ios_base.h revision f759b92d2877872c2f9300304d5aee0e41bd1306 
1/* -*- c++ -*- */
2/*
3 * Copyright (C) 2010 The Android Open Source Project
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *  * Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 *  * Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in
13 *    the documentation and/or other materials provided with the
14 *    distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
19 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
20 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
22 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
23 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
24 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
26 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#ifndef ANDROID_ASTL_IOS_BASE_H__
31#define ANDROID_ASTL_IOS_BASE_H__
32
33#include <ios_pos_types.h>
34
35namespace android {
36// Flags are used to put the stream is a certain state which affect
37// how data is formatted.
38enum IosBaseFlags {
39    ios_baseflags_boolalpha   = 1 << 0,
40    ios_baseflags_dec         = 1 << 1,
41    ios_baseflags_fixed       = 1 << 2,
42    ios_baseflags_hex         = 1 << 3,
43    ios_baseflags_internal    = 1 << 4,
44    ios_baseflags_left        = 1 << 5,
45    ios_baseflags_oct         = 1 << 6,
46    ios_baseflags_right       = 1 << 7,
47    ios_baseflags_scientific  = 1 << 8,
48    ios_baseflags_showbase    = 1 << 9,
49    ios_baseflags_showpoint   = 1 << 10,
50    ios_baseflags_showpos     = 1 << 11,
51    ios_baseflags_skipws      = 1 << 12,
52    ios_baseflags_unitbuf     = 1 << 13,
53    ios_baseflags_uppercase   = 1 << 14,
54    ios_baseflags_adjustfield = ios_baseflags_left | ios_baseflags_right | ios_baseflags_internal,
55    ios_baseflags_basefield   = ios_baseflags_dec | ios_baseflags_oct | ios_baseflags_hex,
56    ios_baseflags_floatfield  = ios_baseflags_scientific | ios_baseflags_fixed,
57    ios_baseflags_end         = 1 << 15
58};
59
60// Openmode
61enum IosBaseOpenmode {
62    ios_baseopenmode_app    = 1 << 0,
63    ios_baseopenmode_ate    = 1 << 1,
64    ios_baseopenmode_binary = 1 << 2,
65    ios_baseopenmode_in     = 1 << 3,
66    ios_baseopenmode_out    = 1 << 4,
67    ios_baseopenmode_trunc  = 1 << 5,
68    ios_baseopenmode_end    = 1 << 6
69};
70
71}  // namespace android
72
73namespace std {
74
75/**
76 * Root of the streams inheritance.
77 * The STL defines ios_base as a template with 2 params char types and
78 * traits. We support only char and no traits.
79 * ios_base defines flags, types and fields to hold these values.
80 * ios_base is extended by basic_ios which wraps a streambuf and
81 * provides common methods for all streams.
82 * The only mode supported for the standards streams (cout, cerr, cin)
83 * is synced with stdio.
84 */
85
86class ios_base
87{
88  public:
89    typedef std::streampos streampos;
90    typedef std::streamoff streamoff;
91
92
93  protected:
94    ios_base();
95
96  public:
97    virtual ~ios_base();
98    typedef int fmtflags;
99    typedef int iostate;
100    typedef int openmode;
101    typedef int seekdir;
102
103    // FLAGS
104
105    // boolalpha:  Insert and extract bool type in alphabetic format.
106    // dec:        Convert integer input or generates integer output in
107    //             decimal base.
108    // fixed:      Generate floating-point output in a fixed-point notation.
109    // hex:        Convert integer input or generates integer output in
110    //             hexadecimal base.
111    // internal:   Adds fill characters as the designated interanl point
112    //             in certain generated output, or identical to right
113    //             if no such point is designated.
114    // left:       Adds fill characters on the right (final positions) of
115    //             certain generated output.
116    // oct:        Convert integer input or generates integer output in octal
117    //             base.
118    // right:      Adds fill characters on the left (initial positions) of
119    //             certain generated output.
120    // scientific: Generates floating point output in scientific notation.
121    // showbase:   Generates a prefix indicating the numeric base of generated
122    //             integer output.
123    // showpoint:  Generate a decimal point character unconditionally in
124    //             generated floating point output.
125    // showpos:    Generate a + sign in non-negative generated numeric output.
126    // skipws:     Skips leading white space before certain input operations.
127    // unitbuf:    Flushes output after each output operation.
128    // uppercase:  Replaces certain lowercase letters with their upppercase
129    //             equivalents in generated output.
130    static const fmtflags boolalpha   = android::ios_baseflags_boolalpha;
131    static const fmtflags dec         = android::ios_baseflags_dec;
132    static const fmtflags fixed       = android::ios_baseflags_fixed;
133    static const fmtflags hex         = android::ios_baseflags_hex;
134    static const fmtflags internal    = android::ios_baseflags_internal;
135    static const fmtflags left        = android::ios_baseflags_left;
136    static const fmtflags oct         = android::ios_baseflags_oct;
137    static const fmtflags right       = android::ios_baseflags_right;
138    static const fmtflags scientific  = android::ios_baseflags_scientific;
139    static const fmtflags showbase    = android::ios_baseflags_showbase;
140    static const fmtflags showpoint   = android::ios_baseflags_showpoint;
141    static const fmtflags showpos     = android::ios_baseflags_showpos;
142    static const fmtflags skipws      = android::ios_baseflags_skipws;
143    static const fmtflags unitbuf     = android::ios_baseflags_unitbuf;
144    static const fmtflags uppercase   = android::ios_baseflags_uppercase;
145
146    static const fmtflags adjustfield = android::ios_baseflags_adjustfield;
147    static const fmtflags basefield   = android::ios_baseflags_basefield;
148    static const fmtflags floatfield  = android::ios_baseflags_floatfield;
149
150    // Set all the flags at once.
151    // @return the previous value of the format flags
152    fmtflags flags(fmtflags flags);
153
154    // @return all the flags at once
155    fmtflags flags() const { return mFlags; }
156
157    // Set flags.
158    // @return the previous value of the format flags
159    fmtflags setf(fmtflags flags);
160
161    // Clears 'mask' and set the 'flags' & 'mask'.
162    // @return the previous value of the format flags
163    fmtflags setf(fmtflags flags, fmtflags mask);
164
165    // Clears 'mask'.
166    void unsetf(fmtflags mask);
167
168
169    // OPENMODE
170
171    // app:    seek to end before each write.
172    // ate:    open and seek to end imediately after opening.
173    // binary: perform I/O in binary mode.
174    // in:     open for input.
175    // out:    open for output.
176    // trunc:  truncate and existing stream when opening.
177    static const openmode app = android::ios_baseopenmode_app;
178    static const openmode ate = android::ios_baseopenmode_ate;
179    static const openmode binary = android::ios_baseopenmode_binary;
180    static const openmode in = android::ios_baseopenmode_in;
181    static const openmode out = android::ios_baseopenmode_out;
182    static const openmode trunc = android::ios_baseopenmode_trunc;
183
184    // PRECISION and WIDTH
185
186    /**
187     * @return The precision (number of digits after the decimal
188     * point) to generate on certain output conversions. 6 by default.
189     */
190    streamsize precision() const { return mPrecision; }
191
192    /**
193     *  @param precision The new precision value. Values < 0 are ignored.
194     *  @return The previous value of precision(). 0 by default;
195     */
196    streamsize precision(streamsize precision);
197
198    /**
199     * @return The minimum field width to generate on output
200     * operations.
201     */
202    streamsize width() const { return mWidth; }
203
204    /**
205     *  @param width The new width value. Values < 0 are ignored.
206     *  @return The previous value of width().
207     */
208    streamsize width(streamsize width);
209
210    // Helper class to initialize the standard streams. Its
211    // construction ensures the initialization of the stdio streams
212    // (cout, cerr,...) declared in iostream. These wrap the standard
213    // C streams declared in <cstdio>.
214    // The destruction of the last instance of this class will flush
215    // the streams.
216    class Init {
217      public:
218        Init();
219        ~Init();
220
221        static bool done() { return sDone; }
222      private:
223        static int sGuard;
224        static bool sDone;
225    };
226
227  private:
228    fmtflags   mFlags;
229    streamsize mPrecision;
230    streamsize mWidth;
231};
232
233}  // namespace std
234
235#endif
236