brotli/enc/streams.cc
2016-06-03 11:19:23 +02:00

115 lines
2.5 KiB
C++

/* Copyright 2009 Google Inc. All Rights Reserved.
Distributed under MIT license.
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/
/* Convience routines to make Brotli I/O classes from some memory containers and
files. */
#include "./streams.h"
#include <assert.h>
#include <stdlib.h>
#include <string.h> /* memcpy */
namespace brotli {
BrotliMemOut::BrotliMemOut(void* buf, size_t len)
: buf_(buf),
len_(len),
pos_(0) {}
void BrotliMemOut::Reset(void* buf, size_t len) {
buf_ = buf;
len_ = len;
pos_ = 0;
}
/* Brotli output routine: copy n bytes to the output buffer. */
bool BrotliMemOut::Write(const void *buf, size_t n) {
if (n + pos_ > len_)
return false;
char* p = reinterpret_cast<char*>(buf_) + pos_;
memcpy(p, buf, n);
pos_ += n;
return true;
}
BrotliStringOut::BrotliStringOut(std::string* buf, size_t max_size)
: buf_(buf),
max_size_(max_size) {
assert(buf->empty());
}
void BrotliStringOut::Reset(std::string* buf, size_t max_size) {
buf_ = buf;
max_size_ = max_size;
}
/* Brotli output routine: add n bytes to a string. */
bool BrotliStringOut::Write(const void *buf, size_t n) {
if (buf_->size() + n > max_size_)
return false;
buf_->append(static_cast<const char*>(buf), n);
return true;
}
BrotliMemIn::BrotliMemIn(const void* buf, size_t len)
: buf_(buf),
len_(len),
pos_(0) {}
void BrotliMemIn::Reset(const void* buf, size_t len) {
buf_ = buf;
len_ = len;
pos_ = 0;
}
/* Brotli input routine: read the next chunk of memory. */
const void* BrotliMemIn::Read(size_t n, size_t* output) {
if (pos_ == len_) {
return NULL;
}
if (n > len_ - pos_)
n = len_ - pos_;
const char* p = reinterpret_cast<const char*>(buf_) + pos_;
pos_ += n;
*output = n;
return p;
}
BrotliFileIn::BrotliFileIn(FILE* f, size_t max_read_size)
: f_(f),
buf_(new char[max_read_size]),
buf_size_(max_read_size) { }
BrotliFileIn::~BrotliFileIn(void) {
delete[] buf_;
}
const void* BrotliFileIn::Read(size_t n, size_t* bytes_read) {
if (n > buf_size_) {
n = buf_size_;
} else if (n == 0) {
return feof(f_) ? NULL : buf_;
}
*bytes_read = fread(buf_, 1, n, f_);
if (*bytes_read == 0) {
return NULL;
} else {
return buf_;
}
}
BrotliFileOut::BrotliFileOut(FILE* f) : f_(f) {}
bool BrotliFileOut::Write(const void* buf, size_t n) {
if (fwrite(buf, n, 1, f_) != 1) {
return false;
}
return true;
}
} /* namespace brotli */