# This file will be copied into //third_party/externals/zlib via the new_local_repository
# rule in WORKSPACE.bazel, so all files should be relative to that path.

load("@rules_cc//cc:cc_library.bzl", "cc_library")

# We define this here because the emscripten toolchain calls the cpu wasm, whereas the
# bazelbuild/platforms call it wasm32. https://github.com/emscripten-core/emsdk/issues/919
config_setting(
    name = "cpu_wasm",
    values = {
        "cpu": "wasm",
    },
)

constraint_value(
    name = "fuchsia",
    constraint_setting = "@platforms//os:os",
)

config_setting(
    name = "fuchsia_arm64",
    constraint_values = [
        "@platforms//cpu:arm64",
        ":fuchsia",
    ],
)

config_setting(
    name = "linux_x64",
    constraint_values = [
        "@platforms//cpu:x86_64",
        "@platforms//os:linux",
    ],
)

config_setting(
    name = "linux_arm64",
    constraint_values = [
        "@platforms//cpu:arm64",
        "@platforms//os:linux",
    ],
)

config_setting(
    name = "mac_x64",
    constraint_values = [
        "@platforms//cpu:x86_64",
        "@platforms//os:macos",
    ],
)

config_setting(
    name = "mac_arm64",
    constraint_values = [
        "@platforms//cpu:arm64",
        "@platforms//os:macos",
    ],
)

config_setting(
    name = "windows_x64",
    constraint_values = [
        "@platforms//cpu:x86_64",
        "@platforms//os:windows",
    ],
)

ZLIB_SRCS = [
    "adler32.c",
    "compress.c",
    "contrib/optimizations/insert_string.h",
    "cpu_features.c",
    "cpu_features.h",
    "crc32.h",
    "crc32.c",
    "deflate.c",
    "deflate.h",
    "gzclose.c",
    "gzguts.h",
    "gzlib.c",
    "gzread.c",
    "gzwrite.c",
    "infback.c",
    "inffast.c",
    "inffast.h",
    "inflate.h",
    "inftrees.c",
    "inftrees.h",
    "trees.c",
    "trees.h",
    "uncompr.c",
    "inffixed.h",
    "zutil.c",
    "zutil.h",
] + select({
    "@platforms//cpu:x86_64": [
        "adler32_simd.h",
        "adler32_simd.c",
        "contrib/optimizations/chunkcopy.h",
        "contrib/optimizations/inffast_chunk.h",
        "contrib/optimizations/inffast_chunk.c",
        "contrib/optimizations/inflate.c",
        "crc32_simd.h",
        "crc32_simd.c",
        "crc_folding.c",
    ],
    "@platforms//cpu:arm64": [
        "adler32_simd.h",
        "adler32_simd.c",
        "contrib/optimizations/chunkcopy.h",
        "contrib/optimizations/inffast_chunk.h",
        "contrib/optimizations/inffast_chunk.c",
        "contrib/optimizations/inflate.c",
        "crc32_simd.h",
        "crc32_simd.c",
    ],
    # No SIMD support in wasm for now
    ":cpu_wasm": ["inflate.c"],
    # The default is to avoid using SIMD
    "//conditions:default": ["inflate.c"],
})

ZLIB_DEFINES = ["ZLIB_IMPLEMENTATION"] + select({
    "@platforms//cpu:x86_64": [
        "ADLER32_SIMD_SSSE3",
        "CRC32_SIMD_SSE42_PCLMUL",
        "INFLATE_CHUNK_READ_64LE",
        "INFLATE_CHUNK_SIMD_SSE2",
        "DEFLATE_FILL_WINDOW_SSE2",
    ],
    "@platforms//cpu:arm64": [
        "ADLER32_SIMD_NEON",
        "INFLATE_CHUNK_SIMD_NEON",
        "INFLATE_CHUNK_READ_64LE",
    ],
    ":cpu_wasm": ["CPU_NO_SIMD"],
    "//conditions:default": ["CPU_NO_SIMD"],
}) + select({
    ":fuchsia_arm64": [
        "X86_NOT_WINDOWS",
        "ARMV8_OS_FUCHSIA",
    ],
    ":linux_x64": ["X86_NOT_WINDOWS"],
    ":mac_x64": ["X86_NOT_WINDOWS"],
    ":mac_arm64": [
        "ARMV8_OS_MACOS",
        "CRC32_ARMV8_CRC32",
    ],
    ":windows_x64": ["X86_WINDOWS"],
    # TODO(kjlubick) other arm flavors
    "//conditions:default": ["X86_NOT_WINDOWS"],
})

ZLIB_COPTS = [
    "-Wno-unused-function",
    "-Wno-deprecated-non-prototype",
    # no-deprecated-non-prototype was added in Clang 14+, used in emscripten for CanvasKit, but
    # it is not in Clang 13, currently used for Skia.
    "-Wno-unknown-warning-option",
] + select({
    ":linux_x64": [
        "-mssse3",
        "-msse4.2",
        "-mpclmul",
    ],
    ":mac_x64": [
        "-mpclmul",
    ],
    ":windows_x64": [
        "-mssse3",
        "-msse4.2",
        "-mpclmul",
    ],
    "@platforms//cpu:arm": ["-march=armv8-a+crc"],
    # If empty list isn't set for wasm, select picks linux_x64
    ":cpu_wasm": [],
    "//conditions:default": [],
})

# TODO(kjlubick) this is not the most optimal build of zlib, but it's good enough for
# our tests at the moment. We should re-evaluate how we are compiling in SIMD instructions.
cc_library(
    name = "zlib",
    srcs = ZLIB_SRCS,
    hdrs = [
        "chromeconf.h",
        "zconf.h",
        "zlib.h",
    ],
    copts = ZLIB_COPTS,
    local_defines = ZLIB_DEFINES,
    visibility = ["//visibility:public"],
)