MdePkg/BaseLib: rewrite Base64Decode()

Rewrite Base64Decode() from scratch, due to reasons listed in the second
reference below.

Implement Base64Decode() according to the specification added in the
previous patch. The decoder scans the input buffer once, it has no inner
loop(s), and it spills each output byte as soon as the output byte is

The intent is to only strengthen the checks (sanity and input) relative to
the previous implementation, hence the MAX_ADDRESS checks are reinstated.

Cc: Liming Gao <>
Cc: Marvin Häuser <>
Cc: Michael D Kinney <>
Cc: Philippe Mathieu-Daudé <>
Cc: Zhichao Gao <>
Signed-off-by: Laszlo Ersek <>
Reviewed-by: Liming Gao <>
Tested-by: Zhichao Gao <>
Reviewed-by: Philippe Mathieu-Daude <>
[ add last para to commit msg per talks w/ Marvin & Phil]
1 file changed
tree: 5b631e60bd2f4c0c85f21ccf33244752c5ffc7ab
  1. .gitignore
  2. .gitmodules
  3. ArmPkg/
  4. ArmPlatformPkg/
  5. ArmVirtPkg/
  6. BaseTools/
  7. Conf/
  8. CryptoPkg/
  9. DynamicTablesPkg/
  10. EmbeddedPkg/
  11. EmulatorPkg/
  12. FatPkg/
  13. FmpDevicePkg/
  14. IntelFsp2Pkg/
  15. IntelFsp2WrapperPkg/
  16. License-History.txt
  17. License.txt
  18. Maintainers.txt
  19. MdeModulePkg/
  20. MdePkg/
  21. NetworkPkg/
  22. OvmfPkg/
  23. PcAtChipsetPkg/
  25. SecurityPkg/
  26. ShellPkg/
  27. SignedCapsulePkg/
  28. SourceLevelDebugPkg/
  29. StandaloneMmPkg/
  30. UefiCpuPkg/
  31. UefiPayloadPkg/
  32. edksetup.bat

EDK II Project

A modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications from

The majority of the content in the EDK II open source project uses a BSD-2-Clause Plus Patent License. The EDK II open source project contains the following components that are covered by additional licenses:

The EDK II Project is composed of packages. The maintainers for each package are listed in Maintainers.txt.


Code Contributions

To make a contribution to a TianoCore project, follow these steps.

  1. Create a change description in the format specified below to use in the source control commit log.

  2. Your commit message must include your Signed-off-by signature

  3. Submit your code to the TianoCore project using the process that the project documents on its web page. If the process is not documented, then submit the code on development email list for the project.

  4. It is preferred that contributions are submitted using the same copyright license as the base project. When that is not possible, then contributions using the following licenses can be accepted:

    For documentation:

    Contributions of code put into the public domain can also be accepted.

    Contributions using other licenses might be accepted, but further review will be required.

Developer Certificate of Origin

Your change description should use the standard format for a commit message, and must include your Signed-off-by signature.

In order to keep track of who did what, all patches contributed must include a statement that to the best of the contributor's knowledge they have the right to contribute it under the specified license.

The test for this is as specified in the Developer's Certificate of Origin (DCO) 1.1. The contributor certifies compliance by adding a line saying

Signed-off-by: Developer Name

where Developer Name is the contributor's real name, and the email address is one the developer is reachable through at the time of contributing.

Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
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Sample Change Description / Commit Message

From: Contributor Name <>
Subject: [Repository/Branch PATCH] Pkg-Module: Brief-single-line-summary


Signed-off-by: Contributor Name <>

Notes for sample patch email

  • The first line of commit message is taken from the email‘s subject line following [Repository/Branch PATCH]. The remaining portion of the commit message is the email’s content.
  • git format-patch is one way to create this format

Definitions for sample patch email

  • Repository is the identifier of the repository the patch applies. This identifier should only be provided for repositories other than edk2. For example edk2-BuildSpecification or staging.
  • Branch is the identifier of the branch the patch applies. This identifier should only be provided for branches other than edk2/master. For example edk2/UDK2015, edk2-BuildSpecification/release/1.27, or staging/edk2-test.
  • Module is a short identifier for the affected code or documentation. For example MdePkg, MdeModulePkg/UsbBusDxe, Introduction, or EDK II INF File Format.
  • Brief-single-line-summary is a short summary of the change.
  • The entire first line should be less than ~70 characters.
  • Full-commit-message a verbose multiple line comment describing the change. Each line should be less than ~70 characters.
  • Signed-off-by is the contributor's signature identifying them by their real/legal name and their email address.