diff -r b60487c3ec36 -r af685cc9d623 ucx/cx/buffer.h
--- a/ucx/cx/buffer.h	Sun Aug 31 14:39:13 2025 +0200
+++ b/ucx/cx/buffer.h	Sat Nov 08 23:06:11 2025 +0100
@@ -62,7 +62,7 @@
  * If this flag is enabled, the buffer will automatically free its contents when destroyed.
  *
  * Do NOT set this flag together with #CX_BUFFER_COPY_ON_WRITE. It will be automatically
- * set when the copy-on-write operations is performed.
+ * set when the copy-on-write operation is performed.
  */
 #define CX_BUFFER_FREE_CONTENTS 0x01
 
@@ -74,7 +74,7 @@
 /**
  * If this flag is enabled, the buffer will allocate new memory when written to.
  *
- * The current contents of the buffer will be copied to the new memory and the flag
+ * The current contents of the buffer will be copied to the new memory, and the flag
  * will be cleared while the #CX_BUFFER_FREE_CONTENTS flag will be set automatically.
  */
 #define CX_BUFFER_COPY_ON_WRITE 0x04
@@ -127,7 +127,7 @@
     size_t blkmax;
 
     /**
-     * The target for write function.
+     * The target for the write function.
      */
     void *target;
 
@@ -202,7 +202,7 @@
  * you will need to cast the pointer, and you should set the
  * #CX_BUFFER_COPY_ON_WRITE flag.
  *
- * You need to set the size manually after initialization, if
+ * You need to set the size manually after initialization if
  * you provide @p space which already contains data.
  *
  * When you specify stack memory as @p space and decide to use
@@ -210,7 +210,7 @@
  * #CX_BUFFER_COPY_ON_EXTEND flag, instead of the
  * #CX_BUFFER_AUTO_EXTEND flag.
  *
- * @note You may provide @c NULL as argument for @p space.
+ * @note You may provide @c NULL as the argument for @p space.
  * Then this function will allocate the space and enforce
  * the #CX_BUFFER_FREE_CONTENTS flag. In that case, specifying
  * copy-on-write should be avoided, because the allocated
@@ -222,19 +222,13 @@
  * @param capacity the capacity of the buffer
  * @param allocator the allocator this buffer shall use for automatic
  * memory management
- * (if @c NULL, a default stdlib allocator will be used)
+ * (if @c NULL, the cxDefaultAllocator will be used)
  * @param flags buffer features (see cx_buffer_s.flags)
  * @return zero on success, non-zero if a required allocation failed
  */
 cx_attr_nonnull_arg(1)
-cx_attr_export
-int cxBufferInit(
-        CxBuffer *buffer,
-        void *space,
-        size_t capacity,
-        const CxAllocator *allocator,
-        int flags
-);
+CX_EXPORT int cxBufferInit(CxBuffer *buffer, void *space, size_t capacity,
+        const CxAllocator *allocator, int flags);
 
 /**
  * Configures the buffer for flushing.
@@ -251,11 +245,7 @@
  * @see cxBufferWrite()
  */
 cx_attr_nonnull
-cx_attr_export
-int cxBufferEnableFlushing(
-    CxBuffer *buffer,
-    CxBufferFlushConfig config
-);
+CX_EXPORT int cxBufferEnableFlushing(CxBuffer *buffer, CxBufferFlushConfig config);
 
 /**
  * Destroys the buffer contents.
@@ -267,8 +257,7 @@
  * @see cxBufferInit()
  */
 cx_attr_nonnull
-cx_attr_export
-void cxBufferDestroy(CxBuffer *buffer);
+CX_EXPORT void cxBufferDestroy(CxBuffer *buffer);
 
 /**
  * Deallocates the buffer.
@@ -276,14 +265,10 @@
  * If the #CX_BUFFER_FREE_CONTENTS feature is enabled, this function also destroys
  * the contents. If you @em only want to destroy the contents, use cxBufferDestroy().
  *
- * @remark As with all free() functions, this accepts @c NULL arguments in which
- * case it does nothing.
- *
  * @param buffer the buffer to deallocate
  * @see cxBufferCreate()
  */
-cx_attr_export
-void cxBufferFree(CxBuffer *buffer);
+CX_EXPORT void cxBufferFree(CxBuffer *buffer);
 
 /**
  * Allocates and initializes a fresh buffer.
@@ -296,7 +281,7 @@
  * #CX_BUFFER_COPY_ON_EXTEND flag, instead of the
  * #CX_BUFFER_AUTO_EXTEND flag.
  *
- * @note You may provide @c NULL as argument for @p space.
+ * @note You may provide @c NULL as the argument for @p space.
  * Then this function will allocate the space and enforce
  * the #CX_BUFFER_FREE_CONTENTS flag.
  *
@@ -305,20 +290,13 @@
  * @param capacity the capacity of the buffer
  * @param allocator the allocator to use for allocating the structure and the automatic
  * memory management within the buffer
- * (if @c NULL, a default stdlib allocator will be used)
+ * (if @c NULL, the cxDefaultAllocator will be used)
  * @param flags buffer features (see cx_buffer_s.flags)
  * @return a pointer to the buffer on success, @c NULL if a required allocation failed
  */
-cx_attr_malloc
-cx_attr_dealloc(cxBufferFree, 1)
-cx_attr_nodiscard
-cx_attr_export
-CxBuffer *cxBufferCreate(
-        void *space,
-        size_t capacity,
-        const CxAllocator *allocator,
-        int flags
-);
+cx_attr_malloc cx_attr_dealloc(cxBufferFree, 1) cx_attr_nodiscard
+CX_EXPORT CxBuffer *cxBufferCreate(void *space, size_t capacity,
+        const CxAllocator *allocator, int flags);
 
 /**
  * Shifts the contents of the buffer by the given offset.
@@ -327,8 +305,8 @@
  * If auto extension is enabled, the buffer grows, if necessary.
  * In case the auto extension fails, this function returns a non-zero value and
  * no contents are changed.
- * If auto extension is disabled, the contents that do not fit into the buffer
- * are discarded.
+ * When the auto extension is disabled, the contents that do not fit into the
+ * buffer are discarded.
  *
  * If the offset is negative, the contents are shifted to the left where the
  * first @p shift bytes are discarded.
@@ -336,15 +314,15 @@
  * If this value is larger than the buffer size, the buffer is emptied (but
  * not cleared, see the security note below).
  *
- * The buffer position gets shifted alongside with the content but is kept
+ * The buffer position gets shifted alongside the content but is kept
  * within the boundaries of the buffer.
  *
  * @note For situations where @c off_t is not large enough, there are specialized cxBufferShiftLeft() and
- * cxBufferShiftRight() functions using a @c size_t as parameter type.
+ * cxBufferShiftRight() functions using a @c size_t as the parameter type.
  *
  * @attention
  * Security Note: The shifting operation does @em not erase the previously occupied memory cells.
- * But you can easily do that manually, e.g. by calling
+ * But you can do that manually by calling
  * <code>memset(buffer->bytes, 0, shift)</code> for a right shift or
  * <code>memset(buffer->bytes + buffer->size, 0, buffer->capacity - buffer->size)</code>
  * for a left shift.
@@ -357,11 +335,7 @@
  * @see cxBufferShiftRight()
  */
 cx_attr_nonnull
-cx_attr_export
-int cxBufferShift(
-        CxBuffer *buffer,
-        off_t shift
-);
+CX_EXPORT int cxBufferShift(CxBuffer *buffer, off_t shift);
 
 /**
  * Shifts the buffer to the right.
@@ -374,11 +348,7 @@
  * @see cxBufferShift()
  */
 cx_attr_nonnull
-cx_attr_export
-int cxBufferShiftRight(
-        CxBuffer *buffer,
-        size_t shift
-);
+CX_EXPORT int cxBufferShiftRight(CxBuffer *buffer, size_t shift);
 
 /**
  * Shifts the buffer to the left.
@@ -391,11 +361,7 @@
  * @see cxBufferShift()
  */
 cx_attr_nonnull
-cx_attr_export
-int cxBufferShiftLeft(
-        CxBuffer *buffer,
-        size_t shift
-);
+CX_EXPORT int cxBufferShiftLeft(CxBuffer *buffer, size_t shift);
 
 
 /**
@@ -419,12 +385,7 @@
  *
  */
 cx_attr_nonnull
-cx_attr_export
-int cxBufferSeek(
-        CxBuffer *buffer,
-        off_t offset,
-        int whence
-);
+CX_EXPORT int cxBufferSeek(CxBuffer *buffer, off_t offset, int whence);
 
 /**
  * Clears the buffer by resetting the position and deleting the data.
@@ -439,8 +400,7 @@
  * @see cxBufferReset()
  */
 cx_attr_nonnull
-cx_attr_export
-void cxBufferClear(CxBuffer *buffer);
+CX_EXPORT void cxBufferClear(CxBuffer *buffer);
 
 /**
  * Resets the buffer by resetting the position and size to zero.
@@ -452,8 +412,7 @@
  * @see cxBufferClear()
  */
 cx_attr_nonnull
-cx_attr_export
-void cxBufferReset(CxBuffer *buffer);
+CX_EXPORT void cxBufferReset(CxBuffer *buffer);
 
 /**
  * Tests, if the buffer position has exceeded the buffer size.
@@ -463,10 +422,8 @@
  * byte of the buffer's contents
  * @retval false otherwise
  */
-cx_attr_nonnull
-cx_attr_nodiscard
-cx_attr_export
-bool cxBufferEof(const CxBuffer *buffer);
+cx_attr_nonnull cx_attr_nodiscard
+CX_EXPORT bool cxBufferEof(const CxBuffer *buffer);
 
 
 /**
@@ -474,23 +431,42 @@
  *
  * If the current capacity is not sufficient, the buffer will be extended.
  *
+ * The new capacity will be a power of two until the system's page size is reached.
+ * Then, the new capacity will be a multiple of the page size.
+ *
  * @param buffer the buffer
  * @param capacity the minimum required capacity for this buffer
  * @retval zero the capacity was already sufficient or successfully increased
  * @retval non-zero on allocation failure
+ * @see cxBufferShrink()
  */
 cx_attr_nonnull
-cx_attr_export
-int cxBufferMinimumCapacity(
-        CxBuffer *buffer,
-        size_t capacity
-);
+CX_EXPORT int cxBufferMinimumCapacity(CxBuffer *buffer, size_t capacity);
+
+/**
+ * Shrinks the capacity of the buffer to fit its current size.
+ *
+ * If @p reserve is larger than zero, the buffer is shrunk to its size plus
+ * the number of reserved bytes.
+ *
+ * If the current capacity is not larger than the size plus the reserved bytes,
+ * nothing happens.
+ *
+ * If the #CX_BUFFER_COPY_ON_WRITE or #CX_BUFFER_COPY_ON_EXTEND flag is set,
+ * this function does nothing.
+ *
+ * @param buffer the buffer
+ * @param reserve the number of bytes that shall remain reserved
+ * @see cxBufferMinimumCapacity()
+ */
+cx_attr_nonnull
+CX_EXPORT void cxBufferShrink(CxBuffer *buffer, size_t reserve);
 
 /**
  * Writes data to a CxBuffer.
  *
  * If automatic flushing is not enabled, the data is simply written into the
- * buffer at the current position and the position of the buffer is increased
+ * buffer at the current position, and the position of the buffer is increased
  * by the number of bytes written.
  *
  * If flushing is enabled and the buffer needs to flush, the data is flushed to
@@ -499,7 +475,7 @@
  * data in this buffer is shifted to the beginning of this buffer so that the
  * newly available space can be used to append as much data as possible.
  *
- * This function only stops writing more elements, when the flush target and this
+ * This function only stops writing more elements when the flush target and this
  * buffer are both incapable of taking more data or all data has been written.
  *
  * If, after flushing, the number of items that shall be written still exceeds
@@ -507,14 +483,14 @@
  * to the flush target, if possible.
  *
  * The number returned by this function is the number of elements from
- * @c ptr that could be written to either the flush target or the buffer
- * (so it does not include the number of items that had been already in the buffer
- * in were flushed during the process).
+ * @c ptr that could be written to either the flush target or the buffer.
+ * That means it does @em not include the number of items that were already in
+ * the buffer and were also flushed during the process.
  *
  * @attention
  * When @p size is larger than one and the contents of the buffer are not aligned
  * with @p size, flushing stops after all complete items have been flushed, leaving
- * the mis-aligned part in the buffer.
+ * the misaligned part in the buffer.
  * Afterward, this function only writes as many items as possible to the buffer.
  *
  * @note The signature is compatible with the fwrite() family of functions.
@@ -528,13 +504,8 @@
  * @see cxBufferRead()
  */
 cx_attr_nonnull
-cx_attr_export
-size_t cxBufferWrite(
-        const void *ptr,
-        size_t size,
-        size_t nitems,
-        CxBuffer *buffer
-);
+CX_EXPORT size_t cxBufferWrite(const void *ptr, size_t size,
+        size_t nitems, CxBuffer *buffer);
 
 /**
  * Appends data to a CxBuffer.
@@ -556,13 +527,8 @@
  * @see cxBufferRead()
  */
 cx_attr_nonnull
-cx_attr_export
-size_t cxBufferAppend(
-        const void *ptr,
-        size_t size,
-        size_t nitems,
-        CxBuffer *buffer
-);
+CX_EXPORT size_t cxBufferAppend(const void *ptr, size_t size,
+        size_t nitems, CxBuffer *buffer);
 
 /**
  * Performs a single flush-run on the specified buffer.
@@ -587,19 +553,19 @@
  * at position 200. The flush configuration is
  * @c blkmax=4 and @c blksize=64 .
  * Assume that the entire flush operation is successful.
- * All 200 bytes on the left hand-side from the current
+ * All 200 bytes on the left-hand-side from the current
  * position are written.
- * That means, the size of the buffer is now 140 and the
+ * That means the size of the buffer is now 140 and the
  * position is zero.
  *
  * @par Example 2
  * Same as Example 1, but now the @c blkmax is 1.
- * The size of the buffer is now 276 and the position is 136.
+ * The size of the buffer is now 276, and the position is 136.
  *
  * @par Example 3
  * Same as Example 1, but now assume the flush target
  * only accepts 100 bytes before returning zero.
- * That means, the flush operations manages to flush
+ * That means the flush operation manages to flush
  * one complete block and one partial block, ending
  * up with a buffer with size 240 and position 100.
  *
@@ -609,8 +575,8 @@
  * @remark When the buffer uses copy-on-write, the memory
  * is copied first, before attempting any flush.
  * This is, however, considered an erroneous use of the
- * buffer, because it does not make much sense to put
- * readonly data into an UCX buffer for flushing, instead
+ * buffer because it makes little sense to put
+ * readonly data into an UCX buffer for flushing instead
  * of writing it directly to the target.
  *
  * @param buffer the buffer
@@ -618,8 +584,7 @@
  * @see cxBufferEnableFlushing()
  */
 cx_attr_nonnull
-cx_attr_export
-size_t cxBufferFlush(CxBuffer *buffer);
+CX_EXPORT size_t cxBufferFlush(CxBuffer *buffer);
 
 /**
  * Reads data from a CxBuffer.
@@ -637,13 +602,8 @@
  * @see cxBufferAppend()
  */
 cx_attr_nonnull
-cx_attr_export
-size_t cxBufferRead(
-        void *ptr,
-        size_t size,
-        size_t nitems,
-        CxBuffer *buffer
-);
+CX_EXPORT size_t cxBufferRead(void *ptr, size_t size,
+        size_t nitems, CxBuffer *buffer);
 
 /**
  * Writes a character to a buffer.
@@ -651,9 +611,9 @@
  * The least significant byte of the argument is written to the buffer. If the
  * end of the buffer is reached and #CX_BUFFER_AUTO_EXTEND feature is enabled,
  * the buffer capacity is extended by cxBufferMinimumCapacity(). If the feature
- * is disabled or buffer extension fails, @c EOF is returned.
+ * is disabled or the buffer extension fails, @c EOF is returned.
  *
- * On successful write, the position of the buffer is increased.
+ * On successful writing, the position of the buffer is increased.
  *
  * If you just want to write a null-terminator at the current position, you
  * should use cxBufferTerminate() instead.
@@ -661,31 +621,25 @@
  * @param buffer the buffer to write to
  * @param c the character to write
  * @return the byte that has been written or @c EOF when the end of the stream is
- * reached and automatic extension is not enabled or not possible
+ * reached, and automatic extension is not enabled or not possible
  * @see cxBufferTerminate()
  */
 cx_attr_nonnull
-cx_attr_export
-int cxBufferPut(
-        CxBuffer *buffer,
-        int c
-);
+CX_EXPORT int cxBufferPut(CxBuffer *buffer, int c);
 
 /**
  * Writes a terminating zero to a buffer at the current position.
  *
- * On successful write, @em neither the position @em nor the size of the buffer is
- * increased.
+ * If successful, sets the size to the current position and advances the position by one.
  *
  * The purpose of this function is to have the written data ready to be used as
- * a C string.
+ * a C string with the buffer's size being the length of that string.
  *
  * @param buffer the buffer to write to
  * @return zero, if the terminator could be written, non-zero otherwise
  */
 cx_attr_nonnull
-cx_attr_export
-int cxBufferTerminate(CxBuffer *buffer);
+CX_EXPORT int cxBufferTerminate(CxBuffer *buffer);
 
 /**
  * Writes a string to a buffer.
@@ -696,13 +650,8 @@
  * @param str the zero-terminated string
  * @return the number of bytes written
  */
-cx_attr_nonnull
-cx_attr_cstr_arg(2)
-cx_attr_export
-size_t cxBufferPutString(
-        CxBuffer *buffer,
-        const char *str
-);
+cx_attr_nonnull cx_attr_cstr_arg(2)
+CX_EXPORT size_t cxBufferPutString(CxBuffer *buffer, const char *str);
 
 /**
  * Gets a character from a buffer.
@@ -713,8 +662,7 @@
  * @return the character or @c EOF, if the end of the buffer is reached
  */
 cx_attr_nonnull
-cx_attr_export
-int cxBufferGet(CxBuffer *buffer);
+CX_EXPORT int cxBufferGet(CxBuffer *buffer);
 
 #ifdef __cplusplus
 }