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vn-mysql/udfs/sql_printf.cc

135 lines
2.8 KiB
C++

#include <stdio.h>
#include <string.h>
#include <mysql/mysql.h>
#define NAME "sql_printf"
#define N_ARGS 1
#define BLOCK_SIZE 1024
extern "C" {
typedef struct {
int * org_type;
char * data;
unsigned long len;
unsigned long alloc;
}
Buffer;
static void buffer_append_len(Buffer *buffer, const char *string, unsigned long len) {
if (!string) return;
unsigned long new_len = buffer->len + len;
if (new_len > buffer->alloc) {
buffer->alloc = new_len + BLOCK_SIZE - (new_len % BLOCK_SIZE);
buffer->data = (char *) realloc(buffer->data, sizeof(char) * buffer->alloc);
}
strncpy(&buffer->data[buffer->len], string, len);
buffer->len = new_len;
}
static void buffer_append(Buffer *buffer, const char *string) {
if (!string) return;
buffer_append_len(buffer, string, strlen(string));
}
char * sql_printf(UDF_INIT *initid, UDF_ARGS *args, char *result, unsigned long *length, char *is_null, char *error) {
unsigned int i = 1;
unsigned long j = 0;
Buffer *buffer = (Buffer *) initid->ptr;
char *format = args->args[0];
if (!format) {
*is_null = 1;
return NULL;
}
while (1) {
const char *delimiter = NULL;
unsigned long aux = j;
while (j < args->lengths[0] && format[j] != '%')
j++;
buffer_append_len(buffer, &format[aux], j - aux);
if (j == args->lengths[0])
break;
char c = format[j+1];
j += 2;
switch (c) {
case 't':
delimiter = "`";
break;
case 'v':
if (buffer->org_type[i] == STRING_RESULT)
delimiter = "'";
break;
case 's':
break;
case '%':
buffer_append(buffer, "%");
continue;
default:
*error = 1;
return NULL;
}
if (i >= args->arg_count) {
*error = 1;
return NULL;
}
char *arg = args->args[i];
if (arg != NULL) {
buffer_append(buffer, delimiter);
buffer_append_len(buffer, arg, args->lengths[i]);
buffer_append(buffer, delimiter);
} else
buffer_append(buffer, "NULL");
i++;
}
*length = buffer->len;
return buffer->data;
}
bool sql_printf_init(UDF_INIT *initid, UDF_ARGS *args, char *message) {
if (args->arg_count >= N_ARGS) {
unsigned int i;
Buffer *buffer = (Buffer *) malloc(sizeof(Buffer));
buffer->org_type = (int *) malloc(sizeof(int) * args->arg_count);
buffer->alloc = BLOCK_SIZE;
buffer->data = (char *) malloc(sizeof(char) * buffer->alloc);
buffer->len = 0;
for (i = 0; i < args->arg_count; i++) {
buffer->org_type[i] = args->arg_type[i];
args->arg_type[i] = STRING_RESULT;
}
initid->ptr = (char *) buffer;
initid->maybe_null = 1;
initid->const_item = 0;
return 0;
} else {
sprintf(message, "%s must have at least %d parameters", NAME, N_ARGS);
return 1;
}
}
void sql_printf_deinit(UDF_INIT *initid) {
Buffer *buffer = (Buffer *) initid->ptr;
free(buffer->org_type);
free(buffer->data);
free(buffer);
}
}