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-rw-r--r--csum-file.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/csum-file.c b/csum-file.c
new file mode 100644
index 0000000000..98cb59ddda
--- /dev/null
+++ b/csum-file.c
@@ -0,0 +1,120 @@
+/*
+ * csum-file.c
+ *
+ * Copyright (C) 2005 Linus Torvalds
+ *
+ * Simple file write infrastructure for writing SHA1-summed
+ * files. Useful when you write a file that you want to be
+ * able to verify hasn't been messed with afterwards.
+ */
+#include "cache.h"
+#include "csum-file.h"
+
+static int sha1flush(struct sha1file *f, unsigned int count)
+{
+ void *buf = f->buffer;
+
+ for (;;) {
+ int ret = write(f->fd, buf, count);
+ if (ret > 0) {
+ buf += ret;
+ count -= ret;
+ if (count)
+ continue;
+ return 0;
+ }
+ if (!ret)
+ die("sha1 file write error. Out of diskspace");
+ if (errno == EAGAIN || errno == EINTR)
+ continue;
+ die("sha1 file write error (%s)", strerror(errno));
+ }
+}
+
+int sha1close(struct sha1file *f)
+{
+ unsigned offset = f->offset;
+ if (offset) {
+ SHA1_Update(&f->ctx, f->buffer, offset);
+ sha1flush(f, offset);
+ }
+ SHA1_Final(f->buffer, &f->ctx);
+ sha1flush(f, 20);
+ return 0;
+}
+
+int sha1write(struct sha1file *f, void *buf, unsigned int count)
+{
+ while (count) {
+ unsigned offset = f->offset;
+ unsigned left = sizeof(f->buffer) - offset;
+ unsigned nr = count > left ? left : count;
+
+ memcpy(f->buffer + offset, buf, nr);
+ count -= nr;
+ offset += nr;
+ left -= nr;
+ if (!left) {
+ SHA1_Update(&f->ctx, f->buffer, offset);
+ sha1flush(f, offset);
+ offset = 0;
+ }
+ f->offset = offset;
+ }
+ return 0;
+}
+
+struct sha1file *sha1create(const char *fmt, ...)
+{
+ static char filename[PATH_MAX];
+ struct sha1file *f;
+ unsigned len;
+ va_list arg;
+ int fd;
+
+ va_start(arg, fmt);
+ len = vsnprintf(filename, PATH_MAX, fmt, arg);
+ va_end(arg);
+
+ if (len >= PATH_MAX)
+ die("you wascally wabbit, you");
+ fd = open(filename, O_CREAT | O_EXCL | O_WRONLY, 0644);
+ if (fd < 0)
+ die("unable to open %s (%s)", filename, strerror(errno));
+ f = xmalloc(sizeof(*f));
+ f->fd = fd;
+ f->error = 0;
+ f->offset = 0;
+ SHA1_Init(&f->ctx);
+ return f;
+}
+
+int sha1write_compressed(struct sha1file *f, void *in, unsigned int size)
+{
+ z_stream stream;
+ unsigned long maxsize;
+ void *out;
+
+ memset(&stream, 0, sizeof(stream));
+ deflateInit(&stream, Z_DEFAULT_COMPRESSION);
+ maxsize = deflateBound(&stream, size);
+ out = xmalloc(maxsize);
+
+ /* Compress it */
+ stream.next_in = in;
+ stream.avail_in = size;
+
+ stream.next_out = out;
+ stream.avail_out = maxsize;
+
+ while (deflate(&stream, Z_FINISH) == Z_OK)
+ /* nothing */;
+ deflateEnd(&stream);
+
+ size = stream.total_out;
+ sha1write(f, out, size);
+ free(out);
+ return size;
+}
+
+