Files
glava/glsl_ext.c
2018-10-21 10:28:06 -07:00

533 lines
19 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdarg.h>
#include <errno.h>
#include <string.h>
#include <dirent.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "glsl_ext.h"
struct sbuf {
char* buf;
size_t at; /* index of final null character */
size_t bsize; /* actual buffer size */
};
#define append(sbuf, str) n_append(sbuf, strlen(str), str)
static inline void expand_for(struct sbuf* sbuf, size_t len) {
bool resize = false;
while (len + 1 > sbuf->bsize - sbuf->at) {
sbuf->bsize *= 2;
resize = true;
}
if (resize)
sbuf->buf = realloc(sbuf->buf, sbuf->bsize);
}
/* append 'n' bytes from 'str' to the resizable buffer */
static void n_append(struct sbuf* sbuf, size_t len, const char* str) {
expand_for(sbuf, len);
memcpy(sbuf->buf + sbuf->at, str, len);
sbuf->at += len;
sbuf->buf[sbuf->at] = '\0';
}
#define s_append(sbuf, fmt, ...) se_append(sbuf, 64, fmt, __VA_ARGS__)
/* append the formatted string to the resizable buffer, where elen is extra space for formatted chars */
static void se_append(struct sbuf* sbuf, size_t elen, const char* fmt, ...) {
size_t space = strlen(fmt) + elen;
expand_for(sbuf, space);
va_list args;
va_start(args, fmt);
int written;
if ((written = vsnprintf(sbuf->buf + sbuf->at, space, fmt, args)) < 0)
abort();
sbuf->at += written;
va_end(args);
}
#define parse_error(line, f, fmt, ...) \
fprintf(stderr, "[%s:%d] " fmt "\n", f, (int) line, __VA_ARGS__); \
abort()
#define parse_error_s(line, f, s) \
fprintf(stderr, "[%s:%d] " s "\n", f, (int) line); \
abort()
struct schar {
char* buf;
size_t sz;
};
bool ext_parse_color(const char* str, size_t elem_sz, float** results) {
size_t t, len = strlen(str), i = 0, s = 0;
uint8_t elem_bytes[elem_sz];
/* Ignore '0x' prefix, if present */
if (len >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')) {
len -= 2;
str += 2;
}
for (t = 0; t < len && t < 8; ++t) {
char c = str[t];
uint8_t b;
/* obtain value from character */
switch (c) {
case 'a' ... 'f': b = (c - 'a') + 10; break;
case 'A' ... 'F': b = (c - 'A') + 10; break;
case '0' ... '9': b = c - '0'; break;
default: return false;
}
elem_bytes[s] = b;
if (s >= elem_sz - 1) { /* advance to next element */
uint32_t e = 0; /* component storage */
/* mask storage with input data */
for (size_t v = 0; v < elem_sz; ++v) {
e |= (uint32_t) elem_bytes[v] << (((elem_sz - 1) - v) * 4);
}
/* convert to [0, 1] as floating point value */
*results[i] = (float) e / (float) ((1 << (elem_sz * 4)) - 1);
s = 0;
++i;
} else { /* advance character */
++s;
}
}
return true;
}
static void free_after(struct glsl_ext* ext, void* ptr) {
++ext->destruct_sz;
ext->destruct = realloc(ext->destruct, sizeof(void*) * ext->destruct_sz);
ext->destruct[ext->destruct_sz - 1] = ptr;
}
static void inherit(struct glsl_ext* parent, struct glsl_ext* child) {
free_after(parent, child->processed);
parent->destruct = realloc(parent->destruct, sizeof(void*) * (parent->destruct_sz + child->destruct_sz));
memcpy(parent->destruct + parent->destruct_sz, child->destruct, sizeof(void*) * child->destruct_sz);
parent->destruct_sz += child->destruct_sz;
free(child->destruct);
}
/* handle raw arguments for #include and #request directives */
static struct schar directive(struct glsl_ext* ext, char** args,
size_t args_sz, bool include,
size_t line, const char* f) {
if (include) {
if (args_sz == 0) {
parse_error_s(line, f, "No arguments provided to #include directive!");
}
char* target = args[0];
/* Handle `:` config specifier */
size_t tsz = strlen(target);
if (tsz && target[0] == ':' && ext->cfd) {
target = &target[1];
ext->cd = ext->cfd;
}
char path[strlen(ext->cd) + tsz + 2];
snprintf(path, sizeof(path) / sizeof(char), "%s/%s", ext->cd, target);
int fd = open(path, O_RDONLY);
if (fd == -1) {
parse_error(line, f, "failed to load GLSL shader source "
"specified by #include directive '%s': %s\n",
path, strerror(errno));
}
struct stat st;
fstat(fd, &st);
char* map = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
if (!map) {
parse_error(line, f, "failed to map GLSL shader source "
"specified by #include directive '%s': %s\n",
path, strerror(errno));
}
struct glsl_ext next = {
.source = map,
.source_len = st.st_size,
.cd = ext->cd,
.cfd = ext->cfd,
.handlers = ext->handlers
};
/* recursively process */
ext_process(&next, target);
inherit(ext, &next);
munmap(map, st.st_size);
struct schar ret = {
.buf = next.processed,
.sz = next.p_len
};
return ret;
} else {
if (args_sz > 0) {
char* request = args[0];
struct request_handler* handler;
bool found = false;
size_t t;
for (t = 0; (handler = &ext->handlers[t])->name != NULL; ++t) {
if(!strcmp(handler->name, request)) {
found = true;
void** processed_args = malloc(strlen(handler->fmt) * sizeof(void*));
char c;
size_t i;
for (i = 0; (c = handler->fmt[i]) != '\0'; ++i) {
if (args_sz <= 1 + i) {
parse_error(line, f,
"failed to execute request '%s': expected format '%s'\n",
request, handler->fmt);
}
char* raw = args[1 + i];
switch (c) {
case 'i':
{
int v = (int) strtol(raw, NULL, 0);
processed_args[i] = malloc(sizeof(int));
*(int*) processed_args[i] = v;
break;
}
case 'f':
{
float f = strtof(raw, NULL);
processed_args[i] = malloc(sizeof(float));
*(float*) processed_args[i] = f;
break;
}
case 's': { *(char**) &processed_args[i] = raw; break; }
case 'b':
{
bool v;
if (!strcmp(raw, "true")) {
v = true;
} else if (!strcmp(raw, "false")) {
v = false;
} else if (strlen(raw) == 1) {
switch (raw[0]) {
case 't': { v = true; break; }
case 'f': { v = false; break; }
case '1': { v = true; break; }
case '0': { v = false; break; }
default:
parse_error_s(line, f,
"tried to parse invalid raw string into a boolean");
}
} else {
parse_error_s(line, f,
"tried to parse invalid raw string into a boolean");
}
processed_args[i] = malloc(sizeof(bool));
*(bool*) processed_args[i] = v;
break;
}
}
}
handler->handler(request, processed_args);
for (i = 0; (c = handler->fmt[i]) != '\0'; ++i)
if (c != 's')
free(processed_args[i]);
free(processed_args);
}
}
if (!found) {
parse_error(line, f, "unknown request type '%s'", request);
}
}
struct schar ret = {
.buf = NULL,
.sz = 0
};
return ret;
}
}
/* state machine parser */
void ext_process(struct glsl_ext* ext, const char* f) {
ext->destruct = malloc(1);
ext->destruct_sz = 0;
#define LINE_START 0
#define GLSL 1
#define MACRO 2
#define REQUEST 3
#define INCLUDE 4
#define COLOR 5
struct sbuf sbuf = {
.buf = malloc(256),
.at = 0,
.bsize = 256
};
size_t source_len = ext->source_len;
size_t t;
char at;
int state = LINE_START;
size_t macro_start_idx, arg_start_idx, cbuf_idx;
size_t line = 1;
bool quoted = false, arg_start;
char cbuf[9];
char** args = malloc(sizeof(char*));
size_t args_sz = 0;
bool prev_slash = false, comment = false, comment_line = false, prev_asterix = false,
prev_escape = false, string = false;
for (t = 0; t <= source_len; ++t) {
at = source_len == t ? '\0' : ext->source[t];
if (at == '\n')
++line;
switch (state) {
case LINE_START: /* processing start of line */
{
switch (at) {
case '#': {
macro_start_idx = t;
state = MACRO;
continue; }
case '\n':
if (comment && comment_line) {
comment = false;
comment_line = false;
}
case '\t':
case ' ':
goto copy;
default: state = GLSL;
/* let execution continue into next state */
}
}
case GLSL: /* copying GLSL source or unrelated preprocessor syntax */
{
switch (at) {
case '"':
if (!comment && !prev_escape)
string = !string;
goto normal_char;
case '\\':
if (!comment) {
prev_escape = !prev_escape;
prev_asterix = false;
prev_slash = false;
goto copy;
} else goto normal_char;
case '/':
if (!comment) {
if (prev_slash) {
comment = true;
comment_line = true;
prev_slash = false;
} else prev_slash = true;
} else if (!comment_line) {
if (prev_asterix) {
comment = false;
prev_asterix = false;
}
}
prev_escape = false;
goto copy;
case '*':
if (!comment) {
if (prev_slash) {
comment = true;
prev_slash = false;
}
} else prev_asterix = true;
prev_escape = false;
goto copy;
case '#': {
/* handle hex color syntax */
if (!comment && !string) {
state = COLOR;
cbuf_idx = 0;
continue;
} else goto normal_char;
}
case '\n':
if (comment && comment_line) {
comment = false;
comment_line = false;
}
state = LINE_START;
normal_char:
default:
prev_asterix = false;
prev_slash = false;
prev_escape = false;
goto copy;
}
}
case COLOR: /* parse hex color syntax (#ffffffff -> vec4(1.0, 1.0, 1.0, 1.0)) */
{
switch (at) {
case 'a' ... 'z':
case 'A' ... 'Z':
case '0' ... '9': {
cbuf[cbuf_idx] = at;
++cbuf_idx;
if (cbuf_idx >= 8)
goto emit_color;
else continue;
}
emit_color:
default:
cbuf[cbuf_idx] = '\0'; /* null terminate */
float r = 0.0F, g = 0.0F, b = 0.0F, a = 1.0F;
if (ext_parse_color(cbuf, 2, (float*[]) { &r, &g, &b, &a })) {
se_append(&sbuf, 64, " vec4(%.6f, %.6f, %.6f, %.6f) ", r, g, b, a);
} else {
parse_error(line, f, "Invalid color format '#%s' while "
"parsing GLSL color syntax extension", cbuf);
}
state = at == '\n' ? LINE_START : GLSL;
if (cbuf_idx >= 8)
continue;
else goto copy; /* copy character if it ended the sequence */
}
}
case MACRO: /* processing start of macro */
{
switch (at) {
case '\n':
case ' ':
case '\t':
case '\0':
{
/* end parsing directive */
if (!strncmp("#request", &ext->source[macro_start_idx], t - macro_start_idx)
|| !strncmp("#REQUEST", &ext->source[macro_start_idx], t - macro_start_idx)) {
state = REQUEST;
goto prepare_arg_parse;
} else if (!strncmp("#include", &ext->source[macro_start_idx],
t - macro_start_idx)
|| !strncmp("#INCLUDE", &ext->source[macro_start_idx],
t - macro_start_idx)) {
state = INCLUDE;
goto prepare_arg_parse;
} else {
n_append(&sbuf, t - macro_start_idx, &ext->source[macro_start_idx]);
state = at == '\n' ? LINE_START : GLSL;
goto copy;
}
prepare_arg_parse:
{
arg_start_idx = t + 1;
arg_start = true;
args_sz = 0;
*args = NULL;
}
}
case 'a' ... 'z':
case 'A' ... 'Z':
continue;
default:
/* invalid char, malformed! */
parse_error(line, f, "Unexpected character '%c' while parsing GLSL directive", at);
}
}
/* scope-violating macro to copy the result of the currently parsed argument */
#define copy_arg(end) \
do { if (end - arg_start_idx > 0) { \
++args_sz; \
args = realloc(args, sizeof(char*) * args_sz); \
args[args_sz - 1] = malloc((end - arg_start_idx) + 1); \
memcpy(args[args_sz - 1], &ext->source[arg_start_idx], end - arg_start_idx); \
args[args_sz - 1][end - arg_start_idx] = '\0'; \
} } while (0)
case REQUEST:
case INCLUDE:
{
switch (at) {
case ' ':
case '\t':
case '\n':
case '\0':
if (!quoted) {
/* end arg */
copy_arg(t);
arg_start = true;
arg_start_idx = t + 1;
} else arg_start = false;
if (at == '\n') {
/* end directive */
size_t a;
struct schar r = directive(ext, args, args_sz, state == INCLUDE, line, f);
for (a = 0; a < args_sz; ++a) {
free(args[a]);
}
args_sz = 0;
/* if something was returned (ie. included file), paste the results */
if (r.buf) {
n_append(&sbuf, r.sz, r.buf);
append(&sbuf, "\n");
}
state = LINE_START;
}
break;
case '"':
if (quoted) {
/* end arg */
copy_arg(t);
quoted = false;
arg_start = true;
arg_start_idx = t + 1;
} else if (arg_start) {
++arg_start_idx;
quoted = true;
} else arg_start = false;
break;
default:
arg_start = false;
}
continue;
}
}
copy:
if (at != '\0')
n_append(&sbuf, 1, &at);
}
ext->processed = sbuf.buf;
ext->p_len = sbuf.at;
if (args) {
for (t = 0; t < args_sz; ++t) {
free(args[t]);
}
free(args);
}
}
void ext_free(struct glsl_ext* ext) {
free(ext->processed);
size_t t;
for (t = 0; t < ext->destruct_sz; ++t) {
free(ext->destruct[t]);
}
free(ext->destruct);
}