Setup basic piece table like data structure.

include/pch.h

@@ -1,5 +1,4 @@
-#ifndef PCH_H
-#define PCH_H
+#pragma once
 
 #define PCRE2_CODE_UNIT_WIDTH 8
 #define PCRE_WORKSPACE_SIZE 512
@@ -54,5 +53,3 @@ extern "C" {
 #include <vector>
 
 using namespace std::chrono_literals;
-
-#endif

include/vase/append_buffer.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "pch.h"
+
+struct AppendBuffer {
+  static constexpr uint32_t CHUNK_SIZE = 1 << 16;
+  using TChunk = char[CHUNK_SIZE];
+  std::vector<TChunk *> buf;
+  TChunk *t_current;
+  uint32_t current_offset{0};
+  uint32_t t_offset{0};
+
+  using LChunk = uint32_t[CHUNK_SIZE];
+  std::vector<LChunk *> newlines;
+  LChunk *l_current;
+  uint32_t l_offset{0};
+
+  AppendBuffer();
+
+  ~AppendBuffer();
+
+  inline void key(char c);
+  void append(const char *text, uint32_t length);
+
+private:
+  inline void new_text_chunk();
+  inline void new_line_chunk();
+
+  inline void _append(const char *text, uint32_t length);
+};

include/vase/original_buffer.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include "pch.h"
+
+struct OriginalBuffer {
+  char *buf;
+  uint32_t length;
+  std::vector<uint32_t> newlines;
+
+  // TODO: replace with file io or even lazy loaded file io for large files/logs etc. later.
+  OriginalBuffer(char *buf, uint32_t length) : buf(buf), length(length) {
+    const char *p = buf;
+    const char *end = buf + length;
+    while (p < end) {
+      p = (const char *)memchr(p, '\n', end - p);
+      if (!p)
+        break;
+      newlines.push_back(uint32_t(p - buf));
+      p++;
+    }
+  }
+
+  ~OriginalBuffer() {
+    free(buf);
+  }
+};

include/vase/shard.h

@@ -0,0 +1,69 @@
+#pragma once
+
+#include "pch.h"
+
+struct Shard {
+  enum struct ShardKind {
+    Branch,
+    Petal
+  } kind;
+
+  uint32_t length;
+  uint32_t lines;
+
+  std::atomic_uint32_t refs;
+
+  Shard(ShardKind kind, uint32_t length, uint32_t lines)
+      : kind(kind), length(length), lines(lines) {};
+};
+
+struct ShardPtr {
+  Shard *ptr;
+
+  ShardPtr(const ShardPtr &other) : ptr(other.ptr) {
+    if (ptr)
+      ptr->refs++;
+  }
+
+  ShardPtr &operator=(const ShardPtr &other) {
+    if (ptr == other.ptr)
+      return *this;
+    if (ptr && --ptr->refs == 0)
+      delete ptr;
+    ptr = other.ptr;
+    if (ptr)
+      ptr->refs++;
+    return *this;
+  }
+
+  ShardPtr(Shard *p = nullptr) : ptr(p) {
+    if (ptr)
+      ptr->refs++;
+  }
+
+  ~ShardPtr() {
+    if (ptr && --ptr->refs == 0)
+      delete ptr;
+  }
+};
+
+struct Branch : Shard {
+  ShardPtr left;
+  ShardPtr right;
+
+  Branch(Shard *l, Shard *r)
+      : Shard(ShardKind::Branch, l->length + r->length, l->lines + r->lines),
+        left(ShardPtr(l)), right(ShardPtr(r)) {};
+};
+
+struct Petal : Shard {
+  enum struct Kind {
+    Original,
+    Append
+  } source;
+
+  uint32_t pos;
+
+  Petal(uint32_t length, uint32_t lines, Kind source, uint32_t pos)
+      : Shard(ShardKind::Petal, length, lines), source(source), pos(pos) {};
+};

include/vase/vase.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "append_buffer.h"
+#include "original_buffer.h"
+#include "pch.h"
+#include "shard.h"
+
+struct Vase {
+  OriginalBuffer original;
+  AppendBuffer append;
+
+  std::vector<ShardPtr> undo;
+  uint8_t top; // of the undo stack.
+  uint8_t max; // for redo when no edits have been done after some undo.
+
+  ShardPtr root;
+
+  Vase(char *data, uint32_t length)
+      : original(data, length),
+        append() {
+    root = new Petal(
+      length,
+      original.newlines.size(),
+      Petal::Kind::Original,
+      0
+    );
+  }
+};

src/main.cc

@@ -1,3 +1,5 @@
 #include "pch.h"
 
-int main() { return 0; }
+int main() {
+  return 0;
+}

src/vase/append_buffer.cc

@@ -0,0 +1,71 @@
+#include "vase/append_buffer.h"
+
+AppendBuffer::AppendBuffer() {
+  new_text_chunk();
+  new_line_chunk();
+}
+
+AppendBuffer::~AppendBuffer() {
+  for (auto p : buf)
+    free(p);
+  for (auto p : newlines)
+    free(p);
+}
+
+inline void AppendBuffer::key(char c) {
+  if (t_offset == CHUNK_SIZE)
+    new_text_chunk();
+  (*t_current)[t_offset++] = c;
+  if (c == '\n') {
+    if (l_offset == CHUNK_SIZE)
+      new_line_chunk();
+    (*l_current)[l_offset++] = current_offset;
+  }
+  ++current_offset;
+}
+
+void AppendBuffer::append(const char *text, uint32_t length) {
+  while (length) {
+    uint32_t space = CHUNK_SIZE - t_offset;
+    if (space == 0) {
+      new_text_chunk();
+      space = CHUNK_SIZE;
+    }
+    uint32_t copy = length < space ? length : space;
+    _append(text, copy);
+    text += copy;
+    length -= copy;
+  }
+}
+
+inline void AppendBuffer::new_text_chunk() {
+  t_current = (TChunk *)malloc(sizeof(TChunk));
+  buf.push_back(t_current);
+  t_offset = 0;
+}
+
+inline void AppendBuffer::new_line_chunk() {
+  l_current = (LChunk *)malloc(sizeof(LChunk));
+  newlines.push_back(l_current);
+  l_offset = 0;
+}
+
+inline void AppendBuffer::_append(const char *text, uint32_t length) {
+  memcpy((*t_current) + t_offset, text, length);
+
+  const char *p = text;
+  const char *end = text + length;
+
+  while (p < end) {
+    p = (const char *)memchr(p, '\n', end - p);
+    if (!p)
+      break;
+    if (l_offset == CHUNK_SIZE)
+      new_line_chunk();
+    (*l_current)[l_offset++] = current_offset + uint32_t(p - text);
+    p++;
+  }
+
+  t_offset += length;
+  current_offset += length;
+}