From 703c6c12dab5ef059f5eaa2e1dfa79c6b00194a9 Mon Sep 17 00:00:00 2001
From: Patrick Pelissier <patrick.pelissier@gmail.com>
Date: Sat, 18 Feb 2017 20:31:08 +0100
Subject: [PATCH] Add more functions for bitset: * bitset_equal_p *
 bitset_out_str * bitset_in_str * bitset_get_str

---
 m-bitset.h           | 72 +++++++++++++++++++++++++++++++++++++++++++-
 tests/test-mbitset.c | 33 ++++++++++++++++++++
 2 files changed, 104 insertions(+), 1 deletion(-)

diff --git a/m-bitset.h b/m-bitset.h
index 2cc38a4d..475dead3 100644
--- a/m-bitset.h
+++ b/m-bitset.h
@@ -32,6 +32,7 @@
 #include <limits.h>
 
 #include "m-core.h"
+#include "m-string.h"   // Only for bitset_get_str function
 
 typedef struct bitset_s {
   size_t size;            // Size is the number of bits
@@ -316,6 +317,29 @@ bitset_pop_at(bool *dest, bitset_t set, size_t key)
    BITSETI_CONTRACT (set);
 }
 
+static inline bool
+bitset_equal_p (const bitset_t set1, const bitset_t set2)
+{
+  BITSETI_CONTRACT (set1);
+  BITSETI_CONTRACT (set2);
+  if (set1->size != set2->size)
+    return false;
+  /* We won't parse each bit individualy, but instead compare
+     them per byte */
+  size_t size = (set1->size) / CHAR_BIT;
+  for(size_t i = 0 ; i < size;i++)
+    if (set1->ptr[i] != set2->ptr[i])
+      return false;
+  /* Compare last byte if needed */
+  size_t index = set1->size % CHAR_BIT;
+  if (index > 0) {
+    size_t mask = (1 << index) - 1;
+    if ((set1->ptr[size] & mask) != (set2->ptr[size] & mask))
+      return false;
+  }
+  return true;
+}
+
 static inline void
 bitset_it(bitset_it_t it, bitset_t set)
 {
@@ -375,7 +399,53 @@ bitset_ref(const bitset_it_t it)
 }
 #define bitset_cref bitset_ref
 
-// TODO: stringify...
+static inline void
+bitset_out_str(FILE *file, const bitset_t set)
+{
+  BITSETI_CONTRACT (set);
+  assert(file != NULL);
+  fputc ('[', file);
+  for(size_t i = 0; i < set->size; i++) {
+    const bool b = bitset_get (set, i);
+    const char c = b ? '1' : '0';
+    fputc (c, file);
+  }
+  fputc (']', file);
+}
+
+static inline bool
+bitset_in_str(bitset_t set, FILE *file)
+{
+  BITSETI_CONTRACT (set);
+  assert(file != NULL);
+  bitset_clean(set);
+  char c = fgetc(file);
+  if (c != '[') return false;
+  c = fgetc(file);
+  do {
+    if (c != '0' && c != '1') return false;
+    bool b = (c == '1');
+    bitset_push_back (set, b);
+    c = fgetc(file);
+  } while (c != ']' && !feof(file) && !ferror(file));
+  BITSETI_CONTRACT (set);
+  return c == ']';
+}
+
+static inline void
+bitset_get_str(string_t str, const bitset_t set, bool append)
+{
+  BITSETI_CONTRACT (set);
+  assert(str != NULL);
+  (append ? string_cat_str : string_set_str) (str, "[");
+  for(size_t i = 0; i < set->size; i++) {
+    const bool b = bitset_get (set, i);
+    const char c = b ? '1' : '0';
+    string_push_back (str, c);
+  }
+  string_push_back (str, ']');
+}
+
 // TODO: OPLIST
 // TODO: set_at2, insert_v, remove_v, shrink_to_fit,
 
diff --git a/tests/test-mbitset.c b/tests/test-mbitset.c
index fa113a02..a376aa0e 100644
--- a/tests/test-mbitset.c
+++ b/tests/test-mbitset.c
@@ -108,8 +108,41 @@ static void test1(void)
   bitset_clear(set2);
 }
 
+static void test_str(void)
+{
+  bitset_t set1, set2;
+
+  bitset_init(set1);
+  bitset_init(set2);
+
+  for(int i = 0; i < 200; i++)
+    bitset_push_back(set1, (i*17547854547UL >> 4)&1) ;
+  
+  FILE *f = fopen ("a.dat", "wt");
+  if (!f) abort();
+  bitset_out_str(f, set1);
+  fclose (f);
+
+  f = fopen ("a.dat", "rt");
+  if (!f) abort();
+  bool b = bitset_in_str (set2, f);
+  assert (b == true);
+  assert (bitset_equal_p (set1, set2));
+  fclose(f);
+
+  string_t s;
+  string_init (s);
+  bitset_get_str(s, set1, false);
+  assert (string_equal_str_p (s, "[01010110101101011010100101001010010101101011010110101001010010100101011010110101101010010100101001010110101101011010100101001010010101101011010110101001010010100101011010110101101010010100101001010110]"));
+
+  string_clear(s);
+  bitset_clear(set1);
+  bitset_clear(set2);
+}
+
 int main(void)
 {
   test1();
+  test_str();
   exit(0);
 }