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authorPetteri Aimonen <jpa@npb.mail.kapsi.fi>2011-08-10 20:08:06 +0000
committerPetteri Aimonen <jpa@npb.mail.kapsi.fi>2011-08-10 20:08:06 +0000
commit09f92bafa59460ea4597c557e469e982386c9e3b (patch)
treea5949245e6544eb5795e9b71f4df112ec52b31d3 /docs
parent0c5bc4caf9cfb221822fead442b462be2f47b97b (diff)
Started writing documentation
git-svn-id: https://svn.kapsi.fi/jpa/nanopb@953 e3a754e5-d11d-0410-8d38-ebb782a927b9
Diffstat (limited to 'docs')
-rw-r--r--docs/Makefile4
-rw-r--r--docs/index.rst92
-rw-r--r--docs/lsr.css231
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diff --git a/docs/Makefile b/docs/Makefile
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+all: index.html
+
+%.html: %.rst
+ rst2html --stylesheet=lsr.css --link-stylesheet $< $@ \ No newline at end of file
diff --git a/docs/index.rst b/docs/index.rst
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+=============================================
+Nanopb: Protocol Buffers with small code size
+=============================================
+
+Nanopb is an ANSI-C library for encoding and decoding messages in Google's `Protocol Buffers`__ format with minimal requirements for RAM and code space.
+It is primarily suitable for 32-bit microcontrollers.
+
+__ http://code.google.com/apis/protocolbuffers/
+
+Overall structure
+=================
+
+For the runtime program, you always need *pb.h* for type declarations.
+Depending on whether you want to encode, decode or both, you also need *pb_encode.h/c* or *pb_decode.h/c*.
+
+The high-level encoding and decoding functions take an array of *pb_field_t* structures, which describes the fields of a message structure. Usually you want these autogenerated from a *.proto* file. The tool string *nanopb_generator.py* accomplishes this.
+
+So a typical project might include these files:
+
+1) Nanopb runtime library:
+ - pb.h
+ - pb_decode.h and pb_decode.c
+ - pb_encode.h and pb_encode.c
+2) Protocol description (you can have many):
+ - person.proto
+ - person.c (autogenerated, contains initializers for const arrays)
+ - person.h (autogenerated, contains type declarations)
+
+Features and limitations
+========================
+
+**Features**
+
+#) Pure C runtime
+#) Small code size (2–10 kB depending on processor)
+#) Small ram usage (typically 200 bytes)
+#) Allows specifying maximum size for strings and arrays, so that they can be allocated statically.
+#) No malloc needed: everything is stored on the stack.
+#) You can use either encoder or decoder alone to cut the code size in half.
+
+**Limitations**
+
+#) User must provide callbacks when decoding arrays or strings without maximum size.
+#) Some speed has been sacrificed for code size. For example varint calculations are always done in 64 bits.
+#) Encoding is focused on writing to streams. For memory buffers only it could be made more efficient.
+#) The deprecated Protocol Buffers feature called "groups" is not supported.
+
+Getting started
+===============
+
+For starters, consider this simple message::
+
+ message Example {
+ required int32 value = 1;
+ }
+
+Save this in *example.proto* and run it through *nanopb_generate.py*. You
+should now have in *example.h*::
+
+ typedef struct {
+ int32_t value;
+ } Example;
+
+ extern const pb_field_t Example_fields[2];
+
+Now in your main program do this to encode a message::
+
+ Example mymessage = {42};
+ uint8_t buffer[10];
+ pb_ostream_t stream = pb_ostream_from_buffer(buffer, sizeof(buffer));
+ pb_encode(&stream, Example_fields, &mymessage);
+
+After that, buffer will contain the encoded message.
+The number of bytes in the message is stored in *stream.bytes_written*.
+You can feed the message to *protoc --decode=Example example.proto* to verify its validity.
+
+Library reference
+=================
+
+**Encoding**
+
+**Decoding**
+
+**Specifying field options**
+
+**Generated code**
+
+Wishlist
+========
+#) A specialized encoder for encoding to a memory buffer. Should serialize in reverse order to avoid having to determine submessage size beforehand.
+#) A cleaner rewrite of the source generator.
+#) Better performance for 16- and 8-bit platforms.
diff --git a/docs/lsr.css b/docs/lsr.css
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+/*
+Author: Peter Parente
+Date: 2008/01/22
+Version: 1.0 (modified)
+Copyright: This stylesheet has been placed in the public domain - free to edit and use for all uses.
+*/
+
+body {
+ font: 100% sans-serif;
+ background: #ffffff;
+ color: black;
+ margin: 2em;
+ padding: 0em 2em;
+}
+
+p.topic-title {
+ font-weight: bold;
+}
+
+table.docinfo {
+ text-align: left;
+ margin: 2em 0em;
+}
+
+a[href] {
+ color: #436976;
+ background-color: transparent;
+}
+
+a.toc-backref {
+ text-decoration: none;
+}
+
+h1 a[href] {
+ color: #003a6b;
+ text-decoration: none;
+ background-color: transparent;
+}
+
+a.strong {
+ font-weight: bold;
+}
+
+img {
+ margin: 0;
+ border: 0;
+}
+
+p {
+ margin: 0.5em 0 1em 0;
+ line-height: 1.5em;
+}
+
+p a:visited {
+ color: purple;
+ background-color: transparent;
+}
+
+p a:active {
+ color: red;
+ background-color: transparent;
+}
+
+a:hover {
+ text-decoration: none;
+}
+
+p img {
+ border: 0;
+ margin: 0;
+}
+
+p.rubric {
+ font-weight: bold;
+ font-style: italic;
+}
+
+em {
+ font-style: normal;
+ font-family: monospace;
+ font-weight: bold;
+}
+
+pre {
+ border-left: 3px double #aaa;
+ padding-left: 10px;
+}
+
+h1.title {
+ color: #003a6b;
+ font-size: 250%;
+ margin-bottom: 0em;
+}
+
+h2.subtitle {
+ color: #003a6b;
+ border-bottom: 0px;
+}
+
+h1, h2, h3, h4, h5, h6 {
+ color: #555;
+ background-color: transparent;
+ margin: 0em;
+ padding-top: 0.5em;
+}
+
+h1 {
+ font-size: 160%;
+ margin-bottom: 0.5em;
+ border-bottom: 2px solid #aaa;
+}
+
+h2 {
+ font-size: 140%;
+ margin-bottom: 0.5em;
+ border-bottom: 1px solid #aaa;
+}
+
+h3 {
+ font-size: 130%;
+ margin-bottom: 0.5em;
+}
+
+h4 {
+ font-size: 110%;
+ font-weight: bold;
+ margin-bottom: 0.5em;
+}
+
+h5 {
+ font-size: 105%;
+ font-weight: bold;
+ margin-bottom: 0.5em;
+}
+
+h6 {
+ font-size: 100%;
+ font-weight: bold;
+ margin-bottom: 0.5em;
+}
+
+dt {
+ font-style: italic;
+}
+
+dd {
+ margin-bottom: 1.5em;
+}
+
+div.admonition, div.note, div.tip, div.caution, div.important {
+ margin: 2em 2em;
+ padding: 0em 1em;
+ border-top: 1px solid #aaa;
+ border-left: 1px solid #aaa;
+ border-bottom: 2px solid #555;
+ border-right: 2px solid #555;
+}
+
+div.important {
+ background: transparent url('../images/important.png') 10px 2px no-repeat;
+}
+
+div.caution {
+ background: transparent url('../images/caution.png') 10px 2px no-repeat;
+}
+
+div.note {
+ background: transparent url('../images/note.png') 10px 2px no-repeat;
+}
+
+div.tip {
+ background: transparent url('../images/tip.png') 10px 2px no-repeat;
+}
+
+div.admonition-example {
+ background: transparent url('../images/tip.png') 10px 2px no-repeat;
+}
+
+div.admonition-critical-example {
+ background: transparent url('../images/important.png') 10px 2px no-repeat;
+}
+
+p.admonition-title {
+ font-weight: bold;
+ border-bottom: 1px solid #aaa;
+ padding-left: 30px;
+}
+
+table.docutils {
+ text-align: left;
+ border: 1px solid gray;
+ border-collapse: collapse;
+ width: 100%;
+ margin: 1.5em 0em;
+}
+
+table.docutils caption {
+ font-style: italic;
+}
+
+table.docutils td, table.docutils th {
+ padding: 0.25em 0.5em;
+}
+
+table.docutils th {
+ background-color: #dddddd;
+}
+
+div.sidebar {
+ width: 33%;
+ float: right;
+ margin: 0em 2em;
+ padding: 0em 1em;
+ border-top: 1px solid #aaa;
+ border-left: 1px solid #aaa;
+ border-bottom: 2px solid #555;
+ border-right: 2px solid #555;
+}
+
+p.sidebar-title {
+ margin-bottom: 0em;
+ color: #003a6b;
+ border-bottom: 1px solid #aaa;
+ font-weight: bold;
+}
+
+p.sidebar-subtitle {
+ margin-top: 0em;
+ font-style: italic;
+ color: #003a6b;
+}