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#include <cerrno>
#include <cstdlib>
#include <cstring>
#include <limits>
#include <zip.h>
struct context
{
zip_uint64_t offset;
long long size;
};
zip_int64_t callback(void *user, void *data, zip_uint64_t len, enum zip_source_cmd cmd)
{
struct context *ctx = (struct context*)user;
switch (cmd) {
case ZIP_SOURCE_OPEN:
ctx->offset = 0;
return 0;
case ZIP_SOURCE_READ:
{
size_t nr = std::numeric_limits<size_t>::max();
if (len < nr)
nr = static_cast<size_t>(len);
if (ctx->size - ctx->offset < nr)
nr = static_cast<size_t>(ctx->size - ctx->offset);
memset(data, 0, nr);
ctx->offset += nr;
return nr;
}
case ZIP_SOURCE_STAT:
{
struct zip_stat *st = (struct zip_stat*)data;
zip_stat_init(st);
st->valid = ZIP_STAT_SIZE | ZIP_STAT_MTIME;
st->size = ctx->size;
st->mtime = time(NULL);
return sizeof(struct zip_stat);
}
case ZIP_SOURCE_FREE:
return 0;
case ZIP_SOURCE_CLOSE:
return 0;
case ZIP_SOURCE_ERROR:
{
int *errs = static_cast<int *>(data);
errs[0] = ZIP_ER_OPNOTSUPP;
errs[1] = EINVAL;
return 2 * sizeof(int);
}
case ZIP_SOURCE_SUPPORTS:
return ZIP_SOURCE_SUPPORTS_READABLE;
default:
// indicate unsupported operation
return -1;
}
}
int main(int argc, char **argv) {
if (argc != 3) {
fprintf(stderr, "usage: %s <output-zip-file> <size>\n", argv[0]);
return EXIT_FAILURE;
}
struct context ctx;
ctx.size = atoll(argv[2]);
printf("creating %s of size %llx bytes\n", argv[1], ctx.size);
int err;
struct zip *z = zip_open(argv[1], ZIP_CREATE | ZIP_TRUNCATE, &err);
struct zip_source *s = zip_source_function(z, callback, &ctx);
zip_add(z, "content", s);
zip_close(z);
return 0;
}
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