miller/c/input/stdio_byte_reader.c
2017-03-05 11:10:13 -05:00

98 lines
2.9 KiB
C

#include <stdio.h>
#include <string.h>
#include "input/byte_readers.h"
#include "lib/mlr_globals.h"
#include "lib/mlr_arch.h"
#include "lib/mlrutil.h"
#include "lib/mlrescape.h"
typedef struct _stdio_byte_reader_state_t {
char* filename;
FILE* fp;
} stdio_byte_reader_state_t;
static int stdio_byte_reader_open_func(struct _byte_reader_t* pbr, char* prepipe, char* filename);
static int stdio_byte_reader_read_func(struct _byte_reader_t* pbr);
static void stdio_byte_reader_close_func(struct _byte_reader_t* pbr, char* prepipe);
// ----------------------------------------------------------------
byte_reader_t* stdio_byte_reader_alloc() {
byte_reader_t* pbr = mlr_malloc_or_die(sizeof(byte_reader_t));
pbr->pvstate = NULL;
pbr->popen_func = stdio_byte_reader_open_func;
pbr->pread_func = stdio_byte_reader_read_func;
pbr->pclose_func = stdio_byte_reader_close_func;
return pbr;
}
void stdio_byte_reader_free(byte_reader_t* pbr) {
stdio_byte_reader_state_t* pstate = pbr->pvstate;
if (pstate != NULL) {
free(pstate->filename); // null-ok semantics
}
free(pbr);
}
// ----------------------------------------------------------------
static int stdio_byte_reader_open_func(struct _byte_reader_t* pbr, char* prepipe, char* filename) {
stdio_byte_reader_state_t* pstate = mlr_malloc_or_die(sizeof(stdio_byte_reader_state_t));
pstate->filename = mlr_strdup_or_die(filename);
if (prepipe == NULL) {
if (streq(pstate->filename, "-")) {
pstate->fp = stdin;
} else {
pstate->fp = fopen(filename, "r");
if (pstate->fp == NULL) {
perror("fopen");
fprintf(stderr, "%s: Couldn't fopen \"%s\" for read.\n", MLR_GLOBALS.bargv0, filename);
exit(1);
}
}
} else {
char* escaped_filename = alloc_file_name_escaped_for_popen(filename);
char* command = mlr_malloc_or_die(strlen(prepipe) + 3 + strlen(escaped_filename) + 1);
if (streq(filename, "-"))
sprintf(command, "%s", prepipe);
else
sprintf(command, "%s < %s", prepipe, escaped_filename);
pstate->fp = popen(command, "r");
if (pstate->fp == NULL) {
fprintf(stderr, "%s: Couldn't popen \"%s\" for read.\n", MLR_GLOBALS.bargv0, command);
perror(command);
exit(1);
}
free(escaped_filename);
free(command);
}
pbr->pvstate = pstate;
return TRUE;
}
static int stdio_byte_reader_read_func(struct _byte_reader_t* pbr) {
stdio_byte_reader_state_t* pstate = pbr->pvstate;
int c = mlr_arch_getc(pstate->fp);
if (c == EOF && ferror(pstate->fp)) {
perror("fread");
fprintf(stderr, "%s: Read error on file \"%s\".\n", MLR_GLOBALS.bargv0, pstate->filename);
exit(1);
}
return c;
}
static void stdio_byte_reader_close_func(struct _byte_reader_t* pbr, char* prepipe) {
stdio_byte_reader_state_t* pstate = pbr->pvstate;
if (prepipe == NULL) {
if (pstate->fp != stdin)
fclose(pstate->fp);
} else {
pclose(pstate->fp);
}
free(pstate->filename);
free(pstate);
pbr->pvstate = NULL;
}