1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227
|
/*
* Copyright (C) 2012, 2015 Andrew Ayer
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Except as contained in this notice, the name(s) of the above copyright
* holders shall not be used in advertising or otherwise to promote the
* sale, use or other dealings in this Software without prior written
* authorization.
*/
#include <cstring>
#include <algorithm> // for std::min
#include "fhstream.hpp"
/*
* ofhstream
*/
ofhbuf::ofhbuf (void* arg_handle, size_t (*arg_write_fun)(void*, const void*, size_t))
: handle(arg_handle),
write_fun(arg_write_fun),
buffer(new char[default_buffer_size]),
buffer_size(default_buffer_size)
{
reset_buffer();
}
ofhbuf::~ofhbuf ()
{
if (handle) {
try {
sync();
} catch (...) {
// Ignore exception since we're in the destructor.
// To catch write errors, call sync() explicitly.
}
}
delete[] buffer;
}
ofhbuf::int_type ofhbuf::overflow (ofhbuf::int_type c)
{
const char* p = pbase();
std::streamsize bytes_to_write = pptr() - p;
if (!is_eof(c)) {
*pptr() = c;
++bytes_to_write;
}
while (bytes_to_write > 0) {
const size_t bytes_written = write_fun(handle, p, bytes_to_write);
bytes_to_write -= bytes_written;
p += bytes_written;
}
reset_buffer();
return traits_type::to_int_type(0);
}
int ofhbuf::sync ()
{
return !is_eof(overflow(traits_type::eof())) ? 0 : -1;
}
std::streamsize ofhbuf::xsputn (const char* s, std::streamsize n)
{
// Use heuristic to decide whether to write directly or just use buffer
// Write directly only if n >= MIN(4096, available buffer capacity)
// (this is similar to what basic_filebuf does)
if (n < std::min<std::streamsize>(4096, epptr() - pptr())) {
// Not worth it to do a direct write
return std::streambuf::xsputn(s, n);
}
// Before we can do a direct write of this string, we need to flush
// out the current contents of the buffer.
if (pbase() != pptr()) {
overflow(traits_type::eof()); // throws an exception or it succeeds
}
// Now we can go ahead and write out the string.
size_t bytes_to_write = n;
while (bytes_to_write > 0) {
const size_t bytes_written = write_fun(handle, s, bytes_to_write);
bytes_to_write -= bytes_written;
s += bytes_written;
}
return n; // Return the total bytes written
}
std::streambuf* ofhbuf::setbuf (char* s, std::streamsize n)
{
if (s == 0 && n == 0) {
// Switch to unbuffered
// This won't take effect until the next overflow or sync
// (We defer it taking effect so that write errors can be properly reported)
// To cause it to take effect as soon as possible, we artificially reduce the
// size of the buffer so it has no space left. This will trigger an overflow
// on the next put.
std::streambuf::setp(pbase(), pptr());
std::streambuf::pbump(pptr() - pbase());
buffer_size = 1;
}
return this;
}
/*
* ifhstream
*/
ifhbuf::ifhbuf (void* arg_handle, size_t (*arg_read_fun)(void*, void*, size_t))
: handle(arg_handle),
read_fun(arg_read_fun),
buffer(new char[default_buffer_size + putback_size]),
buffer_size(default_buffer_size)
{
reset_buffer(0, 0);
}
ifhbuf::~ifhbuf ()
{
delete[] buffer;
}
ifhbuf::int_type ifhbuf::underflow ()
{
if (gptr() >= egptr()) { // A true underflow (no bytes in buffer left to read)
// Move the putback_size most-recently-read characters into the putback area
size_t nputback = std::min<size_t>(gptr() - eback(), putback_size);
std::memmove(buffer + (putback_size - nputback), gptr() - nputback, nputback);
// Now read new characters from the file descriptor
const size_t nread = read_fun(handle, buffer + putback_size, buffer_size);
if (nread == 0) {
// EOF
return traits_type::eof();
}
// Reset the buffer
reset_buffer(nputback, nread);
}
// Return the next character
return traits_type::to_int_type(*gptr());
}
std::streamsize ifhbuf::xsgetn (char* s, std::streamsize n)
{
// Use heuristic to decide whether to read directly
// Read directly only if n >= bytes_available + 4096
std::streamsize bytes_available = egptr() - gptr();
if (n < bytes_available + 4096) {
// Not worth it to do a direct read
return std::streambuf::xsgetn(s, n);
}
std::streamsize total_bytes_read = 0;
// First, copy out the bytes currently in the buffer
std::memcpy(s, gptr(), bytes_available);
s += bytes_available;
n -= bytes_available;
total_bytes_read += bytes_available;
// Now do the direct read
while (n > 0) {
const size_t bytes_read = read_fun(handle, s, n);
if (bytes_read == 0) {
// EOF
break;
}
s += bytes_read;
n -= bytes_read;
total_bytes_read += bytes_read;
}
// Fill up the putback area with the most recently read characters
size_t nputback = std::min<size_t>(total_bytes_read, putback_size);
std::memcpy(buffer + (putback_size - nputback), s - nputback, nputback);
// Reset the buffer with no bytes available for reading, but with some putback characters
reset_buffer(nputback, 0);
// Return the total number of bytes read
return total_bytes_read;
}
std::streambuf* ifhbuf::setbuf (char* s, std::streamsize n)
{
if (s == 0 && n == 0) {
// Switch to unbuffered
// This won't take effect until the next underflow (we don't want to
// lose what's currently in the buffer!)
buffer_size = 1;
}
return this;
}
|