Mercurial > hg > ucx / changeset

--- a/src/CMakeLists.txt	Mon Dec 27 14:44:08 2021 +0100
+++ b/src/CMakeLists.txt	Mon Dec 27 16:51:10 2021 +0100
@@ -1,13 +1,17 @@
 set(sources
+        utils.c
         allocator.c
         linked_list.c
         tree.c
+        buffer.c
 )
 set(headers
+        cx/utils.h
         cx/allocator.h
         cx/list.h
         cx/linked_list.h
         cx/tree.h
+        cx/buffer.h
 )
 
 add_library(ucx SHARED ${sources})

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/buffer.c	Mon Dec 27 16:51:10 2021 +0100
@@ -0,0 +1,328 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
+ */
+
+#include "cx/buffer.h"
+#include "cx/utils.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+CxBuffer cxBufferCreate(
+        void *space,
+        size_t capacity,
+        int flags
+) {
+    CxBuffer buffer = (CxBuffer) malloc(sizeof(cx_buffer_s));
+    if (buffer) {
+        buffer->flags = flags;
+        if (!space) {
+            buffer->bytes = malloc(capacity);
+            if (!buffer->bytes) {
+                free(buffer);
+                return NULL;
+            }
+            memset(buffer->bytes, 0, capacity);
+            buffer->flags |= CX_BUFFER_FREE_CONTENTS;
+        } else {
+            buffer->bytes = space;
+        }
+        buffer->capacity = capacity;
+        buffer->size = 0;
+
+        buffer->pos = 0;
+    }
+
+    return buffer;
+}
+
+void cxBufferDestroy(CxBuffer buffer) {
+    if ((buffer->flags & CX_BUFFER_FREE_CONTENTS) == CX_BUFFER_FREE_CONTENTS) {
+        free(buffer->bytes);
+    }
+    free(buffer);
+}
+
+CxBuffer cxBufferExtract(
+        CxBuffer src,
+        size_t start,
+        size_t length,
+        int flags
+) {
+    if (src->size == 0 || length == 0 ||
+        ((size_t) -1) - start < length || start + length > src->capacity) {
+        return NULL;
+    }
+
+    CxBuffer dst = (CxBuffer) malloc(sizeof(cx_buffer_s));
+    if (dst) {
+        dst->bytes = malloc(length);
+        if (!dst->bytes) {
+            free(dst);
+            return NULL;
+        }
+        dst->capacity = length;
+        dst->size = length;
+        dst->flags = flags | CX_BUFFER_FREE_CONTENTS;
+        dst->pos = 0;
+        memcpy(dst->bytes, src->bytes + start, length);
+    }
+    return dst;
+}
+
+int cxBufferSeek(
+        CxBuffer buffer,
+        off_t offset,
+        int whence
+) {
+    size_t npos;
+    switch (whence) {
+        case SEEK_CUR:
+            npos = buffer->pos;
+            break;
+        case SEEK_END:
+            npos = buffer->size;
+            break;
+        case SEEK_SET:
+            npos = 0;
+            break;
+        default:
+            return -1;
+    }
+
+    size_t opos = npos;
+    npos += offset;
+
+    if ((offset > 0 && npos < opos) || (offset < 0 && npos > opos)) {
+        return -1;
+    }
+
+    if (npos >= buffer->size) {
+        return -1;
+    } else {
+        buffer->pos = npos;
+        return 0;
+    }
+
+}
+
+int cxBufferEof(CxBuffer buffer) {
+    return buffer->pos >= buffer->size;
+}
+
+int cxBufferMinimumCapacity(
+        CxBuffer buffer,
+        size_t additional_bytes
+) {
+    size_t newcap = buffer->capacity + additional_bytes;
+
+    // overflow protection
+    if (newcap < buffer->capacity) {
+        return -1;
+    }
+
+    unsigned char *newspace = realloc(buffer->bytes, newcap);
+    if (newspace) {
+        memset(newspace + buffer->size, 0, newcap - buffer->size);
+        buffer->bytes = newspace;
+        buffer->capacity = newcap;
+    } else {
+        return -1;
+    }
+
+    return 0;
+}
+
+size_t cxBufferWrite(
+        const void *ptr,
+        size_t size,
+        size_t nitems,
+        CxBuffer buffer
+) {
+    size_t len;
+    if (cx_szmul(size, nitems, &len)) {
+        return 0;
+    }
+    size_t required = buffer->pos + len;
+    if (buffer->pos > required) {
+        return 0;
+    }
+
+    if (required > buffer->capacity) {
+        if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
+            if (cxBufferMinimumCapacity(buffer, required)) {
+                return 0;
+            }
+        } else {
+            len = buffer->capacity - buffer->pos;
+            if (size > 1) {
+                len -= len % size;
+            }
+        }
+    }
+
+    if (len == 0) {
+        return len;
+    }
+
+    memcpy(buffer->bytes + buffer->pos, ptr, len);
+    buffer->pos += len;
+    if (buffer->pos > buffer->size) {
+        buffer->size = buffer->pos;
+    }
+
+    return len / size;
+}
+
+size_t cxBufferRead(
+        void *ptr,
+        size_t size,
+        size_t nitems,
+        CxBuffer buffer
+) {
+    size_t len;
+    if (cx_szmul(size, nitems, &len)) {
+        return 0;
+    }
+    if (buffer->pos + len > buffer->size) {
+        len = buffer->size - buffer->pos;
+        if (size > 1) len -= len % size;
+    }
+
+    if (len <= 0) {
+        return len;
+    }
+
+    memcpy(ptr, buffer->bytes + buffer->pos, len);
+    buffer->pos += len;
+
+    return len / size;
+}
+
+int cxBufferPut(
+        CxBuffer buffer,
+        int c
+) {
+    if (buffer->pos >= buffer->capacity) {
+        if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
+            if (cxBufferMinimumCapacity(buffer, buffer->capacity + 1)) {
+                return EOF;
+            }
+        } else {
+            return EOF;
+        }
+    }
+
+    c &= 0xFF;
+    buffer->bytes[buffer->pos] = (unsigned char) c;
+    buffer->pos++;
+    if (buffer->pos > buffer->size) {
+        buffer->size = buffer->pos;
+    }
+    return c;
+}
+
+int cxBufferGet(CxBuffer buffer) {
+    if (cxBufferEof(buffer)) {
+        return EOF;
+    } else {
+        int c = buffer->bytes[buffer->pos];
+        buffer->pos++;
+        return c;
+    }
+}
+
+size_t cxBufferPutString(
+        CxBuffer buffer,
+        const char *str
+) {
+    return cxBufferWrite(str, 1, strlen(str), buffer);
+}
+
+int cxBufferShiftLeft(
+        CxBuffer buffer,
+        size_t shift
+) {
+    if (shift >= buffer->size) {
+        buffer->pos = buffer->size = 0;
+    } else {
+        memmove(buffer->bytes, buffer->bytes + shift, buffer->size - shift);
+        buffer->size -= shift;
+
+        if (buffer->pos >= shift) {
+            buffer->pos -= shift;
+        } else {
+            buffer->pos = 0;
+        }
+    }
+    return 0;
+}
+
+int cxBufferShiftRight(
+        CxBuffer buffer,
+        size_t shift
+) {
+    size_t req_capacity = buffer->size + shift;
+    size_t movebytes;
+
+    // auto extend buffer, if required and enabled
+    if (buffer->capacity < req_capacity) {
+        if ((buffer->flags & CX_BUFFER_AUTO_EXTEND) == CX_BUFFER_AUTO_EXTEND) {
+            if (cxBufferMinimumCapacity(buffer, req_capacity)) {
+                return 1;
+            }
+            movebytes = buffer->size;
+        } else {
+            movebytes = buffer->capacity - shift;
+        }
+    } else {
+        movebytes = buffer->size;
+    }
+
+    memmove(buffer->bytes + shift, buffer->bytes, movebytes);
+    buffer->size = shift + movebytes;
+
+    buffer->pos += shift;
+    if (buffer->pos > buffer->size) {
+        buffer->pos = buffer->size;
+    }
+
+    return 0;
+}
+
+int cxBufferShift(
+        CxBuffer buffer,
+        off_t shift
+) {
+    if (shift < 0) {
+        return cxBufferShiftLeft(buffer, (size_t) (-shift));
+    } else if (shift > 0) {
+        return cxBufferShiftRight(buffer, (size_t) shift);
+    } else {
+        return 0;
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/cx/buffer.h	Mon Dec 27 16:51:10 2021 +0100
@@ -0,0 +1,377 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
+ */
+
+/**
+ * \file buffer.h
+ *
+ * \brief Advanced buffer implementation.
+ *
+ * Instances of CxBuffer can be used to read from or to write to like one
+ * would do with a stream.
+ *
+ * Some features for convenient use of the buffer
+ * can be enabled. See the documentation of the macro constants for more
+ * information.
+ *
+ * \author Mike Becker
+ * \author Olaf Wintermann
+ * \version 3.0
+ * \copyright 2-Clause BSD License
+ */
+
+#ifndef UCX_BUFFER_H
+#define    UCX_BUFFER_H
+
+#include <sys/types.h>
+#include <stdio.h>
+
+#ifdef    __cplusplus
+extern "C" {
+#endif
+
+/**
+ * No buffer features enabled (all flags cleared).
+ */
+#define CX_BUFFER_DEFAULT 0x00
+
+/**
+ * If this flag is enabled, the buffer will automatically free its contents when destroyed.
+ */
+#define CX_BUFFER_FREE_CONTENTS 0x01
+
+/**
+ * If this flag is enabled, the buffer will automatically extends its capacity.
+ */
+#define CX_BUFFER_AUTO_EXTEND 0x02
+
+/** Structure for the UCX buffer data. */
+typedef struct {
+    /** A pointer to the buffer contents. */
+    union {
+        /**
+         * Data is interpreted as text.
+         */
+        char *space;
+        /**
+         * Data is interpreted as binary.
+         */
+        unsigned char *bytes;
+    };
+    /** Current position of the buffer. */
+    size_t pos;
+    /** Current capacity (i.e. maximum size) of the buffer. */
+    size_t capacity;
+    /** Current size of the buffer content. */
+    size_t size;
+    /**
+     * Flag register for buffer features.
+     * \see #CX_BUFFER_DEFAULT
+     * \see #CX_BUFFER_FREE_CONTENTS
+     * \see #CX_BUFFER_AUTO_EXTEND
+     */
+    int flags;
+} cx_buffer_s;
+
+/**
+ * UCX buffer.
+ */
+typedef cx_buffer_s *CxBuffer;
+
+/**
+ * Creates a new buffer.
+ *
+ * \note You may provide \c NULL as argument for \p space.
+ * Then this function will allocate the space and enforce
+ * the #CX_BUFFER_FREE_CONTENTS flag.
+ *
+ * \param space pointer to the memory area, or <code>NULL</code> to allocate
+ * new memory
+ * \param capacity the capacity of the buffer
+ * \param flags buffer features (see cx_buffer_s.flags)
+ * \return the new buffer
+ */
+CxBuffer cxBufferCreate(
+        void *space,
+        size_t capacity,
+        int flags
+);
+
+/**
+ * Destroys a buffer.
+ *
+ * If the #CX_BUFFER_FREE_CONTENTS feature is enabled, the contents of the buffer
+ * are also freed.
+ *
+ * \param buffer the buffer to destroy
+ */
+void cxBufferDestroy(CxBuffer buffer);
+
+/**
+ * Creates a new buffer and fills it with content copied from another buffer.
+ *
+ * \note The #CX_BUFFER_FREE_CONTENTS feature is enforced for the new buffer.
+ *
+ * \param src the source buffer
+ * \param start the start position of extraction
+ * \param length the count of bytes to extract (must not be zero)
+ * \param flags features for the new buffer (#CX_BUFFER_FREE_CONTENTS will always be enabled)
+ * \return a new buffer containing the extraction
+ */
+CxBuffer cxBufferExtract(
+        CxBuffer src,
+        size_t start,
+        size_t length,
+        int flags
+);
+
+/**
+ * A shorthand macro for copying an entire buffer.
+ *
+ * \param src the source buffer
+ * \param flags features for the new buffer (#CX_BUFFER_FREE_CONTENTS will always be enabled)
+ * \return a new buffer with the copied content
+ */
+#define cxBufferClone(src, flags) cxBufferExtract(src, 0, (src)->capacity, flags)
+
+
+/**
+ * Shifts the contents of the buffer by the given offset.
+ *
+ * If the offset is positive, the contents are shifted to the right.
+ * 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.
+ *
+ * If the offset is negative, the contents are shifted to the left where the
+ * first \p shift bytes are discarded.
+ * The new size of the buffer is the old size minus the absolute shift value.
+ * 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
+ * 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.
+ *
+ * \par Security Note
+ * The shifting operation does \em not erase the previously occupied memory cells.
+ * You can easily do that manually, e.g. by calling
+ * <code>memset(buffer->bytes, 0, shift)</code> for a right shift or
+ * <code>memset(buffer->size, 0, buffer->capacity - buffer->size)</code>
+ * for a left shift.
+ *
+ * \param buffer the buffer
+ * \param shift the shift offset (negative means left shift)
+ * \return 0 on success, non-zero if a required auto-extension fails
+ */
+int cxBufferShift(
+        CxBuffer buffer,
+        off_t shift
+);
+
+/**
+ * Shifts the buffer to the right.
+ * See cxBufferShift() for details.
+ *
+ * \param buffer the buffer
+ * \param shift the shift offset
+ * \return 0 on success, non-zero if a required auto-extension fails
+ * \see cxBufferShift()
+ */
+int cxBufferShiftRight(
+        CxBuffer buffer,
+        size_t shift
+);
+
+/**
+ * Shifts the buffer to the left.
+ * See cxBufferShift() for details.
+ *
+ * \note Since a left shift cannot fail due to memory allocation problems, this
+ * function always returns zero.
+ *
+ * \param buffer the buffer
+ * \param shift the positive shift offset
+ * \return always zero
+ * \see cxBufferShift()
+ */
+int cxBufferShiftLeft(
+        CxBuffer buffer,
+        size_t shift
+);
+
+
+/**
+ * Moves the position of the buffer.
+ *
+ * The new position is relative to the \p whence argument.
+ *
+ * \li \c SEEK_SET marks the start of the buffer.
+ * \li \c SEEK_CUR marks the current position.
+ * \li \c SEEK_END marks the end of the buffer.
+ *
+ * With an offset of zero, this function sets the buffer position to zero
+ * (\c SEEK_SET), the buffer size (\c SEEK_END) or leaves the buffer position
+ * unchanged (\c SEEK_CUR).
+ *
+ * \param buffer the buffer
+ * \param offset position offset relative to \p whence
+ * \param whence one of \c SEEK_SET, \c SEEK_CUR or \c SEEK_END
+ * \return 0 on success, non-zero if the position is invalid
+ *
+ */
+int cxBufferSeek(
+        CxBuffer buffer,
+        off_t offset,
+        int whence
+);
+
+/**
+ * Clears the buffer by resetting the position and deleting the data.
+ *
+ * The data is deleted by zeroing it with a call to memset().
+ *
+ * \param buffer the buffer to be cleared
+ */
+#define cxBufferClear(buffer) memset((buffer)->bytes, 0, (buffer)->size); \
+        (buffer)->size = 0; (buffer)->pos = 0;
+
+/**
+ * Tests, if the buffer position has exceeded the buffer capacity.
+ *
+ * \param buffer the buffer to test
+ * \return non-zero, if the current buffer position has exceeded the last
+ * available byte of the buffer.
+ */
+int cxBufferEof(CxBuffer buffer);
+
+
+/**
+ * Ensures that the buffer has a minimum capacity.
+ *
+ * If the current capacity is not sufficient, the buffer will be extended.
+ *
+ * \param buffer the buffer
+ * \param capacity the minimum required capacity for this buffer
+ * \return 0 on success or a non-zero value on failure
+ */
+int cxBufferMinimumCapacity(
+        CxBuffer buffer,
+        size_t capacity
+);
+
+/**
+ * Writes data to a CxBuffer.
+ *
+ * The position of the buffer is increased by the number of bytes written.
+ *
+ * \note The signature is compatible with the fwrite() family of functions.
+ *
+ * \param ptr a pointer to the memory area containing the bytes to be written
+ * \param size the length of one element
+ * \param nitems the element count
+ * \param buffer the CxBuffer to write to
+ * \return the total count of bytes written
+ */
+size_t cxBufferWrite(
+        const void *ptr,
+        size_t size,
+        size_t nitems,
+        CxBuffer buffer
+);
+
+/**
+ * Reads data from a CxBuffer.
+ *
+ * The position of the buffer is increased by the number of bytes read.
+ *
+ * \note The signature is compatible with the fread() family of functions.
+ *
+ * \param ptr a pointer to the memory area where to store the read data
+ * \param size the length of one element
+ * \param nitems the element count
+ * \param buffer the CxBuffer to read from
+ * \return the total number of elements read
+ */
+size_t cxBufferRead(
+        void *ptr,
+        size_t size,
+        size_t nitems,
+        CxBuffer buffer
+);
+
+/**
+ * Writes a character to a buffer.
+ *
+ * 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.
+ *
+ * On successful write, the position of the buffer is increased.
+ *
+ * \param buffer the buffer to write to
+ * \param c the character to write
+ * \return the byte that has bean written or \c EOF when the end of the stream is
+ * reached and automatic extension is not enabled or not possible
+ */
+int cxBufferPut(
+        CxBuffer buffer,
+        int c
+);
+
+/**
+ * Gets a character from a buffer.
+ *
+ * The current position of the buffer is increased after a successful read.
+ *
+ * \param buffer the buffer to read from
+ * \return the character or \c EOF, if the end of the buffer is reached
+ */
+int cxBufferGet(CxBuffer buffer);
+
+/**
+ * Writes a string to a buffer.
+ *
+ * \param buffer the buffer
+ * \param str the zero-terminated string
+ * \return the number of bytes written
+ */
+size_t cxBufferPutString(
+        CxBuffer buffer,
+        const char *str
+);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* UCX_BUFFER_H */

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/cx/common.h	Mon Dec 27 16:51:10 2021 +0100
@@ -0,0 +1,73 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
+ */
+
+/**
+ * \file common.h
+ *
+ * \brief Common definitions and feature checks.
+ *
+ * \author Mike Becker
+ * \author Olaf Wintermann
+ * \version 3.0
+ * \copyright 2-Clause BSD License
+ */
+
+#ifndef UCX_COMMON_H
+#define UCX_COMMON_H
+
+/** Major UCX version as integer constant. */
+#define UCX_VERSION_MAJOR   3
+
+/** Minor UCX version as integer constant. */
+#define UCX_VERSION_MINOR   0
+
+/** Version constant which ensures to increase monotonically. */
+#define UCX_VERSION (((UCX_VERSION_MAJOR)<<16)|UCX_VERSION_MINOR)
+
+
+#ifdef _WIN32
+#if !(defined __ssize_t_defined || defined _SSIZE_T_)
+#include <BaseTsd.h>
+typedef SSIZE_T ssize_t;
+#define __ssize_t_defined
+#define _SSIZE_T_
+#endif /* __ssize_t_defined and _SSIZE_T */
+#ifndef __WORDSIZE
+#ifdef _WIN64
+#define __WORDSIZE 64
+#else
+#define __WORDSIZE 32
+#endif
+#endif /* __WORDSIZE */
+#else /* !_WIN32 */
+
+#include <sys/types.h>
+
+#endif /* _WIN32 */
+
+#endif /* UCX_COMMON_H */

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/cx/utils.h	Mon Dec 27 16:51:10 2021 +0100
@@ -0,0 +1,120 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
+ */
+
+/**
+ * \file utils.h
+ *
+ * \brief General purpose utility functions.
+ *
+ * \author Mike Becker
+ * \author Olaf Wintermann
+ * \version 3.0
+ * \copyright 2-Clause BSD License
+ */
+
+#ifndef UCX_UTILS_H
+#define UCX_UTILS_H
+
+#include "common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* ----------------------
+ * cx_szmul() definition.
+ * ---------------------- */
+
+#if (__GNUC__ >= 5 || defined(__clang__)) && !defined(CX_NO_SZMUL_BUILTIN)
+#define CX_SZMUL_BUILTIN
+
+#if __WORDSIZE == 32
+/**
+ * Alias for \c __builtin_umul_overflow.
+ *
+ * Performs a multiplication of size_t values and checks for overflow.
+ *
+ * @param a first operand
+ * @param b second operand
+ * @param result a pointer to a size_t, where the result should
+ * be stored
+ * @return zero, if no overflow occurred and the result is correct, non-zero
+ * otherwise
+ */
+#define cx_szmul(a, b, result) __builtin_umul_overflow(a, b, result)
+#else /* __WORDSIZE != 32 */
+/**
+ * Alias for \c __builtin_umull_overflow.
+ *
+ * Performs a multiplication of size_t values and checks for overflow.
+ *
+ * @param a first operand
+ * @param b second operand
+ * @param result a pointer to a size_t, where the result should
+ * be stored
+ * @return zero, if no overflow occurred and the result is correct, non-zero
+ * otherwise
+ */
+#define cx_szmul(a, b, result) __builtin_umull_overflow(a, b, result)
+#endif /* __WORDSIZE */
+
+#else /* no GNUC or clang bultin */
+
+/**
+ * Performs a multiplication of size_t values and checks for overflow.
+  *
+ * @param a first operand
+ * @param b second operand
+ * @param result a pointer to a size_t, where the result should
+ * be stored
+ * @return zero, if no overflow occurred and the result is correct, non-zero
+ * otherwise
+ */
+#define cx_szmul(a, b, result) cx_szmul_impl(a, b, result)
+
+/**
+ * Performs a multiplication of size_t values and checks for overflow.
+ *
+ * This is a custom implementation in case there is no compiler builtin
+ * available.
+ *
+ * @param a first operand
+ * @param b second operand
+ * @param result a pointer to a size_t where the result should be stored
+ * @return zero, if no overflow occurred and the result is correct, non-zero
+ * otherwise
+ */
+int cx_szmul_impl(size_t a, size_t b, size_t *result);
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* UCX_UTILS_H */

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/utils.c	Mon Dec 27 16:51:10 2021 +0100
@@ -0,0 +1,46 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
+ */
+
+#include "cx/utils.h"
+
+#ifndef CX_SZMUL_BUILTIN
+int cx_szmul_impl(size_t a, size_t b, size_t *result) {
+    if(a == 0 || b == 0) {
+        *result = 0;
+        return 0;
+    }
+    size_t r = a * b;
+    if(r / b == a) {
+        *result = r;
+        return 0;
+    } else {
+        *result = 0;
+        return 1;
+    }
+}
+#endif