4 files changed, 33 insertions, 3 deletions

diff --git a/TODO.txt b/TODO.txt
index f0c81a6..614e8e5 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -3,7 +3,6 @@ Solver
 
 More utilities for tables (in cube.h)
   - cleanup solve and gendata in cube.h and cube_public.h
-  - for tables, a "dryrun" function that only tells you the size needed
   - check hash of generated data
 
 Goal: find out which k value is best
diff --git a/src/cube.h b/src/cube.h
index ab8e964..0eedfec 100644
--- a/src/cube.h
+++ b/src/cube.h
@@ -51,6 +51,16 @@ int nissy_convertcube(
         char *result
 );
 
+/*
+Returns the size of the data generated by nissy_gendata, when called with
+the same parameters, or -1 in case of error. The returned value can be
+slightly larger than the actual table size.
+*/
+int64_t nissy_datasize(
+        const char *solver,
+        const char *options
+);
+
 /* Returns the number of bytes written, or -1 in case of error */
 int64_t nissy_gendata(
         const char *solver,
@@ -59,7 +69,7 @@ int64_t nissy_gendata(
 );
 
 /* Returns the number of solutions found, or -1 in case of error */
-int nissy_solve(
+int64_t nissy_solve(
         const char cube[static 22],
         const char *solver, 
         const char *options,
diff --git a/src/cube_public.h b/src/cube_public.h
index 1b0cc14..01b6dac 100644
--- a/src/cube_public.h
+++ b/src/cube_public.h
@@ -1,3 +1,5 @@
+#include "cube.h"
+
 int write_result(cube_t, char [static 22]);
 
 int
@@ -127,6 +129,16 @@ nissy_writecube(
 }
 
 int64_t
+nissy_datasize(
+        const char *solver,
+        const char *options
+)
+{
+        /* gendata() handles a NULL *data as a "dryrun" request */
+        return nissy_gendata(solver, options, NULL);
+}
+
+int64_t
 nissy_gendata(
         const char *solver,
         const char *options,
diff --git a/src/solve_h48.h b/src/solve_h48.h
index 8691d49..8be67b6 100644
--- a/src/solve_h48.h
+++ b/src/solve_h48.h
@@ -129,6 +129,9 @@ gendata_cocsep(void *buf, uint64_t *selfsim, cube_t *rep)
         uint8_t i, j, visited[COCSEP_VISITEDSIZE];
         dfsarg_cocsep_t arg;
 
+        if (buf == NULL)
+                goto gendata_cocsep_return_size;
+
         buf32 = (uint32_t *)buf;
         info = buf32 + COCSEP_TABLESIZE;
         memset(buf32, 0xFF, sizeof(uint32_t) * COCSEP_TABLESIZE);
@@ -165,6 +168,7 @@ gendata_cocsep(void *buf, uint64_t *selfsim, cube_t *rep)
         for (j = 0; j < 10; j++)
                 DBG_LOG("%" PRIu8 ":\t%" PRIu32 "\n", j, info[j+2]);
 
+gendata_cocsep_return_size:
         return COCSEP_FULLSIZE;
 }
 
@@ -234,8 +238,12 @@ gendata_h48(void *buf, uint8_t h, uint8_t maxdepth)
         cube_t crep[COCSEP_CLASSES];
         size_t cocsepsize, infosize;
 
-        esep_max = (int64_t)ESEP_MAX(h);
+        infosize = 4 * maxdepth;
         cocsepsize = gendata_cocsep(buf, selfsim, crep);
+        if (buf == NULL)
+                goto gendata_h48_return_size;
+
+        esep_max = (int64_t)ESEP_MAX(h);
         cocsepdata = (uint32_t *)buf;
         buf32 = cocsepdata + cocsepsize / 4;
         info = buf32 + (ESEP_TABLESIZE(h, k) / sizeof(uint32_t));
@@ -272,6 +280,7 @@ gendata_h48(void *buf, uint8_t h, uint8_t maxdepth)
         for (j = 0; j <= info[0]; j++)
                 DBG_LOG("%" PRIu8 ":\t%" PRIu32 "\n", j, info[j+1]);
 
+gendata_h48_return_size:
         return cocsepsize + ESEP_TABLESIZE(h, k) + infosize;
 }