Factor out growth of String and make it scale by 1.5x.

1 files changed, 56 insertions, 15 deletions

diff --git a/source/fud_string.cpp b/source/fud_string.cpp
index 4dddedb..33e41c3 100644
--- a/source/fud_string.cpp
+++ b/source/fud_string.cpp
@@ -327,6 +327,42 @@ FudStatus String::nullTerminate()
     return FudStatus::StringInvalid;
 }
 
+FudStatus String::grow()
+{
+    auto cap = capacity();
+    if (cap >= maxStringLength) {
+        return FudStatus::Full;
+    }
+    size_t additional = cap / 2;
+    if (maxStringLength - additional < cap) {
+        additional = maxStringLength - cap;
+    }
+
+    FudStatus reserveStatus{};
+    while (additional > 0) {
+        reserveStatus = reserve(additional + cap);
+        if (reserveStatus == FudStatus::Success) {
+            break;
+        }
+        if (reserveStatus == FudStatus::AllocFailure) {
+            additional /= 2;
+        } else {
+            return reserveStatus;
+        }
+    }
+    if (reserveStatus != FudStatus::Success) {
+        return reserveStatus;
+    }
+
+    auto newCapacity = cap < maxStringLength / 2 ? cap * 2 : maxStringLength - 1U;
+    const auto resizeStatus = resize(newCapacity);
+    if (resizeStatus != FudStatus::Success) {
+        return resizeStatus;
+    }
+    fudAssert(isLarge());
+    fudAssert(m_repr.large.capacity == newCapacity);
+}
+
 FudStatus String::reserve(size_t newCapacity)
 {
     if (!valid()) {
@@ -391,15 +427,12 @@ FudStatus String::pushBack(utf8 letter)
         return FudStatus::StringInvalid;
     }
 
-    if (remainingLength() < 1) {
-        auto cap = capacity() + 1U;
-        auto newCapacity = cap < maxStringLength / 2 ? cap * 2 : maxStringLength - 1U;
-        const auto resizeStatus = resize(newCapacity);
-        if (resizeStatus != FudStatus::Success) {
-            return resizeStatus;
+    if (remainingCapacity() < 1) {
+        auto growStatus = grow();
+        if (growStatus != FudStatus::Success) {
+            return growStatus;
         }
         fudAssert(isLarge());
-        fudAssert(m_repr.large.capacity == newCapacity);
     }
 
     if (isLarge()) {
@@ -431,7 +464,15 @@ FudStatus String::pushBack(const FudUtf8& letter)
     }
 
     auto letterSize = letter.size();
-    if (remainingLength() < letterSize) {
+    if (remainingCapacity() < letterSize) {
+        auto growStatus = grow();
+        if (growStatus != FudStatus::Success) {
+            return growStatus;
+        }
+        fudAssert(isLarge());
+    }
+
+    if (remainingCapacity() < letterSize) {
         auto cap = capacity() + 1U;
         auto newCapacity = cap < maxStringLength / 2 ? cap * 2 : maxStringLength - 1U;
         if ((newCapacity - cap) < (letterSize + 1)) {
@@ -445,7 +486,7 @@ FudStatus String::pushBack(const FudUtf8& letter)
         fudAssert(m_repr.large.capacity == newCapacity);
     }
 
-    auto copyStatus = copyMem(dataMut() + length(), remainingLength(), letterData, letterSize);
+    auto copyStatus = copyMem(dataMut() + length(), remainingCapacity(), letterData, letterSize);
 
     if (copyStatus != FudStatus::Success) {
         return copyStatus;
@@ -506,7 +547,7 @@ FudStatus String::append(StringView source)
     }
 
     auto* destPtr = dataMut() + length();
-    auto status = copyMem(destPtr, remainingLength(), source.data(), source.length());
+    auto status = copyMem(destPtr, remainingCapacity(), source.data(), source.length());
     fudAssert(status == FudStatus::Success);
 
     addToLength(source.length());
@@ -551,13 +592,13 @@ DrainResult String::drain(StringView source)
         return result;
     }
 
-    if (remainingLength() > 0) {
+    if (remainingCapacity() > 0) {
         StringView firstPart{source};
-        if (source.length() > remainingLength()) {
-            firstPart.m_length = remainingLength();
+        if (source.length() > remainingCapacity()) {
+            firstPart.m_length = remainingCapacity();
         }
         auto* destPtr = dataMut() + length();
-        auto status = copyMem(destPtr, remainingLength(), firstPart.m_data, firstPart.m_length);
+        auto status = copyMem(destPtr, remainingCapacity(), firstPart.m_data, firstPart.m_length);
         fudAssert(status == FudStatus::Success);
         addToLength(firstPart.m_length);
         result.bytesDrained += firstPart.m_length;
@@ -592,7 +633,7 @@ DrainResult String::drain(StringView source)
     }
 
     auto* destPtr = dataMut() + length();
-    result.status = copyMem(destPtr, remainingLength(), source.data(), source.length());
+    result.status = copyMem(destPtr, remainingCapacity(), source.data(), source.length());
     fudAssert(result.status == FudStatus::Success);
     result.bytesDrained += source.length();