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/* SPDX-License-Identifier: Unlicense
*/
#include "data_buffer.h"
#include <cassert>
#include <cerrno>
#include <cstdlib>
#include <cstring>
void DataBuffer::Expand(size_t new_size)
{
assert(buffer);
if (new_size <= buffer_size) {
return;
}
uint8_t *new_buffer{new uint8_t[new_size]};
assert(new_buffer);
memcpy(new_buffer, buffer, occupied_size);
delete [] buffer;
buffer = new_buffer;
buffer_size = new_size;
}
DataBuffer::~DataBuffer()
{
delete [] buffer;
buffer = nullptr;
buffer_size = 0;
occupied_size = 0;
}
DataBuffer DataBuffer::FromStream(FILE *stream)
{
DataBuffer db{};
assert(db.buffer && db.buffer_size >= db.kInitialSize);
while (1) {
const size_t read_size = db.buffer_size - db.occupied_size;
const size_t fread_ret = fread(
db.buffer + db.occupied_size, sizeof(*db.buffer), read_size, stream);
db.occupied_size += fread_ret;
if (fread_ret >= db.buffer_size) {
assert(fread_ret == db.buffer_size);
db.Expand(db.buffer_size * 2);
} else {
const int err = errno;
if (feof(stream)) {
break;
} else if (ferror(stream)) {
fprintf(
stderr,
"DataBuffer::FromStream: fread(%zu): "
"Error (%d): \"%s\"\n",
read_size,
err,
strerror(err));
} else if (db.buffer_size == db.occupied_size) {
db.Expand(db.buffer_size * 2);
} else {
assert(false);
}
}
}
return db;
}
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