zip_source_window.c [plain text]
#include <stdlib.h>
#include <string.h>
#include "zipint.h"
struct window {
zip_uint64_t start;
zip_uint64_t end;
zip_uint64_t offset;
zip_stat_t stat;
zip_error_t error;
zip_int64_t supports;
bool needs_seek;
};
static zip_int64_t window_read(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);
zip_source_t *
zip_source_window(zip_t *za, zip_source_t *src, zip_uint64_t start, zip_uint64_t len)
{
return _zip_source_window_new(src, start, len, NULL, &za->error);
}
zip_source_t *
_zip_source_window_new(zip_source_t *src, zip_uint64_t start, zip_uint64_t length, zip_stat_t *st, zip_error_t *error)
{
struct window *ctx;
if (src == NULL || start + length < start) {
zip_error_set(error, ZIP_ER_INVAL, 0);
return NULL;
}
if ((ctx=(struct window *)malloc(sizeof(*ctx))) == NULL) {
zip_error_set(error, ZIP_ER_MEMORY, 0);
return NULL;
}
ctx->start = start;
ctx->end = start + length;
zip_stat_init(&ctx->stat);
zip_error_init(&ctx->error);
ctx->supports = (zip_source_supports(src) & ZIP_SOURCE_SUPPORTS_SEEKABLE) | (zip_source_make_command_bitmap(ZIP_SOURCE_SUPPORTS, ZIP_SOURCE_TELL, -1));
ctx->needs_seek = (ctx->supports & ZIP_SOURCE_MAKE_COMMAND_BITMASK(ZIP_SOURCE_SEEK)) ? true : false;
if (st) {
if (_zip_stat_merge(&ctx->stat, st, error) < 0) {
free(ctx);
return NULL;
}
}
return zip_source_layered_create(src, window_read, ctx, error);
}
int
_zip_source_set_source_archive(zip_source_t *src, zip_t *za)
{
src->source_archive = za;
return _zip_register_source(za, src);
}
void
_zip_source_invalidate(zip_source_t *src)
{
src->source_closed = 1;
if (zip_error_code_zip(&src->error) == ZIP_ER_OK) {
zip_error_set(&src->error, ZIP_ER_ZIPCLOSED, 0);
}
}
static zip_int64_t
window_read(zip_source_t *src, void *_ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd)
{
struct window *ctx;
zip_int64_t ret;
zip_uint64_t n, i;
char b[8192];
ctx = (struct window *)_ctx;
switch (cmd) {
case ZIP_SOURCE_CLOSE:
return 0;
case ZIP_SOURCE_ERROR:
return zip_error_to_data(&ctx->error, data, len);
case ZIP_SOURCE_FREE:
free(ctx);
return 0;
case ZIP_SOURCE_OPEN:
if (!ctx->needs_seek) {
for (n=0; n<ctx->start; n+=(zip_uint64_t)ret) {
i = (ctx->start-n > sizeof(b) ? sizeof(b) : ctx->start-n);
if ((ret=zip_source_read(src, b, i)) < 0) {
_zip_error_set_from_source(&ctx->error, src);
return -1;
}
if (ret==0) {
zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
return -1;
}
}
}
ctx->offset = ctx->start;
return 0;
case ZIP_SOURCE_READ:
if (len > ctx->end - ctx->offset)
len = ctx->end - ctx->offset;
if (len == 0)
return 0;
if (ctx->needs_seek) {
if (zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET) < 0) {
_zip_error_set_from_source(&ctx->error, src);
return -1;
}
}
if ((ret=zip_source_read(src, data, len)) < 0) {
zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
return -1;
}
ctx->offset += (zip_uint64_t)ret;
if (ret == 0) {
if (ctx->offset < ctx->end) {
zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
return -1;
}
}
return ret;
case ZIP_SOURCE_SEEK:
{
zip_int64_t new_offset = zip_source_seek_compute_offset(ctx->offset - ctx->start, ctx->end - ctx->start, data, len, &ctx->error);
if (new_offset < 0) {
return -1;
}
ctx->offset = (zip_uint64_t)new_offset + ctx->start;
return 0;
}
case ZIP_SOURCE_STAT:
{
zip_stat_t *st;
st = (zip_stat_t *)data;
if (_zip_stat_merge(st, &ctx->stat, &ctx->error) < 0) {
return -1;
}
return 0;
}
case ZIP_SOURCE_SUPPORTS:
return ctx->supports;
case ZIP_SOURCE_TELL:
return (zip_int64_t)(ctx->offset - ctx->start);
default:
zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
return -1;
}
}
void
_zip_deregister_source(zip_t *za, zip_source_t *src)
{
unsigned int i;
for (i=0; i<za->nopen_source; i++) {
if (za->open_source[i] == src) {
za->open_source[i] = za->open_source[za->nopen_source-1];
za->nopen_source--;
break;
}
}
}
int
_zip_register_source(zip_t *za, zip_source_t *src)
{
zip_source_t **open_source;
if (za->nopen_source+1 >= za->nopen_source_alloc) {
unsigned int n;
n = za->nopen_source_alloc + 10;
open_source = (zip_source_t **)realloc(za->open_source, n*sizeof(zip_source_t *));
if (open_source == NULL) {
zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
return -1;
}
za->nopen_source_alloc = n;
za->open_source = open_source;
}
za->open_source[za->nopen_source++] = src;
return 0;
}