Add IPS patching.

docs/ssnes.1

@@ -192,6 +192,12 @@ If this flag is not specified, SSNES will look for a .ups file with same basenam
 Attempts to apply a BPS patch to the current ROM image. No files are altered. 
 If this flag is not specified, SSNES will look for a .bps file with same basename as ROM specified.
 
+.TP
+\fB--ips PATCH\fR
+Attempts to apply a IPS patch to the current ROM image. No files are altered. 
+If this flag is not specified, SSNES will look for a .ips file with same basename as ROM specified.
+Note that SSNES cannot perform any error checking if patching was successful due to how IPS works.
+
 .TP
 \fB--xml MAP, -X MAP\fR
 Specifies path to XML memory map for the given ROM.

file.c

@@ -150,24 +150,34 @@ static void patch_rom(uint8_t **buf, ssize_t *size)
    void *patch_data = NULL;
    bool success = false;
 
-   if (g_extern.ups_pref && g_extern.bps_pref)
+   if (g_extern.ups_pref + g_extern.bps_pref + g_extern.ips_pref > 1)
    {
-      SSNES_WARN("Both UPS and BPS patch explicitly defined, ignoring both ...\n");
+      SSNES_WARN("Several patches are explicitly defined, ignoring all ...\n");
       return;
    }
 
-   if (!g_extern.bps_pref && *g_extern.ups_name && (patch_size = read_file(g_extern.ups_name, &patch_data)) >= 0)
+   bool allow_bps = !g_extern.ups_pref && !g_extern.ips_pref;
+   bool allow_ups = !g_extern.bps_pref && !g_extern.ips_pref;
+   bool allow_ips = !g_extern.ups_pref && !g_extern.bps_pref;
+
+   if (allow_ups && *g_extern.ups_name && (patch_size = read_file(g_extern.ups_name, &patch_data)) >= 0)
    {
       patch_desc = "UPS";
       patch_path = g_extern.ups_name;
       func = ups_apply_patch;
    }
-   else if (!g_extern.ups_pref && *g_extern.bps_name && (patch_size = read_file(g_extern.bps_name, &patch_data)) >= 0)
+   else if (allow_bps && *g_extern.bps_name && (patch_size = read_file(g_extern.bps_name, &patch_data)) >= 0)
    {
       patch_desc = "BPS";
       patch_path = g_extern.bps_name;
       func = bps_apply_patch;
    }
+   else if (allow_ips && *g_extern.ips_name && (patch_size = read_file(g_extern.ips_name, &patch_data)) >= 0)
+   {
+      patch_desc = "IPS";
+      patch_path = g_extern.ips_name;
+      func = ips_apply_patch;
+   }
    else
    {
       SSNES_LOG("Did not find a valid ROM patch.\n");
@@ -279,6 +289,9 @@ static ssize_t read_rom_file(FILE* file, void** buf)
       ret_buf = (uint8_t*)rom_buf;
    }
 
+   // Attempt to apply a patch.
+   patch_rom(&ret_buf, &ret);
+   
    // Remove copier header if present (512 first bytes).
    if ((ret & 0x7fff) == 512)
    {
@@ -286,9 +299,6 @@ static ssize_t read_rom_file(FILE* file, void** buf)
       ret -= 512;
    }
 
-   // Attempt to apply a patch :)
-   patch_rom(&ret_buf, &ret);
-   
    g_extern.cart_crc = crc32_calculate(ret_buf, ret);
 #ifdef HAVE_XML
    sha256_hash(g_extern.sha256, ret_buf, ret);

general.h

@@ -288,8 +288,10 @@ struct global
 
    bool ups_pref;
    bool bps_pref;
+   bool ips_pref;
    char ups_name[PATH_MAX];
    char bps_name[PATH_MAX];
+   char ips_name[PATH_MAX];
 
    unsigned state_slot;
 

patch.c

@@ -15,11 +15,15 @@
  *  If not, see <http://www.gnu.org/licenses/>.
  */
 
+// BPS/UPS/IPS implementation from bSNES (nall::).
+// Modified for SSNES.
+
 #include "patch.h"
 #include "movie.h"
 #include "boolean.h"
 #include "msvc/msvc_compat.h"
 #include <stdint.h>
+#include <string.h>
 
 enum bps_mode
 {
@@ -316,3 +320,82 @@ patch_error_t ups_apply_patch(
       return PATCH_SOURCE_INVALID;
 }
 
+patch_error_t ips_apply_patch(
+      const uint8_t *patchdata, size_t patchlen,
+      const uint8_t *sourcedata, size_t sourcelength,
+      uint8_t *targetdata, size_t *targetlength)
+{
+   if (patchlen < 8 ||
+         patchdata[0] != 'P' ||
+         patchdata[1] != 'A' ||
+         patchdata[2] != 'T' ||
+         patchdata[3] != 'C' ||
+         patchdata[4] != 'H')
+      return PATCH_PATCH_INVALID;
+
+   memcpy(targetdata, sourcedata, sourcelength);
+
+   uint32_t offset = 5;
+   *targetlength = sourcelength;
+
+   for (;;)
+   {
+      if (offset > patchlen - 3)
+         break;
+
+      uint32_t address = patchdata[offset++] << 16;
+      address |= patchdata[offset++] << 8;
+      address |= patchdata[offset++] << 0;
+
+      if (address == 0x454f46) // EOF
+      {
+         if (offset == patchlen)
+            return PATCH_SUCCESS;
+         else if (offset == patchlen - 3)
+         {
+            uint32_t size = patchdata[offset++] << 16;
+            size |= patchdata[offset++] << 8;
+            size |= patchdata[offset++] << 0;
+            *targetlength = size;
+            return PATCH_SUCCESS;
+         }
+      }
+
+      if (offset > patchlen - 2)
+         break;
+
+      unsigned length = patchdata[offset++] << 8;
+      length |= patchdata[offset++] << 0;
+
+      if (length) // Copy
+      {
+         if (offset > patchlen - length)
+            break;
+
+         while (length--)
+            targetdata[address++] = patchdata[offset++];
+      }
+      else // RLE
+      {
+         if (offset > patchlen - 3)
+            break;
+
+         length  = patchdata[offset++] << 8;
+         length |= patchdata[offset++] << 0;
+
+         if (length == 0) // Illegal
+            break;
+
+         while (length--)
+            targetdata[address++] = patchdata[offset];
+
+         offset++;
+      }
+
+      if (address > *targetlength)
+         *targetlength = address;
+   }
+
+   return PATCH_PATCH_INVALID;
+}
+

patch.h

@@ -21,7 +21,8 @@
 #include <stdint.h>
 #include <stddef.h>
 
-// BPS/UPS implementation from bSNES (nall::).
+// BPS/UPS/IPS implementation from bSNES (nall::).
+// Modified for SSNES.
 
 typedef enum
 {
@@ -51,4 +52,10 @@ patch_error_t ups_apply_patch(
       const uint8_t *source_data, size_t source_length,
       uint8_t *target_data, size_t *target_length);
 
+
+patch_error_t ips_apply_patch(
+      const uint8_t *patch_data, size_t patch_length,
+      const uint8_t *source_data, size_t source_length,
+      uint8_t *target_data, size_t *target_length);
+
 #endif

ssnes.c

@@ -536,6 +536,7 @@ static void print_help(void)
    puts("\t-v/--verbose: Verbose logging.");
    puts("\t-U/--ups: Specifies path for UPS patch that will be applied to ROM.");
    puts("\t--bps: Specifies path for BPS patch that will be applied to ROM.");
+   puts("\t--ips: Specifies path for IPS patch that will be applied to ROM.");
    puts("\t-X/--xml: Specifies path to XML memory map.");
    puts("\t-D/--detach: Detach SSNES from the running console. Not relevant for all platforms.\n");
 }
@@ -683,6 +684,7 @@ static void parse_input(int argc, char *argv[])
 #endif
       { "ups", 1, NULL, 'U' },
       { "bps", 1, &val, 'B' },
+      { "ips", 1, &val, 'I' },
       { "xml", 1, NULL, 'X' },
       { "detach", 0, NULL, 'D' },
       { "features", 0, &val, 'f' },
@@ -909,6 +911,11 @@ static void parse_input(int argc, char *argv[])
                   g_extern.bps_pref = true;
                   break;
 
+               case 'I':
+                  strlcpy(g_extern.ips_name, optarg, sizeof(g_extern.ips_name));
+                  g_extern.ips_pref = true;
+                  break;
+
 #ifdef HAVE_FFMPEG
                case 's':
                {
@@ -1511,6 +1518,9 @@ static void fill_pathnames(void)
       if (!(*g_extern.bps_name))
          fill_pathname_noext(g_extern.bps_name, g_extern.basename, ".bps", sizeof(g_extern.bps_name));
 
+      if (!(*g_extern.ips_name))
+         fill_pathname_noext(g_extern.ips_name, g_extern.basename, ".ips", sizeof(g_extern.ips_name));
+
       if (!(*g_extern.xml_name))
          fill_pathname_noext(g_extern.xml_name, g_extern.basename, ".xml", sizeof(g_extern.xml_name));