Change TextLoader for gap buffer approach

- for CR line endings, convert all CR to LF
- for CRLF line endings, convert all CRLF to LF

src/core/TextLoader.cc

@@ -1,68 +1,65 @@
 #include "TextLoader.h"
 #include <stdint.h>
+#include <string.h>
 
 /** Create a TextLoader. */
 TextLoader::TextLoader()
 {
     m_line_endings = LineEndings::LF;
     m_encoding = Encoding::UTF_8;
-    m_lines = NULL;
     m_eol_at_eof = true;
+    m_num_lines = 0u;
 }
 
 /**
  * Scan text to detect line endings and record their positions.
  *
  * @param buffer Buffer containing the text to import.
- * @param size Size of the buffer.
+ * @param size Size of the text to load. The buffer must be at least one
+ *   byte larger than this.
+ * @param out_size Size of the loaded buffer.
  */
-void TextLoader::load_buffer(uint8_t * buffer, size_t size)
+void TextLoader::load_buffer(uint8_t * buffer, size_t size, size_t * out_size)
 {
-    std::shared_ptr<std::list<Span>> lines[LineEndings::COUNT];
-    size_t line_start[LineEndings::COUNT] = {0};
-    unsigned int n_cr = 0;
-    unsigned int n_lf = 0;
+    std::list<size_t> cr_indexes;
+    size_t n_lines[LineEndings::COUNT] = {0};
     bool crlf = true;
-    for (size_t i = 0; i < LineEndings::COUNT; i++)
-    {
-        lines[i] = std::make_shared<std::list<Span>>();
-    }
+    size_t next_start_of_line_index = 0u;
+    size_t out_size_local = size;
     for (size_t i = 0; i < size; i++)
     {
         if (buffer[i] == '\r')
         {
-            lines[LineEndings::CR]->push_back(Span(&buffer[line_start[LineEndings::CR]], i - line_start[LineEndings::CR]));
-            n_cr++;
-            line_start[LineEndings::CR] = i + 1;
+            cr_indexes.push_back(i);
+            n_lines[LineEndings::CR]++;
             if (crlf)
             {
                 if ((i < (size - 1)) && (buffer[i + 1] == '\n'))
                 {
-                    lines[LineEndings::CRLF]->push_back(Span(&buffer[line_start[LineEndings::CRLF]], i - line_start[LineEndings::CRLF]));
-                    n_lf++;
+                    n_lines[LineEndings::LF]++;
+                    n_lines[LineEndings::CRLF]++;
                     i++;
-                    line_start[LineEndings::CRLF] = i + 1;
                 }
                 else
                 {
                     crlf = false;
                 }
             }
+            next_start_of_line_index = i + 1;
         }
         else if (buffer[i] == '\n')
         {
-            lines[LineEndings::LF]->push_back(Span(&buffer[line_start[LineEndings::LF]], i - line_start[LineEndings::LF]));
             crlf = false;
-            n_lf++;
-            line_start[LineEndings::LF] = i + 1;
+            n_lines[LineEndings::LF]++;
+            next_start_of_line_index = i + 1;
         }
     }
 
-    if (crlf && (n_lf > 0u))
+    if (crlf && (n_lines[LineEndings::LF] > 0u))
     {
         m_line_endings = LineEndings::CRLF;
     }
-    else if ((n_cr > 0u) && (n_lf == 0u))
+    else if ((n_lines[LineEndings::CR] > 0u) && (n_lines[LineEndings::LF] == 0u))
     {
         m_line_endings = LineEndings::CR;
     }
@@ -71,15 +68,53 @@ void TextLoader::load_buffer(uint8_t * buffer, size_t size)
         m_line_endings = LineEndings::LF;
     }
 
-    m_lines = lines[m_line_endings];
+    m_num_lines = n_lines[m_line_endings];
 
     /* Check if there is a line that was not terminated by a EOL sequence at
      * the end of the file. */
-    if (line_start[m_line_endings] < size)
+    if (next_start_of_line_index < size)
     {
-        m_lines->push_back(Span(&buffer[line_start[m_line_endings]], size - line_start[m_line_endings]));
+        m_num_lines++;
         m_eol_at_eof = false;
+        if (crlf)
+        {
+            cr_indexes.push_back(size);
+        }
+        else
+        {
+            buffer[size] = '\n';
+            out_size_local++;
+        }
     }
 
     m_encoding = Encoding::detect_encoding(buffer, size);
+
+    if (m_line_endings == LineEndings::CRLF)
+    {
+        /* Compress all CRLF sequences to LF in memory. */
+        size_t dest = 0u;
+        size_t src = 0u;
+        for (auto cr_index : cr_indexes)
+        {
+            size_t size = cr_index - src;
+            if ((src != dest) && (size > 0u))
+            {
+                memmove(&buffer[dest], &buffer[src], size);
+            }
+            dest += size;
+            src = cr_index + 2u;
+            buffer[dest++] = '\n';
+        }
+        out_size_local = dest;
+    }
+    else if (m_line_endings == LineEndings::CR)
+    {
+        /* Convert all \r to \n */
+        for (auto cr_index : cr_indexes)
+        {
+            buffer[cr_index] = '\n';
+        }
+    }
+
+    *out_size = out_size_local;
 }

src/core/TextLoader.h

@@ -12,29 +12,20 @@ class TextLoader
 {
 public:
     TextLoader();
-    void load_buffer(uint8_t * buffer, size_t size);
+    void load_buffer(uint8_t * buffer, size_t size, size_t * out_size);
     size_t num_lines()
     {
-        if (m_lines == nullptr)
-        {
-            return 0u;
-        }
-        else
-        {
-            return m_lines->size();
-        }
+        return m_num_lines;
     }
     LineEndings::Type get_line_endings() { return m_line_endings; }
     Encoding::Type get_encoding() { return m_encoding; }
-    auto begin() { return m_lines->begin(); }
-    auto end() { return m_lines->end(); }
     bool get_eol_at_eof() { return m_eol_at_eof; }
 
 protected:
     LineEndings::Type m_line_endings;
     Encoding::Type m_encoding;
     bool m_eol_at_eof;
-    std::shared_ptr<std::list<Span>> m_lines;
+    size_t m_num_lines;
 };
 
 #endif