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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkStream.h"
#include <unistd.h>
//#define TRACE_FDSTREAM
SkFDStream::SkFDStream(int fileDesc, bool closeWhenDone)
: fFD(fileDesc), fCloseWhenDone(closeWhenDone) {
}
SkFDStream::~SkFDStream() {
if (fFD >= 0 && fCloseWhenDone) {
::close(fFD);
}
}
bool SkFDStream::rewind() {
if (fFD >= 0) {
off_t value = ::lseek(fFD, 0, SEEK_SET);
#ifdef TRACE_FDSTREAM
if (value) {
SkDebugf("xxxxxxxxxxxxxx rewind failed %d\n", value);
}
#endif
return value == 0;
}
return false;
}
size_t SkFDStream::read(void* buffer, size_t size) {
if (fFD >= 0) {
if (buffer == NULL && size == 0) { // request total size
off_t curr = ::lseek(fFD, 0, SEEK_CUR);
if (curr < 0) {
#ifdef TRACE_FDSTREAM
SkDebugf("xxxxxxxxxxxxx lseek failed 0 CURR\n");
#endif
return 0; // error
}
off_t size = ::lseek(fFD, 0, SEEK_END);
if (size < 0) {
#ifdef TRACE_FDSTREAM
SkDebugf("xxxxxxxxxxxxx lseek failed 0 END\n");
#endif
size = 0; // error
}
if (::lseek(fFD, curr, SEEK_SET) != curr) {
// can't restore, error
#ifdef TRACE_FDSTREAM
SkDebugf("xxxxxxxxxxxxx lseek failed %d SET\n", curr);
#endif
return 0;
}
return (size_t) size;
} else if (NULL == buffer) { // skip
off_t oldCurr = ::lseek(fFD, 0, SEEK_CUR);
if (oldCurr < 0) {
#ifdef TRACE_FDSTREAM
SkDebugf("xxxxxxxxxxxxx lseek1 failed %d CUR\n", oldCurr);
#endif
return 0; // error;
}
off_t newCurr = ::lseek(fFD, size, SEEK_CUR);
if (newCurr < 0) {
#ifdef TRACE_FDSTREAM
SkDebugf("xxxxxxxxxxxxx lseek2 failed %d CUR\n", newCurr);
#endif
return 0; // error;
}
// return the actual amount we skipped
return (size_t) (newCurr - oldCurr);
} else { // read
ssize_t actual = ::read(fFD, buffer, size);
// our API can't return an error, so we return 0
if (actual < 0) {
#ifdef TRACE_FDSTREAM
SkDebugf("xxxxxxxxxxxxx read failed %d actual %d\n", size, actual);
#endif
actual = 0;
}
return actual;
}
}
return 0;
}
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