pushpull: new module.

[ccan] / ccan / pushpull / _info

diff --git a/ccan/pushpull/_info b/ccan/pushpull/_info
new file mode 100644 (file)
index 0000000..536744b
--- /dev/null
+++ b/ccan/pushpull/_info
@@ -0,0 +1,76 @@
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+
+/**
+ * pushpull - simple marshalling/unmarshalling routines
+ *
+ * This code lets you clearly add simple types into a buffer (the push
+ * functions) and remove them (the pull functions).  The buffer stores
+ * the values as little-endian for machine portability.  The pull functions
+ * don't need to be checked on every call, but error state is kept so you
+ * can check if there was an error at the end.
+ *
+ * The normal way to use this is to create your own higher-level marshal
+ * and unmarshal functions in terms of these.
+ *
+ * Author: Rusty Russell <rusty@rustcorp.com.au>
+ * License: CC0 (Public domain)
+ *
+ * Example:
+ *     #include <ccan/pushpull/push.h>
+ *     #include <ccan/pushpull/pull.h>
+ *     #include <ccan/err/err.h>
+ *     #include <string.h>
+ *     #include <stdio.h>
+ *     #include <unistd.h>
+ *
+ *     int main(int argc, char *argv[])
+ *     {
+ *             if (argv[1] && !strcmp(argv[1], "push")) {
+ *                     int i;
+ *                     char *buf = malloc(1);
+ *                     size_t len = 0;
+ *
+ *                     // We ignore allocation failure!
+ *                     for (i = 2; i < argc; i++)
+ *                             push_u32(&buf, &len, atol(argv[i]));
+ *
+ *                     write(STDOUT_FILENO, buf, len);
+ *             } else if (argc == 2 && !strcmp(argv[1], "pull")) {
+ *                     int r, max = 32;
+ *                     size_t len = 0;
+ *                     char *buf = malloc(max);
+ *                     const char *p;
+ *                     uint32_t val;
+ *
+ *                     while ((r = read(STDIN_FILENO, buf+len, max-len)) > 0) {
+ *                             len += r;
+ *                             if (len == max) {
+ *                                     max *= 2;
+ *                                     // We crash on allocation failure
+ *                                     buf = realloc(buf, max);
+ *                             }
+ *                     }
+ *
+ *                     p = buf;
+ *                     while (pull_u32(&p, &len, &val))
+ *                             printf("%u ", val);
+ *             } else
+ *                     errx(1, "Usage: %s [push|pull] [<number>...]", argv[0]);
+ *             return 0;
+ *     }
+ */
+int main(int argc, char *argv[])
+{
+       /* Expect exactly one argument */
+       if (argc != 2)
+               return 1;
+
+       if (strcmp(argv[1], "depends") == 0) {
+               printf("ccan/endian\n");
+               return 0;
+       }
+
+       return 1;
+}