External/fmt
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Return size_t instead of streamsize in File::read and File::write

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File::read and File::write throw exception on error, so they don't need to return a negative value to indicate error.
This commit is contained in:
Victor Zverovich 2014-09-12 09:38:37 -07:00
parent 6cd9be2c06
commit f175591923
2 changed files with 14 additions and 9 deletions
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18
posix.cc
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@ -55,12 +55,18 @@
namespace {
#ifdef _WIN32
// Return type of read and write functions.
typedef int RWResult;
// On Windows the count argument to read and write is unsigned, so convert
// it from size_t preventing integer overflow.
inline unsigned convert_rwcount(std::size_t count) {
return count <= UINT_MAX ? static_cast<unsigned>(count) : UINT_MAX;
}
#else
// Return type of read and write functions.
typedef ssize_t RWResult;
inline std::size_t convert_rwcount(std::size_t count) { return count; }
#endif
}
@ -122,18 +128,18 @@ void fmt::File::close() {
throw SystemError(errno, "cannot close file");
}
std::streamsize fmt::File::read(void *buffer, std::size_t count) {
std::streamsize result = 0;
std::size_t fmt::File::read(void *buffer, std::size_t count) {
RWResult result = 0;
FMT_RETRY(result, FMT_POSIX_CALL(read(fd_, buffer, convert_rwcount(count))));
if (result == -1)
if (result < 0)
throw SystemError(errno, "cannot read from file");
return result;
}
std::streamsize fmt::File::write(const void *buffer, std::size_t count) {
std::streamsize result = 0;
std::size_t fmt::File::write(const void *buffer, std::size_t count) {
RWResult result = 0;
FMT_RETRY(result, FMT_POSIX_CALL(write(fd_, buffer, convert_rwcount(count))));
if (result == -1)
if (result < 0)
throw SystemError(errno, "cannot write to file");
return result;
}

5
posix.h
View File

@ -33,7 +33,6 @@
#include <stdio.h>
#include <cstddef>
#include <ios>
#include "format.h"
@ -279,10 +278,10 @@ class File {
void close();
// Attempts to read count bytes from the file into the specified buffer.
std::streamsize read(void *buffer, std::size_t count);
std::size_t read(void *buffer, std::size_t count);
// Attempts to write count bytes from the specified buffer to the file.
std::streamsize write(const void *buffer, std::size_t count);
std::size_t write(const void *buffer, std::size_t count);
// Duplicates a file descriptor with the dup function and returns
// the duplicate as a file object.