73 lines
1.6 KiB
C++
73 lines
1.6 KiB
C++
// (C) 2018-2024 by Folkert van Heusden
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// Released under MIT license
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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#include "disk_backend_file.h"
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#include "log.h"
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disk_backend_file::disk_backend_file(const std::string & filename) :
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filename(filename)
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{
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}
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disk_backend_file::~disk_backend_file()
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{
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close(fd);
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}
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bool disk_backend_file::begin()
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{
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fd = open(filename.c_str(), O_RDWR);
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if (fd == -1) {
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DOLOG(ll_error, true, "disk_backend_file: cannot open \"%s\": %s", filename.c_str(), strerror(errno));
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return false;
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}
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return true;
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}
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bool disk_backend_file::read(const off_t offset, const size_t n, uint8_t *const target)
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{
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DOLOG(debug, false, "disk_backend_file::read: read %zu bytes from offset %zu", n, offset);
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#if defined(_WIN32) // hope for the best
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if (lseek(fd, offset, SEEK_SET) == -1)
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return false;
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return ::read(fd, target, n) == ssize_t(n);
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#else
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ssize_t rc = pread(fd, target, n, offset);
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if (rc != ssize_t(n)) {
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DOLOG(warning, false, "disk_backend_file::read: read failure. expected %zu bytes, got %zd", n, rc);
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return false;
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}
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return true;
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#endif
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}
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bool disk_backend_file::write(const off_t offset, const size_t n, const uint8_t *const from)
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{
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DOLOG(debug, false, "disk_backend_file::write: write %zu bytes to offset %zu", n, offset);
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#if defined(_WIN32) // hope for the best
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if (lseek(fd, offset, SEEK_SET) == -1)
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return false;
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return ::write(fd, from, n) == ssize_t(n);
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#else
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ssize_t rc = pwrite(fd, from, n, offset);
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if (rc != ssize_t(n)) {
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DOLOG(warning, false, "disk_backend_file::write: write failure. expected %zu bytes, got %zd", n, rc);
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return false;
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}
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return true;
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#endif
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}
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