--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/leptonica/src/stack.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,279 @@
+/*====================================================================*
+ -  Copyright (C) 2001 Leptonica.  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 ANY
+ -  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 stack.c
+ * <pre>
+ *
+ *      Generic stack
+ *
+ *      The lstack is an array of void * ptrs, onto which
+ *      objects can be stored.  At any time, the number of
+ *      stored objects is lstack->n.  The object at the bottom
+ *      of the lstack is at array[0]; the object at the top of
+ *      the lstack is at array[n-1].  New objects are added
+ *      to the top of the lstack; i.e., the first available
+ *      location, which is at array[n].  The lstack is expanded
+ *      by doubling, when needed.  Objects are removed
+ *      from the top of the lstack.  When an attempt is made
+ *      to remove an object from an empty lstack, the result is null.
+ *
+ *      Create/Destroy
+ *           L_STACK        *lstackCreate()
+ *           void            lstackDestroy()
+ *
+ *      Accessors
+ *           l_int32         lstackAdd()
+ *           void           *lstackRemove()
+ *           static l_int32  lstackExtendArray()
+ *           l_int32         lstackGetCount()
+ *
+ *      Text description
+ *           l_int32         lstackPrint()
+ * </pre>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config_auto.h>
+#endif  /* HAVE_CONFIG_H */
+
+#include "allheaders.h"
+
+    /* Bounds on initial array size */
+static const l_uint32  MaxPtrArraySize = 100000;
+static const l_int32 InitialPtrArraySize = 20;      /*!< n'importe quoi */
+
+    /* Static function */
+static l_int32 lstackExtendArray(L_STACK *lstack);
+
+/*---------------------------------------------------------------------*
+ *                          Create/Destroy                             *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   lstackCreate()
+ *
+ * \param[in]    n   initial ptr array size; use 0 for default
+ * \return  lstack, or NULL on error
+ */
+L_STACK *
+lstackCreate(l_int32  n)
+{
+L_STACK  *lstack;
+
+    if (n <= 0 || n > (l_int32)MaxPtrArraySize)
+        n = InitialPtrArraySize;
+
+    lstack = (L_STACK *)LEPT_CALLOC(1, sizeof(L_STACK));
+    lstack->array = (void **)LEPT_CALLOC(n, sizeof(void *));
+    if (!lstack->array) {
+        lstackDestroy(&lstack, FALSE);
+        return (L_STACK *)ERROR_PTR("lstack array not made", __func__, NULL);
+    }
+
+    lstack->nalloc = n;
+    lstack->n = 0;
+    return lstack;
+}
+
+
+/*!
+ * \brief   lstackDestroy()
+ *
+ * \param[in,out]   plstack    will be set to null before returning
+ * \param[in]    freeflag TRUE to free each remaining struct in the array
+ * \return  void
+ *
+ * <pre>
+ * Notes:
+ *      (1) If %freeflag is TRUE, frees each struct in the array.
+ *      (2) If %freeflag is FALSE but there are elements on the array,
+ *          gives a warning and destroys the array.  This will
+ *          cause a memory leak of all the items that were on the lstack.
+ *          So if the items require their own destroy function, they
+ *          must be destroyed before the lstack.
+ *      (3) To destroy the lstack, we destroy the ptr array, then
+ *          the lstack, and then null the contents of the input ptr.
+ * </pre>
+ */
+void
+lstackDestroy(L_STACK  **plstack,
+              l_int32    freeflag)
+{
+void     *item;
+L_STACK  *lstack;
+
+    if (plstack == NULL) {
+        L_WARNING("ptr address is NULL\n", __func__);
+        return;
+    }
+    if ((lstack = *plstack) == NULL)
+        return;
+
+    if (freeflag) {
+        while(lstack->n > 0) {
+            item = lstackRemove(lstack);
+            LEPT_FREE(item);
+        }
+    } else if (lstack->n > 0) {
+        L_WARNING("memory leak of %d items in lstack\n", __func__, lstack->n);
+    }
+
+    if (lstack->auxstack)
+        lstackDestroy(&lstack->auxstack, freeflag);
+
+    if (lstack->array)
+        LEPT_FREE(lstack->array);
+    LEPT_FREE(lstack);
+    *plstack = NULL;
+}
+
+
+
+/*---------------------------------------------------------------------*
+ *                               Accessors                             *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   lstackAdd()
+ *
+ * \param[in]    lstack
+ * \param[in]    item      to be added to the lstack
+ * \return  0 if OK; 1 on error.
+ */
+l_ok
+lstackAdd(L_STACK  *lstack,
+          void     *item)
+{
+    if (!lstack)
+        return ERROR_INT("lstack not defined", __func__, 1);
+    if (!item)
+        return ERROR_INT("item not defined", __func__, 1);
+
+        /* Do we need to extend the array? */
+    if (lstack->n >= lstack->nalloc) {
+        if (lstackExtendArray(lstack))
+            return ERROR_INT("extension failed", __func__, 1);
+    }
+
+        /* Store the new pointer */
+    lstack->array[lstack->n] = (void *)item;
+    lstack->n++;
+
+    return 0;
+}
+
+
+/*!
+ * \brief   lstackRemove()
+ *
+ * \param[in]    lstack
+ * \return  ptr to item popped from the top of the lstack,
+ *              or NULL if the lstack is empty or on error
+ */
+void *
+lstackRemove(L_STACK  *lstack)
+{
+void  *item;
+
+    if (!lstack)
+        return ERROR_PTR("lstack not defined", __func__, NULL);
+
+    if (lstack->n == 0)
+        return NULL;
+
+    lstack->n--;
+    item = lstack->array[lstack->n];
+
+    return item;
+}
+
+
+/*!
+ * \brief   lstackExtendArray()
+ *
+ * \param[in]    lstack
+ * \return  0 if OK; 1 on error
+ */
+static l_int32
+lstackExtendArray(L_STACK  *lstack)
+{
+    if (!lstack)
+        return ERROR_INT("lstack not defined", __func__, 1);
+
+    if ((lstack->array = (void **)reallocNew((void **)&lstack->array,
+                              sizeof(void *) * lstack->nalloc,
+                              2 * sizeof(void *) * lstack->nalloc)) == NULL)
+        return ERROR_INT("new lstack array not defined", __func__, 1);
+
+    lstack->nalloc = 2 * lstack->nalloc;
+    return 0;
+}
+
+
+/*!
+ * \brief   lstackGetCount()
+ *
+ * \param[in]    lstack
+ * \return  count, or 0 on error
+ */
+l_int32
+lstackGetCount(L_STACK  *lstack)
+{
+    if (!lstack)
+        return ERROR_INT("lstack not defined", __func__, 1);
+
+    return lstack->n;
+}
+
+
+
+/*---------------------------------------------------------------------*
+ *                            Debug output                             *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   lstackPrint()
+ *
+ * \param[in]    fp       file stream
+ * \param[in]    lstack
+ * \return  0 if OK; 1 on error
+ */
+l_ok
+lstackPrint(FILE     *fp,
+            L_STACK  *lstack)
+{
+l_int32  i;
+
+    if (!fp)
+        return ERROR_INT("stream not defined", __func__, 1);
+    if (!lstack)
+        return ERROR_INT("lstack not defined", __func__, 1);
+
+    fprintf(fp, "\n Stack: nalloc = %d, n = %d, array = %p\n",
+            lstack->nalloc, lstack->n, lstack->array);
+    for (i = 0; i < lstack->n; i++)
+        fprintf(fp,   "array[%d] = %p\n", i, lstack->array[i]);
+
+    return 0;
+}