Setup basic piece table like data structure.

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;
+}