linker

src/linker/base_ext/base_bit_array.c

@@ -0,0 +1,276 @@
+// Copyright (c) 2024 Epic Games Tools
+// Licensed under the MIT license (https://opensource.org/license/mit/)
+
+internal U32Array
+bit_array_init32(Arena *arena, U64 word_count)
+{
+  U32Array result;
+  result.count = CeilIntegerDiv(word_count, 32);
+  result.v = push_array(arena, U32, word_count);
+  return result;
+}
+
+internal U64
+bit_array_scan_left_to_right32(U32Array bit_array, U64 lo, U64 hi, B32 state)
+{
+  Assert(lo < bit_array.count*32);
+  Assert(hi <= bit_array.count*32);
+  Assert(lo <= hi);
+  Assert(state == 0 || state == 1);
+  
+  U64 word_lo = lo / 32;
+  U64 word_hi = CeilIntegerDiv(hi, 32) - 1;
+  
+  U64 word_idx = word_lo;
+  U64 bit_idx = 0;
+  
+  U64 scan_count = hi - lo;
+  if (scan_count < 32) {
+    U64 bit_lo = lo % 32;
+    U64 bit_hi = hi % 32;
+    U64 word = bit_array.v[word_idx];
+    word ^= state - 1;
+    word &= (1U << bit_hi) - (1U << bit_lo);
+    if (word) {
+      bit_idx = ctz32(word);
+      goto exit;
+    }
+  } else {
+    U32 first_word = bit_array.v[word_idx];
+    first_word ^= state - 1;
+    first_word &= ~0u << (lo % 32);
+    if (first_word) {
+      bit_idx = ctz32(first_word);
+      goto exit;
+    }
+    
+    for (word_idx += 1; word_idx < word_hi; word_idx += 1) {
+      U32 word = bit_array.v[word_idx];
+      word ^= state - 1;
+      if (word != 0) {
+        bit_idx = ctz32(word);
+        goto exit;
+      }
+    }
+    
+    U64 bit_hi = hi - (word_idx * 32);
+    U32 last_word = bit_array.v[word_idx];
+    last_word ^= state - 1;
+    last_word &= (1 << bit_hi) - 1;
+    if (last_word) {
+      bit_idx = ctz32(last_word);
+      goto exit;
+    }
+  }
+  
+  word_idx = 0;
+  bit_idx = max_U32;
+  
+  exit:;
+  
+  U64 result = word_idx * 32 + bit_idx;
+  return result;
+}
+
+internal U64
+bit_array_scan_right_to_left32(U32Array bit_array, U64 lo, U64 hi, B32 state)
+{
+  Assert(lo <= hi);
+  Assert(state == 0 || state == 1);
+  
+  S64 word_lo = lo / 32;
+  S64 word_hi = CeilIntegerDiv(hi, 32) - 1;
+  
+  S64 word_idx = word_hi;
+  S64 bit_idx = -1;
+  
+  U64 scan_count = hi - lo;
+  if (scan_count < 32) {
+    S64 bit_lo = lo % 32;
+    S64 bit_hi = bit_lo + scan_count;
+    U32 word = bit_array.v[word_idx];
+    for (bit_idx = bit_hi; bit_idx >= bit_lo; bit_idx -= 1) {
+      U32 bit = ExtractBit(word, bit_idx);
+      if (bit == state) {
+        goto exit;
+      }
+    }
+  } else {
+    U32 last_word = bit_array.v[word_idx];
+    S64 bit_hi = hi % 32;
+    for (bit_idx = bit_hi; bit_idx >= 0; bit_idx -= 1) {
+      U32 bit = ExtractBit(last_word, bit_idx);
+      if (bit == state) {
+        goto exit;
+      }
+    }
+    
+    for (word_idx -= 1; word_idx > word_lo; word_idx -= 1) {
+      U32 word = bit_array.v[word_idx];
+      for (bit_idx = 32 - 1; bit_idx >= 0; bit_idx -= 1) {
+        U32 bit = ExtractBit(word, bit_idx);
+        if (bit == state) {
+          goto exit;
+        }
+      }
+    }
+    
+    U32 first_word = bit_array.v[word_idx];
+    S64 bit_lo = lo % 32;
+    for (bit_idx = 32 - 1; bit_idx >= bit_lo; bit_idx -= 1) {
+      U32 bit = ExtractBit(first_word, bit_idx);
+      if (bit == state) {
+        goto exit;
+      }
+    }
+  }
+  
+  word_idx = 0;
+  bit_idx = max_U32;
+  
+  exit:;
+  
+  S64 result_s64 = word_idx * 32 + bit_idx;
+  U64 result_u64 = (U64)result_s64;
+  return result_u64;
+}
+
+internal Rng1U64
+bit_array_scan_left_to_right32_contiguous(U32Array bit_array, U64 lo, U64 hi, B32 state, U64 in_row_count)
+{
+  Rng1U64 result = rng_1u64(max_U64, max_U64);
+  
+  U64 curr_count = 0, rover = lo;
+  while (curr_count < in_row_count) {
+    rover = bit_array_scan_left_to_right32(bit_array, rover, hi, state);
+    
+    // no more bits in range
+    if (rover >= hi) {
+      break;
+    }
+    
+    // set first match
+    if (result.v[0] == max_U64) {
+      result = rng_1u64(rover, rover);
+      continue;
+    }
+    
+    // reset on non-contiguous range
+    B32 is_bit_index_not_adjoined = (result.v[0] + 1 < rover);
+    if (is_bit_index_not_adjoined) {
+      curr_count = 0;
+      result = rng_1u64(max_U64, max_U64);
+      continue;
+    }
+    
+    // advance
+    result.v[1] = rover;
+    curr_count -= 1;
+  }
+  
+  // did we allocate enough bits?
+  if (curr_count != in_row_count) {
+    result = rng_1u64(max_U64, max_U64);
+  }
+  
+  return result;
+}
+
+internal Rng1U64
+bit_array_scan_right_to_left32_contiguous(U32Array bit_array, U64 lo, U64 hi, B32 state, U64 in_row_count)
+{
+  Rng1U64 result = rng_1u64(max_U64, max_U64);
+  
+  U64 curr_count = 0, rover = lo;
+  while (curr_count < in_row_count) {
+    rover = bit_array_scan_right_to_left32(bit_array, lo, rover, state);
+    
+    // no more bits in range
+    if (rover >= hi) {
+      break;
+    }
+    
+    // set first match
+    if (result.v[0] == max_U64) {
+      result = rng_1u64(rover, rover);
+      continue;
+    }
+    
+    // reset on non-contiguous range
+    B32 is_bit_index_not_adjoined = (result.v[0] + 1 < rover);
+    if (is_bit_index_not_adjoined) {
+      curr_count = 0;
+      result = rng_1u64(max_U64, max_U64);
+      continue;
+    }
+    
+    // advance
+    result.v[0] = rover;
+    curr_count -= 1;
+  }
+  
+  // did we allocate enough bits?
+  if (curr_count != in_row_count) {
+    result = rng_1u64(max_U64, max_U64);
+  }
+  
+  return result;
+}
+
+internal U64
+bit_array_find_next_unset_bit32(U32Array bit_array)
+{
+  U64 result = bit_array_scan_left_to_right32(bit_array, 0, bit_array.count*32, 0);
+  return result;
+}
+
+internal U64
+bit_array_find_next_set_bit32(U32Array bit_array)
+{
+  U64 result = bit_array_scan_left_to_right32(bit_array, 0, bit_array.count*32, 1);
+  return result;
+}
+
+internal void
+bit_array_set_bit32(U32Array bit_array, U64 idx, B32 state)
+{
+  Assert(idx < bit_array.count*32);
+  U64 word_idx = idx / 32;
+  U64 bit_idx = idx % 32;
+  if (state) {
+    bit_array.v[word_idx] |= (1 << bit_idx);
+  } else {
+    bit_array.v[word_idx] &= ~(1 << bit_idx);
+  }
+}
+
+internal void
+bit_array_set_bit_range32(U32Array bit_array, Rng1U64 range, B32 state)
+{
+  for (U64 idx = range.min ; idx < range.max; idx += 1) {
+    bit_array_set_bit32(bit_array, idx, state);
+  }
+}
+
+internal U32
+bit_array_get_bit32(U32Array bit_array, U64 idx)
+{
+  Assert(idx < bit_array.count*32);
+  U64 word_idx = idx / 32;
+  U64 bit_idx = idx % 32;
+  U32 bit = (bit_array.v[word_idx] & (1 << bit_idx)) >> bit_idx;
+  return bit;
+}
+
+internal B32
+bit_array_is_bit_set(U32Array bit_arr, U64 bit_pos)
+{
+  U64 word_idx = bit_pos / 32;
+  Assert(word_idx < bit_arr.count);
+  U32 word = bit_arr.v[word_idx];
+  U64 bit_idx = bit_pos % 32;
+  B32 is_set = !!(word & (1 << bit_idx));
+  return is_set;
+}
+
+