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/* vim: set expandtab ts=4 sw=4: */
/*
* You may redistribute this program and/or modify it under the terms of
* the GNU General Public License as published by the Free Software Foundation,
* either version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef Writer_H
#define Writer_H
#include <stdint.h>
/**
* Writer interface which writes data to a destination and fails safe rather than overflowing.
*/
struct Writer {
/**
* Write some content from a buffer or other source.
*
* @param w the Writer which is being called.
* @param toWrite a pointer to a memory location where content will be sourced from.
* @param length the number of bytes to write.
* @return 0 if write went well, -1 if there is no more space to write.
* if a write fails then all subsequent writes will fail with the same error
* so writing a large piece of content then a small footer does not require
* checking if the content wrote correctly before writing the footer.
*/
int (* const write)(struct Writer* w, const void* toWrite, unsigned long length);
uint64_t bytesWritten;
};
#define Writer_writeGeneric(bytes) \
static inline int Writer_write##bytes (struct Writer* writer, uint##bytes##_t number) \
{ \
uint##bytes##_t num = number; \
return writer->write(writer, &num, bytes/8); \
}
Writer_writeGeneric(8)
Writer_writeGeneric(16)
Writer_writeGeneric(32)
Writer_writeGeneric(64)
#define Writer_write(writer, bytes, amount) \
((writer)->write((writer), (bytes), (amount)))
#define Writer_bytesWritten(writer) \
((writer)->bytesWritten + 0)
#endif