diff options
| -rw-r--r-- | ext/stringio/stringio.c | 43 | ||||
| -rw-r--r-- | test/stringio/test_stringio.rb | 19 |
2 files changed, 62 insertions, 0 deletions
diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c index 68306cac4b..f5213f2fc0 100644 --- a/ext/stringio/stringio.c +++ b/ext/stringio/stringio.c @@ -1584,6 +1584,48 @@ strio_read(int argc, VALUE *argv, VALUE self) } /* + * call-seq: + * pread(maxlen, offset) -> string + * pread(maxlen, offset, out_string) -> string + * + * See IO#pread. + */ +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 (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; +} + + +/* * call-seq: * strio.sysread(integer[, outbuf]) -> string * strio.readpartial(integer[, outbuf]) -> string @@ -1843,6 +1885,7 @@ Init_stringio(void) rb_define_method(StringIO, "gets", strio_gets, -1); rb_define_method(StringIO, "readlines", strio_readlines, -1); rb_define_method(StringIO, "read", strio_read, -1); + rb_define_method(StringIO, "pread", strio_pread, -1); rb_define_method(StringIO, "write", strio_write_m, -1); rb_define_method(StringIO, "putc", strio_putc, 1); diff --git a/test/stringio/test_stringio.rb b/test/stringio/test_stringio.rb index fd9974caeb..246f107d05 100644 --- a/test/stringio/test_stringio.rb +++ b/test/stringio/test_stringio.rb @@ -729,6 +729,25 @@ class TestStringIO < Test::Unit::TestCase assert_equal Encoding::ASCII_8BIT, f.sysread(3).encoding end + def test_pread + f = StringIO.new("pread") + f.read + + assert_equal "pre".b, f.pread(3, 0) + assert_equal "read".b, f.pread(4, 1) + assert_equal Encoding::ASCII_8BIT, f.pread(4, 1).encoding + + buf = "".b + f.pread(3, 0, buf) + assert_equal "pre".b, buf + f.pread(4, 1, buf) + assert_equal "read".b, buf + + assert_raise(EOFError) { f.pread(1, 5) } + assert_raise(ArgumentError) { f.pread(-1, 0) } + assert_raise(Errno::EINVAL) { f.pread(3, -1) } + end + def test_size f = StringIO.new("1234") assert_equal(4, f.size) |