From 17a3ea880402338420699e03bcb24181e4ff3924 Mon Sep 17 00:00:00 2001
From: Rutger Broekhoff
Date: Thu, 2 May 2024 20:27:40 +0200
Subject: Initial commit

Based on dc4ba6a
---
 lib/libtmi8/src/kv1_lexer.cpp | 152 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 152 insertions(+)
 create mode 100644 lib/libtmi8/src/kv1_lexer.cpp

(limited to 'lib/libtmi8/src/kv1_lexer.cpp')

diff --git a/lib/libtmi8/src/kv1_lexer.cpp b/lib/libtmi8/src/kv1_lexer.cpp
new file mode 100644
index 0000000..028127b
--- /dev/null
+++ b/lib/libtmi8/src/kv1_lexer.cpp
@@ -0,0 +1,152 @@
+// vim:set sw=2 ts=2 sts et:
+
+#include <tmi8/kv1_lexer.hpp>
+
+Kv1Lexer::Kv1Lexer(std::string_view input)
+  : input(input), slice(input)
+{}
+
+// Does not eat newline character.
+void Kv1Lexer::eatRestOfLine() {
+  size_t end = slice.size();
+  for (size_t i = 0; i < slice.size(); i++) {
+    if (slice[i] == '\r' || slice[i] == '\n') {
+      end = i;
+      break;
+    }
+  }
+  slice = slice.substr(end);
+}
+
+void Kv1Lexer::lexOptionalHeader() {
+  if (slice.starts_with('[')) eatRestOfLine();
+}
+
+void Kv1Lexer::lexOptionalComment() {
+  if (slice.starts_with(';')) eatRestOfLine();
+}
+
+inline bool Kv1Lexer::isWhitespace(int c) {
+  return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == '\v';
+}
+
+void Kv1Lexer::readQuotedColumn() {
+  Kv1Token token{ .type = KV1_TOKEN_CELL };
+
+  if (slice.size() == 0 || slice[0] != '"') {
+    errors.push_back("(internal error) readQuotedColumn: slice[0] != '\"'");
+    return;
+  }
+  slice = slice.substr(1);
+  while (true) {
+    size_t quote = slice.find('"');
+    if (quote == std::string_view::npos) {
+      errors.push_back("readQuotedColumn: no matching closing quote found");
+      return;
+    }
+    if (quote+1 == slice.size() || slice[quote + 1] != '"') {
+      token.data.append(slice.substr(0, quote));
+      break;
+    }
+    token.data.append(slice.substr(0, quote + 1));
+    slice = slice.substr(quote + 2);
+  }
+
+  size_t end = slice.size();
+  for (size_t i = 0; i < slice.size(); i++) {
+    if (slice[i] == '|' || slice[i] == '\r' || slice[i] == '\n') {
+      end = i;
+      break;
+    }
+    if (!isWhitespace(slice[i])) {
+      errors.push_back("readQuotedColumn: encountered non-whitespace character after closing quote");
+      return;
+    }
+  }
+  if (end != std::string_view::npos) slice = slice.substr(end);
+  else slice = slice.substr(slice.size());
+
+  tokens.push_back(std::move(token));
+}
+
+void Kv1Lexer::readUnquotedColumn() {
+  size_t end = slice.size();
+  size_t content_end = 0;
+  for (size_t i = 0; i < slice.size(); i++) {
+    if (slice[i] == '|' || slice[i] == '\r' || slice[i] == '\n') {
+      end = i;
+      break;
+    } else if (!isWhitespace(slice[i])) {
+      content_end = i + 1;
+    }
+  }
+  tokens.emplace_back(KV1_TOKEN_CELL, std::string(slice.substr(0, content_end)));
+  if (end != std::string_view::npos) slice = slice.substr(end);
+  else slice = slice.substr(slice.size());
+}
+
+void Kv1Lexer::lexRow() {
+  size_t cols = 0;
+  while (slice.size() > 0 && slice[0] != '\r' && slice[0] != '\n') {
+    if (slice[0] == '"') readQuotedColumn();
+    else readUnquotedColumn();
+    if (!errors.empty()) return;
+    cols++;
+    if (slice.size() != 0) {
+      if (slice[0] == '|') {
+        slice = slice.substr(1);
+        // A newline/eof right after pipe? That means an empty field at the end
+        // of the record, we also want to emit that as a token.
+        if (slice.size() == 0 || slice[0] == '\r' || slice[0] == '\n') {
+          tokens.push_back({ .type = KV1_TOKEN_CELL });
+        }
+      } else if (slice[0] == '\r') {
+        if (slice.size() > 1 && slice[1] == '\n') slice = slice.substr(2);
+        else slice = slice.substr(1);
+        break;
+      } else if (slice[0] == '\n') {
+        slice = slice.substr(1);
+        break;
+      } else {
+        errors.push_back("lexRow: expected CR, LF or |");
+        return;
+      }
+    }
+  }
+  tokens.push_back({ .type = KV1_TOKEN_ROW_END });
+}
+
+// Returns true when a line ending was consumed.
+bool Kv1Lexer::eatWhitespace() {
+  for (size_t i = 0; i < slice.size(); i++) {
+    if (slice[i] == '\r') {
+      slice = slice.substr(i + 1);
+      if (slice.size() > 1 && slice[i + 1] == '\n')
+        slice = slice.substr(i + 2);
+      return true;
+    }
+    if (slice[i] == '\n') {
+      slice = slice.substr(i + 1);
+      return true;
+    }
+    
+    if (slice[i] != ' ' && slice[i] != '\f' && slice[i] != '\t' && slice[i] != '\v') {
+      slice = slice.substr(i);
+      return false;
+    }
+  }
+  return false;
+}
+
+void Kv1Lexer::lex() {
+  lexOptionalHeader();
+  eatWhitespace();
+
+  while (errors.empty() && !slice.empty()) {
+    lexOptionalComment();
+    bool newline = eatWhitespace();
+    if (newline) continue;
+    // We are now either (1) at the end of the file or (2) at the start of some column data
+    if (errors.empty()) lexRow();
+  }
+}
-- 
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