arsc 0.1.1

Android resource file parsing & writing
Documentation 
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use super::write_util;
use crate::components::{
    Arsc, Config, Header, Package, ResourceEntry, ResourceValue, Spec, Specs, StringPool, Type,
    Value,
};
use crate::writer::components_sizing::{padding, ByteSizing};
use crate::writer::with_header::WithHeader;
use std::io::{Result, Write};

/// types that implement this trait should define the function
/// `write` to serialize and write the serialized bytes to the output
pub(crate) trait ArscSerializable {
    /// Serialize and write bytes to output
    /// # Argument:
    /// * output - a writer, where the bytes should be written to
    /// # Returns:
    /// the number of bytes that have been written out
    /// # Errors:
    /// io errors
    fn write<W: Write>(&self, output: &mut W) -> Result<usize>;
}

impl ArscSerializable for Value {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut written = write_util::write_u16(output, self.size)?;
        written += write_util::write_u8(output, self.zero)?;
        written += write_util::write_u8(output, self.r#type)?;
        written += write_util::write_u32(output, self.data_index)?;
        Ok(written)
    }
}

impl ArscSerializable for ResourceValue {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        match self {
            ResourceValue::Plain(value) => value.write(output),
            ResourceValue::Bag { parent, values } => {
                let mut written = write_util::write_u32(output, *parent)?;
                written += write_util::write_u32(output, values.len())?;
                for (index, value) in values {
                    written += write_util::write_u32(output, *index)?;
                    written += value.write(output)?;
                }
                Ok(written)
            }
        }
    }
}

impl ArscSerializable for ResourceEntry {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        let size = if self.flags & ResourceEntry::ENTRY_FLAG_COMPLEX != 0 {
            16
        } else {
            8
        };
        let mut written = write_util::write_u16(output, size)?;
        written += write_util::write_u16(output, self.flags)?;
        written += write_util::write_u32(output, self.name_index)?;
        written += self.value.write(output)?;
        Ok(written)
    }
}

impl ArscSerializable for Header {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut written = write_util::write_u16(output, self.resource_type as u16)?;
        written += write_util::write_u16(output, self.header_size)?;
        written += write_util::write_u32(output, self.size)?;
        Ok(written)
    }
}

impl ArscSerializable for StringPool {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut position = self.header().write(output)?;
        position += write_util::write_u32(output, self.strings.len())?;
        position += write_util::write_u32(output, 0)?; // style_count
        position += write_util::write_u32(output, self.flags)?;
        position += write_util::write_u32(output, 7 * 4 + self.strings.len() * 4)?; // string_offset
        position += write_util::write_u32(output, 0)?; // style offset
        position += self.write_offsets(output)?;
        position += self.write_strings(output)?;
        position += output.write(&vec![0; padding(position)])?;

        Ok(position)
    }
}

impl StringPool {
    fn write_offsets<W: Write>(&self, output: &mut W) -> Result<usize> {
        if self.flags & StringPool::UTF8_FLAG != 0 {
            self.write_utf8_offsets(output)
        } else {
            self.write_utf16_offsets(output)
        }
    }

    fn write_utf8_offsets<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut offset = 0;
        let mut written = 0;
        for string in &self.strings {
            written += write_util::write_u32(output, offset)?;
            let char_count = string.chars().count();
            offset += if char_count > 0x7F { 2 } else { 1 };
            let byte_count = string.len();
            offset += if byte_count > 0x7F { 2 } else { 1 };
            offset += byte_count + 1; // 1 for null terminator
        }
        Ok(written)
    }

    fn write_utf16_offsets<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut offset = 0;
        let mut written = 0;
        for string in &self.strings {
            written += write_util::write_u32(output, offset)?;
            let char_count = string.encode_utf16().count();
            offset += if char_count > 0x7FFF { 4 } else { 2 };
            offset += char_count * 2 + 2; // 2 for null terminator
        }
        Ok(written)
    }

    fn write_strings<W: Write>(&self, buffer: &mut W) -> Result<usize> {
        let mut position = 0;
        for string in &self.strings {
            if self.flags & StringPool::UTF8_FLAG != 0 {
                let char_count = string.chars().count();
                position += Self::write_utf8_length(buffer, char_count)?;
                position += Self::write_utf8_length(buffer, string.len())?;
                position += buffer.write(string.as_bytes())?;
                position += write_util::write_u8(buffer, 0)?;
            } else {
                position += Self::write_utf16_length(buffer, string.encode_utf16().count())?;
                position += write_util::write_string_utf16(buffer, string)?;
                position += write_util::write_u16(buffer, 0)?;
            }
        }
        Ok(position)
    }

    fn write_utf8_length<W: Write>(buffer: &mut W, length: usize) -> Result<usize> {
        let mut offset = 0;
        if length > 0x7F {
            offset += write_util::write_u8(buffer, (length >> 8) | 0x80)?;
        }
        offset += write_util::write_u8(buffer, length & 0xFF)?;
        Ok(offset)
    }

    fn write_utf16_length<W: Write>(buffer: &mut W, length: usize) -> Result<usize> {
        let mut offset = 0;
        if length > 0x7FFF {
            let leading_two_bytes = (length >> 16) | 0x8000;
            offset += write_util::write_u8(buffer, leading_two_bytes & 0xFF)?;
            offset += write_util::write_u8(buffer, leading_two_bytes >> 8)?;
        }
        offset += write_util::write_u8(buffer, length & 0xFF)?;
        offset += write_util::write_u8(buffer, (length >> 8) & 0xFF)?;
        Ok(offset)
    }
}

impl ArscSerializable for Specs {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut position = self.header().write(output)?;
        position += write_util::write_u8(output, self.type_id)?;
        position += write_util::write_u8(output, self.res0)?;
        position += write_util::write_u16(output, self.res1)?;
        position += write_util::write_u32(output, self.specs.len())?;
        for spec in &self.specs {
            position += spec.write(output)?;
        }
        Ok(position)
    }
}

impl ArscSerializable for Spec {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        write_util::write_u32(output, self.flags)
    }
}

impl ArscSerializable for Config {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut position = self.header().write(output)?;
        position += write_util::write_u8(output, self.type_id)?;
        position += write_util::write_u8(output, self.res0)?;
        position += write_util::write_u16(output, self.res1)?;
        position += write_util::write_u32(output, self.entry_count)?;
        let entry_start =
            position + 4 + self.id.len() + padding(self.id.len()) + self.entry_count * 4;
        position += write_util::write_u32(output, entry_start)?;
        position += output.write(&self.id)?;
        position += output.write(&vec![0; padding(self.id.len())])?;
        position += self.write_resources(output)?;

        Ok(position)
    }
}

impl Config {
    fn write_resources<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut position = self.write_entries(output)?;
        for resource in self.resources.values() {
            position += resource.write(output)?;
        }
        Ok(position)
    }

    fn write_entries<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut offset = 0;
        let mut written = 0;
        for entry in 0..self.entry_count {
            if let Some(resource) = self.resources.get(&entry) {
                written += write_util::write_i32(output, offset)?;
                offset += 2 + resource.size(); // _size + resource
            } else {
                written += write_util::write_i32(output, -1)?;
            }
        }
        Ok(written)
    }
}

impl ArscSerializable for Type {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut position = 0;
        for specs in &self.specs {
            position += specs.write(output)?;
        }
        for config in &self.configs {
            position += config.write(output)?;
        }
        Ok(position)
    }
}

impl ArscSerializable for Package {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut position = self.header().write(output)?;
        position += write_util::write_u32(output, self.id)?;
        let string_written = write_util::write_string_utf16(output, &self.name)?;
        position += string_written;
        if string_written < 256 {
            position += output.write(&vec![0; 256 - string_written])?;
        }

        let type_string_offset = position + 5 * 4;
        position += write_util::write_u32(output, type_string_offset)?; // type_string_offset
        position += write_util::write_u32(output, 0)?; // last_public_type
        let key_string_offset = type_string_offset + self.type_names.size();
        position += write_util::write_u32(output, key_string_offset)?; // key_string_offset
        position += write_util::write_u32(output, 0)?; // last_public_key
        position += write_util::write_u32(output, 0)?; // type_id_offset

        position += self.type_names.write(output)?;
        position += self.key_names.write(output)?;
        for r#type in &self.types {
            position += r#type.write(output)?;
        }
        Ok(position)
    }
}

impl ArscSerializable for Arsc {
    fn write<W: Write>(&self, output: &mut W) -> Result<usize> {
        let mut position = self.header().write(output)?;
        position += write_util::write_u32(output, self.packages.len())?;
        position += self.global_string_pool.write(output)?;
        for package in &self.packages {
            position += package.write(output)?;
        }
        Ok(position)
    }
}