4.1

1 files changed, 91 insertions, 0 deletions

diff --git a/zen/read_txt.cpp b/zen/read_txt.cpp
new file mode 100644
index 00000000..fd92a10c
--- /dev/null
+++ b/zen/read_txt.cpp
@@ -0,0 +1,91 @@
+#include "read_txt.h"
+
+using namespace zen;
+
+
+namespace
+{
+std::string detectLineBreak(const Zstring& filename) //throw (FileError)
+{
+    //read a (hopefully) significant portion of data
+    zen::FileInput input(filename);
+
+    std::vector<char> buffer(64 * 1024);
+    size_t bytesRead = input.read(&buffer[0], buffer.size()); //throw (FileError);
+    buffer.resize(bytesRead);
+
+    //detect line break
+    std::string linebreakChars = "\r\n";
+    std::vector<char>::iterator iter = std::find_first_of(buffer.begin(), buffer.end(),
+                                                          linebreakChars.begin(), linebreakChars.end());
+    if (iter != buffer.end())
+    {
+        if (*iter == '\r')
+        {
+            ++iter;
+            if (iter != buffer.end())
+            {
+
+                if (*iter == '\n')
+                    return "\r\n"; //Windows
+                else
+                    return "\r"; //Mac
+            }
+        }
+        else if (*iter == '\n')
+            return "\n"; //Linux
+    }
+    //fallback
+    return "\n";
+}
+}
+
+
+ExtractLines::ExtractLines(const Zstring& filename, const std::string& lineBreak) :  //throw (FileError)
+    inputStream(filename), bufferLogBegin(buffer.begin()), lineBreak_(lineBreak)
+{
+    if (lineBreak.empty())
+        lineBreak_ = detectLineBreak(filename); //throw (FileError)
+}
+
+
+bool ExtractLines::getLine(std::string& output) //throw (FileError)
+{
+    for (;;)
+    {
+        //check if full line is in buffer
+        std::vector<char>::iterator iter = std::search(bufferLogBegin, buffer.end(), lineBreak_.begin(), lineBreak_.end());
+        if (iter != buffer.end())
+        {
+            output.assign(bufferLogBegin, iter);
+            bufferLogBegin = iter + lineBreak_.size();
+            return true;
+        }
+
+        buffer.erase(buffer.begin(), bufferLogBegin);
+        bufferLogBegin = buffer.begin();
+
+        //if done: cleanup
+        if (inputStream.eof())
+        {
+            if (buffer.empty())
+                return false;
+
+            output.assign(buffer.begin(), buffer.end());
+            buffer.clear();
+            return true;
+        }
+
+        //read next block
+        const size_t BLOCK_SIZE = 512 * 1024;
+        buffer.resize(buffer.size() + BLOCK_SIZE);
+
+        size_t bytesRead = inputStream.read(&buffer[0] + buffer.size() - BLOCK_SIZE, BLOCK_SIZE); //throw (FileError);
+        assert(bytesRead <= BLOCK_SIZE); //promised by FileInput()
+
+        if (bytesRead < BLOCK_SIZE)
+            buffer.resize(buffer.size() - (BLOCK_SIZE - bytesRead));
+
+        bufferLogBegin = buffer.begin();
+    }
+}