add proxy support for resource downloads

- Added ProxyPPC module to prepend proxy prefix to resource URLs
- Modified MusicAsset_Download in resources.c to use proxy
- Re-added legacy texture pack proxy code from ClassiCube-PPC1.3.7rev4

(Compiles ✅ on PowerMac G4 1.24GHz + ATI Radeon 9000 Pro)

src/ProxyPPC.c

@@ -0,0 +1,59 @@
+#include <string.h> 
+#include "ProxyPPC.h"
+
+int HasProxyPrefix(const cc_string* url) {
+    const char* proxyPrefix = PROXY_PREFIX;
+    int prefixLen = strlen(proxyPrefix);
+    int i;
+    
+    if (url->length < prefixLen) return 0;
+    
+    for (i = 0; i < prefixLen; i++) {
+        if (url->buffer[i] != proxyPrefix[i]) {
+            return 0;
+        }
+    }
+    return 1;
+}
+
+void RemoveProxyPrefix(cc_string* url) {
+    int prefixLen, newLength;
+    
+    if (!url || url->length == 0) return;
+    
+    if (HasProxyPrefix(url)) {
+        const char* proxyPrefix = PROXY_PREFIX;
+        prefixLen = strlen(proxyPrefix);
+        newLength = url->length - prefixLen;
+        
+        if (newLength > 0) {
+            memmove(url->buffer, url->buffer + prefixLen, newLength);
+        }
+        url->buffer[newLength] = '\0';
+        url->length = newLength;
+    }
+}
+
+void ApplyProxyPPC(cc_string* url) {
+    int prefixLen, newLength;
+    
+    if (!url || url->length == 0) return;
+    
+    if (HasProxyPrefix(url)) return;
+    
+    {
+        const char* proxyPrefix = PROXY_PREFIX;
+        prefixLen = strlen(proxyPrefix);
+        newLength = url->length + prefixLen;
+        
+        if (newLength + 1 > url->capacity) {
+            return;
+        }
+        
+        memmove(url->buffer + prefixLen, url->buffer, url->length + 1);
+        
+        memcpy(url->buffer, proxyPrefix, prefixLen);
+        
+        url->length = newLength;
+    }
+}

src/ProxyPPC.h

@@ -0,0 +1,11 @@
+#ifndef PROXY_PPC_H
+#define PROXY_PPC_H
+#include "String.h"
+
+#define PROXY_PREFIX "http://ppcproxy.andreiixe.website/?url="
+
+void ApplyProxyPPC(cc_string* url);
+int HasProxyPrefix(const cc_string* url);
+void RemoveProxyPrefix(cc_string* url);
+
+#endif // PROXY_PPC_H

src/Resources.c

@@ -333,13 +333,20 @@ static void MusicAssets_CountMissing(void) {
 /*########################################################################################################################*
 *-----------------------------------------------------Music asset fetching -----------------------------------------------*
 *#########################################################################################################################*/
-CC_NOINLINE static int MusicAsset_Download(const char* hash) {
-	cc_string url; char urlBuffer[URL_MAX_SIZE];
+#include "ProxyPPC.h"
 
-	String_InitArray(url, urlBuffer);
-	String_Format3(&url, "https://resources.download.minecraft.net/%r%r/%c", 
-					&hash[0], &hash[1], hash);
-	return Http_AsyncGetData(&url, 0);
+CC_NOINLINE static int MusicAsset_Download(const char* hash) {
+    cc_string url; 
+    char urlBuffer[256]; 
+    
+    String_InitArray(url, urlBuffer);
+    
+    String_Format3(&url, "https://resources.download.minecraft.net/%r%r/%c", 
+                    &hash[0], &hash[1], hash);
+    
+    ApplyProxyPPC(&url);
+    
+    return Http_AsyncGetData(&url, 0);
 }
 
 static void MusicAssets_DownloadAssets(void) {

src/TexturePack.c

@@ -676,19 +676,21 @@ void TexturePack_CheckPending(void) {
 }
 
 /* Asynchronously downloads the given texture pack */
-static void DownloadAsync(const cc_string* url) {
-	cc_string etag = String_Empty;
-	cc_string time = String_Empty;
-
-	/* Only retrieve etag/last-modified headers if the file exists */
-	/* This inconsistency can occur if user deleted some cached files */
-	if (IsCached(url)) {
-		time = GetCachedLastModified(url);
-		etag = GetCachedETag(url);
-	}
+#include "ProxyPPC.h"
 
+static void DownloadAsync(cc_string* url) {
+    cc_string etag = String_Empty;
+    cc_string time = String_Empty;
+    /*Proxy From ProxyPPC.h*/
+    ApplyProxyPPC(url);
+    if (IsCached(url)) {
+        time = GetCachedLastModified(url);
+        etag = GetCachedETag(url);
+    }
 	Http_TryCancel(TexturePack_ReqID);
 	TexturePack_ReqID = Http_AsyncGetDataEx(url, HTTP_FLAG_PRIORITY, &time, &etag, NULL);
+    Http_TryCancel(TexturePack_ReqID);
+    TexturePack_ReqID = Http_AsyncGetDataEx(url, HTTP_FLAG_PRIORITY, &time, &etag, NULL);
 }
 
 void TexturePack_Extract(const cc_string* url) {