libdex/DexProto.cpp - platform/dalvik - Gitiles

 /*
  * Copyright (C) 2008 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 /*
  * Functions for dealing with method prototypes
  */

 #include "DexProto.h"

 #include <stdlib.h>
 #include <string.h>

 /*
  * ===========================================================================
  *      String Cache
  * ===========================================================================
  */

 /*
  * Make sure that the given cache can hold a string of the given length,
  * including the final '\0' byte.
  */
 void dexStringCacheAlloc(DexStringCache* pCache, size_t length) {
     if (pCache->allocatedSize != 0) {
         if (pCache->allocatedSize >= length) {
             return;
         }
         free((void*) pCache->value);
     }

     if (length <= sizeof(pCache->buffer)) {
         pCache->value = pCache->buffer;
         pCache->allocatedSize = 0;
     } else {
         pCache->value = (char*) malloc(length);
         pCache->allocatedSize = length;
     }
 }

 /*
  * Initialize the given DexStringCache. Use this function before passing
  * one into any other function.
  */
 void dexStringCacheInit(DexStringCache* pCache) {
     pCache->value = pCache->buffer;
     pCache->allocatedSize = 0;
     pCache->buffer[0] = '\0';
 }

 /*
  * Release the allocated contents of the given DexStringCache, if any.
  * Use this function after your last use of a DexStringCache.
  */
 void dexStringCacheRelease(DexStringCache* pCache) {
     if (pCache->allocatedSize != 0) {
         free((void*) pCache->value);
         pCache->value = pCache->buffer;
         pCache->allocatedSize = 0;
     }
 }

 /*
  * If the given DexStringCache doesn't already point at the given value,
  * make a copy of it into the cache. This always returns a writable
  * pointer to the contents (whether or not a copy had to be made). This
  * function is intended to be used after making a call that at least
  * sometimes doesn't populate a DexStringCache.
  */
 char* dexStringCacheEnsureCopy(DexStringCache* pCache, const char* value) {
     if (value != pCache->value) {
         size_t length = strlen(value) + 1;
         dexStringCacheAlloc(pCache, length);
         memcpy(pCache->value, value, length);
     }

     return pCache->value;
 }

 /*
  * Abandon the given DexStringCache, and return a writable copy of the
  * given value (reusing the string cache's allocation if possible).
  * The return value must be free()d by the caller. Use this instead of
  * dexStringCacheRelease() if you want the buffer to survive past the
  * scope of the DexStringCache.
  */
 char* dexStringCacheAbandon(DexStringCache* pCache, const char* value) {
     if ((value == pCache->value) && (pCache->allocatedSize != 0)) {
         char* result = pCache->value;
         pCache->allocatedSize = 0;
         pCache->value = pCache->buffer;
         return result;
     } else {
         return strdup(value);
     }
 }


 /*
  * ===========================================================================
  *      Method Prototypes
  * ===========================================================================
  */

 /*
  * Return the DexProtoId from the given DexProto. The DexProto must
  * actually refer to a DexProtoId.
  */
 static inline const DexProtoId* getProtoId(const DexProto* pProto) {
     return dexGetProtoId(pProto->dexFile, pProto->protoIdx);
 }

 /* (documented in header file) */
 const char* dexProtoGetShorty(const DexProto* pProto) {
     const DexProtoId* protoId = getProtoId(pProto);

     return dexStringById(pProto->dexFile, protoId->shortyIdx);
 }

 /* (documented in header file) */
 const char* dexProtoGetMethodDescriptor(const DexProto* pProto,
         DexStringCache* pCache) {
     const DexFile* dexFile = pProto->dexFile;
     const DexProtoId* protoId = getProtoId(pProto);
     const DexTypeList* typeList = dexGetProtoParameters(dexFile, protoId);
     size_t length = 3; // parens and terminating '\0'
     u4 paramCount = (typeList == NULL) ? 0 : typeList->size;
     u4 i;

     for (i = 0; i < paramCount; i++) {
         u4 idx = dexTypeListGetIdx(typeList, i);
         length += strlen(dexStringByTypeIdx(dexFile, idx));
     }

     length += strlen(dexStringByTypeIdx(dexFile, protoId->returnTypeIdx));

     dexStringCacheAlloc(pCache, length);

     char *at = (char*) pCache->value;
     *(at++) = '(';

     for (i = 0; i < paramCount; i++) {
         u4 idx = dexTypeListGetIdx(typeList, i);
         const char* desc = dexStringByTypeIdx(dexFile, idx);
         strcpy(at, desc);
         at += strlen(desc);
     }

     *(at++) = ')';

     strcpy(at, dexStringByTypeIdx(dexFile, protoId->returnTypeIdx));
     return pCache->value;
 }

 /* (documented in header file) */
 char* dexProtoCopyMethodDescriptor(const DexProto* pProto) {
     DexStringCache cache;

     dexStringCacheInit(&cache);
     return dexStringCacheAbandon(&cache,
             dexProtoGetMethodDescriptor(pProto, &cache));
 }

 /* (documented in header file) */
 const char* dexProtoGetParameterDescriptors(const DexProto* pProto,
         DexStringCache* pCache) {
     DexParameterIterator iterator;
     size_t length = 1; /* +1 for the terminating '\0' */

     dexParameterIteratorInit(&iterator, pProto);

     for (;;) {
         const char* descriptor = dexParameterIteratorNextDescriptor(&iterator);
         if (descriptor == NULL) {
             break;
         }

         length += strlen(descriptor);
     }

     dexParameterIteratorInit(&iterator, pProto);

     dexStringCacheAlloc(pCache, length);
     char *at = (char*) pCache->value;

     for (;;) {
         const char* descriptor = dexParameterIteratorNextDescriptor(&iterator);
         if (descriptor == NULL) {
             break;
         }

         strcpy(at, descriptor);
         at += strlen(descriptor);
     }

     return pCache->value;
 }

 /* (documented in header file) */
 const char* dexProtoGetReturnType(const DexProto* pProto) {
     const DexProtoId* protoId = getProtoId(pProto);
     return dexStringByTypeIdx(pProto->dexFile, protoId->returnTypeIdx);
 }

 /* (documented in header file) */
 size_t dexProtoGetParameterCount(const DexProto* pProto) {
     const DexProtoId* protoId = getProtoId(pProto);
     const DexTypeList* typeList =
         dexGetProtoParameters(pProto->dexFile, protoId);
     return (typeList == NULL) ? 0 : typeList->size;
 }

 /* (documented in header file) */
 int dexProtoComputeArgsSize(const DexProto* pProto) {
     const char* shorty = dexProtoGetShorty(pProto);
     int count = 0;

     /* Skip the return type. */
     shorty++;

     for (;;) {
         switch (*(shorty++)) {
             case '\0': {
                 return count;
             }
             case 'D':
             case 'J': {
                 count += 2;
                 break;
             }
             default: {
                 count++;
                 break;
             }
         }
     }
 }

 /*
  * Common implementation for dexProtoCompare() and dexProtoCompareParameters().
  */
 static int protoCompare(const DexProto* pProto1, const DexProto* pProto2,
         bool compareReturnType) {

     if (pProto1 == pProto2) {
         // Easy out.
         return 0;
     } else {
         const DexFile* dexFile1 = pProto1->dexFile;
         const DexProtoId* protoId1 = getProtoId(pProto1);
         const DexTypeList* typeList1 =
             dexGetProtoParameters(dexFile1, protoId1);
         int paramCount1 = (typeList1 == NULL) ? 0 : typeList1->size;

         const DexFile* dexFile2 = pProto2->dexFile;
         const DexProtoId* protoId2 = getProtoId(pProto2);
         const DexTypeList* typeList2 =
             dexGetProtoParameters(dexFile2, protoId2);
         int paramCount2 = (typeList2 == NULL) ? 0 : typeList2->size;

         if (protoId1 == protoId2) {
             // Another easy out.
             return 0;
         }

         // Compare return types.

         if (compareReturnType) {
             int result =
                 strcmp(dexStringByTypeIdx(dexFile1, protoId1->returnTypeIdx),
                         dexStringByTypeIdx(dexFile2, protoId2->returnTypeIdx));

             if (result != 0) {
                 return result;
             }
         }

         // Compare parameters.

         int minParam = (paramCount1 > paramCount2) ? paramCount2 : paramCount1;
         int i;

         for (i = 0; i < minParam; i++) {
             u4 idx1 = dexTypeListGetIdx(typeList1, i);
             u4 idx2 = dexTypeListGetIdx(typeList2, i);
             int result =
                 strcmp(dexStringByTypeIdx(dexFile1, idx1),
                         dexStringByTypeIdx(dexFile2, idx2));

             if (result != 0) {
                 return result;
             }
         }

         if (paramCount1 < paramCount2) {
             return -1;
         } else if (paramCount1 > paramCount2) {
             return 1;
         } else {
             return 0;
         }
     }
 }

 /* (documented in header file) */
 int dexProtoCompare(const DexProto* pProto1, const DexProto* pProto2) {
     return protoCompare(pProto1, pProto2, true);
 }

 /* (documented in header file) */
 int dexProtoCompareParameters(const DexProto* pProto1, const DexProto* pProto2){
     return protoCompare(pProto1, pProto2, false);
 }


 /*
  * Helper for dexProtoCompareToDescriptor(), which gets the return type
  * descriptor from a method descriptor string.
  */
 static const char* methodDescriptorReturnType(const char* descriptor) {
     const char* result = strchr(descriptor, ')');

     if (result == NULL) {
         return NULL;
     }

     // The return type is the character just past the ')'.
     return result + 1;
 }

 /*
  * Helper for dexProtoCompareToDescriptor(), which indicates the end
  * of an embedded argument type descriptor, which is also the
  * beginning of the next argument type descriptor. Since this is for
  * argument types, it doesn't accept 'V' as a valid type descriptor.
  */
 static const char* methodDescriptorNextType(const char* descriptor) {
     // Skip any array references.

     while (*descriptor == '[') {
         descriptor++;
     }

     switch (*descriptor) {
         case 'B': case 'C': case 'D': case 'F':
         case 'I': case 'J': case 'S': case 'Z': {
             return descriptor + 1;
         }
         case 'L': {
             const char* result = strchr(descriptor + 1, ';');
             if (result != NULL) {
                 // The type ends just past the ';'.
                 return result + 1;
             }
         }
     }

     return NULL;
 }

 /*
  * Common implementation for dexProtoCompareToDescriptor() and
  * dexProtoCompareToParameterDescriptors(). The descriptor argument
  * can be either a full method descriptor (with parens and a return
  * type) or an unadorned concatenation of types (e.g. a list of
  * argument types).
  */
 static int protoCompareToParameterDescriptors(const DexProto* proto,
         const char* descriptor, bool expectParens) {
     char expectedEndChar = expectParens ? ')' : '\0';
     DexParameterIterator iterator;
     dexParameterIteratorInit(&iterator, proto);

     if (expectParens) {
         // Skip the '('.
         assert (*descriptor == '(');
         descriptor++;
     }

     for (;;) {
         const char* protoDesc = dexParameterIteratorNextDescriptor(&iterator);

         if (*descriptor == expectedEndChar) {
             // It's the end of the descriptor string.
             if (protoDesc == NULL) {
                 // It's also the end of the prototype's arguments.
                 return 0;
             } else {
                 // The prototype still has more arguments.
                 return 1;
             }
         }

         if (protoDesc == NULL) {
             /*
              * The prototype doesn't have arguments left, but the
              * descriptor string does.
              */
             return -1;
         }

         // Both prototype and descriptor have arguments. Compare them.

         const char* nextDesc = methodDescriptorNextType(descriptor);
         assert(nextDesc != NULL);

         for (;;) {
             char c1 = *(protoDesc++);
             char c2 = (descriptor < nextDesc) ? *(descriptor++) : '\0';

             if (c1 < c2) {
                 // This includes the case where the proto is shorter.
                 return -1;
             } else if (c1 > c2) {
                 // This includes the case where the desc is shorter.
                 return 1;
             } else if (c1 == '\0') {
                 // The two types are equal in length. (c2 necessarily == '\0'.)
                 break;
             }
         }

         /*
          * If we made it here, the two arguments matched, and
          * descriptor == nextDesc.
          */
     }
 }

 /* (documented in header file) */
 int dexProtoCompareToDescriptor(const DexProto* proto,
         const char* descriptor) {
     // First compare the return types.

     const char *returnType = methodDescriptorReturnType(descriptor);
     assert(returnType != NULL);

     int result = strcmp(dexProtoGetReturnType(proto), returnType);

     if (result != 0) {
         return result;
     }

     // The return types match, so we have to check arguments.
     return protoCompareToParameterDescriptors(proto, descriptor, true);
 }

 /* (documented in header file) */
 int dexProtoCompareToParameterDescriptors(const DexProto* proto,
         const char* descriptors) {
     return protoCompareToParameterDescriptors(proto, descriptors, false);
 }


 /*
  * ===========================================================================
  *      Parameter Iterators
  * ===========================================================================
  */

 /*
  * Initialize the given DexParameterIterator to be at the start of the
  * parameters of the given prototype.
  */
 void dexParameterIteratorInit(DexParameterIterator* pIterator,
         const DexProto* pProto) {
     pIterator->proto = pProto;
     pIterator->cursor = 0;

     pIterator->parameters =
         dexGetProtoParameters(pProto->dexFile, getProtoId(pProto));
     pIterator->parameterCount = (pIterator->parameters == NULL) ? 0
         : pIterator->parameters->size;
 }

 /*
  * Get the type_id index for the next parameter, if any. This returns
  * kDexNoIndex if the last parameter has already been consumed.
  */
 u4 dexParameterIteratorNextIndex(DexParameterIterator* pIterator) {
     int cursor = pIterator->cursor;
     int parameterCount = pIterator->parameterCount;

     if (cursor >= parameterCount) {
         // The iteration is complete.
         return kDexNoIndex;
     } else {
         u4 idx = dexTypeListGetIdx(pIterator->parameters, cursor);
         pIterator->cursor++;
         return idx;
     }
 }

 /*
  * Get the type descriptor for the next parameter, if any. This returns
  * NULL if the last parameter has already been consumed.
  */
 const char* dexParameterIteratorNextDescriptor(
         DexParameterIterator* pIterator) {
     u4 idx = dexParameterIteratorNextIndex(pIterator);

     if (idx == kDexNoIndex) {
         return NULL;
     }

     return dexStringByTypeIdx(pIterator->proto->dexFile, idx);
 }
	/*
	* Copyright (C) 2008 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	/*
	* Functions for dealing with method prototypes
	*/

	#include "DexProto.h"

	#include <stdlib.h>
	#include <string.h>

	/*
	* ===========================================================================
	* String Cache
	* ===========================================================================
	*/

	/*
	* Make sure that the given cache can hold a string of the given length,
	* including the final '\0' byte.
	*/
	void dexStringCacheAlloc(DexStringCache* pCache, size_t length) {
	if (pCache->allocatedSize != 0) {
	if (pCache->allocatedSize >= length) {
	return;
	}
	free((void*) pCache->value);
	}

	if (length <= sizeof(pCache->buffer)) {
	pCache->value = pCache->buffer;
	pCache->allocatedSize = 0;
	} else {
	pCache->value = (char*) malloc(length);
	pCache->allocatedSize = length;
	}
	}

	/*
	* Initialize the given DexStringCache. Use this function before passing
	* one into any other function.
	*/
	void dexStringCacheInit(DexStringCache* pCache) {
	pCache->value = pCache->buffer;
	pCache->allocatedSize = 0;
	pCache->buffer[0] = '\0';
	}

	/*
	* Release the allocated contents of the given DexStringCache, if any.
	* Use this function after your last use of a DexStringCache.
	*/
	void dexStringCacheRelease(DexStringCache* pCache) {
	if (pCache->allocatedSize != 0) {
	free((void*) pCache->value);
	pCache->value = pCache->buffer;
	pCache->allocatedSize = 0;
	}
	}

	/*
	* If the given DexStringCache doesn't already point at the given value,
	* make a copy of it into the cache. This always returns a writable
	* pointer to the contents (whether or not a copy had to be made). This
	* function is intended to be used after making a call that at least
	* sometimes doesn't populate a DexStringCache.
	*/
	char* dexStringCacheEnsureCopy(DexStringCache* pCache, const char* value) {
	if (value != pCache->value) {
	size_t length = strlen(value) + 1;
	dexStringCacheAlloc(pCache, length);
	memcpy(pCache->value, value, length);
	}

	return pCache->value;
	}

	/*
	* Abandon the given DexStringCache, and return a writable copy of the
	* given value (reusing the string cache's allocation if possible).
	* The return value must be free()d by the caller. Use this instead of
	* dexStringCacheRelease() if you want the buffer to survive past the
	* scope of the DexStringCache.
	*/
	char* dexStringCacheAbandon(DexStringCache* pCache, const char* value) {
	if ((value == pCache->value) && (pCache->allocatedSize != 0)) {
	char* result = pCache->value;
	pCache->allocatedSize = 0;
	pCache->value = pCache->buffer;
	return result;
	} else {
	return strdup(value);
	}
	}


	/*
	* ===========================================================================
	* Method Prototypes
	* ===========================================================================
	*/

	/*
	* Return the DexProtoId from the given DexProto. The DexProto must
	* actually refer to a DexProtoId.
	*/
	static inline const DexProtoId* getProtoId(const DexProto* pProto) {
	return dexGetProtoId(pProto->dexFile, pProto->protoIdx);
	}

	/* (documented in header file) */
	const char* dexProtoGetShorty(const DexProto* pProto) {
	const DexProtoId* protoId = getProtoId(pProto);

	return dexStringById(pProto->dexFile, protoId->shortyIdx);
	}

	/* (documented in header file) */
	const char* dexProtoGetMethodDescriptor(const DexProto* pProto,
	DexStringCache* pCache) {
	const DexFile* dexFile = pProto->dexFile;
	const DexProtoId* protoId = getProtoId(pProto);
	const DexTypeList* typeList = dexGetProtoParameters(dexFile, protoId);
	size_t length = 3; // parens and terminating '\0'
	u4 paramCount = (typeList == NULL) ? 0 : typeList->size;
	u4 i;

	for (i = 0; i < paramCount; i++) {
	u4 idx = dexTypeListGetIdx(typeList, i);
	length += strlen(dexStringByTypeIdx(dexFile, idx));
	}

	length += strlen(dexStringByTypeIdx(dexFile, protoId->returnTypeIdx));

	dexStringCacheAlloc(pCache, length);

	char at = (char) pCache->value;
	*(at++) = '(';

	for (i = 0; i < paramCount; i++) {
	u4 idx = dexTypeListGetIdx(typeList, i);
	const char* desc = dexStringByTypeIdx(dexFile, idx);
	strcpy(at, desc);
	at += strlen(desc);
	}

	*(at++) = ')';

	strcpy(at, dexStringByTypeIdx(dexFile, protoId->returnTypeIdx));
	return pCache->value;
	}

	/* (documented in header file) */
	char* dexProtoCopyMethodDescriptor(const DexProto* pProto) {
	DexStringCache cache;

	dexStringCacheInit(&cache);
	return dexStringCacheAbandon(&cache,
	dexProtoGetMethodDescriptor(pProto, &cache));
	}

	/* (documented in header file) */
	const char* dexProtoGetParameterDescriptors(const DexProto* pProto,
	DexStringCache* pCache) {
	DexParameterIterator iterator;
	size_t length = 1; /* +1 for the terminating '\0' */

	dexParameterIteratorInit(&iterator, pProto);

	for (;;) {
	const char* descriptor = dexParameterIteratorNextDescriptor(&iterator);
	if (descriptor == NULL) {
	break;
	}

	length += strlen(descriptor);
	}

	dexParameterIteratorInit(&iterator, pProto);

	dexStringCacheAlloc(pCache, length);
	char at = (char) pCache->value;

	for (;;) {
	const char* descriptor = dexParameterIteratorNextDescriptor(&iterator);
	if (descriptor == NULL) {
	break;
	}

	strcpy(at, descriptor);
	at += strlen(descriptor);
	}

	return pCache->value;
	}

	/* (documented in header file) */
	const char* dexProtoGetReturnType(const DexProto* pProto) {
	const DexProtoId* protoId = getProtoId(pProto);
	return dexStringByTypeIdx(pProto->dexFile, protoId->returnTypeIdx);
	}

	/* (documented in header file) */
	size_t dexProtoGetParameterCount(const DexProto* pProto) {
	const DexProtoId* protoId = getProtoId(pProto);
	const DexTypeList* typeList =
	dexGetProtoParameters(pProto->dexFile, protoId);
	return (typeList == NULL) ? 0 : typeList->size;
	}

	/* (documented in header file) */
	int dexProtoComputeArgsSize(const DexProto* pProto) {
	const char* shorty = dexProtoGetShorty(pProto);
	int count = 0;

	/* Skip the return type. */
	shorty++;

	for (;;) {
	switch (*(shorty++)) {
	case '\0': {
	return count;
	}
	case 'D':
	case 'J': {
	count += 2;
	break;
	}
	default: {
	count++;
	break;
	}
	}
	}
	}

	/*
	* Common implementation for dexProtoCompare() and dexProtoCompareParameters().
	*/
	static int protoCompare(const DexProto* pProto1, const DexProto* pProto2,
	bool compareReturnType) {

	if (pProto1 == pProto2) {
	// Easy out.
	return 0;
	} else {
	const DexFile* dexFile1 = pProto1->dexFile;
	const DexProtoId* protoId1 = getProtoId(pProto1);
	const DexTypeList* typeList1 =
	dexGetProtoParameters(dexFile1, protoId1);
	int paramCount1 = (typeList1 == NULL) ? 0 : typeList1->size;

	const DexFile* dexFile2 = pProto2->dexFile;
	const DexProtoId* protoId2 = getProtoId(pProto2);
	const DexTypeList* typeList2 =
	dexGetProtoParameters(dexFile2, protoId2);
	int paramCount2 = (typeList2 == NULL) ? 0 : typeList2->size;

	if (protoId1 == protoId2) {
	// Another easy out.
	return 0;
	}

	// Compare return types.

	if (compareReturnType) {
	int result =
	strcmp(dexStringByTypeIdx(dexFile1, protoId1->returnTypeIdx),
	dexStringByTypeIdx(dexFile2, protoId2->returnTypeIdx));

	if (result != 0) {
	return result;
	}
	}

	// Compare parameters.

	int minParam = (paramCount1 > paramCount2) ? paramCount2 : paramCount1;
	int i;

	for (i = 0; i < minParam; i++) {
	u4 idx1 = dexTypeListGetIdx(typeList1, i);
	u4 idx2 = dexTypeListGetIdx(typeList2, i);
	int result =
	strcmp(dexStringByTypeIdx(dexFile1, idx1),
	dexStringByTypeIdx(dexFile2, idx2));

	if (result != 0) {
	return result;
	}
	}

	if (paramCount1 < paramCount2) {
	return -1;
	} else if (paramCount1 > paramCount2) {
	return 1;
	} else {
	return 0;
	}
	}
	}

	/* (documented in header file) */
	int dexProtoCompare(const DexProto* pProto1, const DexProto* pProto2) {
	return protoCompare(pProto1, pProto2, true);
	}

	/* (documented in header file) */
	int dexProtoCompareParameters(const DexProto* pProto1, const DexProto* pProto2){
	return protoCompare(pProto1, pProto2, false);
	}


	/*
	* Helper for dexProtoCompareToDescriptor(), which gets the return type
	* descriptor from a method descriptor string.
	*/
	static const char* methodDescriptorReturnType(const char* descriptor) {
	const char* result = strchr(descriptor, ')');

	if (result == NULL) {
	return NULL;
	}

	// The return type is the character just past the ')'.
	return result + 1;
	}

	/*
	* Helper for dexProtoCompareToDescriptor(), which indicates the end
	* of an embedded argument type descriptor, which is also the
	* beginning of the next argument type descriptor. Since this is for
	* argument types, it doesn't accept 'V' as a valid type descriptor.
	*/
	static const char* methodDescriptorNextType(const char* descriptor) {
	// Skip any array references.

	while (*descriptor == '[') {
	descriptor++;
	}

	switch (*descriptor) {
	case 'B': case 'C': case 'D': case 'F':
	case 'I': case 'J': case 'S': case 'Z': {
	return descriptor + 1;
	}
	case 'L': {
	const char* result = strchr(descriptor + 1, ';');
	if (result != NULL) {
	// The type ends just past the ';'.
	return result + 1;
	}
	}
	}

	return NULL;
	}

	/*
	* Common implementation for dexProtoCompareToDescriptor() and
	* dexProtoCompareToParameterDescriptors(). The descriptor argument
	* can be either a full method descriptor (with parens and a return
	* type) or an unadorned concatenation of types (e.g. a list of
	* argument types).
	*/
	static int protoCompareToParameterDescriptors(const DexProto* proto,
	const char* descriptor, bool expectParens) {
	char expectedEndChar = expectParens ? ')' : '\0';
	DexParameterIterator iterator;
	dexParameterIteratorInit(&iterator, proto);

	if (expectParens) {
	// Skip the '('.
	assert (*descriptor == '(');
	descriptor++;
	}

	for (;;) {
	const char* protoDesc = dexParameterIteratorNextDescriptor(&iterator);

	if (*descriptor == expectedEndChar) {
	// It's the end of the descriptor string.
	if (protoDesc == NULL) {
	// It's also the end of the prototype's arguments.
	return 0;
	} else {
	// The prototype still has more arguments.
	return 1;
	}
	}

	if (protoDesc == NULL) {
	/*
	* The prototype doesn't have arguments left, but the
	* descriptor string does.
	*/
	return -1;
	}

	// Both prototype and descriptor have arguments. Compare them.

	const char* nextDesc = methodDescriptorNextType(descriptor);
	assert(nextDesc != NULL);

	for (;;) {
	char c1 = *(protoDesc++);
	char c2 = (descriptor < nextDesc) ? *(descriptor++) : '\0';

	if (c1 < c2) {
	// This includes the case where the proto is shorter.
	return -1;
	} else if (c1 > c2) {
	// This includes the case where the desc is shorter.
	return 1;
	} else if (c1 == '\0') {
	// The two types are equal in length. (c2 necessarily == '\0'.)
	break;
	}
	}

	/*
	* If we made it here, the two arguments matched, and
	* descriptor == nextDesc.
	*/
	}
	}

	/* (documented in header file) */
	int dexProtoCompareToDescriptor(const DexProto* proto,
	const char* descriptor) {
	// First compare the return types.

	const char *returnType = methodDescriptorReturnType(descriptor);
	assert(returnType != NULL);

	int result = strcmp(dexProtoGetReturnType(proto), returnType);

	if (result != 0) {
	return result;
	}

	// The return types match, so we have to check arguments.
	return protoCompareToParameterDescriptors(proto, descriptor, true);
	}

	/* (documented in header file) */
	int dexProtoCompareToParameterDescriptors(const DexProto* proto,
	const char* descriptors) {
	return protoCompareToParameterDescriptors(proto, descriptors, false);
	}






	/*
	* ===========================================================================
	* Parameter Iterators
	* ===========================================================================
	*/

	/*
	* Initialize the given DexParameterIterator to be at the start of the
	* parameters of the given prototype.
	*/
	void dexParameterIteratorInit(DexParameterIterator* pIterator,
	const DexProto* pProto) {
	pIterator->proto = pProto;
	pIterator->cursor = 0;

	pIterator->parameters =
	dexGetProtoParameters(pProto->dexFile, getProtoId(pProto));
	pIterator->parameterCount = (pIterator->parameters == NULL) ? 0
	: pIterator->parameters->size;
	}

	/*
	* Get the type_id index for the next parameter, if any. This returns
	* kDexNoIndex if the last parameter has already been consumed.
	*/
	u4 dexParameterIteratorNextIndex(DexParameterIterator* pIterator) {
	int cursor = pIterator->cursor;
	int parameterCount = pIterator->parameterCount;

	if (cursor >= parameterCount) {
	// The iteration is complete.
	return kDexNoIndex;
	} else {
	u4 idx = dexTypeListGetIdx(pIterator->parameters, cursor);
	pIterator->cursor++;
	return idx;
	}
	}

	/*
	* Get the type descriptor for the next parameter, if any. This returns
	* NULL if the last parameter has already been consumed.
	*/
	const char* dexParameterIteratorNextDescriptor(
	DexParameterIterator* pIterator) {
	u4 idx = dexParameterIteratorNextIndex(pIterator);

	if (idx == kDexNoIndex) {
	return NULL;
	}

	return dexStringByTypeIdx(pIterator->proto->dexFile, idx);
	}