6.6.3 - Alpha5 - images.save 方法使用 quality 参数时支持 png 格式的文件体积压缩 (issue #367)

libs/imagequant/external/libimagequant/mempool.c

@@ -0,0 +1,70 @@
+/*
+** © 2009-2017 by Kornel Lesiński.
+** © 1989, 1991 by Jef Poskanzer.
+** © 1997, 2000, 2002 by Greg Roelofs; based on an idea by Stefan Schneider.
+**
+** See COPYRIGHT file for license.
+*/
+
+#include "libimagequant.h"
+#include "mempool.h"
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+
+#define ALIGN_MASK 15UL
+#define MEMPOOL_RESERVED ((sizeof(struct mempool)+ALIGN_MASK) & ~ALIGN_MASK)
+
+struct mempool {
+    unsigned int used, size;
+    void* (*malloc)(size_t);
+    void (*free)(void*);
+    struct mempool *next;
+};
+LIQ_PRIVATE void* mempool_create(mempoolptr *mptr, const unsigned int size, unsigned int max_size, void* (*malloc)(size_t), void (*free)(void*))
+{
+    if (*mptr && ((*mptr)->used+size) <= (*mptr)->size) {
+        unsigned int prevused = (*mptr)->used;
+        (*mptr)->used += (size+15UL) & ~0xFUL;
+        return ((char*)(*mptr)) + prevused;
+    }
+
+    mempoolptr old = *mptr;
+    if (!max_size) max_size = (1<<17);
+    max_size = size+ALIGN_MASK > max_size ? size+ALIGN_MASK : max_size;
+
+    *mptr = malloc(MEMPOOL_RESERVED + max_size);
+    if (!*mptr) return NULL;
+    **mptr = (struct mempool){
+        .malloc = malloc,
+        .free = free,
+        .size = MEMPOOL_RESERVED + max_size,
+        .used = sizeof(struct mempool),
+        .next = old,
+    };
+    uintptr_t mptr_used_start = (uintptr_t)(*mptr) + (*mptr)->used;
+    (*mptr)->used += (ALIGN_MASK + 1 - (mptr_used_start & ALIGN_MASK)) & ALIGN_MASK; // reserve bytes required to make subsequent allocations aligned
+    assert(!(((uintptr_t)(*mptr) + (*mptr)->used) & ALIGN_MASK));
+
+    return mempool_alloc(mptr, size, size);
+}
+
+LIQ_PRIVATE void* mempool_alloc(mempoolptr *mptr, const unsigned int size, const unsigned int max_size)
+{
+    if (((*mptr)->used+size) <= (*mptr)->size) {
+        unsigned int prevused = (*mptr)->used;
+        (*mptr)->used += (size + ALIGN_MASK) & ~ALIGN_MASK;
+        return ((char*)(*mptr)) + prevused;
+    }
+
+    return mempool_create(mptr, size, max_size, (*mptr)->malloc, (*mptr)->free);
+}
+
+LIQ_PRIVATE void mempool_destroy(mempoolptr m)
+{
+    while (m) {
+        mempoolptr next = m->next;
+        m->free(m);
+        m = next;
+    }
+}