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path: root/lib/sqfshelper/io_stdin.c
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Diffstat (limited to 'lib/sqfshelper/io_stdin.c')
-rw-r--r--lib/sqfshelper/io_stdin.c67
1 files changed, 65 insertions, 2 deletions
diff --git a/lib/sqfshelper/io_stdin.c b/lib/sqfshelper/io_stdin.c
index 6cb45d4..8568f5e 100644
--- a/lib/sqfshelper/io_stdin.c
+++ b/lib/sqfshelper/io_stdin.c
@@ -11,12 +11,14 @@
#include <stdlib.h>
#include <unistd.h>
+#include <string.h>
#include <errno.h>
typedef struct {
sqfs_file_t base;
+ const sparse_map_t *map;
uint64_t offset;
uint64_t size;
} sqfs_file_stdin_t;
@@ -78,6 +80,60 @@ static int stdin_read_at(sqfs_file_t *base, uint64_t offset,
return 0;
}
+static int stdin_read_condensed(sqfs_file_t *base, uint64_t offset,
+ void *buffer, size_t size)
+{
+ sqfs_file_stdin_t *file = (sqfs_file_stdin_t *)base;
+ uint64_t poffset = 0, src_start;
+ size_t dst_start, diff, count;
+ const sparse_map_t *it;
+ int err;
+
+ memset(buffer, 0, size);
+
+ for (it = file->map; it != NULL; it = it->next) {
+ if (it->offset + it->count <= offset) {
+ poffset += it->count;
+ continue;
+ }
+
+ if (it->offset >= offset + size) {
+ poffset += it->count;
+ continue;
+ }
+
+ count = size;
+
+ if (offset + count >= it->offset + it->count)
+ count = it->offset + it->count - offset;
+
+ if (it->offset < offset) {
+ diff = offset - it->offset;
+
+ src_start = poffset + diff;
+ dst_start = 0;
+ count -= diff;
+ } else if (it->offset > offset) {
+ diff = it->offset - offset;
+
+ src_start = poffset;
+ dst_start = diff;
+ } else {
+ src_start = poffset;
+ dst_start = 0;
+ }
+
+ err = stdin_read_at(base, src_start,
+ (char *)buffer + dst_start, count);
+ if (err)
+ return err;
+
+ poffset += it->count;
+ }
+
+ return 0;
+}
+
static int stdin_write_at(sqfs_file_t *base, uint64_t offset,
const void *buffer, size_t size)
{
@@ -96,7 +152,7 @@ static int stdin_truncate(sqfs_file_t *base, uint64_t size)
return SQFS_ERROR_IO;
}
-sqfs_file_t *sqfs_get_stdin_file(uint64_t size)
+sqfs_file_t *sqfs_get_stdin_file(const sparse_map_t *map, uint64_t size)
{
sqfs_file_stdin_t *file = calloc(1, sizeof(*file));
sqfs_file_t *base = (sqfs_file_t *)file;
@@ -105,10 +161,17 @@ sqfs_file_t *sqfs_get_stdin_file(uint64_t size)
return NULL;
file->size = size;
+ file->map = map;
+
base->destroy = stdin_destroy;
- base->read_at = stdin_read_at;
base->write_at = stdin_write_at;
base->get_size = stdin_get_size;
base->truncate = stdin_truncate;
+
+ if (map == NULL) {
+ base->read_at = stdin_read_at;
+ } else {
+ base->read_at = stdin_read_condensed;
+ }
return base;
}