Fix BASISU_ZSTD=OFF

CMakeLists.txt

@@ -42,7 +42,7 @@ else()
     option(BASISU_BUILD_X64 "build 64-bit" TRUE)
 endif()
 
-option(BASISU_ZSTD "ZSTD support for KTX2 transcoding/encoding" TRUE)
+option(BASISU_ZSTD "ZSTD support for KTX2 transcoding/encoding and ASTC LDR encoding" TRUE)
 option(BASISU_OPENCL "OpenCL support in encoder" FALSE)
 
 # Old option to new (BASISU_ prefixed) automatic remapping
@@ -290,12 +290,24 @@ set(ENCODER_LIB_SRC_LIST
 )
 
 if (BASISU_ZSTD)
-    set(ENCODER_LIB_SRC_LIST ${ENCODER_LIB_SRC_LIST} zstd/zstd.c)
+    # Full zstd library (encoder + decoder) for the encoder
+    add_library(basisu_zstd_encoder STATIC zstd/zstd.c)
+    target_include_directories(basisu_zstd_encoder PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/zstd)
+    set_property(TARGET basisu_zstd_encoder PROPERTY POSITION_INDEPENDENT_CODE ON)
+
+    # Decoder-only zstd library for transcoder-only targets (smaller footprint)
+    add_library(basisu_zstd_decoder STATIC zstd/zstddeclib.c)
+    target_include_directories(basisu_zstd_decoder PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/zstd)
+    set_property(TARGET basisu_zstd_decoder PROPERTY POSITION_INDEPENDENT_CODE ON)
 endif()
 
 # Create the static library
 add_library(basisu_encoder STATIC ${ENCODER_LIB_SRC_LIST})
 
+if (BASISU_ZSTD)
+    target_link_libraries(basisu_encoder PUBLIC basisu_zstd_encoder)
+endif()
+
 # Create the basisu executable and link against the static library
 add_executable(basisu basisu_tool.cpp)
 target_link_libraries(basisu PRIVATE basisu_encoder)
@@ -308,7 +320,10 @@ if(BASISU_EXAMPLES)
     add_executable(example_capi example_capi/example_capi.c encoder/basisu_wasm_api.cpp encoder/basisu_wasm_transcoder_api.cpp)
     target_link_libraries(example_capi PRIVATE basisu_encoder)
 
-    add_executable(example_transcoding example_transcoding/example_transcoding.cpp example_transcoding/utils.cpp zstd/zstddeclib.c transcoder/basisu_transcoder.cpp)
+    add_executable(example_transcoding example_transcoding/example_transcoding.cpp example_transcoding/utils.cpp transcoder/basisu_transcoder.cpp)
+    if (BASISU_ZSTD)
+        target_link_libraries(example_transcoding PRIVATE basisu_zstd_decoder)
+    endif()
 endif() 
 
 if (BASISU_BUILD_WASM)
@@ -343,7 +358,7 @@ if (BASISU_BUILD_WASM)
 
     endif()
 
-    # 256 MB initial, 3.5 GB max � safe defaults for BasisU
+    # 256 MB initial, 3.5 GB max safe defaults for BasisU
     target_link_options(basisu PRIVATE
         -Wl,--initial-memory=268435456
         -Wl,--max-memory=3758096384
@@ -375,14 +390,16 @@ endif()
 #endif()
 
 if (BASISU_ZSTD)
-    target_compile_definitions(basisu PRIVATE BASISD_SUPPORT_KTX2_ZSTD=1)
+    target_compile_definitions(basisu_encoder PRIVATE BASISD_SUPPORT_KTX2_ZSTD=1 BASISU_ASTC_LDR_SUPPORT_ZSTD=1)
+    target_compile_definitions(basisu PRIVATE BASISD_SUPPORT_KTX2_ZSTD=1 BASISU_ASTC_LDR_SUPPORT_ZSTD=1)
     if(BASISU_EXAMPLES)
         target_compile_definitions(example PRIVATE BASISD_SUPPORT_KTX2_ZSTD=1)
         target_compile_definitions(example_capi PRIVATE BASISD_SUPPORT_KTX2_ZSTD=1)
         target_compile_definitions(example_transcoding PRIVATE BASISD_SUPPORT_KTX2_ZSTD=1)
     endif()         
 else()
-    target_compile_definitions(basisu PRIVATE BASISD_SUPPORT_KTX2_ZSTD=0)
+    target_compile_definitions(basisu_encoder PRIVATE BASISD_SUPPORT_KTX2_ZSTD=0 BASISU_ASTC_LDR_SUPPORT_ZSTD=0)
+    target_compile_definitions(basisu PRIVATE BASISD_SUPPORT_KTX2_ZSTD=0 BASISU_ASTC_LDR_SUPPORT_ZSTD=0)
     if(BASISU_EXAMPLES)
         target_compile_definitions(example PRIVATE BASISD_SUPPORT_KTX2_ZSTD=0)
         target_compile_definitions(example_capi PRIVATE BASISD_SUPPORT_KTX2_ZSTD=0)
@@ -581,8 +598,11 @@ if (BASISU_BUILD_WASM)
 
     add_executable(${BASISU_TRANSCODER_WASM_OUTPUT_NAME} 
         ${CMAKE_CURRENT_SOURCE_DIR}/encoder/basisu_wasm_transcoder_api.cpp
-        ${CMAKE_CURRENT_SOURCE_DIR}/transcoder/basisu_transcoder.cpp
-        ${CMAKE_CURRENT_SOURCE_DIR}/zstd/zstddeclib.c)
+        ${CMAKE_CURRENT_SOURCE_DIR}/transcoder/basisu_transcoder.cpp)
+
+    if (BASISU_ZSTD)
+        target_link_libraries(${BASISU_TRANSCODER_WASM_OUTPUT_NAME} PRIVATE basisu_zstd_decoder)
+    endif()
 
     set_target_properties(${BASISU_TRANSCODER_WASM_OUTPUT_NAME} PROPERTIES SUFFIX ".wasm")
 
@@ -645,9 +665,12 @@ if (BASISU_BUILD_PYTHON AND NOT BASISU_BUILD_WASM)
         python/basisu_transcoder_pybind11.cpp
         encoder/basisu_wasm_transcoder_api.cpp  
         transcoder/basisu_transcoder.cpp
-        zstd/zstddeclib.c
     )
 
+    if (BASISU_ZSTD)
+        target_link_libraries(basisu_transcoder_python PRIVATE basisu_zstd_decoder)
+    endif()
+
     # Ensure PIC ONLY for this target
     set_property(TARGET basisu_transcoder_python PROPERTY POSITION_INDEPENDENT_CODE ON)
 

encoder/basisu_astc_ldr_encode.cpp

@@ -1,4 +1,4 @@
-// File: basisu_astc_ldr_encode.cpp
+// File: basisu_astc_ldr_encode.cpp
 // Copyright (C) 2019-2026 Binomial LLC. All Rights Reserved.
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -18,7 +18,14 @@
 #include "3rdparty/android_astc_decomp.h"
 #include <queue>
 
-#include "../zstd/zstd.h"
+// Set BASISU_ASTC_LDR_SUPPORT_ZSTD to 0 to disable Zstd support for ASTC LDR encoding (cFullZStd and cHybridArithZStd syntaxes)
+#ifndef BASISU_ASTC_LDR_SUPPORT_ZSTD
+	#define BASISU_ASTC_LDR_SUPPORT_ZSTD 1
+#endif
+
+#if BASISU_ASTC_LDR_SUPPORT_ZSTD
+#include "zstd.h"
+#endif
 
 namespace basisu {
 namespace astc_ldr {
@@ -8061,6 +8068,7 @@ void configure_encoder_effort_level(int level, ldr_astc_block_encode_image_high_
 	}
 }
 
+#if BASISU_ASTC_LDR_SUPPORT_ZSTD
 static bool zstd_compress(const uint8_t* pData, size_t data_len, uint8_vec& comp_data, int zstd_level)
 {
 	if (!data_len)
@@ -8100,7 +8108,9 @@ static bool zstd_compress(const uint8_vec& vec, uint8_vec& comp_data, int zstd_l
 {
 	return zstd_compress(vec.data(), vec.size(), comp_data, zstd_level);
 }
+#endif // BASISU_ASTC_LDR_SUPPORT_ZSTD
 
+#if BASISU_ASTC_LDR_SUPPORT_ZSTD
 static uint32_t encode_values(bitwise_coder& coder, uint32_t total_values, const uint8_t* pVals, uint32_t endpoint_range)
 {
 	const uint32_t MAX_VALS = 64;
@@ -9323,6 +9333,7 @@ static bool compress_image_full_zstd(
 
 	return true;
 }
+#endif // BASISU_ASTC_LDR_SUPPORT_ZSTD
 
 bool compress_image(
 	const image& orig_img, uint8_vec& comp_data, vector2D<astc_helpers::log_astc_block>& coded_blocks,
@@ -9445,6 +9456,7 @@ bool compress_image(
 	if (total_blocks <= DISABLE_FASTER_FORMAT_TOTAL_BLOCKS_THRESH)
 		syntax = basist::astc_ldr_t::xuastc_ldr_syntax::cFullArith;
 
+#if BASISU_ASTC_LDR_SUPPORT_ZSTD
 	if (syntax == basist::astc_ldr_t::xuastc_ldr_syntax::cFullZStd)
 	{
 		// Full ZStd syntax is so different we'll move that to another function.
@@ -9454,6 +9466,14 @@ bool compress_image(
 			job_pool,
 			enc_cfg, enc_out);
 	}
+#else
+	if ((syntax == basist::astc_ldr_t::xuastc_ldr_syntax::cFullZStd) ||
+		(syntax == basist::astc_ldr_t::xuastc_ldr_syntax::cHybridArithZStd))
+	{
+		fmt_error_printf("ASTC LDR encoder: Zstd syntax requested but BASISU_ASTC_LDR_SUPPORT_ZSTD is disabled\n");
+		return false;
+	}
+#endif
 
 	const bool use_faster_format = (syntax == basist::astc_ldr_t::xuastc_ldr_syntax::cHybridArithZStd);
 
@@ -10803,9 +10823,12 @@ bool compress_image(
 		return false;
 
 	uint8_vec suffix_bytes;
+
+	assert(comp_data.size() == 0);
 
 	if (use_faster_format)
 	{
+#if BASISU_ASTC_LDR_SUPPORT_ZSTD
 		suffix_bytes.reserve(8192);
 
 		mean0_bits.flush();
@@ -10871,13 +10894,13 @@ bool compress_image(
 			fmt_debug_printf(" Weight4 bytes: {} comp size: {}\n", (uint64_t)weight4_bits.get_bytes().size(), (uint64_t)comp_weight4.size());
 			fmt_debug_printf(" Weight8 bytes: {} comp size: {}\n", (uint64_t)weight8_bits.size(), (uint64_t)comp_weight8.size());
 		}
-	}
-
-	assert(comp_data.size() == 0);
-	if (use_faster_format)
-	{
+
 		comp_data.resize(sizeof(hdr));
 		memcpy(comp_data.data(), &hdr, sizeof(hdr));
+#else
+		fmt_error_printf("ASTC LDR encoder: HybridArithZStd format requires BASISU_ASTC_LDR_SUPPORT_ZSTD to be enabled\n");
+		return false;
+#endif // BASISU_ASTC_LDR_SUPPORT_ZSTD
 	}
 	else
 	{

encoder/basisu_comp.cpp

@@ -34,7 +34,7 @@
 #endif
 
 #if BASISD_SUPPORT_KTX2_ZSTD
-#include "../zstd/zstd.h"
+#include "zstd.h"
 #endif
 
 // Set to 1 to disable the mipPadding alignment workaround (which only seems to be needed when no key-values are written at all)

transcoder/basisu_transcoder.cpp

@@ -1,4 +1,4 @@
-// basisu_transcoder.cpp
+// basisu_transcoder.cpp
 // Copyright (C) 2019-2026 Binomial LLC. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -174,7 +174,7 @@
    // If BASISD_SUPPORT_KTX2_ZSTD is 0, UASTC files compressed with Zstd cannot be loaded.
 	#if BASISD_SUPPORT_KTX2_ZSTD
 		// We only use two Zstd API's: ZSTD_decompress() and ZSTD_isError()
-		#include "../zstd/zstd.h"
+		#include "zstd.h"
 	#endif
 #endif
 
@@ -20426,6 +20426,7 @@ namespace basist
 				return false;
 			}
 #else
+			BASISU_NOTE_UNUSED(pComp_data);
 			BASISU_DEVEL_ERROR("ktx2_transcoder::decompress_level_data: File uses Zstd supercompression, but Zstd support was not enabled at compile time (BASISD_SUPPORT_KTX2_ZSTD is 0)\n");
 			return false;
 #endif
@@ -27014,6 +27015,7 @@ namespace astc_ldr_t
 
 		return true;
 #else
+		BASISU_NOTE_UNUSED(pComp_data);
 		BASISU_DEVEL_ERROR("zstd_decompress: file uses ZStd compression, but ZStd support disabled (see BASISD_SUPPORT_KTX2_ZSTD) \n");
 		return false;
 #endif