Replace pcm.py with pcm.c, removing the dependency on Python

4 files changed, 162 insertions, 10 deletions

diff --git a/INSTALL.md b/INSTALL.md
index 0d49fedc..73e1be31 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -39,7 +39,6 @@ Run setup and leave the default settings. At the "**Select Packages**" step, cho
 - `make`
 - `git`
 - `gcc-core`
-- `python`
 
 Double click on the text that says "**Skip**" next to each package to select the most recent version to install.
 
@@ -82,7 +81,7 @@ Open **Terminal** and enter the following commands, depending on which distro yo
 To install the software required for **pokeyellow**:
 
 ```bash
-sudo apt-get install make gcc git python
+sudo apt-get install make gcc git
 ```
 
 Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source) to build **rgbds 0.4.1** from source.
@@ -92,7 +91,7 @@ Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source)
 To install the software required for **pokeyellow**:
 
 ```bash
-sudo zypper install make gcc git python
+sudo zypper install make gcc git
 ```
 
 Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source) to build **rgbds 0.4.1** from source.
@@ -102,7 +101,7 @@ Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source)
 To install the software required for **pokeyellow**:
 
 ```bash
-sudo pacman -S make gcc git python
+sudo pacman -S make gcc git
 ```
 
 Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/arch) for Arch Linux to install **rgbds 0.4.1**.
@@ -133,7 +132,6 @@ If your distro is not listed here, try to find the required software in its repo
 - `gcc` (or `clang`)
 - `git`
 - `rgbds`
-- `python`
 
 If `rgbds` is not available, you'll need to follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source) to build **rgbds 0.4.1** from source.
 
diff --git a/Makefile b/Makefile
index 434a3192..52b6e875 100644
--- a/Makefile
+++ b/Makefile
@@ -27,9 +27,6 @@ RGBFIX  ?= $(RGBDS)rgbfix
 RGBGFX  ?= $(RGBDS)rgbgfx
 RGBLINK ?= $(RGBDS)rgblink
 
-PYTHON := python
-pcm    := $(PYTHON) tools/pokemontools/pcm.py pcm
-
 
 ### Build targets
 
@@ -140,4 +137,4 @@ gfx/surfing_pikachu/surfing_pikachu_3.2bpp: tools/gfx += --trim-whitespace
 %.wav: ;
 
 %.pcm: %.wav
-	@$(pcm) $<
+	tools/pcm $< $@
diff --git a/tools/Makefile b/tools/Makefile
index 13bab1fb..ca99b118 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -3,7 +3,7 @@
 CC := gcc
 CFLAGS := -O3 -std=c99 -Wall -Wextra
 
-tools := scan_includes gfx pkmncompress
+tools := scan_includes gfx pkmncompress pcm
 
 all: $(tools)
 	@:
diff --git a/tools/pcm.c b/tools/pcm.c
new file mode 100644
index 00000000..114fdd38
--- /dev/null
+++ b/tools/pcm.c
@@ -0,0 +1,157 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#define CHUNKID(b1, b2, b3, b4) \
+	(uint32_t)((uint32_t)(b1) | ((uint32_t)(b2) << 8) | \
+	((uint32_t)(b3) << 16) | ((uint32_t)(b4) << 24))
+
+size_t file_size(FILE *f) {
+	if (fseek(f, 0, SEEK_END) == -1) return 0;
+	long f_size = ftell(f);
+	if (f_size == -1) return 0;
+	if (fseek(f, 0, SEEK_SET) == -1) return 0;
+	return (size_t)f_size;
+}
+
+int32_t get_uint16le(uint8_t *data, size_t size, size_t i) {
+	return i + 2 >= size ? -1 :
+		(int32_t)data[i] | ((int32_t)data[i+1] << 8);
+}
+
+int64_t get_uint32le(uint8_t *data, size_t size, size_t i) {
+	return i + 4 >= size ? -1 :
+		(int64_t)data[i] | ((int64_t)data[i+1] << 8) |
+		((int64_t)data[i+2] << 16) | ((int64_t)data[i+3] << 24);
+}
+
+uint8_t *wav2pcm(uint8_t *wavdata, size_t wavsize, size_t *pcmsize) {
+	int64_t fourcc = get_uint32le(wavdata, wavsize, 0);
+	if (fourcc != CHUNKID('R', 'I', 'F', 'F')) {
+		fputs("WAV file does not start with 'RIFF'\n", stderr);
+		return NULL;
+	}
+
+	int64_t waveid = get_uint32le(wavdata, wavsize, 8);
+	if (waveid != CHUNKID('W', 'A', 'V', 'E')) {
+		fputs("RIFF chunk does not start with 'WAVE'\n", stderr);
+		return NULL;
+	}
+
+	size_t sample_offset = 0;
+	int64_t num_samples = 0;
+
+	size_t riffsize = (size_t)get_uint32le(wavdata, wavsize, 4) + 8;
+	for (size_t i = 12; i < riffsize;) {
+		int64_t chunkid = get_uint32le(wavdata, wavsize, i);
+		int64_t chunksize = get_uint32le(wavdata, wavsize, i+4);
+		i += 8;
+		if (chunksize == -1) {
+			fputs("failed to read sub-chunk size\n", stderr);
+			return NULL;
+		}
+
+		if (chunkid == CHUNKID('f', 'm', 't', ' ')) {
+			int32_t audio_format = get_uint16le(wavdata, wavsize, i);
+			if (audio_format != 1) {
+				fputs("WAV data is not PCM format\n", stderr);
+				return NULL;
+			}
+
+			int32_t num_channels = get_uint16le(wavdata, wavsize, i+2);
+			if (num_channels != 1) {
+				fputs("WAV data is not mono\n", stderr);
+				return NULL;
+			}
+
+			int32_t bits_per_sample = get_uint16le(wavdata, wavsize, i+14);
+			if (bits_per_sample != 8) {
+				fputs("WAV data is not 8-bit samples\n", stderr);
+				return NULL;
+			}
+		}
+
+		else if (chunkid == CHUNKID('d', 'a', 't', 'a')) {
+			sample_offset = i;
+			num_samples = chunksize;
+			break;
+		}
+
+		i += (size_t)chunksize;
+	}
+
+	if (!num_samples) {
+		fputs("WAV data has no PCM samples\n", stderr);
+		return NULL;
+	}
+
+	// pack 8 WAV samples per PCM byte, clamping each to 0 or 1
+	*pcmsize = (size_t)((num_samples + 7) / 8);
+	uint8_t *pcmdata = malloc(*pcmsize);
+	for (int64_t i = 0; i < num_samples; i += 8) {
+		uint8_t v = 0;
+		for (int64_t j = 0; j < 8 && i + j < num_samples; j++) {
+			v |= (wavdata[sample_offset + i + j] > 0x80) << (7 - j);
+		}
+		pcmdata[i / 8] = v;
+	}
+
+	return pcmdata;
+}
+
+int main(int argc, char *argv[])
+{
+	if (argc != 3) {
+		fprintf(stderr, "Usage: %s infile.wav outfile.pcm\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	char *wavname = argv[1];
+	char *pcmname = argv[2];
+
+	FILE *wavfile = fopen(wavname, "rb");
+	if (!wavfile) {
+		fprintf(stderr, "failed to open for reading: '%s'\n", wavname);
+		return EXIT_FAILURE;
+	}
+
+	size_t wavsize = file_size(wavfile);
+	if (!wavsize) {
+		fclose(wavfile);
+		fprintf(stderr, "failed to get file size: '%s'\n", wavname);
+		return EXIT_FAILURE;
+	}
+
+	uint8_t *wavdata = malloc(wavsize);
+	size_t readsize = fread(wavdata, 1, wavsize, wavfile);
+	fclose(wavfile);
+	if (readsize != wavsize) {
+		fprintf(stderr, "failed to read: '%s'\n", wavname);
+		return EXIT_FAILURE;
+	}
+
+	size_t pcmsize;
+	uint8_t *pcmdata = wav2pcm(wavdata, wavsize, &pcmsize);
+	free(wavdata);
+	if (!pcmdata) {
+		fprintf(stderr, "failed to convert: '%s'\n", wavname);
+		return EXIT_FAILURE;
+	}
+
+	FILE *pcmfile = fopen(pcmname, "wb");
+	if (!pcmfile) {
+		fprintf(stderr, "failed to open for writing: '%s'\n", pcmname);
+		return EXIT_FAILURE;
+	}
+
+	size_t writesize = fwrite(pcmdata, 1, pcmsize, pcmfile);
+	free(pcmdata);
+	fclose(pcmfile);
+	if (writesize != pcmsize) {
+		fprintf(stderr, "failed to write: '%s'\n", pcmname);
+		return EXIT_FAILURE;
+	}
+
+	return EXIT_SUCCESS;
+}