statically initialize

stb_image.h

@@ -3680,7 +3680,7 @@ stbi_inline static int stbi__bit_reverse(int v, int bits)
    return stbi__bitreverse16(v) >> (16-bits);
 }
 
-static int stbi__zbuild_huffman(stbi__zhuffman *z, stbi_uc *sizelist, int num)
+static int stbi__zbuild_huffman(stbi__zhuffman *z, const stbi_uc *sizelist, int num)
 {
    int i,k=0;
    int code, next_code[16], sizes[17];
@@ -3970,9 +3970,33 @@ static int stbi__parse_zlib_header(stbi__zbuf *a)
    return 1;
 }
 
-// @TODO: should statically initialize these for optimal thread safety
-static stbi_uc stbi__zdefault_length[288], stbi__zdefault_distance[32];
-static void stbi__init_zdefaults(void)
+static const stbi_uc stbi__zdefault_length[288] = {
+   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+   8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+   9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+   9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+   9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+   9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+   9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+   9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+   9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+   7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+   7, 7, 7, 7, 7, 7, 7, 7,
+   8, 8, 8, 8, 8, 8, 8, 8
+};
+static const stbi_uc stbi__zdefault_distance[32] = {
+   5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+   5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5
+};
+/*
+Init algorithm:
 {
    int i;   // use <= to match clearly with spec
    for (i=0; i <= 143; ++i)     stbi__zdefault_length[i]   = 8;
@@ -3982,6 +4006,7 @@ static void stbi__init_zdefaults(void)
 
    for (i=0; i <=  31; ++i)     stbi__zdefault_distance[i] = 5;
 }
+*/
 
 static int stbi__parse_zlib(stbi__zbuf *a, int parse_header)
 {
@@ -4000,7 +4025,6 @@ static int stbi__parse_zlib(stbi__zbuf *a, int parse_header)
       } else {
          if (type == 1) {
             // use fixed code lengths
-            if (!stbi__zdefault_distance[31]) stbi__init_zdefaults();
             if (!stbi__zbuild_huffman(&a->z_length  , stbi__zdefault_length  , 288)) return 0;
             if (!stbi__zbuild_huffman(&a->z_distance, stbi__zdefault_distance,  32)) return 0;
          } else {