diff options
Diffstat (limited to 'talk/sc.c')
| -rw-r--r-- | talk/sc.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/talk/sc.c b/talk/sc.c new file mode 100644 index 0000000..6be9a2d --- /dev/null +++ b/talk/sc.c @@ -0,0 +1,229 @@ +#define _GNU_SOURCE + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <inttypes.h> + +#define MAGIC 0x7d53b605 + +#define MIN_REF_LEN 5 +#define MAX_REF 127 + MIN_REF_LEN + +typedef struct { + unsigned size; + unsigned char *data; + unsigned real_size; +} file_data_t; + +typedef struct __attribute ((packed)) { + uint32_t magic; + uint32_t size; + uint32_t unpacked_size; + uint32_t sample_rate; +} snd_header_t; + +file_data_t *read_file(char *name); +void add_data(file_data_t *d, void *buffer, unsigned size); +void write_data(file_data_t *d, char *name); + +void compr(file_data_t *fd, file_data_t *fd_compr); +unsigned find_longest(unsigned char *data, unsigned len, unsigned start, unsigned *ofs); + + +int main(int argc, char **argv) +{ + file_data_t *fd, fd_compr = { }, fd_samples = { }; + snd_header_t sh; + unsigned sample_rate; + + if(argc != 3) return 1; + + fd = read_file(argv[1]); + + if(fd->size <= 44) return 1; + + if( + *((unsigned *) (fd->data + 0)) != 0x46464952 || + *((unsigned *) (fd->data + 8)) != 0x45564157 || + *((short *) (fd->data + 20)) != 1 || + *((short *) (fd->data + 34)) != 8 || + *((short *) (fd->data + 22)) != 1 + ) { + fprintf(stderr, "invalid data, expecting 8bit mono wav (ms pcm) file\n"); + return 3; + } + sample_rate = *((unsigned *) (fd->data + 24)); + + printf("%s: %u Hz, %u samples\n", argv[1], sample_rate, fd->size - 44); + + add_data(&fd_samples, fd->data + 44, fd->size - 44); + + sh.magic = MAGIC; + sh.unpacked_size = fd_samples.size; + sh.sample_rate = sample_rate; + + add_data(&fd_compr, &sh, sizeof sh); + + compr(&fd_samples, &fd_compr); + + sh.size = fd_compr.size - sizeof (snd_header_t); + + memcpy(fd_compr.data, &sh, sizeof (snd_header_t)); + + write_data(&fd_compr, argv[2]); + + return 0; +} + + +file_data_t *read_file(char *name) +{ + file_data_t *fd; + FILE *f; + + fd = calloc(1, sizeof *fd); + + if(!name) return fd; + + f = fopen(name, "r"); + + if(!f) { perror(name); return fd; } + + if(fseek(f, 0, SEEK_END)) { + perror(name); + exit(30); + } + + fd->size = fd->real_size = ftell(f); + + if(fseek(f, 0, SEEK_SET)) { + perror(name); + exit(30); + } + + if(fd->size) { + fd->data = calloc(1, fd->size); + if(!fd->data) { + fprintf(stderr, "malloc failed\n"); + exit(30); + } + } + + if(fread(fd->data, 1, fd->size, f) != fd->size) { + perror(name); + exit(30); + } + + fclose(f); + + return fd; +} + + +void add_data(file_data_t *d, void *buffer, unsigned size) +{ + if(!size || !d || !buffer) return; + + if(d->size + size > d->real_size) { + d->real_size = d->size + size + 0x1000; + d->data = realloc(d->data, d->real_size); + if(!d->data) d->real_size = 0; + } + + if(d->size + size <= d->real_size) { + memcpy(d->data + d->size, buffer, size); + d->size += size; + } + else { + fprintf(stderr, "Oops, out of memory? Aborted.\n"); + exit(10); + } +} + + +void write_data(file_data_t *d, char *name) +{ + FILE *f; + + f = strcmp(name, "-") ? fopen(name, "w") : stdout; + + if(!f) { + perror(name); + return; + } + + if(fwrite(d->data, d->size, 1, f) != 1) { + perror(name); + exit(3); + } + + fclose(f); +} + + +void compr(file_data_t *fd, file_data_t *fd_compr) +{ + unsigned u, v, l, ofs; + unsigned char uc; + + if(!fd->size) return; + + for(u = 0; u < fd->size; u++) { + if(fd->data[u] == 0xff) fd->data[u] = 0xfe; + } + + // printf("%5u: %02x\n", fd->size, fd->data[0]); + add_data(fd_compr, fd->data, 1); + + for(u = 1; u < fd->size; ) { + l = find_longest(fd->data, fd->size, u, &ofs); + // printf("%u: %u bytes @ %u\n", u, l, ofs); + if(l >= MIN_REF_LEN) { + // printf("%5u: %u bytes @ %u\n", fd->size, l, ofs); + v = (ofs << 7) + l - MIN_REF_LEN; + uc = 0xff; add_data(fd_compr, &uc, 1); + uc = v; add_data(fd_compr, &uc, 1); + uc = v >> 8; add_data(fd_compr, &uc, 1); + uc = v >> 16; add_data(fd_compr, &uc, 1); + u += l; + } + else { + // printf("%5u: %02x\n", fd->size, fd->data[u]); + add_data(fd_compr, fd->data + u, 1); + u++; + } + } +} + + +unsigned find_longest(unsigned char *data, unsigned len, unsigned start, unsigned *ofs) +{ + unsigned l; + unsigned char *p, *p1; + + p = data; + l = MIN_REF_LEN; + + for(;;) { + p1 = memmem(p, data + start + l - 1 - p, data + start, l); + if(!p1) break; + p = p1; + l++; + + if(l > MAX_REF) break; + } + + l--; + + if(l < MIN_REF_LEN) { + *ofs = 0; + return 0; + } + + *ofs = p - data; + return l; +} + + |