From 7ac8c5560340ec0f66506ec37575b5fd7a2c3db3 Mon Sep 17 00:00:00 2001
From: Oliver Schmidt <ol.sc@web.de>
Date: Sat, 4 Aug 2018 13:10:13 +0200
Subject: [PATCH] First step towards download to disk.

So far we were reading (much) more bytes from the W5100 than necessary when processing the HTTP header. The byte were memmove'd to the beginning of the buffer.

However, when downloading a DOS 3.3 sector order disk image (*.dsk / *.do) then we need to place every DOS 3.3 sector at a certain point in the buffer to avoid additional memcpy's later. Therefore the HTTP header processing mustn't read (or rather commit) any body bytes from the W5100. So we now just check for the "\r\n\r\n" after each and every byte. This is of course less than optimal but small/simple - and the header isn't supposed to be that large anyway.
---
 apps/wget65.c | 241 ++++++++++++++++++++++++++------------------------
 1 file changed, 124 insertions(+), 117 deletions(-)

diff --git a/apps/wget65.c b/apps/wget65.c
index df109f3..b97c271 100644
--- a/apps/wget65.c
+++ b/apps/wget65.c
@@ -219,14 +219,88 @@ void exit_on_disconnect(void)
   }
 }
 
+void receive_file(const char *name)
+{
+  uint16_t i;
+  int file;
+  uint16_t rcv;
+  bool cont = true;
+  uint16_t len = 0;
+  uint32_t size = 0;
+
+  printf("- Ok\n\nOpening file ");
+  file = open(name, O_WRONLY | O_CREAT | O_TRUNC);
+  if (file == -1)
+  {
+    w5100_disconnect();
+    file_error_exit();
+  }
+  printf("- Ok\n\n");
+
+  while (cont)
+  {
+    exit_on_key();
+
+    rcv = w5100_receive_request();
+    if (!rcv)
+    {
+      cont = w5100_connected();
+      if (cont)
+      {
+        continue;
+      }
+    }
+
+    if (rcv > sizeof(buffer) - len)
+    {
+      rcv = sizeof(buffer) - len;
+    }
+
+    {
+      // One less to allow for faster pre-increment below
+      char *dataptr = buffer + len - 1;
+      for (i = 0; i < rcv; ++i)
+      {
+        // The variable is necessary to have cc65 generate code
+        // suitable to access the W5100 auto-increment register.
+        char data = *w5100_data;
+        *++dataptr = data;
+      }
+    }
+
+    w5100_receive_commit(rcv);
+    len += rcv;
+
+    if (cont && len < sizeof(buffer))
+    {
+      continue;
+    }
+
+    cprintf("\rWriting ");
+    if (write(file, buffer, len) != len)
+    {
+      w5100_disconnect();
+      file_error_exit();
+    }
+    size += len;
+    cprintf("%lu bytes ", size);
+
+    len = 0;
+  }
+
+  printf("- Ok\n\nClosing file ");
+  if (close(file))
+  {
+    w5100_disconnect();
+    file_error_exit();
+  }
+}
+
 int main(int, char *argv[])
 {
-  uint8_t drv_init = DRV_INIT_DEFAULT;
-  uint16_t i, len;
+  uint16_t i;
   char *arg;
-  char data;
-  char *dataptr;
-  int file;
+  uint8_t drv_init = DRV_INIT_DEFAULT;
 
   if (doesclrscrafterexit())
   {
@@ -250,13 +324,17 @@ int main(int, char *argv[])
     *argv[0] = '\0';
   }
 
-  printf("\nSetting slot ");
-  file = open(self_path("ethernet.slot"), O_RDONLY);
-  if (file != -1)
   {
-    read(file, &drv_init, 1);
-    close(file);
-    drv_init &= ~'0';
+    int file;
+
+    printf("\nSetting slot ");
+    file = open(self_path("ethernet.slot"), O_RDONLY);
+    if (file != -1)
+    {
+      read(file, &drv_init, 1);
+      close(file);
+      drv_init &= ~'0';
+    }
   }
 
   printf("- %d\n\nInitializing ", drv_init);
@@ -304,12 +382,12 @@ int main(int, char *argv[])
     exit(EXIT_FAILURE);
   }
 
-  printf("- Ok\n\nSending Request ");
+  printf("- Ok\n\nSending request ");
   {
     uint16_t snd;
     uint16_t pos = 0;
+    uint16_t len = strlen(url_selector);
 
-    len = strlen(url_selector);
     while (len)
     {
       exit_on_key();
@@ -326,14 +404,16 @@ int main(int, char *argv[])
         snd = len;
       }
 
-      // One less to allow for faster pre-increment below
-      dataptr = url_selector + pos - 1;
-      for (i = 0; i < snd; ++i)
       {
-        // The variable is necessary to have cc65 generate code
-        // suitable to access the W5100 auto-increment register.
-        data = *++dataptr;
-        *w5100_data = data;
+        // One less to allow for faster pre-increment below
+        char *dataptr = url_selector + pos - 1;
+        for (i = 0; i < snd; ++i)
+        {
+          // The variable is necessary to have cc65 generate code
+          // suitable to access the W5100 auto-increment register.
+          char data = *++dataptr;
+          *w5100_data = data;
+        }
       }
 
       w5100_send_commit(snd);
@@ -342,13 +422,13 @@ int main(int, char *argv[])
     }
   }
 
-  printf("- Ok\n\nReceiving Response ");
+  printf("- Ok\n\nReceiving response ");
   {
     uint16_t rcv;
-    char *body;
+    bool body = false;
+    uint16_t len = 0;
 
-    len = 0;
-    while (true)
+    while (!body)
     {
       exit_on_key();
 
@@ -359,34 +439,34 @@ int main(int, char *argv[])
         continue;
       }
 
-      // One less to allow for zero-termination further down below
-      if (rcv > sizeof(buffer) - 1 - len)
+      if (rcv > sizeof(buffer) - len)
       {
-        rcv = sizeof(buffer) - 1 - len;
+        rcv = sizeof(buffer) - len;
       }
 
-      // One less to allow for faster pre-increment below
-      dataptr = buffer + len - 1;
-      for (i = 0; i < rcv; ++i)
       {
-        // The variable is necessary to have cc65 generate code
-        // suitable to access the W5100 auto-increment register.
-        data = *w5100_data;
-        *++dataptr = data;
+        // One less to allow for faster pre-increment below
+        char *dataptr = buffer + len - 1;
+        for (i = 0; i < rcv; ++i)
+        {
+          // The variable is necessary to have cc65 generate code
+          // suitable to access the W5100 auto-increment register.
+          char data = *w5100_data;
+          *++dataptr = data;
+
+          if (!memcmp(dataptr - 3, "\r\n\r\n", 4))
+          {
+            rcv = i + 1;
+            body = true;
+          }
+        }
       }
 
       w5100_receive_commit(rcv);
       len += rcv;
 
-      buffer[len] = '\0';
-      body = strstr(buffer,"\r\n\r\n");
-      if (body)
-      {
-        break;
-      }
-
-      // No body found but full buffer
-      if (len == sizeof(buffer) - 1)
+      // No body found in full buffer
+      if (len == sizeof(buffer))
       {
         printf("- Invalid response\n");
         w5100_disconnect();
@@ -412,82 +492,9 @@ int main(int, char *argv[])
       w5100_disconnect();
       exit(EXIT_FAILURE);
     }
-
-    body += strlen("\r\n\r\n");
-    len -= body - buffer;
-    memmove(buffer, body, len);
   }
 
-  printf("- Ok\n\nOpening file ");
-  file = open(arg, O_WRONLY | O_CREAT | O_TRUNC);
-  if (file == -1)
-  {
-    w5100_disconnect();
-    file_error_exit();
-  }
-  printf("- Ok\n\n");
-
-  {
-    uint16_t rcv;
-    bool cont = true;
-    uint32_t size = 0;
-
-    while (cont)
-    {
-      exit_on_key();
-
-      rcv = w5100_receive_request();
-      if (!rcv)
-      {
-        cont = w5100_connected();
-        if (cont)
-        {
-          continue;
-        }
-      }
-
-      if (rcv > sizeof(buffer) - len)
-      {
-        rcv = sizeof(buffer) - len;
-      }
-
-      // One less to allow for faster pre-increment below
-      dataptr = buffer + len - 1;
-      for (i = 0; i < rcv; ++i)
-      {
-        // The variable is necessary to have cc65 generate code
-        // suitable to access the W5100 auto-increment register.
-        data = *w5100_data;
-        *++dataptr = data;
-      }
-
-      w5100_receive_commit(rcv);
-      len += rcv;
-
-      if (cont && len < sizeof(buffer))
-      {
-        continue;
-      }
-
-      cprintf("\rWriting ");
-      if (write(file, buffer, len) != len)
-      {
-        w5100_disconnect();
-        file_error_exit();
-      }
-      size += len;
-      cprintf("%lu bytes ", size);
-
-      len = 0;
-    }
-  }
-
-  printf("- Ok\n\nClosing file ");
-  if (close(file))
-  {
-    w5100_disconnect();
-    file_error_exit();
-  }
+  receive_file(arg);
 
   printf("- Ok\n\nDisconnecting ");
   w5100_disconnect();