !RB_TYPE_P(*argv, T_STRING)) {
	return strio_copy(self, *argv);
    }
    return strio_init(argc, argv, StringIO(self), self);
}

#rewind ⇒ `0`

Sets the current position and line number to zero; see Position and Line Number.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 782


static VALUE
strio_rewind(VALUE self)
{
    struct StringIO *ptr = StringIO(self);
    ptr->pos = 0;
    ptr->lineno = 0;
    return INT2FIX(0);
}

#seek(offset, whence = SEEK_SET) ⇒ `0`

Sets the current position to the given integer offset (in bytes), with respect to a given constant whence; see Position.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 799


static VALUE
strio_seek(int argc, VALUE *argv, VALUE self)
{
    VALUE whence;
    struct StringIO *ptr = StringIO(self);
    long amount, offset;

    rb_scan_args(argc, argv, "11", NULL, &whence);
    amount = NUM2LONG(argv[0]);
    if (CLOSED(self)) {
	rb_raise(rb_eIOError, "closed stream");
    }
    switch (NIL_P(whence) ? 0 : NUM2LONG(whence)) {
      case 0:
	offset = 0;
	break;
      case 1:
	offset = ptr->pos;
	break;
      case 2:
	offset = RSTRING_LEN(ptr->string);
	break;
      default:
	error_inval("invalid whence");
    }
    if (amount > LONG_MAX - offset || amount + offset < 0) {
	error_inval(0);
    }
    ptr->pos = amount + offset;
    return INT2FIX(0);
}

#set_encoding(ext_enc, [int_enc[, opt]]) ⇒ `strio`

Specify the encoding of the StringIO as ext_enc. Use the default external encoding if ext_enc is nil. 2nd argument int_enc and optional hash opt argument are ignored; they are for API compatibility to ::IO.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1836


static VALUE
strio_set_encoding(int argc, VALUE *argv, VALUE self)
{
    rb_encoding* enc;
    struct StringIO *ptr = StringIO(self);
    VALUE ext_enc, int_enc, opt;

    argc = rb_scan_args(argc, argv, "11:", &ext_enc, &int_enc, &opt);

    if (NIL_P(ext_enc)) {
	enc = rb_default_external_encoding();
    }
    else {
	enc = rb_find_encoding(ext_enc);
	if (!enc) {
	    rb_io_enc_t convconfig;
	    int oflags, fmode;
	    VALUE vmode = rb_str_append(rb_str_new_cstr("r:"), ext_enc);
	    rb_io_extract_modeenc(&vmode, 0, Qnil, &oflags, &fmode, &convconfig);
	    enc = convconfig.enc2;
	}
    }
    ptr->enc = enc;
    if (!NIL_P(ptr->string) && WRITABLE(self)) {
	rb_enc_associate(ptr->string, enc);
    }

    return self;
}

#set_encoding_by_bom ⇒ `strio`^?

Sets the encoding according to the BOM (Byte Order Mark) in the string.

Returns self if the BOM is found, otherwise +nil.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1875


static VALUE
strio_set_encoding_by_bom(VALUE self)
{
    struct StringIO *ptr = StringIO(self);

    if (!set_encoding_by_bom(ptr)) return Qnil;
    return rb_enc_from_encoding(ptr->enc);
}

#length ⇒ `Integer` #size ⇒ `Integer`

Alias for #length.

#sync ⇒ `true`

Returns true; implemented only for compatibility with other stream classes.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 837


static VALUE
strio_get_sync(VALUE self)
{
    StringIO(self);
    return Qtrue;
}

#sync=

[ GitHub ]

#tell

[ GitHub ]

#truncate(integer) ⇒ `0`

Truncates the buffer string to at most integer bytes. The stream must be opened for writing.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1778


static VALUE
strio_truncate(VALUE self, VALUE len)
{
    VALUE string = writable(self)->string;
    long l = NUM2LONG(len);
    long plen;
    if (l < 0) {
	error_inval("negative length");
    }
    if (NIL_P(string)) return 0;
    plen = RSTRING_LEN(string);
    rb_str_resize(string, l);
    if (plen < l) {
	MEMZERO(RSTRING_PTR(string) + plen, char, l - plen);
    }
    return INT2FIX(0);
}

#ungetbyte(byte) ⇒ `nil`

Pushes back (“unshifts”) an 8-bit byte onto the stream; see Byte IO.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 994


static VALUE
strio_ungetbyte(VALUE self, VALUE c)
{
    struct StringIO *ptr = readable(self);

    check_modifiable(ptr);
    if (NIL_P(ptr->string)) return Qnil;
    if (NIL_P(c)) return Qnil;
    if (RB_INTEGER_TYPE_P(c)) {
	/* rb_int_and() not visible from exts */
	VALUE v = rb_funcall(c, '&', 1, INT2FIX(0xff));
	const char cc = NUM2INT(v) & 0xFF;
	strio_unget_bytes(ptr, &cc, 1);
    }
    else {
	StringValue(c);
	strio_unget_string(ptr, c);
    }
    return Qnil;
}

#ungetc(character) ⇒ `nil`

Pushes back (“unshifts”) a character or integer onto the stream; see Character IO.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 952


static VALUE
strio_ungetc(VALUE self, VALUE c)
{
    struct StringIO *ptr = readable(self);
    rb_encoding *enc, *enc2;

    check_modifiable(ptr);
    if (NIL_P(ptr->string)) return Qnil;
    if (NIL_P(c)) return Qnil;
    if (RB_INTEGER_TYPE_P(c)) {
	int len, cc = NUM2INT(c);
	char buf[16];

	enc = rb_enc_get(ptr->string);
	len = rb_enc_codelen(cc, enc);
	if (len <= 0) {
	    rb_enc_uint_chr(cc, enc); /* to raise an exception */
	    UNREACHABLE;
	}
	rb_enc_mbcput(cc, buf, enc);
	return strio_unget_bytes(ptr, buf, len);
    }
    else {
	StringValue(c);
	if (RSTRING_LEN(c) == 0) return Qnil;
	enc = rb_enc_get(ptr->string);
	enc2 = rb_enc_get(c);
	if (enc != enc2 && enc != rb_ascii8bit_encoding()) {
	    c = rb_str_conv_enc(c, enc2, enc);
	}
	strio_unget_string(ptr, c);
	return Qnil;
    }
}

#write(string, ...) ⇒ `Integer` #syswrite(string) ⇒ `Integer`

Appends the given string to the underlying buffer string. The stream must be opened for writing. If the argument is not a string, it will be converted to a string using to_s. Returns the number of bytes written. See IO#write.

[ GitHub ]

# File 'ext/stringio/stringio.c', line 1443


static VALUE
strio_write_m(int argc, VALUE *argv, VALUE self)
{
    long len = 0;
    while (argc-- > 0) {
	/* StringIO can't exceed long limit */
	len += strio_write(self, *argv++);
    }
    return LONG2NUM(len);
}

Class: StringIO

Overview

About the Examples

Constant Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

::IO::generic_readable - Included

::IO::generic_writable - Included

Constructor Details

.new(*args)

#new(string = '', mode = 'r+') ⇒ StringIO

Class Method Details

.open(string = '', mode = 'r+') {|strio| ... }

Instance Attribute Details

#closed? ⇒ Boolean (readonly)

#closed_read? ⇒ Boolean (readonly)

#closed_write? ⇒ Boolean (readonly)

#eof? ⇒ Boolean (readonly) Also known as: #eof?

#eof? ⇒ Boolean (readonly) #eof? ⇒ Boolean

#lineno ⇒ current_line_number (rw)

#lineno=(new_line_number) ⇒ new_line_number (rw)

#pos ⇒ stream_position (rw)

#pos=(new_position) ⇒ new_position (rw)

#string ⇒ String (rw)

#string=(other_string) ⇒ other_string (rw)

#tty? ⇒ Boolean (readonly)

Instance Method Details

#binmode ⇒ self

#close ⇒ nil

#close_read ⇒ nil

#close_write ⇒ nil

#each_line(sep = $/, chomp: false) {|line| ... } ⇒ self #each_line(limit, chomp: false) {|line| ... } ⇒ self #each_line(sep, limit, chomp: false) {|line| ... } ⇒ self Also known as: #each_line

#each_byte {|byte| ... } ⇒ self

#each_char {|c| ... } ⇒ self

#each_codepoint {|codepoint| ... } ⇒ self

#each_line(sep = $/, chomp: false) {|line| ... } ⇒ self #each_line(limit, chomp: false) {|line| ... } ⇒ self #each_line(sep, limit, chomp: false) {|line| ... } ⇒ self

#external_encoding ⇒ Encoding

#fcntl

#fileno

#flush

#fsync

#getbyte ⇒ byte?

#getc ⇒ character?

#gets(sep = $/, chomp: false) ⇒ String? #gets(limit, chomp: false) ⇒ String? #gets(sep, limit, chomp: false) ⇒ String?

#initialize_copy(orig)

#internal_encoding ⇒ Encoding

#isatty

#length ⇒ Integer #size ⇒ Integer Also known as: #size

#pid

#pread(maxlen, offset) ⇒ String #pread(maxlen, offset, out_string) ⇒ String

#putc(obj) ⇒ Object

#read([length [, outbuf]]) ⇒ String, ...

#readlines(sep = $/, chomp: false) ⇒ Array #readlines(limit, chomp: false) ⇒ Array #readlines(sep, limit, chomp: false) ⇒ Array

#reopen(other, mode = 'r+') ⇒ self

#rewind ⇒ 0

#seek(offset, whence = SEEK_SET) ⇒ 0

#set_encoding(ext_enc, [int_enc[, opt]]) ⇒ strio

#set_encoding_by_bom ⇒ strio?

#length ⇒ Integer #size ⇒ Integer

#sync ⇒ true

#sync=

#tell

#truncate(integer) ⇒ 0

#ungetbyte(byte) ⇒ nil

#ungetc(character) ⇒ nil

#write(string, ...) ⇒ Integer #syswrite(string) ⇒ Integer

`::IO::generic_readable` - Included

`::IO::generic_writable` - Included

#new(string = '', mode = 'r+') ⇒ `StringIO`

#closed? ⇒ `Boolean` (readonly)

#closed_read? ⇒ `Boolean` (readonly)

#closed_write? ⇒ `Boolean` (readonly)

#eof? ⇒ `Boolean` (readonly) Also known as: #eof?

#eof? ⇒ `Boolean` (readonly) #eof? ⇒ `Boolean`

#lineno ⇒ `current_line_number` (rw)

#lineno=(new_line_number) ⇒ `new_line_number` (rw)

#pos ⇒ `stream_position` (rw)

#pos=(new_position) ⇒ `new_position` (rw)

#string ⇒ `String` (rw)

#string=(other_string) ⇒ `other_string` (rw)

#tty? ⇒ `Boolean` (readonly)

#binmode ⇒ `self`

#close ⇒ `nil`

#close_read ⇒ `nil`

#close_write ⇒ `nil`

#each_line(sep = $/, chomp: false) {|line| ... } ⇒ `self` #each_line(limit, chomp: false) {|line| ... } ⇒ `self` #each_line(sep, limit, chomp: false) {|line| ... } ⇒ `self`
Also known as: #each_line

#each_byte {|byte| ... } ⇒ `self`

#each_char {|c| ... } ⇒ `self`

#each_codepoint {|codepoint| ... } ⇒ `self`

#each_line(sep = $/, chomp: false) {|line| ... } ⇒ `self` #each_line(limit, chomp: false) {|line| ... } ⇒ `self` #each_line(sep, limit, chomp: false) {|line| ... } ⇒ `self`

#external_encoding ⇒ `Encoding`

#getbyte ⇒ `byte`^?

#getc ⇒ `character`^?

#gets(sep = $/, chomp: false) ⇒ `String`^? #gets(limit, chomp: false) ⇒ `String`^? #gets(sep, limit, chomp: false) ⇒ `String`^?

#internal_encoding ⇒ `Encoding`

#length ⇒ `Integer` #size ⇒ `Integer`
Also known as: #size

#pread(maxlen, offset) ⇒ `String` #pread(maxlen, offset, out_string) ⇒ `String`

#read([length [, outbuf]]) ⇒ `String`, ...

#readlines(sep = $/, chomp: false) ⇒ `Array` #readlines(limit, chomp: false) ⇒ `Array` #readlines(sep, limit, chomp: false) ⇒ `Array`

#reopen(other, mode = 'r+') ⇒ `self`

#rewind ⇒ `0`

#seek(offset, whence = SEEK_SET) ⇒ `0`

#set_encoding(ext_enc, [int_enc[, opt]]) ⇒ `strio`

#set_encoding_by_bom ⇒ `strio`^?

#length ⇒ `Integer` #size ⇒ `Integer`

#sync ⇒ `true`

#truncate(integer) ⇒ `0`

#ungetbyte(byte) ⇒ `nil`

#ungetc(character) ⇒ `nil`

#write(string, ...) ⇒ `Integer` #syswrite(string) ⇒ `Integer`