1 files changed, 164 insertions, 0 deletions
diff --git a/src/base/line_range.hh b/src/base/line_range.hh
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--- /dev/null
+++ b/src/base/line_range.hh
@@ -0,0 +1,164 @@
+/**
+ * Copyright (c) 2023, Timothy Stack
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * * Neither the name of Timothy Stack nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef lnav_base_line_range_hh
+#define lnav_base_line_range_hh
+
+#include <string>
+
+/**
+ * Encapsulates a range in a string.
+ */
+struct line_range {
+    enum class unit {
+        bytes,
+        codepoint,
+    };
+
+    int lr_start;
+    int lr_end;
+    unit lr_unit;
+
+    explicit line_range(int start = -1, int end = -1, unit u = unit::bytes)
+        : lr_start(start), lr_end(end), lr_unit(u)
+    {
+    }
+
+    bool is_valid() const { return this->lr_start != -1; }
+
+    int length() const
+    {
+        return this->lr_end == -1 ? INT_MAX : this->lr_end - this->lr_start;
+    }
+
+    bool empty() const { return this->length() == 0; }
+
+    void clear()
+    {
+        this->lr_start = -1;
+        this->lr_end = -1;
+    }
+
+    int end_for_string(const std::string& str) const
+    {
+        return this->lr_end == -1 ? str.length() : this->lr_end;
+    }
+
+    bool contains(int pos) const
+    {
+        return this->lr_start <= pos
+            && (this->lr_end == -1 || pos < this->lr_end);
+    }
+
+    bool contains(const struct line_range& other) const
+    {
+        return this->contains(other.lr_start)
+            && (this->lr_end == -1 || other.lr_end <= this->lr_end);
+    }
+
+    bool intersects(const struct line_range& other) const
+    {
+        if (this->contains(other.lr_start)) {
+            return true;
+        }
+        if (other.lr_end > 0 && this->contains(other.lr_end - 1)) {
+            return true;
+        }
+        if (other.contains(this->lr_start)) {
+            return true;
+        }
+
+        return false;
+    }
+
+    line_range intersection(const struct line_range& other) const;
+
+    line_range& shift(int32_t start, int32_t amount);
+
+    line_range& shift_range(const line_range& cover, int32_t amount);
+
+    void ltrim(const char* str)
+    {
+        while (this->lr_start < this->lr_end && isspace(str[this->lr_start])) {
+            this->lr_start += 1;
+        }
+    }
+
+    bool operator<(const struct line_range& rhs) const
+    {
+        if (this->lr_start < rhs.lr_start) {
+            return true;
+        }
+        if (this->lr_start > rhs.lr_start) {
+            return false;
+        }
+
+        // this->lr_start == rhs.lr_start
+        if (this->lr_end == rhs.lr_end) {
+            return false;
+        }
+
+        // When the start is the same, the longer range has a lower priority
+        // than the shorter range.
+        if (rhs.lr_end == -1) {
+            return false;
+        }
+
+        if ((this->lr_end == -1) || (this->lr_end > rhs.lr_end)) {
+            return true;
+        }
+        return false;
+    }
+
+    bool operator==(const struct line_range& rhs) const
+    {
+        return (this->lr_start == rhs.lr_start && this->lr_end == rhs.lr_end);
+    }
+
+    const char* substr(const std::string& str) const
+    {
+        if (this->lr_start == -1) {
+            return str.c_str();
+        }
+        return &(str.c_str()[this->lr_start]);
+    }
+
+    size_t sublen(const std::string& str) const
+    {
+        if (this->lr_start == -1) {
+            return str.length();
+        }
+        if (this->lr_end == -1) {
+            return str.length() - this->lr_start;
+        }
+        return this->length();
+    }
+};
+
+#endif