generator: Generators for C

[ccan] / ccan / generator / generator.c

diff --git a/ccan/generator/generator.c b/ccan/generator/generator.c
new file mode 100644 (file)
index 0000000..d217665
--- /dev/null
+++ b/ccan/generator/generator.c
@@ -0,0 +1,54 @@
+/* Licensed LGPLv2.1+ - see LICENSE file for details */
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+#include <ccan/alignof/alignof.h>
+
+#include <ccan/generator/generator.h>
+
+#define DEFAULT_STATE_SIZE     8192
+#define STATE_ALIGN            ALIGNOF(struct generator_)
+
+void *generator_new_(generator_wrapper_ *fn, size_t retsize)
+{
+       char *base;
+       size_t size = DEFAULT_STATE_SIZE;
+       void *ret;
+       struct generator_ *gen;
+
+       base = malloc(size);
+       if (!base)
+               abort();
+
+       retsize = (retsize + STATE_ALIGN) & ~(STATE_ALIGN - 1);
+       ret = base + size - retsize;
+       gen = (struct generator_ *)ret - 1;
+
+       gen->base = base;
+       gen->complete = false;
+
+       getcontext(&gen->gen);
+
+       gen->gen.uc_stack.ss_sp = gen->base;
+       gen->gen.uc_stack.ss_size = (char *)gen - base;
+
+       if (HAVE_POINTER_SAFE_MAKECONTEXT) {
+               makecontext(&gen->gen, (void *)fn, 1, ret);
+       } else {
+               ptrdiff_t si = ptr2int(ret);
+               ptrdiff_t mask = (1UL << (sizeof(int) * 8)) - 1;
+               int lo = si & mask;
+               int hi = si >> (sizeof(int) * 8);
+
+               makecontext(&gen->gen, (void *)fn, 2, lo, hi);
+       }
+
+       return ret;
+}
+
+void generator_free_(void *ret)
+{
+       struct generator_ *gen = generator_state_(ret);
+       free(gen->base);
+}