large commit of C work

[zpackage] / compress.c

diff --git a/compress.c b/compress.c
new file mode 100644 (file)
index 0000000..648a6d9
--- /dev/null
+++ b/compress.c
@@ -0,0 +1,102 @@
+/*
+ * add a file/files to an sqlite db
+ * in the 'files' table.
+ */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <sys/mman.h>
+
+#include "lzma.h"
+
+#include "sha256.h"
+
+void *compresslzma(void *buf, size_t bufsize, size_t *len) {
+       /* xz compress it */
+       size_t outsize;
+       void *outbuf;
+       size_t outlen = 0;
+
+       outsize = lzma_stream_buffer_bound(bufsize);
+       outbuf = malloc(outsize);
+       /* TODO adjust encoding level for size */
+       lzma_easy_buffer_encode(6, LZMA_CHECK_CRC64, NULL,
+                       buf, bufsize,
+                       outbuf, &outlen, outsize
+                       );
+       *len = outlen;
+       return outbuf;
+}
+
+int main(int ac, char **av){
+       int i, j;
+
+       /* insert each file */
+       for (i = 1; i < ac; i++) {
+               int fd;
+               void *content;
+               struct stat sbuf;
+               unsigned char tmp[32];
+               char hash[65]; /* hash in hex */
+               hash_state md;
+
+               fd = open(av[i], O_RDONLY);
+               if (fd == -1) {
+                       exit(1);
+               }
+               if (fstat(fd, &sbuf) == -1) {
+                       exit(1);
+               }
+               /* not a regular file? */
+               if (!S_ISREG(sbuf.st_mode)) {
+                       exit(1);
+               }
+
+               content = mmap(0, sbuf.st_size, PROT_READ,MAP_PRIVATE, fd, 0);
+               if (!content) {
+                       exit(2);
+               }
+
+               sha256_init(&md);
+               sha256_process(&md, content, sbuf.st_size);
+               sha256_done(&md, tmp);
+               for (j=0;j<32;j++) {
+                       sprintf(hash+j*2, "%02x", (unsigned)tmp[j]);
+               }
+               hash[64] = 0;
+               fprintf(stderr, "file %s: %s\n", av[i], hash);
+
+               /* xz compress it */
+               size_t outlen = 0;
+               FILE *save;
+               void *outbuf;
+
+               outbuf = compresslzma(content, sbuf.st_size, &outlen);
+               save = fopen("foo.xz", "w");
+               fwrite(outbuf, outlen, 1, save);
+               fclose(save);
+               free(outbuf);
+
+               //Find out the maximum size of the compressed output for single-call compression:
+//                     zlib: compressBound()
+//                     liblzma: lzma_stream_buffer_bound()
+
+//                     Compressing:
+//zlib: compress() or compress2()
+ //     liblzma: lzma_easy_buffer_encode() or lzma_stream_buffer_encode()
+
+  //    Decompressing:
+//zlib: uncompress()
+ //     liblzma: lzma_stream_buffer_decode()
+
+  //    See container.h (src/liblzma/api/lzma/container.h in the source tree) for details how to use these functions.
+
+               /* either way we're done with this now */
+               munmap(content, sbuf.st_size);
+       }
+       return 0;
+}