diff --git a/src/ifcparse/file_reader.cpp b/src/ifcparse/file_reader.cpp
index 75d5b92213..549b7de335 100644
--- a/src/ifcparse/file_reader.cpp
+++ b/src/ifcparse/file_reader.cpp
@@ -75,33 +75,6 @@ full_buffer_impl::full_buffer_impl(const std::string& content, const caller_fed_
     , size_(content.size()) {
 }
 
-size_t full_buffer_impl::size() const { return size_; }
-
-char full_buffer_impl::get(size_t pos) const {
-    if (pos >= buf_.size()) {
-        throw std::out_of_range("get out of range");
-    }
-    return buf_[pos];
-}
-
-uint64_t full_buffer_impl::get_u64(size_t pos) const {
-    if (pos + sizeof(uint64_t) > buf_.size()) {
-        throw std::out_of_range("get_u64 out of range");
-    }
-    uint64_t value;
-    std::memcpy(&value, buf_.data() + pos, sizeof(value));
-    return value;
-}
-
-uint32_t full_buffer_impl::get_u32(size_t pos) const {
-    if (pos + sizeof(uint32_t) > buf_.size()) {
-        throw std::out_of_range("get_u32 out of range");
-    }
-    uint32_t value;
-    std::memcpy(&value, buf_.data() + pos, sizeof(value));
-    return value;
-}
-
 void full_buffer_impl::push_next_page(const std::string& data) {
     buf_.insert(buf_.end(), data.begin(), data.end());
     size_ = buf_.size();
@@ -247,33 +220,6 @@ mmap_impl::mmap_impl(const std::string& fn) {
     size_ = static_cast<size_t>(map_.size());
 }
 
-size_t mmap_impl::size() const { return size_; }
-
-char mmap_impl::get(size_t pos) const {
-    if (pos >= size_) {
-        throw std::out_of_range("get out of range");
-    }
-    return map_.data()[pos];
-}
-
-uint64_t mmap_impl::get_u64(size_t pos) const {
-    if (pos + sizeof(uint64_t) > size_) {
-        throw std::out_of_range("get_u64 out of range");
-    }
-    uint64_t value;
-    std::memcpy(&value, map_.data() + pos, sizeof(value));
-    return value;
-}
-
-uint32_t mmap_impl::get_u32(size_t pos) const {
-    if (pos + sizeof(uint32_t) > size_) {
-        throw std::out_of_range("get_u32 out of range");
-    }
-    uint32_t value;
-    std::memcpy(&value, map_.data() + pos, sizeof(value));
-    return value;
-}
-
 void mmap_impl::push_next_page(const std::string&) {
     throw std::logic_error("push_next_page: backend does not support pushed mode");
 }
diff --git a/src/ifcparse/file_reader.h b/src/ifcparse/file_reader.h
index a8f924782a..66748b91f3 100644
--- a/src/ifcparse/file_reader.h
+++ b/src/ifcparse/file_reader.h
@@ -37,6 +37,7 @@
 #include <memory>
 #include <stdexcept>
 #include <string>
+#include <cstring>
 #include <type_traits>
 #include <unordered_map>
 #include <utility>
@@ -201,10 +202,29 @@ public:
     explicit full_buffer_impl(const caller_fed_tag& tag);
     full_buffer_impl(const std::string& content, const caller_fed_tag& tag);
 
-    size_t size() const;
-    char get(size_t position) const;
-    uint32_t get_u32(size_t position) const;
-    uint64_t get_u64(size_t position) const;
+    size_t size() const { return size_; }
+    char get(size_t position) const {
+        if (position >= size_) {
+            throw std::out_of_range("get out of range");
+        }
+        return buf_.data()[position];
+    }
+    uint32_t get_u32(size_t position) const {
+        if (position + sizeof(uint32_t) > size_) {
+            throw std::out_of_range("get_u32 out of range");
+        }
+        uint32_t value;
+        std::memcpy(&value, buf_.data() + position, sizeof(value));
+        return value;
+    }
+    uint64_t get_u64(size_t position) const {
+        if (position + sizeof(uint64_t) > size_) {
+            throw std::out_of_range("get_u64 out of range");
+        }
+        uint64_t value;
+        std::memcpy(&value, buf_.data() + position, sizeof(value));
+        return value;
+    }
     void push_next_page(const std::string& page_data);
     void drop_pages(size_t up_to_position);
 
@@ -249,10 +269,29 @@ class IFC_PARSE_API mmap_impl {
 public:
     explicit mmap_impl(const std::string& path);
 
-    size_t size() const;
-    char get(size_t position) const;
-    uint32_t get_u32(size_t position) const;
-    uint64_t get_u64(size_t position) const;
+    size_t size() const { return size_; }
+    char get(size_t position) const {
+        if (position >= size_) {
+            throw std::out_of_range("get out of range");
+        }
+        return map_.data()[position];
+    }
+    uint32_t get_u32(size_t position) const {
+        if (position + sizeof(uint32_t) > size_) {
+            throw std::out_of_range("get_u32 out of range");
+        }
+        uint32_t value;
+        std::memcpy(&value, map_.data() + position, sizeof(value));
+        return value;
+    }
+    uint64_t get_u64(size_t position) const {
+        if (position + sizeof(uint64_t) > size_) {
+            throw std::out_of_range("get_u64 out of range");
+        }
+        uint64_t value;
+        std::memcpy(&value, map_.data() + position, sizeof(value));
+        return value;
+    }
     void push_next_page(const std::string& page_data);
     void drop_pages(size_t up_to_position);
 
diff --git a/src/ifcparse/parse.cpp b/src/ifcparse/parse.cpp
index 8ab7fe12e5..7d25a0c3da 100644
--- a/src/ifcparse/parse.cpp
+++ b/src/ifcparse/parse.cpp
@@ -2412,6 +2412,9 @@ void ifcopenshell::impl::in_memory_file_storage::read_from_stream(Reader* s, con
     std::vector<std::string> schemas;
 
     instance_streamer<Reader> streamer(s, file, logger_.get());
+    // One inverse record per ~32 bytes of SPF text is a slight over-estimate on
+    // real models; reserving avoids the doubling copies and the capacity slack.
+    streamer.inverses().reserve(s->size() / 32);
     streamer.yield_header_instances(false);
 
     if (const auto* header = streamer.header()) {
diff --git a/src/ifcparse/storage.h b/src/ifcparse/storage.h
index 2322bb449b..d889ff889d 100644
--- a/src/ifcparse/storage.h
+++ b/src/ifcparse/storage.h
@@ -448,6 +448,7 @@ namespace ifcopenshell {
             void sort() const {
                 if (!sorted_) {
                     std::sort(base_.begin(), base_.end(), record_less);
+                    base_.shrink_to_fit();
                     sorted_ = true;
                     invalidate_materialized();
                 }