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diff --git a/docs/dex-format.html b/docs/dex-format.html new file mode 100644 index 000000000..88a7fb0c5 --- /dev/null +++ b/docs/dex-format.html @@ -0,0 +1,3043 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> + +<html> + +<head> +<title>.dex — Dalvik Executable Format</title> +<link rel=stylesheet href="dex-format.css"> +</head> + +<body> + +<h1 class="title"><code>.dex</code> — Dalvik Executable Format</h1> +<p>Copyright © 2007 The Android Open Source Project + +<p>This document describes the layout and contents of <code>.dex</code> +files, which are used to hold a set of class definitions and their associated +adjunct data.</p> + +<h1>Guide To Types</h1> + +<table class="guide"> +<thead> +<tr> + <th>Name</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>byte</td> + <td>8-bit signed int</td> +</tr> +<tr> + <td>ubyte</td> + <td>8-bit unsigned int</td> +</tr> +<tr> + <td>short</td> + <td>16-bit signed int, little-endian</td> +</tr> +<tr> + <td>ushort</td> + <td>16-bit unsigned int, little-endian</td> +</tr> +<tr> + <td>int</td> + <td>32-bit signed int, little-endian</td> +</tr> +<tr> + <td>uint</td> + <td>32-bit unsigned int, little-endian</td> +</tr> +<tr> + <td>long</td> + <td>64-bit signed int, little-endian</td> +</tr> +<tr> + <td>ulong</td> + <td>64-bit unsigned int, little-endian</td> +</tr> +<tr> + <td>sleb128</td> + <td>signed LEB128, variable-length (see below)</td> +</tr> +<tr> + <td>uleb128</td> + <td>unsigned LEB128, variable-length (see below)</td> +</tr> +<tr> + <td>uleb128p1</td> + <td>unsigned LEB128 plus <code>1</code>, variable-length (see below)</td> +</tr> +</tbody> +</table> + +<h3>LEB128</h3> + +<p>LEB128 ("<b>L</b>ittle-<b>E</b>ndian <b>B</b>ase <b>128</b>") is a +variable-length encoding for +arbitrary signed or unsigned integer quantities. The format was +borrowed from the <a href="http://dwarfstd.org/Dwarf3Std.php">DWARF3</a> +specification. In a <code>.dex</code> file, LEB128 is only ever used to +encode 32-bit quantities.</p> + +<p>Each LEB128 encoded value consists of one to five +bytes, which together represent a single 32-bit value. Each +byte has its most significant bit set except for the final byte in the +sequence, which has its most significant bit clear. The remaining +seven bits of each byte are payload, with the least significant seven +bits of the quantity in the first byte, the next seven in the second +byte and so on. In the case of a signed LEB128 (<code>sleb128</code>), +the most significant payload bit of the final byte in the sequence is +sign-extended to produce the final value. In the unsigned case +(<code>uleb128</code>), any bits not explicitly represented are +interpreted as <code>0</code>. + +<table class="leb128Bits"> +<thead> +<tr><th colspan="16">Bitwise diagram of a two-byte LEB128 value</th></tr> +<tr> + <th colspan="8">First byte</td> + <th colspan="8">Second byte</td> +</tr> +</thead> +<tbody> +<tr> + <td class="start1"><code>1</code></td> + <td>bit<sub>6</sub></td> + <td>bit<sub>5</sub></td> + <td>bit<sub>4</sub></td> + <td>bit<sub>3</sub></td> + <td>bit<sub>2</sub></td> + <td>bit<sub>1</sub></td> + <td>bit<sub>0</sub></td> + <td class="start2"><code>0</code></td> + <td>bit<sub>13</sub></td> + <td>bit<sub>12</sub></td> + <td>bit<sub>11</sub></td> + <td>bit<sub>10</sub></td> + <td>bit<sub>9</sub></td> + <td>bit<sub>8</sub></td> + <td class="end2">bit<sub>7</sub></td> +</tr> +</tbody> +</table> + +<p>The variant <code>uleb128p1</code> is used to represent a signed +value, where the representation is of the value <i>plus one</i> encoded +as a <code>uleb128</code>. This makes the encoding of <code>-1</code> +(alternatively thought of as the unsigned value <code>0xffffffff</code>) +— but no other negative number — a single byte, and is +useful in exactly those cases where the represented number must either +be non-negative or <code>-1</code> (or <code>0xffffffff</code>), +and where no other negative values are allowed (or where large unsigned +values are unlikely to be needed).</p> + +<p>Here are some examples of the formats:</p> + +<table class="leb128"> +<thead> +<tr> + <th>Encoded Sequence</th> + <th>As <code>sleb128</code></th> + <th>As <code>uleb128</code></th> + <th>As <code>uleb128p1</code></th> +</tr> +</thead> +<tbody> + <tr><td>00</td><td>0</td><td>0</td><td>-1</td></tr> + <tr><td>01</td><td>1</td><td>1</td><td>0</td></tr> + <tr><td>7f</td><td>-1</td><td>127</td><td>126</td></tr> + <tr><td>80 7f</td><td>-128</td><td>16256</td><td>16255</td></tr> +</tbody> +</table> + +<h1>Overall File Layout</h1> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>header</td> + <td>header_item</td> + <td>the header</td> +</tr> +<tr> + <td>string_ids</td> + <td>string_id_item[]</td> + <td>string identifiers list. These are identifiers for all the strings + used by this file, either for internal naming (e.g., type descriptors) + or as constant objects referred to by code. This list must be sorted + by string contents, using UTF-16 code point values (not in a + locale-sensitive manner). + </td> +</tr> +<tr> + <td>type_ids</td> + <td>type_id_item[]</td> + <td>type identifiers list. These are identifiers for all types (classes, + arrays, or primitive types) referred to by this file, whether defined + in the file or not. This list must be sorted by <code>string_id</code> + index. + </td> +</tr> +<tr> + <td>proto_ids</td> + <td>proto_id_item[]</td> + <td>method prototype identifiers list. These are identifiers for all + prototypes referred to by this file. This list must be sorted in + return-type (by <code>type_id</code> index) major order, and then + by arguments (also by <code>type_id</code> index). + </td> +</tr> +<tr> + <td>field_ids</td> + <td>field_id_item[]</td> + <td>field identifiers list. These are identifiers for all fields + referred to by this file, whether defined in the file or not. This + list must be sorted, where the defining type (by <code>type_id</code> + index) is the major order, field name (by <code>string_id</code> index) + is the intermediate order, and type (by <code>type_id</code> index) + is the minor order. + </td> +</tr> +<tr> + <td>method_ids</td> + <td>method_id_item[]</td> + <td>method identifiers list. These are identifiers for all methods + referred to by this file, whether defined in the file or not. This + list must be sorted, where the defining type (by <code>type_id</code> + index) is the major order, method name (by <code>string_id</code> + index) is the intermediate order, and method + prototype (by <code>proto_id</code> index) is the minor order. + </td> +</tr> +<tr> + <td>class_defs</td> + <td>class_def_item[]</td> + <td>class definitions list. The classes must be ordered such that a given + class's superclass and implemented interfaces appear in the + list earlier than the referring class. + </td> +</tr> +<tr> + <td>data</td> + <td>ubyte[]</td> + <td>data area, containing all the support data for the tables listed above. + Different items have different alignment requirements, and + padding bytes are inserted before each item if necessary to achieve + proper alignment. + </td> +</tr> +<tr> + <td>link_data</td> + <td>ubyte[]</td> + <td>data used in statically linked files. The format of the data in + this section is left unspecified by this document; + this section is empty in unlinked files, and runtime implementations + may use it as they see fit. + </td> +</tr> +</tbody> +</table> + +<h1>Bitfield, String, and Constant Definitions</h1> + +<h2><code>DEX_FILE_MAGIC</code></h2> +<h4>embedded in <code>header_item</code></h4> + +<p>The constant array/string <code>DEX_FILE_MAGIC</code> is the list of +bytes that must appear at the beginning of a <code>.dex</code> file +in order for it to be recognized as such. The value intentionally +contains a newline (<code>"\n"</code> or <code>0x0a</code>) and a +null byte (<code>"\0"</code> or <code>0x00</code>) in order to help +in the detection of certain forms of corruption. The value also +encodes a format version number as three decimal digits, which is +expected to increase monotonically over time as the format evolves.</p> + +<pre> +ubyte[8] DEX_FILE_MAGIC = { 0x64 0x65 0x78 0x0a 0x30 0x33 0x35 0x00 } + = "dex\n035\0" +</pre> + +<p><b>Note:</b> At least a couple earlier versions of the format have +been used in widely-available public software releases. For example, +version <code>009</code> was used for the M3 releases of the +Android platform (November-December 2007), +and version <code>013</code> was used for the M5 releases of the Android +platform (February-March 2008). In several respects, these earlier versions +of the format differ significantly from the version described in this +document.</p> + +<h2><code>ENDIAN_CONSTANT</code> and <code>REVERSE_ENDIAN_CONSTANT</code></h2> +<h4>embedded in <code>header_item</code></h4> + +<p>The constant <code>ENDIAN_CONSTANT</code> is used to indicate the +endianness of the file in which it is found. Although the standard +<code>.dex</code> format is little-endian, implementations may choose +to perform byte-swapping. Should an implementation come across a +header whose <code>endian_tag</code> is <code>REVERSE_ENDIAN_CONSTANT</code> +instead of <code>ENDIAN_CONSTANT</code>, it would know that the file +has been byte-swapped from the expected form.</p> + +<pre> +uint ENDIAN_CONSTANT = 0x12345678; +uint REVERSE_ENDIAN_CONSTANT = 0x78563412; +</pre> + +<h2><code>NO_INDEX</code></h2> +<h4>embedded in <code>class_def_item</code> and +<code>debug_info_item</code></h4> + +<p>The constant <code>NO_INDEX</code> is used to indicate that +an index value is absent.</p> + +<p><b>Note:</b> This value isn't defined to be +<code>0</code>, because that is in fact typically a valid index.</p> + +<p><b>Also Note:</b> The chosen value for <code>NO_INDEX</code> is +representable as a single byte in the <code>uleb128p1</code> encoding.</p> + +<pre> +uint NO_INDEX = 0xffffffff; // == -1 if treated as a signed int +</pre> + +<h2><code>access_flags</code> Definitions</h2> +<h4>embedded in <code>class_def_item</code>, +<code>field_item</code>, <code>method_item</code>, and +<code>InnerClass</code></h4> + +<p>Bitfields of these flags are used to indicate the accessibility and +overall properties of classes and class members.</p> + +<table class="accessFlags"> +<thead> +<tr> + <th>Name</th> + <th>Value</th> + <th>For Classes (and <code>InnerClass</code> annotations)</th> + <th>For Fields</th> + <th>For Methods</th> +</tr> +</thead> +<tbody> +<tr> + <td>ACC_PUBLIC</td> + <td>0x1</td> + <td><code>public</code>: visible everywhere</td> + <td><code>public</code>: visible everywhere</td> + <td><code>public</code>: visible everywhere</td> +</tr> +<tr> + <td>ACC_PRIVATE</td> + <td>0x2</td> + <td><super>*</super> + <code>private</code>: only visible to defining class + </td> + <td><code>private</code>: only visible to defining class</td> + <td><code>private</code>: only visible to defining class</td> +</tr> +<tr> + <td>ACC_PROTECTED</td> + <td>0x4</td> + <td><super>*</super> + <code>protected</code>: visible to package and subclasses + </td> + <td><code>protected</code>: visible to package and subclasses</td> + <td><code>protected</code>: visible to package and subclasses</td> +</tr> +<tr> + <td>ACC_STATIC</td> + <td>0x8</td> + <td><super>*</super> + <code>static</code>: is not constructed with an outer + <code>this</code> reference</td> + <td><code>static</code>: global to defining class</td> + <td><code>static</code>: does not take a <code>this</code> argument</td> +</tr> +<tr> + <td>ACC_FINAL</td> + <td>0x10</td> + <td><code>final</code>: not subclassable</td> + <td><code>final</code>: immutable after construction</td> + <td><code>final</code>: not overridable</td> +</tr> +<tr> + <td>ACC_SYNCHRONIZED</td> + <td>0x20</td> + <td> </td> + <td> </td> + <td><code>synchronized</code>: associated lock automatically acquired + around call to this method. <b>Note:</b> This is only valid to set when + <code>ACC_NATIVE</code> is also set.</td> +</tr> +<tr> + <td>ACC_VOLATILE</td> + <td>0x40</td> + <td> </td> + <td><code>volatile</code>: special access rules to help with thread + safety</td> + <td> </td> +</tr> +<tr> + <td>ACC_BRIDGE</td> + <td>0x40</td> + <td> </td> + <td> </td> + <td>bridge method, added automatically by compiler as a type-safe + bridge</td> +</tr> +<tr> + <td>ACC_TRANSIENT</td> + <td>0x80</td> + <td> </td> + <td><code>transient</code>: not to be saved by default serialization</td> + <td> </td> +</tr> +<tr> + <td>ACC_VARARGS</td> + <td>0x80</td> + <td> </td> + <td> </td> + <td>last argument should be treated as a "rest" argument by compiler</td> +</tr> +<tr> + <td>ACC_NATIVE</td> + <td>0x100</td> + <td> </td> + <td> </td> + <td><code>native</code>: implemented in native code</td> +</tr> +<tr> + <td>ACC_INTERFACE</td> + <td>0x200</td> + <td><code>interface</code>: multiply-implementable abstract class</td> + <td> </td> + <td> </td> +</tr> +<tr> + <td>ACC_ABSTRACT</td> + <td>0x400</td> + <td><code>abstract</code>: not directly instantiable</td> + <td> </td> + <td><code>abstract</code>: unimplemented by this class</td> +</tr> +<tr> + <td>ACC_STRICT</td> + <td>0x800</td> + <td> </td> + <td> </td> + <td><code>strictfp</code>: strict rules for floating-point arithmetic</td> +</tr> +<tr> + <td>ACC_SYNTHETIC</td> + <td>0x1000</td> + <td>not directly defined in source code</td> + <td>not directly defined in source code</td> + <td>not directly defined in source code</td> +</tr> +<tr> + <td>ACC_ANNOTATION</td> + <td>0x2000</td> + <td>declared as an annotation class</td> + <td> </td> + <td> </td> +</tr> +<tr> + <td>ACC_ENUM</td> + <td>0x4000</td> + <td>declared as an enumerated type</td> + <td>declared as an enumerated value</td> + <td> </td> +</tr> +<tr> + <td><i>(unused)</i></td> + <td>0x8000</td> + <td> </td> + <td> </td> + <td> </td> +</tr> +<tr> + <td>ACC_CONSTRUCTOR</td> + <td>0x10000</td> + <td> </td> + <td> </td> + <td>constructor method (class or instance initializer)</td> +</tr> +<tr> + <td>ACC_DECLARED_<br/>SYNCHRONIZED</td> + <td>0x20000</td> + <td> </td> + <td> </td> + <td>declared <code>synchronized</code>. <b>Note:</b> This has no effect on + execution (other than in reflection of this flag, per se). + </td> +</tr> +</tbody> +</table> + +<p><super>*</super> Only allowed on for <code>InnerClass</code> annotations, +and must not ever be on in a <code>class_def_item</code>.</p> + +<h2>MUTF-8 (Modified UTF-8) Encoding</h2> + +<p>As a concession to easier legacy support, the <code>.dex</code> format +encodes its string data in a de facto standard modified UTF-8 form, hereafter +referred to as MUTF-8. This form is identical to standard UTF-8, except:</p> + +<ul> + <li>Only the one-, two-, and three-byte encodings are used.</li> + <li>Code points in the range <code>U+10000</code> … + <code>U+10ffff</code> are encoded as a surrogate pair, each of + which is represented as a three-byte encoded value.</li> + <li>The code point <code>U+0000</code> is encoded in two-byte form.</li> + <li>A plain null byte (value <code>0</code>) indicates the end of + a string, as is the standard C language interpretation.</li> +</ul> + +<p>The first two items above can be summarized as: MUTF-8 +is an encoding format for UTF-16, instead of being a more direct +encoding format for Unicode characters.</p> + +<p>The final two items above make it simultaneously possible to include +the code point <code>U+0000</code> in a string <i>and</i> still manipulate +it as a C-style null-terminated string.</p> + +<p>However, the special encoding of <code>U+0000</code> means that, unlike +normal UTF-8, the result of calling the standard C function +<code>strcmp()</code> on a pair of MUTF-8 strings does not always +indicate the properly signed result of comparison of <i>unequal</i> strings. +When ordering (not just equality) is a concern, the most straightforward +way to compare MUTF-8 strings is to decode them character by character, +and compare the decoded values. (However, more clever implementations are +also possible.)</p> + +<p>Please refer to <a href="http://unicode.org">The Unicode +Standard</a> for further information about character encoding. +MUTF-8 is actually closer to the (relatively less well-known) encoding +<a href="http://www.unicode.org/reports/tr26/">CESU-8</a> than to UTF-8 +per se.</p> + +<h2><code>encoded_value</code> Encoding</h2> +<h4>embedded in <code>annotation_element</code> and +<code>encoded_array_item</code></h4> + +<p>An <code>encoded_value</code> is an encoded piece of (nearly) +arbitrary hierarchically structured data. The encoding is meant to +be both compact and straightforward to parse.</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>(value_arg << 5) | value_type</td> + <td>ubyte</td> + <td>byte indicating the type of the immediately subsequent + <code>value</code> along + with an optional clarifying argument in the high-order three bits. + See below for the various <code>value</code> definitions. + In most cases, <code>value_arg</code> encodes the length of + the immediately-subsequent <code>value</code> in bytes, as + <code>(size - 1)</code>, e.g., <code>0</code> means that + the value requires one byte, and <code>7</code> means it requires + eight bytes; however, there are exceptions as noted below. + </td> +</tr> +<tr> + <td>value</td> + <td>ubyte[]</td> + <td>bytes representing the value, variable in length and interpreted + differently for different <code>value_type</code> bytes, though + always little-endian. See the various value definitions below for + details. + </td> +</tr> +</tbody> +</table> + +<h3>Value Formats</h3> + +<table class="encodedValue"> +<thead> +<tr> + <th>Type Name</th> + <th><code>value_type</code></th> + <th><code>value_arg</code> Format</th> + <th><code>value</code> Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>VALUE_BYTE</td> + <td>0x00</td> + <td><i>(none; must be <code>0</code>)</i></td> + <td>ubyte[1]</td> + <td>signed one-byte integer value</td> +</tr> +<tr> + <td>VALUE_SHORT</td> + <td>0x02</td> + <td>size - 1 (0…1)</td> + <td>ubyte[size]</td> + <td>signed two-byte integer value, sign-extended</td> +</tr> +<tr> + <td>VALUE_CHAR</td> + <td>0x03</td> + <td>size - 1 (0…1)</td> + <td>ubyte[size]</td> + <td>unsigned two-byte integer value, zero-extended</td> +</tr> +<tr> + <td>VALUE_INT</td> + <td>0x04</td> + <td>size - 1 (0…3)</td> + <td>ubyte[size]</td> + <td>signed four-byte integer value, sign-extended</td> +</tr> +<tr> + <td>VALUE_LONG</td> + <td>0x06</td> + <td>size - 1 (0…7)</td> + <td>ubyte[size]</td> + <td>signed eight-byte integer value, sign-extended</td> +</tr> +<tr> + <td>VALUE_FLOAT</td> + <td>0x10</td> + <td>size - 1 (0…3)</td> + <td>ubyte[size]</td> + <td>four-byte bit pattern, zero-extended <i>to the right</i>, and + interpreted as an IEEE754 32-bit floating point value + </td> +</tr> +<tr> + <td>VALUE_DOUBLE</td> + <td>0x11</td> + <td>size - 1 (0…7)</td> + <td>ubyte[size]</td> + <td>eight-byte bit pattern, zero-extended <i>to the right</i>, and + interpreted as an IEEE754 64-bit floating point value + </td> +</tr> +<tr> + <td>VALUE_STRING</td> + <td>0x17</td> + <td>size - 1 (0…3)</td> + <td>ubyte[size]</td> + <td>unsigned (zero-extended) four-byte integer value, + interpreted as an index into + the <code>string_ids</code> section and representing a string value + </td> +</tr> +<tr> + <td>VALUE_TYPE</td> + <td>0x18</td> + <td>size - 1 (0…3)</td> + <td>ubyte[size]</td> + <td>unsigned (zero-extended) four-byte integer value, + interpreted as an index into + the <code>type_ids</code> section and representing a reflective + type/class value + </td> +</tr> +<tr> + <td>VALUE_FIELD</td> + <td>0x19</td> + <td>size - 1 (0…3)</td> + <td>ubyte[size]</td> + <td>unsigned (zero-extended) four-byte integer value, + interpreted as an index into + the <code>field_ids</code> section and representing a reflective + field value + </td> +</tr> +<tr> + <td>VALUE_METHOD</td> + <td>0x1a</td> + <td>size - 1 (0…3)</td> + <td>ubyte[size]</td> + <td>unsigned (zero-extended) four-byte integer value, + interpreted as an index into + the <code>method_ids</code> section and representing a reflective + method value + </td> +</tr> +<tr> + <td>VALUE_ENUM</td> + <td>0x1b</td> + <td>size - 1 (0…3)</td> + <td>ubyte[size]</td> + <td>unsigned (zero-extended) four-byte integer value, + interpreted as an index into + the <code>field_ids</code> section and representing the value of + an enumerated type constant + </td> +</tr> +<tr> + <td>VALUE_ARRAY</td> + <td>0x1c</td> + <td><i>(none; must be <code>0</code>)</i></td> + <td>encoded_array</td> + <td>an array of values, in the format specified by + "<code>encoded_array</code> Format" below. The size + of the <code>value</code> is implicit in the encoding. + </td> +</tr> +<tr> + <td>VALUE_ANNOTATION</td> + <td>0x1d</td> + <td><i>(none; must be <code>0</code>)</i></td> + <td>encoded_annotation</td> + <td>a sub-annotation, in the format specified by + "<code>encoded_annotation</code> Format" below. The size + of the <code>value</code> is implicit in the encoding. + </td> +</tr> +<tr> + <td>VALUE_NULL</td> + <td>0x1e</td> + <td><i>(none; must be <code>0</code>)</i></td> + <td><i>(none)</i></td> + <td><code>null</code> reference value</td> +</tr> +<tr> + <td>VALUE_BOOLEAN</td> + <td>0x1f</td> + <td>boolean (0…1)</td> + <td><i>(none)</i></td> + <td>one-bit value; <code>0</code> for <code>false</code> and + <code>1</code> for <code>true</code>. The bit is represented in the + <code>value_arg</code>. + </td> +</tr> +</tbody> +</table> + +<h3><code>encoded_array</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>size</td> + <td>uleb128</td> + <td>number of elements in the array</td> +</tr> +<tr> + <td>values</td> + <td>encoded_value[size]</td> + <td>a series of <code>size</code> <code>encoded_value</code> byte + sequences in the format specified by this section, concatenated + sequentially. + </td> +</tr> +</tbody> +</table> + +<h3><code>encoded_annotation</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>type_idx</td> + <td>uleb128</td> + <td>type of the annotation. This must be a class (not array or primitive) + type. + </td> +</tr> +<tr> + <td>size</td> + <td>uleb128</td> + <td>number of name-value mappings in this annotation</td> +</tr> +<tr> + <td>elements</td> + <td>annotation_element[size]</td> + <td>elements of the annotataion, represented directly in-line (not as + offsets). Elements must be sorted in increasing order by + <code>string_id</code> index. + </td> +</tr> +</tbody> +</table> + +<h3><code>annotation_element</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>name_idx</td> + <td>uleb128</td> + <td>element name, represented as an index into the + <code>string_ids</code> section. The string must conform to the + syntax for <i>MemberName</i>, defined above. + </td> +</tr> +<tr> + <td>value</td> + <td>encoded_value</td> + <td>element value</td> +</tr> +</tbody> +</table> + +<h2>String Syntax</h2> + +<p>There are several kinds of item in a <code>.dex</code> file which +ultimately refer to a string. The following BNF-style definitions +indicate the acceptable syntax for these strings.</p> + +<h3><i>SimpleName</i></h3> + +<p>A <i>SimpleName</i> is the basis for the syntax of the names of other +things. The <code>.dex</code> format allows a fair amount of latitude +here (much more than most common source languages). In brief, a simple +name may consist of any low-ASCII alphabetic character or digit, a few +specific low-ASCII symbols, and most non-ASCII code points that are not +control, space, or special characters. Note that surrogate code points +(in the range <code>U+d800</code> … <code>U+dfff</code>) are not +considered valid name characters, per se, but Unicode supplemental +characters <i>are</i> valid (which are represented by the final +alternative of the rule for <i>SimpleNameChar</i>), and they should be +represented in a file as pairs of surrogate code points in the MUTF-8 +encoding.</p> + +<table class="bnf"> + <tr><td colspan="2" class="def"><i>SimpleName</i> →</td></tr> + <tr> + <td/> + <td><i>SimpleNameChar</i> (<i>SimpleNameChar</i>)*</td> + </tr> + + <tr><td colspan="2" class="def"><i>SimpleNameChar</i> →</td></tr> + <tr> + <td/> + <td><code>'A'</code> … <code>'Z'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'a'</code> … <code>'z'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'0'</code> … <code>'9'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'$'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'-'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'_'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>U+00a1</code> … <code>U+1fff</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>U+2010</code> … <code>U+2027</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>U+2030</code> … <code>U+d7ff</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>U+e000</code> … <code>U+ffef</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>U+10000</code> … <code>U+10ffff</code></td> + </tr> +</table> + +<h3><i>MemberName</i></h3> +<h4>used by <code>field_id_item</code> and <code>method_id_item</code></h4> + +<p>A <i>MemberName</i> is the name of a member of a class, members being +fields, methods, and inner classes.</p> + +<table class="bnf"> + <tr><td colspan="2" class="def"><i>MemberName</i> →</td></tr> + <tr> + <td/> + <td><i>SimpleName</i></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'<'</code> <i>SimpleName</i> <code>'>'</code></td> + </tr> +</table> + +<h3><i>FullClassName</i></h3> + +<p>A <i>FullClassName</i> is a fully-qualified class name, including an +optional package specifier followed by a required name.</p> + +<table class="bnf"> + <tr><td colspan="2" class="def"><i>FullClassName</i> →</td></tr> + <tr> + <td/> + <td><i>OptionalPackagePrefix</i> <i>SimpleName</i></td> + </tr> + + <tr><td colspan="2" class="def"><i>OptionalPackagePrefix</i> →</td></tr> + <tr> + <td/> + <td>(<i>SimpleName</i> <code>'/'</code>)*</td> + </tr> +</table> + +<h3><i>TypeDescriptor</i></h3> +<h4>used by <code>type_id_item</code></h4> + +<p>A <i>TypeDescriptor</i> is the representation of any type, including +primitives, classes, arrays, and <code>void</code>. See below for +the meaning of the various versions.</p> + +<table class="bnf"> + <tr><td colspan="2" class="def"><i>TypeDescriptor</i> →</td></tr> + <tr> + <td/> + <td><code>'V'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><i>FieldTypeDescriptor</i></td> + </tr> + + <tr><td colspan="2" class="def"><i>FieldTypeDescriptor</i> →</td></tr> + <tr> + <td/> + <td><i>NonArrayFieldTypeDescriptor</i></td> + </tr> + <tr> + <td class="bar">|</td> + <td>(<code>'['</code> * 1…255) + <i>NonArrayFieldTypeDescriptor</i></td> + </tr> + + <tr> + <td colspan="2" class="def"><i>NonArrayFieldTypeDescriptor</i>→</td> + </tr> + <tr> + <td/> + <td><code>'Z'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'B'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'S'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'C'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'I'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'J'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'F'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'D'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'L'</code> <i>FullClassName</i> <code>';'</code></td> + </tr> +</table> + +<h3><i>ShortyDescriptor</i></h3> +<h4>used by <code>proto_id_item</code></h4> + +<p>A <i>ShortyDescriptor</i> is the short form representation of a method +prototype, including return and parameter types, except that there is +no distinction between various reference (class or array) types. Instead, +all reference types are represented by a single <code>'L'</code> character.</p> + +<table class="bnf"> + <tr><td colspan="2" class="def"><i>ShortyDescriptor</i> →</td></tr> + <tr> + <td/> + <td><i>ShortyReturnType</i> (<i>ShortyFieldType</i>)*</td> + </tr> + + <tr><td colspan="2" class="def"><i>ShortyReturnType</i> →</td></tr> + <tr> + <td/> + <td><code>'V'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><i>ShortyFieldType</i></td> + </tr> + + <tr><td colspan="2" class="def"><i>ShortyFieldType</i> →</td></tr> + <tr> + <td/> + <td><code>'Z'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'B'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'S'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'C'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'I'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'J'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'F'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'D'</code></td> + </tr> + <tr> + <td class="bar">|</td> + <td><code>'L'</code></td> + </tr> +</table> + +<h2><i>TypeDescriptor</i> Semantics</h2> + +<p>This is the meaning of each of the variants of <i>TypeDescriptor</i>.</p> + +<table class="descriptor"> +<thead> +<tr> + <th>Syntax</th> + <th>Meaning</th> +</tr> +</thead> +<tbody> +<tr> + <td>V</td> + <td><code>void</code>; only valid for return types</td> +</tr> +<tr> + <td>Z</td> + <td><code>boolean</code></td> +</tr> +<tr> + <td>B</td> + <td><code>byte</code></td> +</tr> +<tr> + <td>S</td> + <td><code>short</code></td> +</tr> +<tr> + <td>C</td> + <td><code>char</code></td> +</tr> +<tr> + <td>I</td> + <td><code>int</code></td> +</tr> +<tr> + <td>J</td> + <td><code>long</code></td> +</tr> +<tr> + <td>F</td> + <td><code>float</code></td> +</tr> +<tr> + <td>D</td> + <td><code>double</code></td> +</tr> +<tr> + <td>L<i>fully/qualified/Name</i>;</td> + <td>the class <code><i>fully.qualified.Name</i></code></td> +</tr> +<tr> + <td>[<i>descriptor</i></td> + <td>array of <code><i>descriptor</i></code>, usable recursively for + arrays-of-arrays, though it is invalid to have more than 255 + dimensions. + </td> +</tr> +</tbody> +</table> + +<h1>Items and Related Structures</h1> + +<p>This section includes definitions for each of the top-level items that +may appear in a <code>.dex</code> file. + +<h2><code>header_item</code></h2> +<h4>appears in the <code>header</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>magic</td> + <td>ubyte[8] = DEX_FILE_MAGIC</td> + <td>magic value. See discussion above under "<code>DEX_FILE_MAGIC</code>" + for more details. + </td> +</tr> +<tr> + <td>checksum</td> + <td>uint</td> + <td>adler32 checksum of the rest of the file (everything but + <code>magic</code> and this field); used to detect file corruption + </td> +</tr> +<tr> + <td>signature</td> + <td>ubyte[20]</td> + <td>SHA-1 signature (hash) of the rest of the file (everything but + <code>magic</code>, <code>checksum</code>, and this field); used + to uniquely identify files + </td> +</tr> +<tr> + <td>file_size</td> + <td>uint</td> + <td>size of the entire file (including the header), in bytes +</tr> +<tr> + <td>header_size</td> + <td>uint = 0x70</td> + <td>size of the header (this entire section), in bytes. This allows for at + least a limited amount of backwards/forwards compatibility without + invalidating the format. + </td> +</tr> +<tr> + <td>endian_tag</td> + <td>uint = ENDIAN_CONSTANT</td> + <td>endianness tag. See discussion above under "<code>ENDIAN_CONSTANT</code> + and <code>REVERSE_ENDIAN_CONSTANT</code>" for more details. + </td> +</tr> +<tr> + <td>link_size</td> + <td>uint</td> + <td>size of the link section, or <code>0</code> if this file isn't + statically linked</td> +</tr> +<tr> + <td>link_off</td> + <td>uint</td> + <td>offset from the start of the file to the link section, or + <code>0</code> if <code>link_size == 0</code>. The offset, if non-zero, + should be to an offset into the <code>link_data</code> section. The + format of the data pointed at is left unspecified by this document; + this header field (and the previous) are left as hooks for use by + runtime implementations. + </td> +</tr> +<tr> + <td>map_off</td> + <td>uint</td> + <td>offset from the start of the file to the map item, or + <code>0</code> if this file has no map. The offset, if non-zero, + should be to an offset into the <code>data</code> section, + and the data should be in the format specified by "<code>map_list</code>" + below. + </td> +</tr> +<tr> + <td>string_ids_size</td> + <td>uint</td> + <td>count of strings in the string identifiers list</td> +</tr> +<tr> + <td>string_ids_off</td> + <td>uint</td> + <td>offset from the start of the file to the string identifiers list, or + <code>0</code> if <code>string_ids_size == 0</code> (admittedly a + strange edge case). The offset, if non-zero, + should be to the start of the <code>string_ids</code> section. + </td> +</tr> +<tr> + <td>type_ids_size</td> + <td>uint</td> + <td>count of elements in the type identifiers list</td> +</tr> +<tr> + <td>type_ids_off</td> + <td>uint</td> + <td>offset from the start of the file to the type identifiers list, or + <code>0</code> if <code>type_ids_size == 0</code> (admittedly a + strange edge case). The offset, if non-zero, + should be to the start of the <code>type_ids</code> + section. + </td> +</tr> +<tr> + <td>proto_ids_size</td> + <td>uint</td> + <td>count of elements in the prototype identifiers list</td> +</tr> +<tr> + <td>proto_ids_off</td> + <td>uint</td> + <td>offset from the start of the file to the prototype identifiers list, or + <code>0</code> if <code>proto_ids_size == 0</code> (admittedly a + strange edge case). The offset, if non-zero, + should be to the start of the <code>proto_ids</code> + section. + </td> +</tr> +<tr> + <td>field_ids_size</td> + <td>uint</td> + <td>count of elements in the field identifiers list</td> +</tr> +<tr> + <td>field_ids_off</td> + <td>uint</td> + <td>offset from the start of the file to the field identifiers list, or + <code>0</code> if <code>field_ids_size == 0</code>. The offset, if + non-zero, should be to the start of the <code>field_ids</code> + section.</td> +</td> +</tr> +<tr> + <td>method_ids_size</td> + <td>uint</td> + <td>count of elements in the method identifiers list</td> +</tr> +<tr> + <td>method_ids_off</td> + <td>uint</td> + <td>offset from the start of the file to the method identifiers list, or + <code>0</code> if <code>method_ids_size == 0</code>. The offset, if + non-zero, should be to the start of the <code>method_ids</code> + section.</td> +</tr> +<tr> + <td>class_defs_size</td> + <td>uint</td> + <td>count of elements in the class definitions list</td> +</tr> +<tr> + <td>class_defs_off</td> + <td>uint</td> + <td>offset from the start of the file to the class definitions list, or + <code>0</code> if <code>class_defs_size == 0</code> (admittedly a + strange edge case). The offset, if non-zero, + should be to the start of the <code>class_defs</code> section. + </td> +</tr> +<tr> + <td>data_size</td> + <td>uint</td> + <td>Size of <code>data</code> section in bytes. Must be an even + multiple of sizeof(uint).</td> +</tr> +<tr> + <td>data_off</td> + <td>uint</td> + <td>offset from the start of the file to the start of the + <code>data</code> section. + </td> +</tr> +</tbody> +</table> + +<h2><code>map_list</code></h2> +<h4>appears in the <code>data</code> section</h4> +<h4>referenced from <code>header_item</code></h4> +<h4>alignment: 4 bytes</h4> + +<p>This is a list of the entire contents of a file, in order. It +contains some redundancy with respect to the <code>header_item</code> +but is intended to be an easy form to use to iterate over an entire +file. A given type may appear at most once in a map, but there is no +restriction on what order types may appear in, other than the +restrictions implied by the rest of the format (e.g., a +<code>header</code> section must appear first, followed by a +<code>string_ids</code> section, etc.). Additionally, the map entries must +be ordered by initial offset and must not overlap.</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>size</td> + <td>uint</td> + <td>size of the list, in entries</td> +</tr> +<tr> + <td>list</td> + <td>map_item[size]</td> + <td>elements of the list</td> +</tr> +</tbody> +</table> + +<h3><code>map_item</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>type</td> + <td>ushort</td> + <td>type of the items; see table below</td> +</tr> +<tr> + <td>unused</td> + <td>ushort</td> + <td><i>(unused)</i></td> +</tr> +<tr> + <td>size</td> + <td>uint</td> + <td>count of the number of items to be found at the indicated offset</td> +</tr> +<tr> + <td>offset</td> + <td>uint</td> + <td>offset from the start of the file to the items in question</td> +</tr> +</tbody> +</table> + + +<h3>Type Codes</h3> + +<table class="typeCodes"> +<thead> +<tr> + <th>Item Type</th> + <th>Constant</th> + <th>Value</th> + <th>Item Size In Bytes</th> +</tr> +</thead> +<tbody> +<tr> + <td>header_item</td> + <td>TYPE_HEADER_ITEM</td> + <td>0x0000</td> + <td>0x70</td> +</tr> +<tr> + <td>string_id_item</td> + <td>TYPE_STRING_ID_ITEM</td> + <td>0x0001</td> + <td>0x04</td> +</tr> +<tr> + <td>type_id_item</td> + <td>TYPE_TYPE_ID_ITEM</td> + <td>0x0002</td> + <td>0x04</td> +</tr> +<tr> + <td>proto_id_item</td> + <td>TYPE_PROTO_ID_ITEM</td> + <td>0x0003</td> + <td>0x0c</td> +</tr> +<tr> + <td>field_id_item</td> + <td>TYPE_FIELD_ID_ITEM</td> + <td>0x0004</td> + <td>0x08</td> +</tr> +<tr> + <td>method_id_item</td> + <td>TYPE_METHOD_ID_ITEM</td> + <td>0x0005</td> + <td>0x08</td> +</tr> +<tr> + <td>class_def_item</td> + <td>TYPE_CLASS_DEF_ITEM</td> + <td>0x0006</td> + <td>0x20</td> +</tr> +<tr> + <td>map_list</td> + <td>TYPE_MAP_LIST</td> + <td>0x1000</td> + <td>4 + (item.size * 12)</td> +</tr> +<tr> + <td>type_list</td> + <td>TYPE_TYPE_LIST</td> + <td>0x1001</td> + <td>4 + (item.size * 2)</td> +</tr> +<tr> + <td>annotation_set_ref_list</td> + <td>TYPE_ANNOTATION_SET_REF_LIST</td> + <td>0x1002</td> + <td>4 + (item.size * 4)</td> +</tr> +<tr> + <td>annotation_set_item</td> + <td>TYPE_ANNOTATION_SET_ITEM</td> + <td>0x1003</td> + <td>4 + (item.size * 4)</td> +</tr> +<tr> + <td>class_data_item</td> + <td>TYPE_CLASS_DATA_ITEM</td> + <td>0x2000</td> + <td><i>implicit; must parse</i></td> +</tr> +<tr> + <td>code_item</td> + <td>TYPE_CODE_ITEM</td> + <td>0x2001</td> + <td><i>implicit; must parse</i></td> +</tr> +<tr> + <td>string_data_item</td> + <td>TYPE_STRING_DATA_ITEM</td> + <td>0x2002</td> + <td><i>implicit; must parse</i></td> +</tr> +<tr> + <td>debug_info_item</td> + <td>TYPE_DEBUG_INFO_ITEM</td> + <td>0x2003</td> + <td><i>implicit; must parse</i></td> +</tr> +<tr> + <td>annotation_item</td> + <td>TYPE_ANNOTATION_ITEM</td> + <td>0x2004</td> + <td><i>implicit; must parse</i></td> +</tr> +<tr> + <td>encoded_array_item</td> + <td>TYPE_ENCODED_ARRAY_ITEM</td> + <td>0x2005</td> + <td><i>implicit; must parse</i></td> +</tr> +<tr> + <td>annotations_directory_item</td> + <td>TYPE_ANNOTATIONS_DIRECTORY_ITEM</td> + <td>0x2006</td> + <td><i>implicit; must parse</i></td> +</tr> +</tbody> +</table> + + +<h2><code>string_id_item</code></h2> +<h4>appears in the <code>string_ids</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>string_data_off</td> + <td>uint</td> + <td>offset from the start of the file to the string data for this + item. The offset should be to a location + in the <code>data</code> section, and the data should be in the + format specified by "<code>string_data_item</code>" below. + There is no alignment requirement for the offset. + </td> +</tr> +</tbody> +</table> + +<h2><code>string_data_item</code></h2> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: none (byte-aligned)</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>utf16_size</td> + <td>uleb128</td> + <td>size of this string, in UTF-16 code units (which is the "string + length" in many systems). That is, this is the decoded length of + the string. (The encoded length is implied by the position of + the <code>0</code> byte.)</td> +</tr> +<tr> + <td>data</td> + <td>ubyte[]</td> + <td>a series of MUTF-8 code units (a.k.a. octets, a.k.a. bytes) + followed by a byte of value <code>0</code>. See + "MUTF-8 (Modified UTF-8) Encoding" above for details and + discussion about the data format. + <p><b>Note:</b> It is acceptable to have a string which includes + (the encoded form of) UTF-16 surrogate code units (that is, + <code>U+d800</code> … <code>U+dfff</code>) + either in isolation or out-of-order with respect to the usual + encoding of Unicode into UTF-16. It is up to higher-level uses of + strings to reject such invalid encodings, if appropriate.</p> + </td> +</tr> +</tbody> +</table> + +<h2><code>type_id_item</code></h2> +<h4>appears in the <code>type_ids</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>descriptor_idx</td> + <td>uint</td> + <td>index into the <code>string_ids</code> list for the descriptor + string of this type. The string must conform to the syntax for + <i>TypeDescriptor</i>, defined above. + </td> +</tr> +</tbody> +</table> + +<h2><code>proto_id_item</code></h2> +<h4>appears in the <code>proto_ids</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>shorty_idx</td> + <td>uint</td> + <td>index into the <code>string_ids</code> list for the short-form + descriptor string of this prototype. The string must conform to the + syntax for <i>ShortyDescriptor</i>, defined above, and must correspond + to the return type and parameters of this item. + </td> +</tr> +<tr> + <td>return_type_idx</td> + <td>uint</td> + <td>index into the <code>type_ids</code> list for the return type + of this prototype + </td> +</tr> +<tr> + <td>parameters_off</td> + <td>uint</td> + <td>offset from the start of the file to the list of parameter types + for this prototype, or <code>0</code> if this prototype has no + parameters. This offset, if non-zero, should be in the + <code>data</code> section, and the data there should be in the + format specified by <code>"type_list"</code> below. Additionally, there + should be no reference to the type <code>void</code> in the list. + </td> +</tr> +</tbody> +</table> + +<h2><code>field_id_item</code></h2> +<h4>appears in the <code>field_ids</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>class_idx</td> + <td>ushort</td> + <td>index into the <code>type_ids</code> list for the definer of this + field. This must be a class type, and not an array or primitive type. + </td> +</tr> +<tr> + <td>type_idx</td> + <td>ushort</td> + <td>index into the <code>type_ids</code> list for the type of + this field + </td> +</tr> +<tr> + <td>name_idx</td> + <td>uint</td> + <td>index into the <code>string_ids</code> list for the name of this + field. The string must conform to the syntax for <i>MemberName</i>, + defined above. + </td> +</tr> +</tbody> +</table> + +<h2><code>method_id_item</code></h2> +<h4>appears in the <code>method_ids</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>class_idx</td> + <td>ushort</td> + <td>index into the <code>type_ids</code> list for the definer of this + method. This must be a class or array type, and not a primitive type. + </td> +</tr> +<tr> + <td>proto_idx</td> + <td>ushort</td> + <td>index into the <code>proto_ids</code> list for the prototype of + this method + </td> +</tr> +<tr> + <td>name_idx</td> + <td>uint</td> + <td>index into the <code>string_ids</code> list for the name of this + method. The string must conform to the syntax for <i>MemberName</i>, + defined above. + </td> +</tr> +</tbody> +</table> + +<h2><code>class_def_item</code></h2> +<h4>appears in the <code>class_defs</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>class_idx</td> + <td>uint</td> + <td>index into the <code>type_ids</code> list for this class. + This must be a class type, and not an array or primitive type. + </td> +</tr> +<tr> + <td>access_flags</td> + <td>uint</td> + <td>access flags for the class (<code>public</code>, <code>final</code>, + etc.). See "<code>access_flags</code> Definitions" for details. + </td> +</tr> +<tr> + <td>superclass_idx</td> + <td>uint</td> + <td>index into the <code>type_ids</code> list for the superclass, or + the constant value <code>NO_INDEX</code> if this class has no + superclass (i.e., it is a root class such as <code>Object</code>). + If present, this must be a class type, and not an array or primitive type. + </td> +</tr> +<tr> + <td>interfaces_off</td> + <td>uint</td> + <td>offset from the start of the file to the list of interfaces, or + <code>0</code> if there are none. This offset + should be in the <code>data</code> section, and the data + there should be in the format specified by + "<code>type_list</code>" below. Each of the elements of the list + must be a class type (not an array or primitive type), and there + must not be any duplicates. + </td> +</tr> +<tr> + <td>source_file_idx</td> + <td>uint</td> + <td>index into the <code>string_ids</code> list for the name of the + file containing the original source for (at least most of) this class, + or the special value <code>NO_INDEX</code> to represent a lack of + this information. The <code>debug_info_item</code> of any given method + may override this source file, but the expectation is that most classes + will only come from one source file. + </td> +</tr> +<tr> + <td>annotations_off</td> + <td>uint</td> + <td>offset from the start of the file to the annotations structure + for this class, or <code>0</code> if there are no annotations on + this class. This offset, if non-zero, should be in the + <code>data</code> section, and the data there should be in + the format specified by "<code>annotations_directory_item</code>" below, + with all items referring to this class as the definer. + </td> +</tr> +<tr> + <td>class_data_off</td> + <td>uint</td> + <td>offset from the start of the file to the associated + class data for this item, or <code>0</code> if there is no class + data for this class. (This may be the case, for example, if this class + is a marker interface.) The offset, if non-zero, should be in the + <code>data</code> section, and the data there should be in the + format specified by "<code>class_data_item</code>" below, with all + items referring to this class as the definer. + </td> +</tr> +<tr> + <td>static_values_off</td> + <td>uint</td> + <td>offset from the start of the file to the list of initial + values for <code>static</code> fields, or <code>0</code> if there + are none (and all <code>static</code> fields are to be initialized with + <code>0</code> or <code>null</code>). This offset should be in the + <code>data</code> section, and the data there should be in the + format specified by "<code>encoded_array_item</code>" below. The size + of the array must be no larger than the number of <code>static</code> + fields declared by this class, and the elements correspond to the + <code>static</code> fields in the same order as declared in the + corresponding <code>field_list</code>. The type of each array + element must match the declared type of its corresponding field. + If there are fewer elements in the array than there are + <code>static</code> fields, then the leftover fields are initialized + with a type-appropriate <code>0</code> or <code>null</code>. + </td> +</tr> +</tbody> +</table> + +<h2><code>class_data_item</code></h2> +<h4>referenced from <code>class_def_item</code></h4> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: none (byte-aligned)</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>static_fields_size</td> + <td>uleb128</td> + <td>the number of static fields defined in this item</td> +</tr> +<tr> + <td>instance_fields_size</td> + <td>uleb128</td> + <td>the number of instance fields defined in this item</td> +</tr> +<tr> + <td>direct_methods_size</td> + <td>uleb128</td> + <td>the number of direct methods defined in this item</td> +</tr> +<tr> + <td>virtual_methods_size</td> + <td>uleb128</td> + <td>the number of virtual methods defined in this item</td> +</tr> +<tr> + <td>static_fields</td> + <td>encoded_field[static_fields_size]</td> + <td>the defined static fields, represented as a sequence of + encoded elements. The fields must be sorted by + <code>field_idx</code> in increasing order. + </td> +</tr> +<tr> + <td>instance_fields</td> + <td>encoded_field[instance_fields_size]</td> + <td>the defined instance fields, represented as a sequence of + encoded elements. The fields must be sorted by + <code>field_idx</code> in increasing order. + </td> +</tr> +<tr> + <td>direct_methods</td> + <td>encoded_method[direct_methods_size]</td> + <td>the defined direct (any of <code>static</code>, <code>private</code>, + or constructor) methods, represented as a sequence of + encoded elements. The methods must be sorted by + <code>method_idx</code> in increasing order. + </td> +</tr> +<tr> + <td>virtual_methods</td> + <td>encoded_method[virtual_methods_size]</td> + <td>the defined virtual (none of <code>static</code>, <code>private</code>, + or constructor) methods, represented as a sequence of + encoded elements. This list should <i>not</i> include inherited + methods unless overridden by the class that this item represents. The + methods must be sorted by <code>method_idx</code> in increasing order. + </td> +</tr> +</tbody> +</table> + +<p><b>Note:</b> All elements' <code>field_id</code>s and +<code>method_id</code>s must refer to the same defining class.</p> + +<h3><code>encoded_field</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>field_idx_diff</td> + <td>uleb128</td> + <td>index into the <code>field_ids</code> list for the identity of this + field (includes the name and descriptor), represented as a difference + from the index of previous element in the list. The index of the + first element in a list is represented directly. + </td> +</tr> +<tr> + <td>access_flags</td> + <td>uleb128</td> + <td>access flags for the field (<code>public</code>, <code>final</code>, + etc.). See "<code>access_flags</code> Definitions" for details. + </td> +</tr> +</tbody> +</table> + +<h3><code>encoded_method</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>method_idx_diff</td> + <td>uleb128</td> + <td>index into the <code>method_ids</code> list for the identity of this + method (includes the name and descriptor), represented as a difference + from the index of previous element in the list. The index of the + first element in a list is represented directly. + </td> +</tr> +<tr> + <td>access_flags</td> + <td>uleb128</td> + <td>access flags for the method (<code>public</code>, <code>final</code>, + etc.). See "<code>access_flags</code> Definitions" for details. + </td> +</tr> +<tr> + <td>code_off</td> + <td>uleb128</td> + <td>offset from the start of the file to the code structure for this + method, or <code>0</code> if this method is either <code>abstract</code> + or <code>native</code>. The offset should be to a location in the + <code>data</code> section. The format of the data is specified by + "<code>code_item</code>" below. + </td> +</tr> +</tbody> +</table> + +<h2><code>type_list</code></h2> +<h4>referenced from <code>class_def_item</code> and +<code>proto_id_item</code></h4> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>size</td> + <td>uint</td> + <td>size of the list, in entries</td> +</tr> +<tr> + <td>list</td> + <td>type_item[size]</td> + <td>elements of the list</td> +</tr> +</tbody> +</table> + +<h3><code>type_item</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>type_idx</td> + <td>ushort</td> + <td>index into the <code>type_ids</code> list</td> +</tr> +</tbody> +</table> + +<h2><code>code_item</code></h2> +<h4>referenced from <code>method_item</code></h4> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>registers_size</td> + <td>ushort</td> + <td>the number of registers used by this code</td> +</tr> +<tr> + <td>ins_size</td> + <td>ushort</td> + <td>the number of words of incoming arguments to the method that this + code is for</td> +</tr> +<tr> + <td>outs_size</td> + <td>ushort</td> + <td>the number of words of outgoing argument space required by this + code for method invocation + </td> +</tr> +<tr> + <td>tries_size</td> + <td>ushort</td> + <td>the number of <code>try_item</code>s for this instance. If non-zero, + then these appear as the <code>tries</code> array just after the + <code>insns</code> in this instance. + </td> +</tr> +<tr> + <td>debug_info_off</td> + <td>uint</td> + <td>offset from the start of the file to the debug info (line numbers + + local variable info) sequence for this code, or <code>0</code> if + there simply is no information. The offset, if non-zero, should be + to a location in the <code>data</code> section. The format of + the data is specified by "<code>debug_info_item</code>" below. + </td> +</tr> +<tr> + <td>insns_size</td> + <td>uint</td> + <td>size of the instructions list, in 16-bit code units</td> +</tr> +<tr> + <td>insns</td> + <td>ushort[insns_size]</td> + <td>actual array of bytecode. The format of code in an <code>insns</code> + array is specified by the companion document + <a href="dalvik-bytecode.html">"Bytecode for the Dalvik VM"</a>. Note + that though this is defined as an array of <code>ushort</code>, there + are some internal structures that prefer four-byte alignment. Also, + if this happens to be in an endian-swapped file, then the swapping is + <i>only</i> done on individual <code>ushort</code>s and not on the + larger internal structures. + </td> +</tr> +<tr> + <td>padding</td> + <td>ushort <i>(optional)</i> = 0</td> + <td>two bytes of padding to make <code>tries</code> four-byte aligned. + This element is only present if <code>tries_size</code> is non-zero + and <code>insns_size</code> is odd. + </td> +</tr> +<tr> + <td>tries</td> + <td>try_item[tries_size] <i>(optional)</i></td> + <td>array indicating where in the code exceptions may be caught and + how to handle them. Elements of the array must be non-overlapping in + range and in order from low to high address. This element is only + present if <code>tries_size</code> is non-zero. + </td> +</tr> +<tr> + <td>handlers</td> + <td>encoded_catch_handler_list <i>(optional)</i></td> + <td>bytes representing a list of lists of catch types and associated + handler addresses. Each <code>try_item</code> has a byte-wise offset + into this structure. This element is only present if + <code>tries_size</code> is non-zero. + </td> +</tr> +</tbody> +</table> + +<h3><code>try_item</code> Format </h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>start_addr</td> + <td>uint</td> + <td>start address of the block of code covered by this entry. The address + is a count of 16-bit code units to the start of the first covered + instruction. + </td> +</tr> +<tr> + <td>insn_count</td> + <td>ushort</td> + <td>number of 16-bit code units covered by this entry. The last code + unit covered (inclusive) is <code>start_addr + insn_count - 1</code>. + </td> +</tr> +<tr> + <td>handler_off</td> + <td>ushort</td> + <td>offset in bytes from the start of the associated encoded handler data + to the <code>catch_handler_item</code> for this entry + </td> +</tr> +</tbody> +</table> + +<h3><code>encoded_catch_handler_list</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>size</td> + <td>uleb128</td> + <td>size of this list, in entries</td> +</tr> +<tr> + <td>list</td> + <td>encoded_catch_handler[handlers_size]</td> + <td>actual list of handler lists, represented directly (not as offsets), + and concatenated sequentially</td> +</tr> +</tbody> +</table> + +<h3><code>encoded_catch_handler</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>size</td> + <td>sleb128</td> + <td>number of catch types in this list. If non-positive, then this is + the negative of the number of catch types, and the catches are followed + by a catch-all handler. For example: A <code>size</code> of <code>0</code> + means that there is a catch-all but no explicitly typed catches. + A <code>size</code> of <code>2</code> means that there are two explicitly + typed catches and no catch-all. And a <code>size</code> of <code>-1</code> + means that there is one typed catch along with a catch-all. + </td> +</tr> +<tr> + <td>handlers</td> + <td>encoded_type_addr_pair[abs(size)]</td> + <td>stream of <code>abs(size)</code> encoded items, one for each caught + type, in the order that the types should be tested. + </td> +</tr> +<tr> + <td>catch_all_addr</td> + <td>uleb128 <i>(optional)</i></td> + <td>bytecode address of the catch-all handler. This element is only + present if <code>size</code> is non-positive. + </td> +</tr> +</tbody> +</table> + +<h3><code>encoded_type_addr_pair</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>type_idx</td> + <td>uleb128</td> + <td>index into the <code>type_ids</code> list for the type of the + exception to catch + </td> +</tr> +<tr> + <td>addr</td> + <td>uleb128</td> + <td>bytecode address of the associated exception handler</td> +</tr> +</tbody> +</table> + +<h2><code>debug_info_item</code></h2> +<h4>referenced from <code>code_item</code></h4> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: none (byte-aligned)</h4> + +<p>Each <code>debug_info_item</code> defines a DWARF3-inspired byte-coded +state machine that, when interpreted, emits the positions +table and (potentially) the local variable information for a +<code>code_item</code>. The sequence begins with a variable-length +header (the length of which depends on the number of method +parameters), is followed by the state machine bytecodes, and ends +with an <code>DBG_END_SEQUENCE</code> byte.</p> + +<p>The state machine consists of five registers. The +<code>address</code> register represents the instruction offset in the +associated <code>insns_item</code> in 16-bit code units. The +<code>address</code> register starts at <code>0</code> at the beginning of each +<code>debug_info</code> sequence and may only monotonically increase. +The <code>line</code> register represents what source line number +should be associated with the next positions table entry emitted by +the state machine. It is initialized in the sequence header, and may +change in positive or negative directions but must never be less than +<code>1</code>. The <code>source_file</code> register represents the +source file that the line number entries refer to. It is initialized to +the value of <code>source_file_idx</code> in <code>class_def_item</code>. +The other two variables, <code>prologue_end</code> and +<code>epilogue_begin</code>, are boolean flags (initialized to +<code>false</code>) that indicate whether the next position emitted +should be considered a method prologue or epilogue. The state machine +must also track the name and type of the last local variable live in +each register for the <code>DBG_RESTART_LOCAL</code> code.</p> + +<p>The header is as follows:</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>line_start</td> + <td>uleb128</td> + <td>the initial value for the state machine's <code>line</code> register. + Does not represent an actual positions entry. + </td> +</tr> +<tr> + <td>parameters_size</td> + <td>uleb128</td> + <td>the number of parameter names that are encoded. There should be + one per method parameter, excluding an instance method's <code>this</code>, + if any. + </td> +</tr> +<tr> + <td>parameter_names</td> + <td>uleb128p1[parameters_size]</td> + <td>string index of the method parameter name. An encoded value of + <code>NO_INDEX</code> indicates that no name + is available for the associated parameter. The type descriptor + and signature are implied from the method descriptor and signature. + </td> +</tr> +</tbody> +</table> + +<p>The byte code values are as follows:</p> + +<table class="debugByteCode"> +<thead> +<tr> + <th>Name</th> + <th>Value</th> + <th>Format</th> + <th>Arguments</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>DBG_END_SEQUENCE</td> + <td>0x00</td> + <td></td> + <td><i>(none)</i></td> + <td>terminates a debug info sequence for a <code>code_item</code></td> +</tr> +<tr> + <td>DBG_ADVANCE_PC</td> + <td>0x01</td> + <td>uleb128 addr_diff</td> + <td><code>addr_diff</code>: amount to add to address register</td> + <td>advances the address register without emitting a positions entry</td> +</tr> +<tr> + <td>DBG_ADVANCE_LINE</td> + <td>0x02</td> + <td>sleb128 line_diff</td> + <td><code>line_diff</code>: amount to change line register by</td> + <td>advances the line register without emitting a positions entry</td> +</tr> +<tr> + <td>DBG_START_LOCAL</td> + <td>0x03</td> + <td>uleb128 register_num<br/> + uleb128p1 name_idx<br/> + uleb128p1 type_idx + </td> + <td><code>register_num</code>: register that will contain local<br/> + <code>name_idx</code>: string index of the name<br/> + <code>type_idx</code>: type index of the type + </td> + <td>introduces a local variable at the current address. Either + <code>name_idx</code> or <code>type_idx</code> may be + <code>NO_INDEX</code> to indicate that that value is unknown. + </td> +</tr> +<tr> + <td>DBG_START_LOCAL_EXTENDED</td> + <td>0x04</td> + <td>uleb128 register_num<br/> + uleb128p1 name_idx<br/> + uleb128p1 type_idx<br/> + uleb128p1 sig_idx + </td> + <td><code>register_num</code>: register that will contain local<br/> + <code>name_idx</code>: string index of the name<br/> + <code>type_idx</code>: type index of the type<br/> + <code>sig_idx</code>: string index of the type signature + </td> + <td>introduces a local with a type signature at the current address. + Any of <code>name_idx</code>, <code>type_idx</code>, or + <code>sig_idx</code> may be <code>NO_INDEX</code> + to indicate that that value is unknown. (If <code>sig_idx</code> is + <code>-1</code>, though, the same data could be represented more + efficiently using the opcode <code>DBG_START_LOCAL</code>.) + <p><b>Note:</b> See the discussion under + "<code>dalvik.annotation.Signature</code>" below for caveats about + handling signatures.</p> + </td> +</tr> +<tr> + <td>DBG_END_LOCAL</td> + <td>0x05</td> + <td>uleb128 register_num</td> + <td><code>register_num</code>: register that contained local</td> + <td>marks a currently-live local variable as out of scope at the current + address + </td> +</tr> +<tr> + <td>DBG_RESTART_LOCAL</td> + <td>0x06</td> + <td>uleb128 register_num</td> + <td><code>register_num</code>: register to restart</td> + <td>re-introduces a local variable at the current address. The name + and type are the same as the last local that was live in the specified + register. + </td> +</tr> +<tr> + <td>DBG_SET_PROLOGUE_END</td> + <td>0x07</td> + <td></td> + <td><i>(none)</i></td> + <td>sets the <code>prologue_end</code> state machine register, + indicating that the next position entry that is added should be + considered the end of a method prologue (an appropriate place for + a method breakpoint). The <code>prologue_end</code> register is + cleared by any special (<code>>= 0x0a</code>) opcode. + </td> +</tr> +<tr> + <td>DBG_SET_EPILOGUE_BEGIN</td> + <td>0x08</td> + <td></td> + <td><i>(none)</i></td> + <td>sets the <code>epilogue_begin</code> state machine register, + indicating that the next position entry that is added should be + considered the beginning of a method epilogue (an appropriate place + to suspend execution before method exit). + The <code>epilogue_begin</code> register is cleared by any special + (<code>>= 0x0a</code>) opcode. + </td> +</tr> +<tr> + <td>DBG_SET_FILE</td> + <td>0x09</td> + <td>uleb128p1 name_idx</td> + <td><code>name_idx</code>: string index of source file name; + <code>NO_INDEX</code> if unknown + </td> + <td>indicates that all subsequent line number entries make reference to this + source file name, instead of the default name specified in + <code>code_item</code> + </td> +</tr> +<tr> + <td><i>Special Opcodes</i></td> + <!-- When updating the range below, make sure to search for other + instances of 0x0a in this section. --> + <td>0x0a…0xff</td> + <td></td> + <td><i>(none)</i></td> + <td>advances the <code>line</code> and <code>address</code> registers, + emits a position entry, and clears <code>prologue_end</code> and + <code>epilogue_begin</code>. See below for description. + </td> +</tr> +</tbody> +</table> + +<h3>Special Opcodes</h3> + +<p>Opcodes with values between <code>0x0a</code> and <code>0xff</code> +(inclusive) move both the <code>line</code> and <code>address</code> +registers by a small amount and then emit a new position table entry. +The formula for the increments are as follows:</p> + +<pre> +DBG_FIRST_SPECIAL = 0x0a // the smallest special opcode +DBG_LINE_BASE = -4 // the smallest line number increment +DBG_LINE_RANGE = 15 // the number of line increments represented + +adjusted_opcode = opcode - DBG_FIRST_SPECIAL + +line += DBG_LINE_BASE + (adjusted_opcode % DBG_LINE_RANGE) +address += (adjusted_opcode / DBG_LINE_RANGE) +</pre> + +<h2><code>annotations_directory_item</code></h2> +<h4>referenced from <code>class_def_item</code></h4> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>class_annotations_off</td> + <td>uint</td> + <td>offset from the start of the file to the annotations made directly + on the class, or <code>0</code> if the class has no direct annotations. + The offset, if non-zero, should be to a location in the + <code>data</code> section. The format of the data is specified + by "<code>annotation_set_item</code>" below. + </td> +</tr> +<tr> + <td>fields_size</td> + <td>uint</td> + <td>count of fields annotated by this item</td> +</tr> +<tr> + <td>annotated_methods_off</td> + <td>uint</td> + <td>count of methods annotated by this item</td> +</tr> +<tr> + <td>annotated_parameters_off</td> + <td>uint</td> + <td>count of method parameter lists annotated by this item</td> +</tr> +<tr> + <td>field_annotations</td> + <td>field_annotation[fields_size] <i>(optional)</i></td> + <td>list of associated field annotations. The elements of the list must + be sorted in increasing order, by <code>field_idx</code>. + </td> +</tr> +<tr> + <td>method_annotations</td> + <td>method_annotation[methods_size] <i>(optional)</i></td> + <td>list of associated method annotations. The elements of the list must + be sorted in increasing order, by <code>method_idx</code>. + </td> +</tr> +<tr> + <td>parameter_annotations</td> + <td>parameter_annotation[parameters_size] <i>(optional)</i></td> + <td>list of associated method parameter annotations. The elements of the + list must be sorted in increasing order, by <code>method_idx</code>. + </td> +</tr> +</tbody> +</table> + +<p><b>Note:</b> All elements' <code>field_id</code>s and +<code>method_id</code>s must refer to the same defining class.</p> + +<h3><code>field_annotation</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>field_idx</td> + <td>uint</td> + <td>index into the <code>field_ids</code> list for the identity of the + field being annotated + </td> +</tr> +<tr> + <td>annotations_off</td> + <td>uint</td> + <td>offset from the start of the file to the list of annotations for + the field. The offset should be to a location in the <code>data</code> + section. The format of the data is specified by + "<code>annotation_set_item</code>" below. + </td> +</tr> +</tbody> +</table> + +<h3><code>method_annotation</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>method_idx</td> + <td>uint</td> + <td>index into the <code>method_ids</code> list for the identity of the + method being annotated + </td> +</tr> +<tr> + <td>annotations_off</td> + <td>uint</td> + <td>offset from the start of the file to the list of annotations for + the method. The offset should be to a location in the + <code>data</code> section. The format of the data is specified by + "<code>annotation_set_item</code>" below. + </td> +</tr> +</tbody> +</table> + +<h3><code>parameter_annotation</code> Format</h2> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>method_idx</td> + <td>uint</td> + <td>index into the <code>method_ids</code> list for the identity of the + method whose parameters are being annotated + </td> +</tr> +<tr> + <td>annotations_off</td> + <td>uint</td> + <td>offset from the start of the file to the list of annotations for + the method parameters. The offset should be to a location in the + <code>data</code> section. The format of the data is specified by + "<code>annotation_set_ref_list</code>" below. + </td> +</tr> +</tbody> +</table> + +<h2><code>annotation_set_ref_list</code></h2> +<h4>referenced from <code>parameter_annotations_item</code></h4> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>size</td> + <td>uint</td> + <td>size of the list, in entries</td> +</tr> +<tr> + <td>list</td> + <td>annotation_set_ref_item[size]</td> + <td>elements of the list</td> +</tr> +</tbody> +</table> + +<h3><code>annotation_set_ref_item</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>annotations_off</td> + <td>uint</td> + <td>offset from the start of the file to the referenced annotation set + or <code>0</code> if there are no annotations for this element. + The offset, if non-zero, should be to a location in the <code>data</code> + section. The format of the data is specified by + "<code>annotation_set_item</code>" below. + </td> +</tr> +</tbody> +</table> + +<h2><code>annotation_set_item</code></h2> +<h4>referenced from <code>annotations_directory_item</code>, +<code>field_annotations_item</code>, +<code>method_annotations_item</code>, and +<code>annotation_set_ref_item</code></h4> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: 4 bytes</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>size</td> + <td>uint</td> + <td>size of the set, in entries</td> +</tr> +<tr> + <td>entries</td> + <td>annotation_off_item[size]</td> + <td>elements of the set. The elements must be sorted in increasing order, + by <code>type_idx</code>. + </td> +</tr> +</tbody> +</table> + +<h3><code>annotation_off_item</code> Format</h3> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>annotation_off</td> + <td>uint</td> + <td>offset from the start of the file to an annotation. + The offset should be to a location in the <code>data</code> section, + and the format of the data at that location is specified by + "<code>annotation_item</code>" below. + </td> +</tr> +</tbody> +</table> + + +<h2><code>annotation_item</code></h2> +<h4>referenced from <code>annotation_set_item</code></h4> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: none (byte-aligned)</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>visibility</td> + <td>ubyte</td> + <td>intended visibility of this annotation (see below)</td> +</tr> +<tr> + <td>annotation</td> + <td>encoded_annotation</td> + <td>encoded annotation contents, in the format described by + "<code>encoded_annotation</code> Format" under + "<code>encoded_value</code> Encoding" above. + </td> +</tr> +</tbody> +</table> + +<h3>Visibility values</h3> + +<p>These are the options for the <code>visibility</code> field in an +<code>annotation_item</code>:</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Value</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>VISIBILITY_BUILD</td> + <td>0x00</td> + <td>intended only to be visible at build time (e.g., during compilation + of other code) + </td> +</tr> +<tr> + <td>VISIBILITY_RUNTIME</td> + <td>0x01</td> + <td>intended to visible at runtime</td> +</tr> +<tr> + <td>VISIBILITY_SYSTEM</td> + <td>0x02</td> + <td>intended to visible at runtime, but only to the underlying system + (and not to regular user code) + </td> +</tr> +</tbody> +</table> + +<h2><code>encoded_array_item</code></h2> +<h4>referenced from <code>class_def_item</code></h4> +<h4>appears in the <code>data</code> section</h4> +<h4>alignment: none (byte-aligned)</h4> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>value</td> + <td>encoded_array</td> + <td>bytes representing the encoded array value, in the format specified + by "<code>encoded_array</code> Format" under "<code>encoded_value</code> + Encoding" above. + </td> +</tr> +</tbody> +</table> + +<h1>System Annotations</h1> + +<p>System annotations are used to represent various pieces of reflective +information about classes (and methods and fields). This information is +generally only accessed indirectly by client (non-system) code.</p> + +<p>System annotations are represented in <code>.dex</code> files as +annotations with visibility set to <code>VISIBILITY_SYSTEM</code>. + +<h2><code>dalvik.annotation.AnnotationDefault</code></h2> +<h4>appears on methods in annotation interfaces</h4> + +<p>An <code>AnnotationDefault</code> annotation is attached to each +annotation interface which wishes to indicate default bindings.</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>value</td> + <td>Annotation</td> + <td>the default bindings for this annotation, represented as an annotation + of this type. The annotation need not include all names defined by the + annotation; missing names simply do not have defaults. + </td> +</tr> +</tbody> +</table> + +<h2><code>dalvik.annotation.EnclosingClass</code></h2> +<h4>appears on classes</h4> + +<p>An <code>EnclosingClass</code> annotation is attached to each class +which is either defined as a member of another class, per se, or is +anonymous but not defined within a method body (e.g., a synthetic +inner class). Every class that has this annotation must also have an +<code>InnerClass</code> annotation. Additionally, a class may not have +both an <code>EnclosingClass</code> and an +<code>EnclosingMethod</code> annotation.</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>value</td> + <td>Class</td> + <td>the class which most closely lexically scopes this class</td> +</tr> +</tbody> +</table> + +<h2><code>dalvik.annotation.EnclosingMethod</code></h2> +<h4>appears on classes</h4> + +<p>An <code>EnclosingMethod</code> annotation is attached to each class +which is defined inside a method body. Every class that has this +annotation must also have an <code>InnerClass</code> annotation. +Additionally, a class may not have both an <code>EnclosingClass</code> +and an <code>EnclosingMethod</code> annotation.</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>value</td> + <td>Method</td> + <td>the method which most closely lexically scopes this class</td> +</tr> +</tbody> +</table> + +<h2><code>dalvik.annotation.InnerClass</code></h2> +<h4>appears on classes</h4> + +<p>An <code>InnerClass</code> annotation is attached to each class +which is defined in the lexical scope of another class's definition. +Any class which has this annotation must also have <i>either</i> an +<code>EnclosingClass</code> annotation <i>or</i> an +<code>EnclosingMethod</code> annotation.</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>name</td> + <td>String</td> + <td>the originally declared simple name of this class (not including any + package prefix). If this class is anonymous, then the name is + <code>null</code>. + </td> +</tr> +<tr> + <td>accessFlags</td> + <td>int</td> + <td>the originally declared access flags of the class (which may differ + from the effective flags because of a mismatch between the execution + models of the source language and target virtual machine) + </td> +</tr> +</tbody> +</table> + +<h2><code>dalvik.annotation.MemberClasses</code></h2> +<h4>appears on classes</h4> + +<p>A <code>MemberClasses</code> annotation is attached to each class +which declares member classes. (A member class is a direct inner class +that has a name.)</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>value</td> + <td>Class[]</td> + <td>array of the member classes</td> +</tr> +</tbody> +</table> + +<h2><code>dalvik.annotation.Signature</code></h2> +<h4>appears on classes, fields, and methods</h4> + +<p>A <code>Signature</code> annotation is attached to each class, +field, or method which is defined in terms of a more complicated type +than is representable by a <code>type_id_item</code>. The +<code>.dex</code> format does not define the format for signatures; it +is merely meant to be able to represent whatever signatures a source +language requires for successful implementation of that language's +semantics. As such, signatures are not generally parsed (or verified) +by virtual machine implementations. The signatures simply get handed +off to higher-level APIs and tools (such as debuggers). Any use of a +signature, therefore, should be written so as not to make any +assumptions about only receiving valid signatures, explicitly guarding +itself against the possibility of coming across a syntactically +invalid signature.</p> + +<p>Because signature strings tend to have a lot of duplicated content, +a <code>Signature</code> annotation is defined as an <i>array</i> of +strings, where duplicated elements naturally refer to the same +underlying data, and the signature is taken to be the concatenation of +all the strings in the array. There are no rules about how to pull +apart a signature into separate strings; that is entirely up to the +tools that generate <code>.dex</code> files.</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>value</td> + <td>String[]</td> + <td>the signature of this class or member, as an array of strings that + is to be concatenated together</td> +</tr> +</tbody> +</table> + +<h2><code>dalvik.annotation.Throws</code></h2> +<h4>appears on methods</h4> + +<p>A <code>Throws</code> annotation is attached to each method which is +declared to throw one or more exception types.</p> + +<table class="format"> +<thead> +<tr> + <th>Name</th> + <th>Format</th> + <th>Description</th> +</tr> +</thead> +<tbody> +<tr> + <td>value</td> + <td>Class[]</td> + <td>the array of exception types thrown</td> +</tr> +</tbody> +</table> + +</body> +</html> |